Summation of Activation: Evidence From Multiple Primes That Converge and Diverge Within Semantic Memory

Transcription

1 Journal of Exprimntal Psychology: Larning, mory, and Cognition 1996, Vol. 22, No. 4, Copyright 1996 by th Amrican Psychological Association, Inc /96/S3.00 Summation of Activation: Evidnc From ultipl Prims That Convrg and Divrg Within Smantic mory David A. Balota and Stphn T. Paul Washington Univrsity Six xprimnts addrssd th combinatorial influnc of multipl rlatd prims in naming, lxical dcision, and rlatdnss judgmnt prformanc. Prims ithr convrgd on a singl smantic rprsntation (.g., LION-STRIPES-TIGER) or divrgd onto distinct smantic rprsntations (.g., KIDNEY-PIANO-ORGAN). Th facilitatory influnc of 2 rlatd prims was wll prdictd by th sum of th influncs from th singl-rlatd-prim conditions (a) for both convrgnt and divrgnt prims, (b) in lxical-dcision and naming, (c) across varying prim-targt stimulus onst asynchronis, and (d) undr targt-dgradation conditions that incrasd th priming ffcts. Th rlatdnss-judgmnt task yildd an additiv pattrn of priming for convrgnt prim conditions; howvr, an undradditiv pattrn of priming was found for divrgnt prim conditions. Discussion focuss on th rol of attntional systms that modulat th typ of information usd to prform a givn task. Th smantic-priming ffct rfrs to th obsrvation that participants ar fastr, and oftn mor accurat, in rsponding (.g., nam or mak a lxical dcision) to a targt word (.g., BUTTER) whn it follows a rlatd word (.g., BREAD) compard with whn it follows an unrlatd word (.g., CHAIR). This rlativly simpl obsrvation was first dmonstratd by yr and Schvanvldt (1971) and has sinc gnratd wll ovr 150 publishd articls addrssing th mchanisms undrlying this phnomnon (s, Nly, 1991, for a rcnt rviw). Th prsnt sris of xprimnts addrsss two fundamntal issus concrning smantic-priming ffcts: First, w attmpt to provid vidnc concrning how multipl prims influnc targt procssing. Although thr hav bn studis addrssing multipl-word influncs on targt procssing through sntntial contxt (.g., Stanovich & Wst, 1983), ths studis includd multipl typs of constraint (.g., syntactic, pragmatic, and smantic constraints). Th majority of publishd studis that hav focusd on smantic priming hav involvd singl-word prims. As w show blow, th mannr in which multipl prims convrg on a targt rprsntation has important thortical implications for currnt modls of mmory rtrival. Th scond issu that w addrss David A. Balota and Stphn T. Paul, Dpartmnt of Psychology, Washington Univrsity. This rsarch was supportd by National Institut on Aging (NIA) Grants PO1 AGO3991 and RO1 AG10193 and by a postdoctoral fllowship fundd through NIA Training Grant AG This work rprsnts a collaborativ ffort. Portions of this rsarch wr prsntd at th 34th Annual ting of th Psychonomic Socity in Washington, D.C., Novmbr, W would lik to thank arshall Chny, Lisa Connor, and Shadn arzouk for thir hlp in various aspcts of this rsarch projct, and Danil Spilr and Chris vr Wys for hlpful commnts on a draft of this articl. Corrspondnc concrning this articl should b addrssd to David A. Balota, Dpartmnt of Psychology, Washington Univrsity, Box 1125, St. Louis, issouri Elctronic mail may b snt via Intrnt to dbalota@artsci.wustl.du. concrns th diffrnc in th obtaind multipl-prim ffct btwn conditions in which th prims convrg onto th sam smantic rprsntation (.g., LION-STRIPES-TIGER) vrsus conditions in which th prims divrg onto distinct smantic rprsntations (.g., KIDNEY-PIANO-ORGAN). As w show, th rsults of this comparison hav th potntial to provid information about th locus of smantic priming ffcts (i.., lxical vs. smantic lvl) and th natur of th rtrival procss. Bfor turning to th two cntral issus addrssd in th prsnt sris of xprimnts, it is important to not that thr is currntly considrabl dbat about th mchanisms undrlying smantic-priming ffcts. Th traditional viw is that prims produc a forward sprad of activation within a mmory ntwork that influncs th availability of targt rprsntations. or rcntly, a numbr of rsarchrs hav suggstd that th prim and targt may b combind during ncoding and that it is th familiarity of this compound cu that producs th priming ffcts (.g., Doshr & Rosdal, 1989; ckoon & Ratcliff, 1988). In addition, thr ar connctionist modls of priming (.g., asson, 1991, 1995; Sharky, 1990), which assum distributd rprsntations instad of th traditional localist rprsntations (singl nod corrsponding to a singl word) that ar assumd within th sprading-activation framwork. For simplicity, w fram th prsnt xprimnts within th sprading-activation framwork; howvr, w bliv that th rsults of th prsnt xprimnts ar also clarly rlvant to ths rcnt altrnativ modls, and w rturn to this issu in th Gnral Discussion sction. ultipl Prims: Additivity, Ovradditivity, or Undradditivity? Considr th traditional sprading-activation account of th smantic-priming ffct: Th notion is that concpts can b rprsntd in mmory by nods intrconnctd via associativ pathways. Whn a word is prsntd (.g., BUTTER), its 827

2 828 BALOTA AND PAUL undrlying concpt nod bcoms activatd and activation sprads from this nod to rlatd aras in th ntwork (.g., BREAD). Th rsulting practivation of rlatd aras in th mmory ntwork is assumd to facilitat any subsqunt procss that rquirs accss to information in that ara of mmory (Collins & Loftus, 1975), thrby producing th smantic-priming ffct. Crtain prdictions drivd from th sprading-activation thory hav alrady rcivd mpirical support. For instanc, bcaus activation is assumd to sprad automatically, stratgic control ovr what initially bcoms activatd should not b possibl (cf. Balota, 1983; Nly, 1977; but s Balota, Black, & Chny, 1992; Smith, Bsnr, & iyoshi, 1994, for vidnc challnging strong vrsions of this assumption). Also, bcaus activation is assumd to sprad automatically through th mmory ntwork, nods should bcom activatd that ar not dirctly connctd to th nod from which activation originatd. That is, although two nods may not b dirctly connctd (.g., LION and STRIPES), it is possibl that th two nods ar connctd via an intrmdiat nod (TIGER) through which activation can sprad. Thus, on might xpct to find mdiatd or multipl-stp priming ffcts (.g., from LION to STRIPES), as rportd by Balota and Lorch (1986) and cnamara and Altarriba (1988). On of th goals of th prsnt sris of xprimnts is to dtrmin how multipl sourcs of activation influnc targt procssing. In pursuit of this goal, w usd an xprimntal paradigm in which two prims ar squntially prsntd and th participant is rquird to mak a spdd rspons to a targt word. Thr ar four conditions of intrst, which ar producd by crossing prim-to-targt rlatdnss (rlatd vs. unrlatd) with prim position (first vs. scond), that is, rlatd-rlatd (RR), rlatd-unrlatd (RU), unrlatdrlatd (UR), unrlatd-unrlatd (UU). Thus, within this paradigm, w can obtain an stimat of th facilitatory ffcts on targt procssing of ach prim in ach position (RU and UR) compard with th UU baslin, along with an stimat of th facilitatory ffct whn both prims ar rlatd (RR) compard with th UU baslin. Thr ar thr simpl ways to nvisag th convrgnc of activation from multipl sourcs: additivity, undradditivity, or ovradditivity. First, considr th simpl additivity assumption. Hr, th notion is that th facilitation drivd from rsponding to a targt following two rlatd prims should b qual to th facilitation obsrvd whn only on rlatd prim is prsntd plus th facilitation obtaind whn only th othr rlatd prim is prsntd. This simplistic assumption is implicit in ntwork modls of mmory and is xplicit in modls such as thos outlind by Andrson (1983) and Collins and Loftus (1975). An undradditiv viw would b supportd if th facilitation from two rlatd prims prsntd togthr was lss than th total facilitation of ach rlatd prim whn prsntd sparatly. For xampl, considr th possibility that a singl rlatd prim producs sufficint activation to approach maximal practivation of th targt. Undr ths conditions, it is possibl that multipl rlatd prims will provid no mor bnfit than a singl rlatd prim if th thrshold is surpassd by th activation producd from a singl rlatd prim word. Indd, vidnc consistnt with this possibility is availabl from studis that did not show catgory-dominanc ffcts in lxical-dcision prformanc (.g., Lorch, Balota, & Stamm, 1986; Nly, Kf, & Ross, 1989). That is, th strngth of th smantic rlationship btwn th prim and targt dos not consistntly modulat prformanc, at last not within th lxical-dcision task (LDT). Howvr, low catgory-dominanc xmplars do yild lss priming than high catgory-dominanc xmplars in naming (.g., Kf & Nly, 1990; Lorch t al., 1986). An ovradditiv outcom would b supportd if th facilitation obsrvd with two rlatd prims was gratr than th total facilitation of ach rlatd prim prsntd sparatly. Essntially, this would b xpctd if it is assumd that th convrgnc of activation at a spcific nod srvs to dirct attntion to spcific locations in mmory. Hnc, th additional contribution of activation du to attntion will likly rsult in gratr facilitation than would b xpctd from a simpl additiv modl. In fact, thr is som vidnc for such a synrgistic ffct with highr lvl sntntial matrials (Balota t al., 1985; Rdr, 1983). Thr hav bn only a fw studis that hav attmptd to dirctly xamin th influnc of multipl prims on rsponss to rlatd targts (.g., Brodur & Lupkr, 1989,1994; Klin, Briand, Smith, & Smith-Lamoth, 1988; Schmidt, 1976). Ths studis, in gnral, support a simpl additiv viw of facilitatory influncs of multipl prims. Howvr, thr ar aspcts of ach of ths studis that limit th xtnt to which dfinitiv conclusions can b mad rgarding th way in which multipl prims influnc targt procssing. For xampl, in ach of th prvious studis, th LDT was usd (with th xcption of Brodur & Lupkr, 1989, 1994, who also usd a naming task). Thr is considrabl discussion concrning th locus of smantic-priming ffcts in th LDT (Balota & Lorch, 1986; Nly, 1991; Sidnbrg, Watrs, Sandrs, & Langr, 1984). Bcaus only words ar rlatd to prims in th typical priming situation, participants may us th rlation btwn th prim and targt to bias thir word rspons. Spcifically, if a rlation is found btwn th prim and targt, th targt must b a word; if no rlation is found btwn th prim and targt, th targt could b an unrlatd word or a nonword, thrby making th dcision mor difficult and slowing rspons latncis. Th critical qustion, thn, is to what xtnt ar th ffcts obsrvd with an LDT th rsult of initial sprading activation or of postlxical stratgis spcific to th dcision componnts of th LDT. To xamin this issu, th prsnt sris of xprimnts provids convrging vidnc concrning th mannr in which multipl prims influnc targt procssing in thr diffrnt lxical procssing tasks: lxical dcision, naming, and rlatdnss judgmnts. Anothr problm with th past studis is th tim availabl for participants to procss th prim bfor th targt is prsntd. In many of th prvious studis, th stimulus onst asynchrony (SOA) was long nough that th ffcts of th prims may hav bn primarily du to attntional prdictiv factors instad of to automatic sprading activation (Nly, 1977). To som xtnt, howvr, this possibility was addrssd by Klin t al. (1988), who usd both an 80-ms and 320-ms SOA. Additiv influncs of prims wr obsrvd at th

3 SUATION OF ACTIVATION ms dlay. Howvr, Klin t al. found that thr was no bnfit of two prims ovr a singl prim at th 80-ms SOA (i.., an undradditiv pattrn of priming). Unfortunatly, th infrncs that on can draw from Klin t al.'s study rgarding multipl-priming ffcts ar somwhat limitd by thir us ofthldt. A third problm in all prvious studis is that th prims that wr rlatd to th targts hav also bn obviously rlatd to ach othr (.g., FRUIT-PEAR-APPLE). Th problm hr is that it is unclar whthr th first prim's influnc on targt procssing is dirct or indirct (i.., nhancing th scond prim's influnc on th targt). Thrfor, bcaus of a rlationship btwn th prims, on cannot dtrmin th indpndnt contribution of ach prim on targt rcognition. This concrn was minimizd in th prsnt xprimnt by capitalizing on mdiatd stimuli dvlopd by Balota and Lorch (1986) and homographic stimuli in which both prims ar rlatd to th targt but ar not obviously rlatd to ach othr (.g., LION-STRIPES-TIGER; KIDNEY-PIANO-ORGAN). Finally, it should b notd that in all prvious studis, thr was no indpndnt stimat of th facilitatory ffcts of ach prim at ach position. Thus, on is unabl to obtain an indpndnt stimat of ach of th sourcs of activation to dtrmin th mannr (.g., additiv, undradditiv, ovradditiv) in which ths sparat influncs wr combind to affct targt procssing. As notd arlir, by crossing prim rlatdnss to th targt with prim position, th prsnt xprimnts avoid this problm and provid indpndnt stimats of th influnc of ach prim in ach position. Th Locus of Priming Effcts: Smantic Ovrlap or Lxical-Lvl Associations? Th scond major goal addrssd in th prsnt rsarch was to provid information concrning th possibl sourc of smantic-priming ffcts (i.., lxical vs. smantic-lvl influncs). or spcifically, spdd idntification of a targt word following a rlatd prim (i.., priming) can prsumably rsult from on or mor lvls of analysis (cf. Chiarllo, Burgss, Richards, & Pollock, 1990; Fischlr, 1977; Lupkr, 1984; oss, Ostrin, Tylr, & arsln-wilson, 1995; Shlton & artin, 1992). Th words thmslvs may b associativly linkd bcaus of simpl cooccurrnc within natural languag at th lxical lvl (.g., OU-CHEE), or th concpts rprsnting th words may b linkd at th smantic or maning lvl (.g., OU-RAT), or both. In th prvious studis dsignd to localiz th sourc of priming in th procssing systm, th approach takn has involvd finding pairs of words that cooccur within a smantic catgory (.g., GLOVE-HAT) but that do not occur in association norms (.g., Lupkr, 1984; Sidnbrg t al., 1984). Th argumnt has bn that ths prim-targt pairs prsumably hav only a smantic rlationship. Unfortunatly, th rsults of ths studis hav producd inconsistnt ffcts. For xampl, Lupkr (1984) and Shlton and artin (1992) argud that thr was rlativly littl vidnc of pur smantic priming, whras Fischlr (1977) and Sidnbrg t al. (1984) argud that thr was indd pur smantic priming. In addition to th inconsistnt rsults rgarding th locus of smantic-priming ffcts, w fl that thr is an inhrnt problm in th itm-slction procdurs usd in th past studis that hav attmptd to diffrntiat btwn smantic and lxical priming. Spcifically, it is unclar how on can b assurd that thr is no associativ rlationship btwn words that cooccur within a catgory but do not occur in association norms (ckoon & Ratcliff, 1992). It is possibl that givn xtndd tim to gnrat associats, participants may in fact produc GLOVE whn givn th stimulus HAT. Indd, bcaus CLOTHING would b a mdiator btwn GLOVE and HAT, on might xpct mdiatd smantic-priming ffcts with such stimuli. orovr, givn th right contxt, on might prdict that ths two words do actually cooccur in th languag as in th following sntnc: Don't forgt your hat and glovs bfor going out and playing in th snow. Thus, w do not fl that attmpting to systmatically isolat stimulus typs that ar orthogonal on associativ and smantic rlations is a strong tst of th locus of priming ffcts. Fortunatly, th multipl-priming paradigm usd in th prsnt sris of xprimnts can provid at last som vidnc rgarding th locus of priming ffcts without systmatically attmpting to slct stimuli that ar orthogonal on smantic and associativ dimnsions. Of cours, th xtnt to which on is abl to provid such vidnc dpnds critically on th architctural assumptions concrning th undrlying smantic and lxical systms. Although w considr altrnativ architcturs in th Gnral Discussion sction, our first assumptions ar basd on a simpl localist ntwork rprsntation that includs both facilitatory and inhibitory pathways in th spirit of ccllland and Rumlhart's (1981) intractivactivation modl of lttr procssing and th assumptions of Cottrll (1989), Simpson and Kllas (1989), and Simpson and Kang (1994) concrning ambiguity rsolution. It is important to not hr that, as in th intractiv-activation modl, th facilitatory and inhibitory influncs ar prsumd to b passiv changs in activation rats. Hr, by passiv w intnd to man that as activation accrus at on rprsntation, it ithr automatically incrass or dcrass activation at connctd rprsntations and that this pattrn of facilitation and inhibition occurs without xplicit attntional control. As notd abov, w considr altrnativ architctural and procssing assumptions aftr discussing th rsults of th prsnt xprimnts. Th architctural assumptions that, in part, motivatd th prsnt xprimnts ar displayd in Figur I. 1 Hr on can s localist rprsntations for unambiguous targts and for ambiguous targts. As shown in this figur, thr is only on lxical nod ndd to rprsnt ambiguous and unambiguous 1 It should b notd hr that th inclusion of lxical-lvl associativ pathways within th architctur displayd in Figur 1 is a dpartur from th classic localist logogn modl of word procssing (orton, 1969). W hav includd lxical-lvl associativ links bcaus (a) as notd, thr is at last som vidnc that priming ffcts occur at th lxical lvl (.g., Lupkr, 1984; Shlton & artin, 1992) and (b) thr is som prliminary vidnc that simpl cooccurrnc in languag (as rflctd by masurs takn from th Associatd Prss nws wir, Church & Hanks, 1989) can b a prdictor of priming ffcts (s ckoon & Ratcliff, 1992, Exprimnt 3).

4 830 BALOTA AND PAUL KIDNEY Prim A: Targt B: Targt ORGAN1j^ORGAN2J { STRIPES Prim PIANO Figur 1. Lxical-smantic procssing architctur rprsnting th facilitatory connctions (lins with arrows) btwn two rlatd prims for unambiguous targts and for ambiguous targts. Lins nding with filld circls rprsnt inhibitory connctions. targt words. Howvr, at th smantic lvl, th ambiguous word (.g., ORGAN) rquirs at last two concpt nods (.g., on nod rprsnting th body maning and th othr nod rprsnting th music maning), whras th unambiguous word (.g., TIGER) rquirs only a singl concptual nod. Whn two rlatd prims ar prsntd, both ambiguous and unambiguous conditions ar quivalnt in trms of lxicallvl associations (two ach), but at th smantic lvl, th architcturs divrg. For ambiguous words, th prim concpts do not convrg on a singl smantic rprsntation as thy do for unambiguous stimuli. Rathr, th concpts activatd by ach of th prims ar ntirly unrlatd. Th only facilitatory pathway btwn nods is th on mdiatd by th lxical-lvl form of th homograph (i.., th lttr string ORGAN). On th basis of this concptualization, if priming ffcts ar th rsult of sprading activation among nods at th lxical lvl, th pattrn of priming should b similar for rsponss to both ambiguous and unambiguous targts. Nithr stimulus typ diffrs in trms of th numbr and typ of associations at this lvl of analysis. Howvr, if priming rflcts activation and inhibition influncs at th smantic lvl, th pattrn of priming ffcts might b diffrnt for ambiguous and unambiguous targt conditions. As shown hr, th mannr in which priming ffcts diffr dpnds critically on th xistnc of passiv inhibitory connctions btwn altrnativ intrprtations of ambiguous words. As notd abov, such inhibitory connctions hav bn postulatd by a numbr of rsarchrs in thfild (Cottrll, 1989; Simpson & Kllas, 1989; Simpson & Kang, 1994) and may srv th important rol of supprssing th altrnativ intrprtation of an ambiguous word as th slctd intrprtation bcoms activ. In Figur IB an inhibitory connction is rprsntd by th curvd lin nding in filld circls that conncts th two concpt nods of ORGAN. Bcaus of this inhibitory connction, priming ffcts from two rlatd prims should b largr for unambiguous targt words compard with ambiguous targt words. Vry simply, as activation builds up from th first prim at th smantic lvl of on intrprtation of an ambiguous word, this should hav th ffct of supprssing th altrnativ intrprtation. Hnc, whn thr is a scond prim that is rlatd to th altrnativ intrprtation of an ambiguous word (as in th KIDNEY-PIANO-ORGAN xampl), th scond prim word (PIANO) should hav rlativly littl influnc bcaus its corrsponding smantic rprsntation (musical instrumnt) would hav alrady bn supprssd. Thus, on th basis of this architctur and ths procssing assumptions, on might xpct an undradditiv influnc for th ambiguous targts. Of cours, this prdiction is basd on rlativly simpl linar changs in th activation lvls within this simplifid ntwork. Spcifically, as on intrprtation bcoms activatd to som xtnt, th altrnativ intrprtation bcoms inhibitd to th sam xtnt. Altrnativ activation framworks ar clarly quit plausibl, and as notd, w rturn to this issu latr. Ovrviw of th Prsnt Exprimnts Thr ar two major issus addrssd in th prsnt xprimnts: Thfirstissu addrsss th mannr in which activation from multipl prims combins to influnc targt procssing (additivity, ovradditivity, or undradditivity). Bcaus of task-spcific difficultis in infrncs drawn from a singl task usd to masur priming, w invstigat such multipl priming ffcts in lxical dcision (Exprimnts 1 and 2), naming (Exprimnt 3, 4, and 5), and rlatdnss judgmnts (Exprimnt 6). Th scond major issu addrssd in ths xprimnts concrns th natur of multipl-priming ffcts undr conditions in which th multipl prims convrg onto th sam smantic rprsntations as opposd to conditions in which th multipl prims divrg onto distinct smantic rprsntations. Thus, in ach of th prsnt xprimnts, w invstigat multipl-priming ffcts with stimuli (smantic catgoris, unambiguous stimuli, and homographic stimuli) that hav diffrnt lxical- and smantic-lvl rprsntations. Tabl 1 displays th thr diffrnt classs of stimuli usd in th prsnt rsarch. Thr ar four major conditions within ach class of stimuli that ar producd by crossing prim rlatdnss to th targt (rlatd vs. unrlatd) with prim position (first vs. scond). As notd, this paradigm allows us to stimat th indpndnt facilitatory ffcts of ach of th individual prims in ach position along with th conjoint ffct whn both prims ar rlatd. For xampl, if th RU condition producs a 10-ms facilitation ffct and th UR condition producs a 20-ms facilitation ffct, thn a simpl additiv modl would prdict a 30-ms facilitation ffct whn both prims ar rlatd to th targt.

5 SUATION OF ACTIVATION 831 Tabl 1 Sampl Word Stimuli Condition RR UR RU UU RR UR RU UU RR UR RU UU Prim 1 Word stimuli Prim 2 Catgory labl targts (Exprimnt 1) COPPER ORDER COPPER ORDER BRONZE BRONZE WOOL WOOL targts (All xprimnts) KIDNEY WAGON KIDNEY WAGON PIANO PIANO SODA SODA targts (Exprimnts 2-6) LION FUEL LION FUEL STRIPES STRIPES SHUTTER SHUTTER Targt ETAL ETAL ETAL ETAL ORGAN ORGAN ORGAN ORGAN TIGER TIGER TIGER TIGER Not. Th on-rlatd-prim and two-rlatd-prim conditions wr cratd by rplacing rlatd prims with an unrlatd word in th first, scond, or both prim positions. R = rlatd; U = unrlatd. Exprimnt 1 On of th goals in th first xprimnt was to xtnd th rsults of prvious studis (dscribd abov) that obtaind additiv influncs of intrrlatd prims but that usd rlativly slow prim-prsntation squncs. Thrfor, in this study w usd rlativly fast prim prsntation squncs (133 ms pr prim, followd by a 33-ms blank intrval). Exprimnt 1 includd th intrrlatd stimuli (catgory targts) and th ambiguous stimuli (homograph targts) displayd in Tabl 1. Th intrrlatd stimuli wr includd to dtrmin if th us of intrrlatd prims in past multiplpriming studis may hav modulatd th rsults. Spcifically, in th COPPER-BRONZE-ETAL xampl, not only ar COPPER and BRONZE rlatd to ETAL, but COPPER is rlatd to BRONZE. Thus, any influnc of COPPER on th procssing of ETAL may b dirct, indirct, or both through th BRONZE prim. Latr xprimnts includ unambiguous stimuli that do not includ intrassociations btwn th prims (.g., LION-STRIPES-TIGER). In addition to th intrrlatd prims, thr is also a st of ambiguous stimuli. On th basis of th assumption of passiv inhibitory connctions btwn altrnativ manings of ambiguous words, as shown in Figur 1, on might xpct rlativly mor of an undradditiv pattrn of priming for ths targts compard with unambiguous targts. thod Participants. Forty participants wr tstd in this study (no participant was tstd in mor than on of th xprimnts). All participants wr rcruitd from undrgraduat courss at Washington Univrsity and wr nativ English spakrs. Stimuli. Two sts of targt stimuli wr constructd (106 homographs and 94 catgory labls), sampls of which can b found in Tabl 1. stimuli (homographs) wr takn from Balota (1983), and intrrlatd unambiguous stimuli wr takn from availabl norms (.g., Ashcraft, 1978; Battig & ontagu, 1969; Hampton, 1984). Four prim conditions wr constructd for ach of th 200 possibl word targts. An additional st of 200 nonword trials was constructd by taking ral words and changing singl lttrs to form pronouncabl word-lik lttr strings that did not actually form English words. Each nonword targt was prcdd by two prim words nvr usd in th word-targt conditions. Th prims wr both unrlatd to ach othr and unrlatd to th targt. Targt stimuli wr countrbalancd across conditions and participants, such that no participant rcivd a stimulus word mor than onc and targts occurrd qually in ach of th four prim conditions. Apparatus. All stimuli in th prsnt xprimnts wr displayd at th cntr of a NEC ultisync 2a monitor that was controlld by an IB-compatibl computr. (Th only xcption is Exprimnt 5, discussd blow.) Stimulus onsts wr synchronizd with th scrnrfrsh cycl such that prsntation and timing (to th narst milliscond) wr dtrmind from th onst of th targt string to th dtction of a rspons. Procdur. Each trial bgan with a 100-ms warning ton followd 500 ms latr by a visual warning signal consisting of thr astrisks (ach sparatd by two spacs) prsntd at th cntr of th computr scrn. Aftr a 500-ms blank-scrn dlay, Prim 1 was prsntd for 133 ms and was followd immdiatly by Prim 2 at th idntical location for 133 ms. Following th offst of th scond prim, thr was a 33-ms blank scrn, which was followd by th targt lttr string at th sam position. Participants wr instructd to rspond with th computr kyboard as quickly and as accuratly as possibl by prssing ithr th Z ky if th targt stimulus was a nonword, or th / ky if th targt stimulus was a word. Th targt was prsntd for up to 3,250 ms if a rspons was not mad. If a rspons was not dtctd within this 3,250-ms intrval, thn a TOO SLOW mssag was prsntd at th cntr of th scrn for 500 ms prior to th onst of th nxt trial. Th intrtrial intrval was 2 s. Th xprimntal trials wr prcdd by 32 practic trials. Th xprimntal stimuli wr dividd into four blocks of tst trials containing th four priming conditions for both catgory targts and ambiguous targts, and ach tst block was prcdd by four buffr trials (not analyzd). Participants wr allowd to rst brifly prior to th start of ach block. All stimuli within ach block wr prsntd in a random ordr (dtrmind by th computr) that was uniqu for ach participant. Rsults Th following procdur was usd to analyz th rsults of th prsnt xprimnt and all subsqunt xprimnts. A 2 (targt typ; unambiguous vs. ambiguous) x 4 (prim typ; RR, RU, UR, UU) within-subjcts analysis of varianc (ANOVA) was prformd on subjct (Fi) and itm (F 2 ) man rspons latncis, xcluding rrors and rsponss gratr than 2.5 standard dviations of th mans abov or blow ach participant's man rspons tim. Bcaus of a machin rror, th first thr xprimntal trials of Exprimnt 1 wr lost. Howvr, bcaus of th randomization of trials, loss of ths trials is unlikly to hav systmatically influncd th data. Elimination of rrors and outlirs togthr rprsntd approximatly 6.9% of th total data (1.7% of which wr rmovd as outlirs). Unlss othrwis notd, ffcts rportd as rliabl in th prsnt xprimnts producdp <.05. Tabl 2 displays th man of th participants' man rspons latncis as a function of condition. As shown in Tabl 2, th rsults ar quit straightforward. Spcifically, for both

6 832 BALOTA AND PAUL Tabl 2 ans and Standard Errors in illisconds and Error Proportion () For th Prim-Typ and Targt-Typ Conditions of Exprimnt 1 (Lxical Dcision) Prim typ RR UR RU UU Not. R = rlatd; U = unrlatd. Targt typ Catgory labl unambiguous and ambiguous targts, th mans ar ordrd from fastst to slowst in th following mannr: RR, UR, RU, and UU. Th ANOVAs yildd a highly rliabl ffct of prim typ, ^(3, 117) = 18.31, = ; F 2 (3, 594) = 7.37, = 12, All prim conditions diffrd significantly from on anothr by both subjcts and itms (all ps <.01), with th xcption of th comparison btwn th RU and UU conditions, which was marginal (p =.08, by subjcts and p =.15 by itms), and th comparison btwn th RU and th UR conditions, which was marginal by itms (p =.065). Of mor importanc, thr was no vidnc of a Targt Typ x Prim Typ intraction (both Fs < 1), thrby suggsting that th pattrn of priming ffcts was idntical for ambiguous and unambiguous targts. To mor dirctly tst th mannr in which th prims combind to influnc targt procssing (i.., additiv, ovradditiv, or undradditiv), w sparatly dtrmind th priming ffct from th RU condition compard with th UU condition and th priming ffct for th UR condition compard with th UU condition. Th notion is that if th priming ffct is additiv thn th sum of th facilitation producd by th singl rlatd conditions should qual th priming ffct btwn th RR condition and th UU condition. In fact, this analysis indicatd that th facilitation for two rlatd prims (34 ms) was not diffrnt from th sum of th two individual facilitation ffcts for th on-rlatd-prim conditions (9 ms + 21 ms = 30 ms), F,(l, 39) = An analysis idntical to th raction-tim analysis was prformd on th prcntag of rrors. Although thr wr no significant ffcts in th rror-rat data, as on can s in Tabl 2, th rror rats mimickd th rspons-latncy data, and hnc, thr is no vidnc for a spd-accuracy trad-off. Discussion Th rsults of Exprimnt 1 ar quit clar: First, th ovrall pattrn is in agrmnt with prvious studis that suggst that th influnc of multipl prims is simply additiv. In fact, contrary to th prdiction of an undradditiv pattrn for ambiguous targt words, as shown in Tabl 2, th rsults yildd som vidnc of an ovradditiv pattrn for th ambiguous targts. Spcifically, th facilitation from two rlatd prims for th ambiguous targts (34 ms) was slightly mor than on would xpct from th sum of th singl rlatd conditions (5 ms + 17 ms = 22 ms). Howvr, it should b pointd out that this diffrnc did not rach significanc, and as discussd blow, this pattrn was not obtaind in any of th subsqunt xprimnts. Hnc, w bliv ths rsults to b most consistnt with a simpl additiv pattrn of priming. A scond notworthy aspct of th rsults of Exprimnt 1 is that thr is an intrsting pattrn of priming ffcts across th UR and th RU conditions. Spcifically, thr was rliably mor priming for th UR condition compard with th RU condition. Thus, th proximity of th rlatd prim to th targt dos modulat th priming ffct. This could b du to a numbr of factors: dcay of priming, disruption of priming du to an intrvning word, or th postlxical chcking procss discussd arlir that is imposd by th LDT (s Nly, 1991, for a discussion). Third, it is intrsting to not that although th priming ffct was rliably smallr in th RU condition compard with th UR condition, thr was som vidnc for priming in th RU condition. This pattrn is furthr confirmd in th following xprimnts. orovr, this pattrn is important bcaus thr has bn som dbat in th litratur concrning priming ffcts across intrvning unrlatd words (.g., Joordns & Bsnr, 1992; asson, 1991,1995). In addition to th abov obsrvations and on th basis of th assumd architctur, th rsults from Exprimnt 1 also suggst that smantic-priming ffcts appar to occur at th lxical lvl instad of th smantic lvl. This is indicatd by th fact that both ambiguous and unambiguous targts producd idntical pattrns of priming. As discussd arlir, this would not b xpctd if rsponss wr drivn by smanticlvl activation and passiv inhibition. If indd thr ar btwn-maning inhibitory pathways for ambiguous words, on would hav xpctd lss of a diffrnc btwn th RR conditions and th singl rlatd conditions for th ambiguous words than for th unambiguous words. Exprimnt 2 Th purpos of Exprimnt 2 was to xtnd th rsults obsrvd in Exprimnt 1 to a situation in which w liminat th intrprim associations in th RR condition for th unambiguous words. W includd th intrrlatd RR condition in Exprimnt 1 bcaus this was th typ of multiplprim condition that was usd in th past multipl-prim studis. In fact, w rplicatd th simpl additiv pattrn obsrvd in th past studis. Th qustion, of cours, rmains whthr on finds th sam pattrn for unambiguous stimuli whn on liminats potntial priming from th first prim to th scond prim in th RR condition. In Exprimnt 2, w attmptd to minimiz this concrn by using prims for unambiguous words that do not hav a dirct rlationship to ach othr. This was accomplishd by rplacing th unambiguous stimuli usd in Exprimnt 1 with mdiatd triplts (cf. Balota & Lorch, 1986). With this mthod, th prim stimuli wr not dirctly rlatd to ach othr (.g., LION-STRIPES), but both convrgd on a rlatd targt (.g., TIGER). By comparing th rsults of Exprimnt 2 with thos obtaind in th first xprimnt, w can addrss whthr th inclusion of intrrlatd prims may hav modulatd th pattrn of priming ffcts in th past multipl-prim studis. In addition, this

7 SUATION OF ACTIVATION 833 study affords a mor dirct comparison of th priming ffcts for th unambiguous and ambiguous targt conditions, bcaus in both conditions th prims ar unrlatd to ach othr in th RR condition (s Tabl 1). thod Participants. A total of 48 participants wr tstd in this study. All participants wr rcruitd from undrgraduat courss at Washington Univrsity and wr nativ English spakrs. Stimuli. Two sts of 48 word-targt stimuli (ambiguous and unambiguous words) wr usd (s Tabl 1). As in Exprimnt 1, for ach of th 96 possibl targt words, four prim conditions wr gnratd (RR, RU, UR, and UU). An additional 96 nonword targts wr slctd, ach of which was prcdd by two prims. As in Exprimnt 1, th prims wr both unrlatd to ach othr and unrlatd to th targt word. Countrbalancing nsurd that targts again occurrd qually in ach condition across participants and that no stimulus was sn mor than onc pr participant. Procdur. All aspcts of th procdur wr th sam as in Exprimnt 1, with th following two xcptions: First, for Exprimnt 2, th xprimntal trials wr prcdd by a block of 16 practic trials. Scond, th xprimntal stimuli wr dividd into two blocks, ach prcdd by four buffr trials. Rsults Tabl 3 displays participant mans, standard rrors of th mans, and proportion of rrors as a function of targt typ and prim typ. Th prcntag of rsponss that wr liminatd bcaus of th scrning procdur was 1.61%. As shown in Tabl 3, th rsults ar quit similar to thos obsrvd for Exprimnt 1. Spcifically, for both ambiguous and unambiguous words, th mans ar ordrd from fastst to slowst in th following mannr: RR, UR, RU, and UU. Th main ffct of prim typ was again highly rliabl, Fi(3, 141) = 27.82, = ; F 2 (3, 282) = 20.27, = 1, Individual comparisons indicatd that all prim typs rliably diffrd from ach othr. Also, as on can s in Tabl 3, rsponss to ambiguous words wr slowr ovrall than rsponss to unambiguous words, F t (l, 47) = 68.57, = 1,066.03; F 2 (l, 94) = 19.15, = 4, Of mor importanc, howvr, thr was no vidnc of a Prim Typ x Targt Typ intraction (both JFS < 1), thrby again suggsting that th pattrn of priming ffcts was quit similar for ambiguous and unambiguous targts. To furthr addrss th mannr in which th multipl prims influncd targt procssing, w compard th facilitatory ffcts of ach of th singl prim conditions to dtrmin if th sum of ths facilitatory ffcts diffrd from thos in th RR condition. Th rsults of this analysis indicatd that th facilitation for two rlatd prims (38 ms) was not diffrnt from th sum of th two facilitation ffcts for th on-rlatdprim conditions (10 ms + 23 ms = 33 ms; Fj < 1). Th rsults of th ANOVA on rror rats yildd main ffcts of targt typ, F,(1, 47) = 6.01, = ; F 2 (l, 94) = 4.72, = , and prim typ, F t (3,141) = 10.73, = ; F 2 (3, 282) = 7.24, = Th targt-typ ffct was du to mor rrors having occurrd in th ambiguous-targt condition compard with th unambiguous-targt condition. For th prim-typ main ffct, th most rrors wr mad in th UU condition; th fwst rrors wr mad in th RR prim condition, and th singl-rlatd-prim conditions yildd rlativly intrmdiat lvls of accuracy. Th intraction was not significant (ps >.15). As shown in Tabl 3, thr was no indication of a spd-accuracy trad-off. Discussion Exprimnt 2 rplicatd th rsults of Exprimnt 1 dspit th changs mad in th stimuli. Bcaus th sam pattrn of additivity was found in Exprimnt 2, in which prims wr unrlatd to ach othr but convrgd onto th targt (.g., LION-STRIPES-TIGER), it dos not appar that th additiv ffcts found in Exprimnt 1 for th catgory prims or th additiv ffcts found in th past multipl-prim studis ar du to priming from th first prim to th scond prim. 2 Thr ar thr furthr notworthy aspcts of th rsults of Exprimnt 2. First, th rsults rplicatd th pattrn obtaind in Exprimnt 1 in that th pattrn of priming ffcts was quivalnt for prim conditions that convrg onto singl smantic rprsntations (unambiguous targts) and prims that divrg onto distinct smantic rprsntations (ambiguous targts). Scond, th tmporal proximity of th singl rlatd prim affctd rsponss (i.., rsponss wr 13 ms fastr in th UR condition than in th RU condition). Finally, priming ffcts wr again obsrvd btwn a rlatd prim and targt whn an unrlatd itm intrvnd (i.., thr was a rliabl priming ffct in th RU condition compard with th UU baslin). Tabl 3 ans and Standard Errors in illisconds and Error Proportion () for th Prim-Typ and Targt-Typ Conditions of Exprimnt 2 (Lxical Dcision) Prim typ RR UR RU UU Not. R = rlatd; U = unrlatd. Targt typ A possibl concrn is that bcaus in both Exprimnts 1 and 2 th word prims for th nonword targts wr both unrlatd to ach othr and unrlatd to th targt nonword, participants may hav had a bias to rspond word whn a rlationship btwn th prims is dtctd. W dcidd to us unrlatd word prims for th nonword targts bcaus both for th prims usd for th unambiguous targts in Exprimnt 2 (.g., LIONS -STRIPES) and for th prims usd for th ambiguous targts usd in Exprimnts 1 and 2 (.g., KIDNEY- PIANO), thr is no obvious rlation btwn th prims bfor th targt is prsntd. orovr, as dscribd latr, bcaus similar rsults ar found in naming xprimnts that do not includ nonword trials, w ar confidnt that th prsnt additiv pattrn of data for both ambiguous and unambiguous targts is not du to a bias to rspond word or nonword bcaus of diffrncs in th charactristics of th prims for word and nonword trials.

8 834 BALOTA AND PAUL Exprimnt 3 Bfor on can mak strong infrncs rgarding th natur of th prsnt priming rsults, on must nsur that taskspcific procsss associatd with th LDT ar not modulating th obtaind pattrn of priming ffcts. As mntiond arlir, priming ffcts in th LDT not only rflct forward influncs of prims on targt procssing (as suggstd by sprading activation modls) but also rflct contributing influncs of postlxical chcking procsss that occur as part of th binary-dcision procss inhrnt in th LDT (Nly, 1991). Exprimnt 3 addrsss th possibility that th outcoms of th prvious two xprimnts wr influncd by task-spcific dcision stratgis associatd with th LDT by using a naming task, which prsumably minimizs such postaccss dcision procsss (cf. Balota & Lorch, 1986; Kf & Nly, 1990; Sidnbrg, Tannhaus, Liman, & Binkowski, 1982). thod Participants. A total of 64 participants wr tstd in this study. All participants wr rcruitd from undrgraduat courss at Washington Univrsity and wr nativ English spakrs. Stimuli. Two sts of 48 targt stimuli (ambiguous and unambiguous) wr constructd (s Tabl 1), along with an additional st of 48 fillr trials to incras th numbr of total trials in approximation to th lxical-dcision xprimnts. Again, thr wr four prim conditions. Finally, 44 additional targt stimuli and accompanying prims wr usd as practic and buffr trials. Targts wr again countrbalancd across participants in th mannr dscribd for th first two xprimnts. Apparatus. To obtain voic-onst latncis, th computr was intrfacd with a Grbrands odl G1341T voic-activatd rlay. Procdur. All aspcts of th procdur wr th sam as in th prvious two xprimnts with th following xcptions. First, this xprimnt did not includ any nonwords. Scond, participants mad a naming rspons instad of a lxical dcision to th targt. Third, xprimntal trials wr prcdd by a block of 36 practic trials. Fourth, th xprimntal stimuli wr randomly dividd into two blocks of 72 trials, and within ach block, ach condition was qually rprsntd. Finally, ach block was prcdd by four buffr trials, and thr was a short rst brak btwn tst blocks. Rsults Tabl 4 displays th mans, standard rrors of th mans, and proportion of rrors as a function of targt typ and prim Tabl 4 ans and Standard Errors in illisconds and Error Proportion () for th Prim-Typ and Targt-Typ Conditions of Exprimnt 3 (Naming) Prim typ RR UR RU UU Not. R = rlatd; U = unrlatd. Targt typ typ. As shown, th influnc of th prims was again quit similar for th ambiguous and unambiguous targt words. Th rsults of th ANO VAs yildd a highly rliabl ffct of prim typ in th subjcts analysis, ^(3,189) = 11.34, = , which was marginally significant in th itms analysis, F 2 (3, 282) = 2.52,,p =.06. Thr was an ffct of targt typ which rachd significanc only in th subjcts analysis, Fi(l, 63) = 9.47, = ; F 2 (l, 94) = 1.26, = l,973.88,/> =.26. As shown in Tabl 4, th prim ffct rsultd in a pattrn similar to that obsrvd in Exprimnts 1 and 2. Sparat xaminations of th prim conditions (by subjcts) wr not significant for th RR-UR or RU-UR comparisons. Th RR-UR comparison, howvr, was marginal by subjcts, Fi(l, 63) = 3.17, = 12230,p =.08. Th UR-UU and RR-UU comparisons wr significant by itms. Of mor importanc, thr was no hint of a Targt Typ x Prim Typ intraction (bothfs < 1.00). W again tstd a simpl additivity assumption by comparing th facilitation ffcts from th sum of th singl-rlatdprim conditions with th facilitation ffct obsrvd from th RR condition. This analysis indicatd that th facilitation for two rlatd prims (14 ms) was not diffrnt from th sum of th two individual facilitation ffcts for th on-rlatd-prim conditions (7 ms + 11 ms = 18 ms; Fi < 1). Analysis of rrors rvald no significant ffcts in ithr th analysis by subjcts or by itms (all ps >.15). Thr was no indication of a spd-accuracy trad-off. Discussion Th rsults of Exprimnt 3 convrgd with th rsults of Exprimnts 1 and 2 in dmonstrating that th influnc of multipl prims producs additiv ffcts. As is typical in th word-rcognition litratur, th priming ffcts wr somwhat diminishd in th naming task compard with th LDT usd in th first two xprimnts. Although th ovrall ffcts wr small, it is notworthy that thr was still rliabl priming across an unrlatd condition in th RU prim condition. In addition, thr was again slightly mor priming (a nonsignificant 4 ms) in th UR condition compard with th RU condition, suggsting that vn in a naming task th proximity of th prim to th targt dos appar to modulat th siz of th priming ffct. On somwhat surprising rsult from th first thr xprimnts is that thr is littl diffrnc btwn th priming pattrns for conditions in which th prims activat diffrnt manings of th targt word vrsus conditions in which th prims activat th sam maning of th targt word. Ths rsults indicat ithr that th assumd architctur displayd in Figur 1 is incorrct or that th obsrvd priming ffcts ar mor likly to hav bn du to lxical-lvl associations instad of smantic-lvl involvmnt. Howvr, bfor drawing strong infrncs from th first thr xprimnts, an attmpt was mad to incras th snsitivity of th xprimnts to dtct a diffrnc btwn ambiguous and unambiguous targts. Thr ar thr factors that might hav minimizd th snsitivity to diffrncs in th pattrn of priming ffcts for ambiguous and unambiguous targts. First, th SOA btwn

9 SUATION OF ACTIVATION 835 th prims and th targt was rlativly short in th first thr xprimnts. It may b th cas that with rlativly short prim durations (133 ms pr prim) thr is insufficint tim for th prim to influnc targt procssing at a smantic lvl. Possibly, participants ar abl to procss and rspond to th targt bfor prim activation has mad sufficint contact with smantic-lvl information to affct rspons latncis. This possibility is addrssd in Exprimnt 4 by incrasing th tim allowd to procss th prims. A scond factor is that for skilld radrs, as with thos in th prsnt xprimnts, targt procssing is rlativly automatic, thrby minimizing th influnc of contxt. This would b consistnt with th intractiv-compnsatory modl proposd by Stanovich and Wst (1983). Thrfor, in Exprimnt 5, w attmptd to incras th rlianc on contxt by dgrading th targt by adding amprsands to th targt-stimulus display (.g., TIGER now was prsntd as &T&I&G&E&R&). Finally, it is possibl that th prsnt xprimnts involv tasks (naming and lxical dcision) that dirct attntion to lxical-lvl procsss instad of smantic-lvl procsss. Thus, in Exprimnt 6, w rquird participants to attnd to smantic-lvl information by using a rlatdnss judgmnt task. Exprimnt 4 Exprimnt 4 was dsignd to allow mor tim for th procssing of th first prim by incrasing th xposur duration of this prim to 1,000 ms. Undr ths conditions, on should b mor likly to obsrv diffrncs in th pattrn of priming ffcts for ambiguous and unambiguous targt words. That is, thr is now sufficint tim for thfirstprim to accss smantics, and this should thn constrain th intrprtation of th upcoming ambiguous word. Hnc, thr should b littl bnfit of a short-duration scond prim that is unrlatd to th mor strongly biasd intrprtation of th ambiguous word. For xampl, incrasing th xposur duration of th prim KIDNEY should rsult in activation of th maning of ORGAN rfrring to a bodily organ, and hnc thr should b littl bnfit from a scond prim {PIANO) prsntd for only 125 ms that is rlatd to th altrnativ maning of ORGAN (i.., th RR condition should b vry similar to th RU condition). An undradditiv pattrn is thrfor prdictd for th ambiguous-targt condition. On th othr hand, for unambiguous targts, thr should b a convrgnc of activation both at lxical- and smantic-lvl rprsntations, and on should again obsrv additivity. thod Participants. A total of 48 participants wr tstd in this study. All participants wr rcruitd from undrgraduat courss at Washington Univrsity and wr nativ English spakrs. Stimuli. Th stimulus st usd in Exprimnt 3 was also usd for th prsnt xprimnt. Procdur. With th xcption of incrasing th xposur duration of th first prim from 133 ms to 1,000 ms, all aspcts of th procdur wr th sam as thos in Exprimnt 3. Rsults Tabl 5 contains participant mans, standard rrors of th mans, and proportion of rrors as a function of prim and targt typ. Th prcntag of rsponss that wr liminatd bcaus of th scrning procdur was 2.63%. As shown in Tabl 5, th rsults ar again quit consistnt with th prvious xprimnts. Spcifically, th ffcts ovrall ar supportiv of a simpl additiv modl and ar quit similar for both ambiguous and unambiguous targt words. Th rsults of th ANO VA yildd significant main ffcts of both prim typ, f](3, 141) = 10.81, = ; F 2 (3,282) = 5.72, = , and targt typ, F,(l, 47) = 15.70, = ; F 2 (l, 94) = 3.20, = 1,828.89, p =.077. Dirct comparisons of th mans rvald that all but two diffrd significantly (p <.01). Spcifically, th diffrnc btwn th RR and th UR condition and th diffrnc btwn th RU and th UR prim conditions did not rach significanc in ithr th subjcts or th itms analysis. Th intraction btwn prim typ and targt typ did not approach significanc (both Fs < 1). W again tstd whthr th priming ffct for th RR condition (13 ms) was diffrnt from th addd ffcts of th two singl-rlatd-prim conditions (6 ms + 9 ms = 15 ms), and again thr was no vidnc of divrgnc from simpl additivity (F t < 1). An analysis idntical to th latncy analysis was also prformd on rrors. No significant diffrncs wr obtaind (all Fs < 1.2). Thr was no vidnc of a spd-accuracy trad-off. Discussion Th rsults of Exprimnt 4 again clarly yildd an additiv pattrn of priming ffcts. orovr, dspit th incrasd duration of th first prim to a full scond, Exprimnt 4 providd an quivalnt pattrn of priming ffcts for both ambiguous and unambiguous targt words. It is particularly notworthy that for th ambiguous targts, th prsnc of a scond rlatd prim word in th RR condition (KIDNEY- PIANO-ORGAN) still producd rliably mor facilitation compard with th RU condition (KIDNEY-CHAIR-OR- GAN), vn though th scond word (PIANO) in th RR condition was unrlatd to th strongly biasing first word (KIDNEY) and was prsntd only for 125 ms. Tabl 5 ans and Standard Errors in illisconds and Error Proportion () for th Prim-Typ and Targt-Typ Conditions of Exprimnt 4 (Long Duration Prim 1) Prim typ Not. RR UR RU UU R = rlatd; U = unrlatd. Targt typ

10 836 BALOTA AND PAUL Exprimnt 5 In Exprimnt 5, an attmpt was mad to incras th participants' rlianc on th contxtual information availabl in th prims. It is possibl that th rlativly flunt lxical procssing that occurs in collg-agd radrs allows thm to complt targt procssing bfor a smantic influnc of th prims can affct th targt rprsntations. This would of cours liminat th possibility of dtcting a diffrnc btwn targt words with multipl and singl smantic rprsntations. In Exprimnt 5, w attmptd to dcras th fficincy of targt procssing by dgrading th targt stimulus. Th notion hr is that whn th targt is dgradd, thr should b mor tim for th prims to ngag smantic rprsntations. As notd arlir, this prdiction is quit consistnt with an intractiv-compnsatory modl in which slowr lxical procssing will lad to incrasd top-down (possibly smantic-lvl) influncs (.g., Stanovich & Wst, 1981). Thus, in Exprimnt 5, th targts wr prsntd with amprsands flanking ach lttr in a word (.g., &T&I&G&E&R&). W chos this typ of dgradation bcaus thr is vidnc indicating that th intrlaving of astrisks primarily influncs th facilitatory ffcts of th prims compard with a nutral prim condition (cf. Durgunoglu, 1988). Bcaus inhibitory ffcts ar blivd to b markrs for attntional procsss (.g., Nly, 1977), w wantd to minimiz th attntional procssing that appars to accompany othr forms of dgradation, such as contrast rduction (cf. Durgunoglu, 1988; Stanovich & Wst, 1983). Finally, w also changd th prim durations to 250 ms pr prim to maximiz th liklihood of obtaining diffrncs btwn th ambiguous and unambiguous targt words. thod Participants. A total of 48 participants wr tstd in this study. All participants wr rcruitd from undrgraduat courss at Washington Univrsity and wr nativ English spakrs. Stimuli. Th targt stimuli usd in Exprimnt 4 wr usd in this xprimnt. Th only xcption is that this xprimnt did not includ th fillr trials. As w s blow, th prsnc of th fillr trials in Exprimnt 4 was unlikly to hav compromisd th rsults. Procdur. Aspcts of th procdur wr th sam as thos of Exprimnt 4 with two xcptions: First, for Exprimnt 5, prim durations wr adjustd to 250 ms ach (to maximiz th possibility of dtcting diffrncs btwn targt conditions), and targts wr prsntd with amprsands flanking ach lttr. Scond, xprimntal trials wr prcdd by a block of 32 practic trials. Third, th xprimntal stimuli wr dividd into two blocks of 48 trials, ach prcdd by 4 buffr trials. Rsults Tabl 6 displays participant mans, standard rrors of th mans, and proportion of rrors as a function of targt typ and prim typ. A total of 3.3% of th trials wr idntifid as outlirs. Thr ar thr points to not in Tabl 6. First, as on can s, ovrall rspons latncis ar ms slowr than in th prvious naming studis (Exprimnts 3 and 4). Hnc, th dgradation manipulation had th dsird ffct of dcrasing th spd of targt procssing. In addition, th contxt Tabl 6 ans and Standard Errors in illisconds and Error Proportion () for th Prim-Typ and Targt-Typ Conditions of Exprimnt 5 (Dgradd Targts) Prim typ RR UR RU UU Not. R = rlatd; U = unrlatd. Targt typ ffcts ar 2 to 3 tims largr in Exprimnt 5 compard with th prvious naming studis (.g., th diffrnc btwn th RR condition and th UU condition was 14 ms in Exprimnt 3 and 13 ms in Exprimnt 4, whras in Exprimnt 5, th diffrnc was 41 ms). Thus, as xpctd (cf. Bsnr & Smith, 1992; yr, Schvanvldt, & Ruddy, 1975; Stolz & Nly, 1995), th dgradation manipulation did incras th contxt ffcts. Although th ovrall priming incrasd in this xprimnt, it is important to not that th pattrn of priming ffcts was quit consistnt with th prvious xprimnts. Spcifically, th facilitatory ffcts of th diffrnt prim conditions wr again similar for ambiguous and unambiguous words, and th priming ffcts appar to bst support a simpl additiv modl. Th rsults of th ANOVA yildd a main ffct of targt typ that rachd significanc only by subjcts, Fi(l, 47) = 7.19, = ; F 2 (l, 94) < 1.00, and yildd a highly rliabl main ffct of prim typ, Fi(3, 141) = 24.58, = 1,084.24; F 2 (3, 282) = 29.28, = 1, Plannd comparisons indicatd that all prim conditions wr rliably diffrnt from on anothr with th xcption of th RU and th UR comparison. Th Targt Typ x Prim Typ intraction did not approach significanc, Fi(3, 141) = 0.68, = ; F 2 (3, 282) = 1.74, = 1, Finally, th comparison of th priming ffct of th two-rlatd-prim conditions (41 ms) against th sum of th priming ffcts of th singl-rlatd-prim conditions (18 ms + 21 ms = 39 ms) did not approach significanc (F < 1). Hnc, again th rsults supportd th simpl additivity assumption. An ANOVA idntical to th raction-tim analysis was prformd on rrors. This analysis yildd a main ffct of prim typ that was rliabl only in th subjcts ANOVA, Fi(3, 141) = 4.51, = 0.66; F 2 (3,282) < As shown in Tabl 6, this ffct mimickd th pattrn in th rspons-latncy data, and thrfor thr is no vidnc of a spd-accuracy trad-off. Discussion Th goal of Exprimnt 5 was to slow lxical procssing of th targt to dtrmin if thr would b an incrasd rlianc on contxtual (possibly smantic) information, thrby incrasing th liklihood of obsrving a diffrnc btwn ambiguous and unambiguous targt conditions. Th dgradation manipulation was succssful in that ovrall rspons latncy

11 SUATION OF ACTIVATION 837 was incrasd by 150 ms to 200 ms compard with th prvious naming studis, and thr was a thrfold incras in th obtaind priming ffcts. Howvr, this study yildd rsults that wr prcisly th sam as thos th prvious studis. Spcifically, th rsults supportd a simpl additiv modl of priming both for targt words that hav distinct smantic rprsntations (ambiguous words) and for targt words that do not hav distinct smantic rprsntations (unambiguous words). Exprimnt 6 In ach of th fiv prvious xprimnts, w usd tasks that dirctd attntion implicitly to lxical-lvl procssing of th targt (i.., spdd naming and lxical dcision). Howvr, in natural languag procssing attntion is not typically focusd on lxical-lvl rprsntations but rathr is mor likly dirctd to maning-lvl intgration procsss. In th following study, w attmptd to dirct participants' attntion to maning-lvl rprsntations by changing th task to a rlatdnss-judgmnt task. On ach trial, participants wr rquird to dtrmin as quickly as possibl whthr at last on of th prim words was rlatd to th targt. Bcaus participants wr rquird to procss th manings of th words in this task, it was xpctd that this task would b mor snsitiv to th distinction btwn lxical- and smantic-lvl rprsntations as dpictd in Figur 1. thod Participants. Thirty-two nativ English-spaking participants wr rcruitd from undrgraduat courss at Washington Univrsity. Stimuli. Th stimuli usd for Exprimnt 4 wr again usd for th prsnt xprimnt. Howvr, bcaus participants wr rquird to rspond rlatd whn ithr or both of th prims wr rlatd to th targt, thr of th four priming conditions producd a ys rspons. To kp th typs of rsponss mad by participants proportional across trials (i..,ys vs. no), an additional st of 48 UUfillrtrials wr includd. Non of th words that wr includd in th buffr trials wr usd in th xprimntal trials. Procdur. Th procdur was similar to th procdurs in th prvious xprimnts with th following xcptions: First, as in Exprimnt 5, th xposur duration of ach prim was 250 ms. Scond, participants wr instructd to prss on mous ky if on or both of th prims wr rlatd to th targt and to prss th othr mous ky if nithr of th prims wr rlatd to th targt. Th rlatd rspons ky was kyd by ach participant's prfrrd fingr. Immdiatly following a rspons, th computr brifly displayd th word CORRECT if participants mad th corrct rspons or INCORRECT if participants mad th incorrct rspons. Rsults Tabl 7 displays participants man rspons latncis, standard rrors of th mans, and proportion of rrors as a function of prim condition for th ambiguous and unambiguous targt words. Only 0.42% of th trials wr trimmd bcaus of th outlir critria. As shown in Tabl 7, th rsults from this xprimnt ar quit diffrnt from thos of th prvious xprimnts in that thr is a considrabl diffrnc btwn th pattrn of priming ffcts for th unambiguous Tabl 7 ans and Standard Errors in illisconds and Error Proportion () for th Prim-Typ and Targt-Typ Conditions of Exprimnt 6 (Rlatdnss Judgmnt) Prim typ RR UR RU UU , Not. R = rlatd; U = unrlatd. Targt typ and ambiguous targt words. For th unambiguous targts, thr was a 131-ms diffrnc btwn th two-rlatd-prim condition and th singl-rlatd-prim conditions, whras for th ambiguous targts, this diffrnc was only 27 ms. This finding strongly suggsts an undradditiv outcom for th ambiguous words only. Th rsults from th ANOVA yildd main ffcts of prim typ, Fi(3, 93) = 24.14, = 24,857.66; F 2 (3, 282) = 63.33, = 16,653.18, and targt typ, F r (l, 31) = 12.59, = 9,176.71; F 2 (l, 94) = 10.05, = 24, Of mor importanc, th rsults yildd a highly rliabl intraction btwn prim typ and targt typ, F t (3, 93) = 4.49, = 8,694.87; F 2 (3, 282) = 2.81, = 16, Dirct xamination of th pattrn of priming for th unambiguous targt conditions by subjcts indicatd that all priming conditions wr rliably diffrnt (ps <.05), with th xcption of th comparison btwn th UR condition and th RU condition (Fs < 1). An analysis of th ambiguousword conditions indicatd that all rlatd conditions wr rliably diffrnt from th UU condition (ps <.05). Non of th comparisons among th rlatd conditions wr significant, although th RR vrsus UR comparison was marginal (p <.07). W again tstd a simpl additivity assumption by comparing th facilitation ffcts from th sum of th singl-rlatdprim conditions with th facilitation ffcts obsrvd for th RR condition. Bcaus th ovrall ANOVA yildd a Targt Typ x Prim Typ intraction, w conductd this sparatly for th unambiguous and ambiguous targts. For th unambiguous targts, th rsults wr quit rmarkably consistnt with th additivity assumption. Spcifically, th facilitation of th two-rlatd-prim condition (262 ms) was idntical to th sum of th two individual facilitation ffcts for th on-rlatd- 3 On may b concrnd that th UU condition is not an appropriat baslin bcaus in this xprimnt participants wr making a diffrnt rspons (i.., ys vs. no) for th thr rlatd conditions compard with th singl unrlatd condition. Bcaus w ar comparing both ambiguous and unambiguous targts to th sam UU baslin, w do not fl that this diminishs th strngth of our argumnts across targt class. Howvr, w also conductd ANOVAs that includd only th thr conditions that producd ys rsponss (i.., RR, RU, and UR). Th rsults wr idntical to thos that includd th UU conditions. Spcifically, thr wr significant main ffcts of targt and prim typ and intractions btwn targt and prim typ for both subjcts and itms ANOVAs (all/?s <.01).

12 838 BALOTA AND PAUL prim conditions (141 ms ms = 263 ms; F < 1). Th pattrn was much diffrnt for th ambiguous targts. Spcifically, th facilitation for th two-rlatd-prim condition (200 ms) was 147 ms smallr than th sum of th singl-rlatdprim conditions (184 ms ms = 347 ms), F(l, 31) = 8.68, = 39, Hnc, for th first tim in th prsnt st of six xprimnts, thr is vidnc of an undradditiv influnc of th multipl prims that was rstrictd to ambiguous targts. Th rsults of th rror analyss yildd main ffcts of targt typ, F^l, 31) = 13.60, = ; F 2 (l, 94) = 11.80, = , and prim typ, Fi(3, 93) = 12.42, = ; F 2 (3, 282) = 13.47, = Th intraction was not significant (both ps >.14). It should b notd hr that although th intractions wr not significant in th rror-rat data, thr was still lss of a diffrnc btwn th two-rlatd-prim conditions and th man of th singl-rlatd-prim conditions for th ambiguous targts (8.5%) compard with th unambiguous targts (12.0%). Thus, th absnc of gratr priming in th two-rlatd-prim condition compard with th singl-rlatd-prim condition in th rspons-latncy data for th homographs is not compromisd by a largr diffrnc in rror rats. Discussion Th rsults for Exprimnt 6 ar quit clar: For th unambiguous targt conditions, th rsults wr consistnt with th prviousfivxprimnts. Spcifically, th facilitation producd by two rlatd prims was nicly prdictd by th sum of th facilitation of ach of th singl-rlatd-prim conditions. Turning to th ambiguous targt-word conditions, th pattrn of rsults is quit diffrnt: Spcifically, thr is rlativly littl diffrnc btwn th two singl-rlatdprim conditions and th two-rlatd-prim condition. This is in sharp contrast with th rsults of th prvious fiv xprimnts whrin thr wr idntical pattrns of facilitation for both ambiguous and unambiguous words. Of cours, this is consistnt with th notion that bcaus of th task dmands ngagd by th rlatdnss judgmnts usd in Exprimnt 6, participants wr forcd to procss th maning of th prim-targt rlationships. It was only undr ths conditions that w wr abl to distinguish btwn th pattrn of priming ffcts for conditions in which th prims convrg onto a singl smantic rprsntation (unambiguous targts) and conditions in which prims divrg onto distinct smantic rprsntations (ambiguous targts). For ambiguous targt words, it appars that th first rlationship found btwn th targt and on of th prims drivs rspons latncy, with littl influnc from having an additional prim that is rlatd to a diffrnt intrprtation of th homograph. Although th rsults of th rlatdnss judgmnt task in Exprimnt 6 clarly divrg from thos of th prvious lxicaldcision and naming tasks, it is important to not that not only did w forc participants to accss maning in Exprimnt 6, but w also forcd participants to mak a comparison btwn th targt stimulus and th prim stimuli. It is possibl that th diffrnc in th obtaind pattrn is not du to accss of maning but rathr is du to th fact that th rlatdnss task forcs a comparison procss. Thr ar two points to not hr: First, as notd arlir, thr is considrabl work suggsting that th LDT also involvs a comparison btwn th targt and th prim, and yt thr was no vidnc of undradditivity in th LDT rsults of Exprimnts 1 or 2. Thus, it dos not appar to b simply th prsnc of a comparison procss that is sufficint to produc th undradditiv ffcts for ambiguous words. Scond, and mor important, w bliv that it may b quit important to ngag xplicitly th comparison procss bcaus this may b th only way to nsur that activ slction has takn plac. In fact, as discussd blow, it may b only undr conditions in which on forcs xplicit slction that on finds vidnc for inhibition btwn altrnativ intrprtations of ambiguous targt words, thrby bringing into qustion th xistnc of th passiv inhibitory pathways displayd in Figur 1. Thus, it may b th natur of th comparison procss that is important, not mrly its prsnc. Gnral Discussion Thr wr two major goals addrssd in th prsnt rsarch. Th first goal was to dtrmin how multipl prims influnc targt procssing. Across a rlativly wid varity of manipulations, th prsnt rsults clarly supportd an additiv modl of priming. Th scond goal was to dtrmin if thr ar diffrncs in th pattrn of multipl priming ffcts for conditions in which th prims convrg on th sam smantic rprsntation (unambiguous targts) and conditions in which prims divrg onto distinct smantic rprsntations (ambiguous targts). Th rsults of th first fiv xprimnts yildd idntical pattrns of priming for unambiguous and ambiguous targts. If on assums that th architctur displayd in Figur 1, along with its passiv inhibitory connction for th multipl manings of ambiguous words, is corrct th prsnt rsults appar most consistnt with th notion that whn tasks mphasiz lxical-lvl rprsntations (lxical dcision and naming), "smantic" priming ffcts may b primarily du to associativ-lvl information within th lxicon. W shall now turn to a discussion that critically valuats ths conclusions and dscrib altrnativ accounts of th prsnt rsults. Th Influnc of ultipl Prims: Additivity, Undradditivity, or Ovradditivity? On of th major goals of th prsnt xprimnts was to dtrmin th influnc of multipl rlatd prims on targt procssing. W wr motivatd to invstigat this phnomnon by thr issus: First, thr ar at last thr possibl outcoms (additivity, ovradditivity, and undradditivity) concrning how multipl prims influnc targt procssing. Each of ths outcoms provids a uniqu constraint on th activationthrshold functions for xtant thortical modls of smantic priming (.g., sprading activation, compound cu, and paralll distributd procssing modls). Scond, in natural languagprocssing situations, thr appar to b multipl sourcs of information that might constrain th maning of a givn word within a contxt. Thrfor, it is important to undrstand how

13 SUATION OF ACTIVATION 839 multipl sourcs of information influnc targt procssing. Third, th prviously xisting data on multipl priming ffcts ar limitd by aspcts of th past xprimntal paradigms and, hnc, diminish th strngth of th infrncs that can b drawn from ths studis. On ach trial in th prsnt sris of xprimnts, two prims wr prsntd, which wr followd by a targt stimulus for a rspons. By crossing prim rlatdnss (rlatd vs. unrlatd) with position (first vs. scond prim), w wr abl to obtain indpndnt stimats of th influnc of ach prim at ach position, along with th combind influnc of both prims. Th rsults of th first two xprimnts, which involvd LDTs and vry brif prim durations, clarly supportd an additiv modl of th influnc of multipl prims. Spcifically, th facilitation obsrvd in th RR condition was simply th sum of th facilitation obsrvd in th RU condition and in th UR condition. Bcaus postlxical procssing could hav influncd prformanc in th LDT, w turnd to spdd naming prformanc in Exprimnt 3. Th rsults again supportd an additiv modl. Th fourth xprimnt incrasd th duration of th first prim to dtrmin th limitations of th additiv modl. Again, th rsults yildd support for th additiv modl. Th fifth xprimnt includd a manipulation that dgradd th targt stimulus to incras th influnc of th prim itms. Th rsults of this xprimnt yildd an incrasd ovrall priming ffct; howvr, th pattrn of priming ffcts across conditions again supportd th additiv modl. Thus, across diffrnt tasks, prim durations, lvls of targt clarity, and diffrnt classs of targt stimuli (ambiguous vs. unambiguous words), thr was clar support for th additiv modl of priming ffcts. Non of th first fiv xprimnts producd any rliabl divrgnc from a simpl additiv modl. Of cours, it is always difficult to argu for th null hypothsis, but in th prsnt cas, w fl quit confidnt that th simpl additiv modl is most appropriat in accounting for multipl priming ffcts. This confidnc is basd on th consistncy of th obsrvd priming ffcts across xprimnts. Tabl 8 displays th prdictd and obsrvd priming ffcts basd on th additiv modl across th various xprimnts for both ambiguous and unambiguous targts. As shown, th only rliabl dpartur from th additiv function is in th rlatdnss judgmnts for ambiguous words in Exprimnt 6. In fact, if on collapss th rsults across Exprimnts 1-5 and simply adds th facilitation obsrvd from th first rlatd prim in th RU prim condition (10 ms) to th facilitation obsrvd from th scond rlatd prim in th UR condition (16 ms), on finds that th prdictd facilitation (26 ms) is only 1 ms away from th obsrvd facilitation in th RR condition (27 ms). Bcaus ths stimats ar basd on 248 participants across fiv diffrnt xprimnts with varying xprimntal paradigms, w ar confidnt in concluding that th simpl additiv modl is th bst account for th mannr in which multipl prims influnc targt procssing. 4 It is intrsting to not hr that in addition to th prsnt xprimnts, thr ar a numbr of publishd studis that ar consistnt with th notion that thr ar additiv influncs of prims along a numbr of distinct procssing dimnsions. For Tabl 8 an Prdictd and Obsrvd Summation Priming Effcts and th Diffrnc Btwn Ths Two asurs as a Function of Exprimnts 1-5 Togthr and Exprimnt 6 by Itslf Exprimnt and targt typ Exprimnt 1 Exprimnt 2 Exprimnt 3 Exprimnt 4 Exprimnt 5 Wightd Avrag Exprimnt 6 "p >.27; **p <.01. n Summation priming ffcts (RU + UR) = (RR) = prdictd < jbsrvd Diffrnc (5 + 17) = 22 ( ) = 37 (9 + 19) = 28 ( ) = 38 (6 + 11) = 17 (8 + 11) = 19 (3 + 7) = 10 (8 + 10) = 18 ( ) = 34 ( ) = 44 (8 + 14) = 22 ( ) = 30 ( ) = 347 ( ) = ns -3 ns 4ns 6 ns _ 2 ns -6 l ns Ans 2ns 2 3" s _jns -147** -l n s xampl, Forstr (1989) has shown that thr ar additiv influncs of brifly prsntd orthographic prims in an LDT. Prims such as FLANKOIL, BRACHALL, and BLOCK- FAIN producd additiv ffcts for th targt stimulus BLA CK- AIL in an LDT. In addition, Blank and Foss (1978) found additiv contributions of spcific componnts of a sntnc (vrb and adjctiv) in a phonm monitoring task. Rdr (1983) has xtndd this simpl additivity to a sntnc compltion task. Thus, on th basis of th convrgnc across diffrnt tasks and diffrnt typs of prims, w bliv that contxtual constraints can produc simpl additiv influncs on targt procssing. It is notworthy that although w hav intrprtd th prsnt additiv ffcts of multipl prims in naming and lxical-dcision prformanc as consistnt with th spradingactivation framwork, it is likly that altrnativ modls of priming will also b abl to account for ths simpl additiv 4 W also conductd an analysis to dtrmin th powr of dtcting a rliabl undradditiv ffct across th first fiv xprimnts. In this analysis, w usd th rliabl undradditiv ffct obtaind in Exprimnt 6 as a basis for our powr calculation. On th basis of Cohn's (1977) discussion, th undradditiv pattrn obsrvd in Exprimnt 6 producd a mdium ffct siz (d =.52). If w now apply this ffct siz (d =.52) to th rsults of th ovrall analysis from th first fiv xprimnts (which producd a 34.7-ms SD), our ability to obtain a similar mdium ffct siz of undradditivity (18 ms) is gratr than.99, on-taild tst. orovr, to b consrvativ, if w considr th powr to dtct half of this ffct siz (d =.26), thn our powr of dtcting an undradditiv ffct of 9 ms across th first fiv xprimnts is.86, on-taild tst.

14 840 BALOTA AND PAUL ffcts. For xampl, using th paramtr stimats availabl from Ratcliff and ckoon (1995), Ratcliff (prsonal communication) has shown that th compound cu modl nicly prdicts th simpl additiv ffcts in lxical dcision (also, s cnamara & Diwadkr, in prss, for dirct comparisons of th compound cu modl and th sprading-activation modl in accounting for th prsnt lxical-dcision rsults). Of cours, it will b important to dtrmin if this modl also can b xtndd to th naming task and can also account for th prsnt lack of a diffrnc btwn ambiguous and unambiguous targt words. W also s no a priori rason that asson's (1995) PDP modl will not b abl to handl th simpl additiv ffcts of multipl prims. Thus, at this lvl, w bliv that th additiv ffcts obtaind in th prsnt naming and lxical-dcision data ar unlikly to discriminat among altrnativ thortical framworks. Howvr, w do bliv ths rsults provid an important additional constraint, along with othr wll-stablishd mpirical obsrvations, on any modl of smantic priming. W shall now turn to possibly mor constraining aspcts of th prsnt rsults: spcifically (a) proximity ffcts of prims at rlativly short SOAs, (b) priming ffcts across an unrlatd intrvning word, and of most importanc, and (c) th similarity in th obsrvd pattrn of priming ffcts for ambiguous and unambiguous targts. Th Influnc of Tmporal Proximity of th Prim In addition to th obsrvation concrning additivity of multipl prims, it should b notd that th prsnt rsults indicat that thr was rliably mor facilitation in th UR condition than in th RU condition. Thus, th proximity of th prim to th targt did indd modulat th obsrvd priming ffct, as on might xpct on th basis of ithr tmporally basd dcay of activation or th prsnc of an intrfring unrlatd word. This is particularly notworthy bcaus in th first thr xprimnts th prims wr prsntd vry quickly (i.., 133 ms pr prim). In fact, bcaus of forward masking of thfirstword onto th scond, on might hav xpctd to find lss of a priming ffct from th scond word bcaus of brakdowns in lowr lvl prcptual oprations. Obviously, this pattrn was not obsrvd in th prsnt rsults. Priming Across an Unrlatd Intrvning Word Although th priming ffct was largr whn th scond prim was rlatd to th targt compard with whn th first prim was rlatd to th targt, it is important to not that th prsnt rsults yildd consistnt vidnc for rliabl priming for th RU condition compard with th UU condition. In fact, if on collapss across th first fiv xprimnts, th prsnt rsults yildd a highly rliabl 11-ms diffrnc btwn th RU condition and th UU condition, Fi(l, 247) = 45.49, = ,/? <.001. Clarly, ths rsults provid substantial vidnc that priming can occur across an unrlatd intrvning itm. This is an important obsrvation bcaus arly rports in th priming litratur indicatd that thr is no rliabl smantic priming across an unrlatd intrvning word (Gough, Alford, & Holly-Wilcox, 1981; asson, 1991; Ratcliff & ckoon, 1988). Howvr, as Joordns and Bsnr (1992) hav pointd out, in ach of th prvious studis thr has bn a nonsignificant tndncy for priming to occur across an unrlatd word. orovr, Joordns and Bsnr (1992) and cnamara (1992) hav rcntly rportd vidnc of priming across an unrlatd word in naming and lxicaldcision prformanc, rspctivly. It should b notd, howvr, that in both Joordns and Bsnr's study and cnamara's study, participants mad rsponss to prims as wll as to targts. Thus, on th basis of ths studis, it is unclar whthr ovrt rsponss to th prims and rlativly long durations (.g., ms) to procss th prims ar ncssary conditions to obtain priming across an unrlatd word. It is possibl that such ffcts wr du to attntional procsss bcaus rsponss to th prims, rlativly long prim durations, or both ar likly to ngag such highr lvl systms. In fact, asson (1995, Exprimnt 1) has rcntly providd vidnc from a naming task that thr is no priming (a nonsignificant 3.3 ms) across an unrlatd word undr conditions of a vry short SOA (200 ms). asson's rsults would appar to run countr to th rsults of th prsnt Exprimnt 3, whrin an vn shortr SOA (133 ms) providd priming across an unrlatd word in a naming task. In fact, th prsnt sris of xprimnts consistntly producd priming across unrlatd words across a wid varity of conditions. On possibl diffrnc btwn th prsnt xprimnts and asson's first xprimnt is that asson includd a forward mask (a row of Xs) bfor th first prim stimulus. This, of cours, may hav minimizd procssing of th first word compard with th prsnt manipulations. Th important point to not is that modls that wr initially motivatd in part by th difficulty of th sprading-activation modl to account for th lack of priming across an unrlatd intrvning word (.g., asson, 1991; Ratcliff & ckoon, 1988) will nd to b modifid to accommodat such ffcts. Although such modls can b modifid to account for priming across unrlatd words (.g., including two prim words in th compound-cu modl), it is unclar how such an accommodation might influnc th modls' ability to account for othr priming phnomna. ultipl Prims for and Targts As notd arlir, thr has bn considrabl intrst in th lvl of th cognitiv architctur at which smantic-priming ffcts occur. On th basis of th architctur displayd in Figur 1, along with its passiv inhibitory smantic connction, w xpctd tofinddiffrncs in th pattrn of priming ffcts for conditions in which th prims convrgd onto th sam maning of an ambiguous word vrsus conditions in which th prims divrgd onto two diffrnt manings of ambiguous words. Spcifically, w suggstd that if priming occurs at th smantic lvl, thn on should find an incrasd tndncy toward an undradditiv pattrn of priming for th ambiguous targts compard with th unambiguous targts. Th assumd architctur and th subsqunt prdictions wr basd on (a) th growing vidnc that suggsts that thr ar inhibitory pathways btwn th multipl manings of ambiguous words (Grnsbachr, Varnr, & Faust, 1990; Simpson & Kang, 1994; Simpson & Kllas, 1989), (b) th inclusion of inhibitory pathways in connctionist modls of lxical-ambiguity rsolu-

15 SUATION OF ACTIVATION 841 tion (Cottrll, 1989), and (c) th fact that without such inhibitory pathways, as discussd blow, it is unclar how slction of maning occurs for such words. 5 Howvr, th prsnt rsults did not support smantic involvmnt, at last not within th framwork displayd in Figur 1. Spcifically, th sam additiv pattrn of priming ffcts occurrd for ambiguous words in which th prims wr rlatd to distinct smantic intrprtations as compard with unambiguous words in which th prims wr rlatd to th sam smantic intrprtation. Th only divrgnc in th pattrn of rsults for ambiguous and unambiguous words occurrd whn participants wr forcd to procss th maning of th words with th rlatdnss judgmnts usd in Exprimnt 6. Although th intrprtation of ths rsults appars to b quit clar within th assumd architctur, it is important to considr altrnativ architcturs, altrnativ procssing assumptions, or both that may b consistnt with th smantic locus of th obsrvd priming ifcts. W shall discuss both of ths issus in turn. ultipl lxical rprsntations for ambiguous words. As shown in Figur 2, considr th possibility that ambiguous words hav multipl smantic and lxical rprsntations. In fact, a numbr of rsarchrs hav suggstd this possibility (.g., Jastrzmbski, 1981; Kllas, Frraro, & Simpson, 1988; Rubnstin, Garfild, & illikan, 1970; Rubnstin, Lwis, & Rubnstin, 1971; Sidnbrg t al., 1982). If this wr th cas and thr wr no inhibitory connctions btwn th multipl intrprtations of ambiguous words, thn it is possibl {(KTONEY^I A: Taroat B: Targt STRIPES Prim that on might find similar pattrns of priming ffcts for ambiguous and unambiguous targt words. or spcifically, it is possibl that th bnfit of convrgnc on a singl lxical rprsntation from two rlatd prims for unambiguous targts (LION-STRIPES-TIGER) would b qual to th bnfit from a rac btwn th two distinct primd lxical rprsntations for ambiguous targts (KIDNEY-PIANO- ORGAN). Unfortunatly, thr ar also a numbr of aspcts of th architctur displayd in Figur 2 that ar inconsistnt with th xtant litratur and aspcts of th currnt rsults. First and formost, within this architctur it is unclar how slction of an appropriat maning of a homograph might occur. For xampl, this modl should prdict that participants would b fastr to rcogniz th word PIANO in th discordant condition, KIDNEY-ORGAN-PIANO, compard with an unrlatd control condition, HEART-PENCIL-PIANO. Howvr, undr conditions in which participants namd both prims, Balota and Duchk (1991) found no diffrnc btwn ths two conditions for ithr a 250- or a 1,250-ms rspons to stimulus intrval. Similarfindingshav bn rportd in othr studis (.g., Schvanvldt, yr, & Bckr, 1976). On th othr hand, considr th possibility that th constraints of th prsnt xprimnts functionally ngagd an architctur as displayd in Figur 2. In fact, thr may b som instancs in which such an architctur is quit rasonabl. Considr, for xampl, Swinny's (1979) oft-citd study. In this study, thr was vidnc that both intrprtations of ambiguous words wr quickly accssd and that only latr was on of th intrprtations slctd. Thus, whn thr ar vry short dlays, it is possibl that th architctur displayd in Figur 2 is at last functionally ngagd. Only aftr som dlay is thr vidnc for slction. Although thr is currntly considrabl controvrsy rgarding th notion of xhaustiv multipl accss (.g., Paul, Kllas, artin, & Clark, 1992; Tabossi, 1988), vn if this assumption wr corrct, it would hav considrabl difficulty in accounting for th rsults of th prsnt Exprimnt 4. In this xprimnt, th first prim word was prsntd for a full 1,000 ms. Clarly, 1,000 ms should b sufficint tim for th first prim to activat th rlvant intrprtation of an ambiguous word, and yt thr was still a rliabl bnfit from th addition of a brifly prsntd scond prim that was rlatd to th altrnat intrprtation of th ambiguous word (compar th RR vs. th RU conditions in Tabl 5). Thus, on cannot simply argu that th rason for th absnc of diffrncs btwn th pattrns of priming for ambiguous and unambiguous words is that th SOAs wr simply too short for slctiv accss to b ngagd. Finally, w nd to considr th functional valu of th multipl smantic-lxical architctur for ambiguous words displayd in Figur 2. First, it should b notd that such a rprsntation would appar to pos som problms at a KIDNEY ORGAN ORGAN PIANO Prim Targt Prim Figur 2. Altrnativ lxical-smantic procssing architctur rprsnting th facilitatory connctions btwn two rlatd prims for unambiguous targts and for ambiguous targts. 5 It should b notd that thr ar altrnativ intractiv-activation modls that do not includ inhibitory pathways. On such modl is Dll's (1986) modl of spch production. Although it is quit possibl that such a framwork may b abl to handl th wid varity of rsults in th ambiguity-rsolution litratur, w do not know of any currntly implmntd vrsion of such a modl that has bn dvlopd to accomplish this goal.

16 842 BALOTA AND PAUL simpl prcptual pattrn-rcognition lvl. Spcifically, it is unclar how th visual-lxical systm might rprsnt two distinct and yt idntical orthographic pattrns for ambiguous words. In som sns, thr would no longr b a uniqu idntification point in lxical procssing (s arsln-wilson & Wlsh, 1978), bcaus for ths itms thr ar always two highly activatd orthographic-rcognition dvics. This would produc considrabl difficulty for th pattrn-rcognition systm; that is, whn would th systm b abl to dtrmin that a uniqu pattrn was idntifid? Of cours, th functional valu of such multipl lxical rprsntations may incras, at last in production, undr conditions in which both intrprtations of th ambiguous words ar linkd to diffrnt syntactic functions (.g., th noun maning oidck rfrring to a part of a boat vs. th vrb maning of dck rfrring to a blow to th had). Howvr, vn if this wr th cas, thn on is still lft with th problm of how th systm slcts from among multipl intrprtations whn th sam orthographic pattrns ar rprsntd by th input lxicon. In summary, bcaus of th abov concrns, w do not bliv that th architctur displayd in Figur 2 is a viabl rprsntation for ambiguous words. At th vry last, vn if on assums two lxical and two smantic rprsntations for ambiguous words, thn it would appar that on would also nd to includ inhibitory connctions btwn th smantic rprsntations to account for th availabl data concrning ambiguity rsolution and to provid a straightforward mannr for th systm to dal with highly activatd idntical lxical rprsntations (but s Footnot 5). Onc such inhibitory connctions ar assumd, thn on must ithr (a) prdict rlativly lss priming in th RR condition for th ambiguous words than for th unambiguous words bcaus of this inhibition or (b) assum th smantic-lvl rprsntations ar not strongly ngagd (s discussion blow) in th prsnt lxicalprocssing tasks. Bcaus thr was no support for this first prdiction in th prsnt rsults, w ar in fact ld to th sam conclusion vn if on assums multipl lxical rprsntations for ambiguous words (along with passiv inhibitory smantic connctions); that is, th prsnt smantic-priming ffcts in both th LDT and th naming task do not strongly ngag smantic-lvl rprsntations. W now turn to th importanc of th passiv natur of ths inhibitory connctions. Th rol of slction in th ngagmnt of inhibitory supprssion. A rlativly simpl altrnativ account of th prsnt rsults is that th architctur of Figur 1 is, at last in part, corrct but that th inhibition of altrnativ intrprtations of ambiguous words is not ngagd unlss th participant is forcd to slct on intrprtation of th ambiguous targt. In th prsnt xprimnts, bcaus th ambiguous word was prsntd as th targt itm, thr was no nd for slction in ordr to mak a spdd naming or lxical-dcision rspons to th targt, and hnc, thr was littl vidnc of smanticlvl inhibition. Howvr, in th rlatdnss judgmnt task of Exprimnt 6, participants wr rquird to slct an intrprtation of th targt word to dtrmin if it was rlatd to on of th prim itms, and hnc, smantic-lvl inhibition occurrd. orovr, bcaus in Balota and Duchk's (1991) xprimnt, dscribd abov, ambiguous words wr prsntd in th scond prim position (i.., KIDNEY-ORGAN-PIANO) instad of th targt position, th rsults of this arlir xprimnt could b viwd as simply indicating that undr conditions in which participants hav sufficint tim to us th first contxt word to slct an intrprtation of th ambiguous word, on willfindvidnc of smantic-lvl inhibition. Thus, in this light, th prsnt rsults could b viwd as ithr indicating that (a) thr is no passiv inhibitory connction btwn altrnativ intrprtations of ambiguous words, and inhibition is not ngagd until maning slction is activly achivd, or (b) thr is a passiv inhibitory connction for ambiguous words at th smantic lvl as displayd in Figur 1, and th currnt priming ffcts in th LDT and th naming task ar most likly du to lxical-lvl associativ ffcts. Th argumnt that th prsnt lxical-dcision and naming rsults involv smantic-lvl rprsntations and that slction is ndd for th ngagmnt of inhibition is furthr bolstrd by two important pattrns of data: First, thr is an intrsting pattrn of intractions among dgradation, wordfrquncy, and smantic contxt (i.., priming ffcts). Spcifically, contxt intracts with both word frquncy and dgradation, whras word frquncy producs additiv ffcts with dgradation. This pattrn has bn rcntly intrprtd by Borowsky and Bsnr (1993) to indicat both that contxt influncs an orthographic input lxicon (through fdback from th smantic systm) and also that contxt ffcts rflct activity dirctly within th smantic systm. For Borowsky and Bsnr, word frquncy modulats th transfr btwn th orthographic-input lxicon and th smantic systm. At th vry last, ths data appar to suggst that contxt can produc two distinct influncs as rflctd by th fact that contxt intracts with two variabls (dgradation and word frquncy) and that whn invstigatd in isolation ths two variabls produc additiv ffcts. Although Borowsky and Bsnr's rsults ar quit important in placing constraints on any modl of word rcognition and priming, w also bliv that it is quit important to us mor dirct manipulations of smantic variabls (.g., concrtnss or numbr of manings as in th prsnt study) to nsur that thir rsults indd rflct a smantic influnc. Th scond pattrn of rsults that support a smantic-lvl influnc is found in studis that involv dirct manipulations of smantic variabls in isolatd lxical-dcision and naming prformanc. For xampl, thr is vidnc that th numbr of manings a word has availabl (.g., Kllas t al., 1988) and targt-word concrtnss (.g., Blasdal, 1987; Jams, 1975) modulat both naming and LDTs (s Balota, Frraro, & Connor, 1991, for a rviw). Although w bliv that smantic variabls (.g., concrtnss and word maning) can play a rol in isolatd naming and lxical-dcision prformanc, w also bliv that th rlativ importanc of ths factors may b diminishd in ths tasks bcaus both naming and lxicaldcision prformanc plac a rlativly high priority on lxical procssing, at last compard with tasks that plac a highr priority on maning-intgration procsss. This is nicly rflctd in th comparison of th prsnt naming and lxicaldcision data, whrin thr wr no influncs of targt

17 SUATION OF ACTIVATION 843 ambiguity with th prsnt rlatdnss-judgmnt data; howvr, thr wr larg influncs of targt ambiguity. In this light, w bliv that it is important to rcogniz that skilld radrs hav considrabl control ovr th influnc of a givn procssing pathway, dpnding on th constraints of a givn task. Obviously, skilld radrs can procss a visually prsntd word along a numbr of distinct procssing pathways: Dos th string of lttrs includ th lttrs t and n (orthographic)? Dos th string rhym with th word dog (phonological)? Is th string a noun or vrb (syntactic)? Dos th word rprsnt a concpt that includs animatnss (smantic)? Th xtnt to which th task dmands rquir output from a givn procssing dimnsion dtrmins th dgr of influnc of this procssing pathway. W would simply argu that th mphasis in both th LDT and th naming task is on spdd lxical-lvl procssing, and thrfor skilld radrs ar likly to primarily ngag th procssing pathway or pathways that ar rquird by thos task dmands. On th othr hand, whn on turns to th rlatdnss dcision task, th notion hr is that participants primarily ngag a smantic-procssing pathway, and hnc on finds th prdictd diffrncs btwn ambiguous and unambiguous words. Intrstingly, thr is alrady vidnc that participants hav attntional control ovr task-appropriat procssing pathways in th lxical domain. For xampl, work by Smith (1979), Smith, Thodor, and Franklin (1983), and Hnik, Fridrich, and Kllogg (1983) has shown that th typ of pathway ngagd on th prim can control th influnc of primtargt rlationships on prformanc. Spcifically, ths rsarchrs hav dmonstratd that whn a lttr sarch task is usd, on can liminat th smantic-priming ffct (Smith t al., 1983). This is quit consistnt with th notion that thr is attntional control of rlvant lxical-procssing pathways and that if attntion is focusd on lowr lvl orthographic pathways, vn th lxical-lvl associations that appar to b involvd in priming ffcts in lxical dcision and naming can b disabld or at last gratly diminishd. Th importanc of this obsrvation is that it is inconsistnt with th notion that thr is xhaustiv and qually automatic accss to all cods availabl in lxical procssing. It is also important to mphasiz that w do not wish to argu that thr is total control ovr procssing pathways within a givn task, but w do wish to argu that thr is modulation of th wight placd on diffrnt procssing dimnsions dpnding on th task dmands. In fact, w bliv that with mor connctd discours that dircts attntion to highr lvl structurs, such as sntnc contxts, it is possibl that priming ffcts rflctd by spdd-naming prformanc may rflct highr lvl smantic structurs in liu of low-lvl lxical-associativ connctions (s Hss, Foss, & Carroll, 1995, for rcnt vidnc). Conclusions Th rsults of th prsnt rsarch provid support for th following two conclusions: First, th influnc of multipl prims within th smantic-priming paradigm ar clarly additiv. W bliv that any modl of smantic priming will nd to account for this simpl additiv function. Scond, th prsnt naming and lxical-dcision rsults yildd idntical pattrns for conditions in which prims convrgd onto a singl smantic rprsntation for th targt and for conditions in which prims divrgd onto distinct smantic rprsntations. If on assums th rlativly simpl architctur displayd in Figur 1, w bliv ths rsults ar most consistnt with on of th following two conclusions: (a) Smantic priming ffcts in naming and lxical dcision primarily rflct lxical-lvl associations, or (b) smantic-priming ffcts in naming and lxical dcision indd rflct smanticlvl information, and th assumd passiv inhibition in Figur 1 is not ngagd until slction of a maning for an ambiguous word actually is implmntd. In ithr cas, th prsnt rsults provid furthr constraints on th dvlopmnt of an adquat modl of lxical procssing and priming. Rfrncs Andrson, J. R. (1983). A sprading activation thory of mmory. Journal of Vrbal Larning and Vrbal Bhavior, 22, Ashcraft,. H. (1978). Proprty norms for typical and atypical itms from 17 catgoris: A dscription and discussion. mory & Cognition, 6, Balota, D. A. (1983). Automatic smantic activation and pisodic mmory ncoding. Journal of Vrbal Larning and Vrbal Bhavior, 22, Balota, D. A., Black, S., & Chny,. (1992). Automatic and attntional procssing in young and old adults: A rvaluation of th two-procss modl of smantic priming. Journal of Exprimntal Psychology: Human Prcption and Prformanc, 18, Balota, D. A., & Duchk, J.. (1991). Smantic priming ffcts, lxical rptition ffcts, and contxtual disambiguation ffcts in halthy agd individuals and individuals with snil dmntia of th Alzhimr's typ. Brain and Languag, 40, Balota, D. A., Frraro, F. R., & Connor, L. T. (1991). On th arly influnc of maning in word rcognition: A rviw of th litratur. In P. J. Schwannflugl (Ed.), Th psychology of word manings (pp ). Hillsdal, NJ: Erlbaum. Balota, D. A., & Lorch, R. (1986). Dpth of automatic sprading activation: diatd priming ffcts in pronunciation but not in lxical dcision. Journal ofexprimntal Psychology: Larning, mory, and Cognition, 12, Balota, D. A., Pollatsk, A., & Raynr, K. (1985). Th intraction of contxtual constraints and parafoval visual information in rading. Cognitiv Psychology, 17, Battig, W. F., & ontagu, W. E. (1969). Catgory norms for vrbal itms in 56 catgoris: A rplication and xtnsion of th Conncticut catgory norms. Journal of Exprimntal Psychology onograph, 80, 1^6. Bsnr, D., & Smith,. C. (1992). odls of visual word rcognition: Whn obscuring th stimulus yilds a clarr viw. Journal of Exprimntal Psychology: Larning, mory, and Cognition, 18, Blank,. A., & Foss, D. J. (1978). Smantic facilitation and lxical accss during sntnc procssing. mory & Cognition, 6, Blasdal, F. A. (1987). Concrtnss-dpndnt associativ priming: Sparat lxical organization for concrt and abstract words. Journal of Exprimntal Psychology: Larning, mory, and Cognition, 13, Borowsky, R., & Bsnr, D. (1993). Visual word rcognition: A

18 844 BALOTA AND PAUL multistag activation modl. Journal of Exprimntal Psychology: Larning, mory, and Cognition, 19, Brodur, D. A., & Lupkr, S. J. (1989). Invstigating th ffcts of multipl prims: Dos activation summatl Papr prsntd at th 30th Annual ting of th Psychonomic Socity, Atlanta, GA. Brodur, D. A., & Lupkr, S. J. (1994). Invstigating th ffcts of multipl prims: An analysis of thortical mchanisms. Psychological Rsarch, 57, Chiarllo, C, Burgss, C, Richards, L., & Pollock, A. (1990). Smantic and associativ priming in th crbral hmisphrs: Som words do, som words don't... somtims, som placs. Brain and Cognition, 38, Church, K., & Hanks, P. (1989). Word association norms, mutual information, and lxiography. Papr prsntd at th 23rd Annual ting of th Association for Computational Linguistics. Vancouvr, British Columbia, Canada: Association for Computational Linguistics. Cohn, J. (1977). Statistical powr analysis for th bhavioral scincs (Rv. d.). Orlando, FL: Acadmic Prss. Collins, A.., & Loftus, E. F. (1975). A sprading-activation thory of smantic procssing. Psychological Rviw, 82, Cottrll, G. W. (1989). A modl of lxical accss of ambiguous words. In S. I. Small, G. W. Cottrll, &. K. Tannhaus (Eds.), Lxical ambiguity rsolution (pp ). San ato, CA: organ Kaufman. Dll, G. S. (1986). A sprading-activation thory of rtrival in sntnc production. Psychological Rviw, 93, Doshr, B. A., & Rosdal, G. (1989). Intgratd rtrival cus as a mchanism for priming in rtrival from mmory. Journal of Exprimntal Psychology: Gnral, 118, Durgunoglu, A. Y. (1988). Rptition, smantic priming, and stimulus quality: Implications for th intractiv-compnsatory rading modl. Journal of Exprimntal Psychology: Larning, mory, and Cognition, 14, Fischlr, I. (1977). Associativ facilitation without xpctancy in a lxical dcision task. Journal of Exprimntal Psychology: Human Prcption and Prformanc, 3, Forstr, K. I. (1989). Summation ffcts in lxical form-priming with maskd prims: Dirct vidnc for activation modls! Papr prsntd at th 30th Annual ting of th Psychonomic Socity, Atlanta, GA. Grnsbachr,. A., Varnr, K. R., & Faust,. E. (1990). Invstigating diffrncs in gnral comprhnsion skin. Journal of Exprimntal Psychology: Larning, mory, and Cognition, 16, Gough, P. B., Alford, J. A., & Holly-Wilcox, P. (1981). Words and contxts. In O. J. L. Tzng & H. Singr (Eds.), Prcption of print- Rading rsarch in xprimntal psychology (pp ). Hillsdal, NJ: Erlbaum. Hampton, J. A. (1984). Th vrification of catgory and proprty statmnts. mory & Cognition, 12, Hnik, A., Fridrich, F. J., & Kllogg, W. A. (1983). Th dpndnc of smantic rlatdnss ffcts upon prim procssing. mory & Cognition, 11, Hss, D. J., Foss, D. J., & Carroll, P. (1995). Effcts of global and local contxt on lxical procssing during languag comprhnsion. Journal of Exprimntal Psychology: Gnral, 124, Jams, C. T. (1975). Th rol of smantic information in lxical dcisions. Journal of Exprimntal Psychology: Human Prcption and Prformanc, 1, Jastrzmbski, J. E. (1981). ultipl manings, numbr of rlatd manings, frquncy of occurrnc, and th lxicon. Cognitiv Psychology, 13, Joordns, S., & Bsnr, D. (1992). Priming ffcts that span an intrvning unrlatd word: Implications for modls of mmory rprsntation and rtrival. Journal of Exprimntal Psychology: Larning, mory, and Cognition, 18, Kf, D. E., & Nly, J. H. (1990). Smantic priming in th pronunciation task: Th rol of prospctiv prim-gnratd xpctancis. mory & Cognition, 18, Kllas, G., Frraro, F. R., & Simpson, G. B. (1988). Lxical ambiguity and th timcours of attntional allocation in word rcognition. Journal of Exprimntal Psychology: Human Prcption and Prformanc, 14, Klin, R., Briand, K., Smith, L., & Smith-Lamoth, J. (1988). Dos sprading activation summat? Psychological Rsarch, 50, Lorch, R. F., Balota, D. A., & Stamm, E. (1986). Locus of inhibition ffcts in th priming of lxical dcisions: Pr- or post-lxical accss? mory & Cognition, 14, Lupkr, S. J. (1984). Smantic priming without association: A scond look. Journal of Vrbal Larning and Vrbal Bhavior, 23, arsln-wilson, W. D., & Wlsh, A. (1978). Procssing intractions and lxical accss during word rcognition in continuous spch. Cognitiv Psychology, 10, asson,. E. J. (1991). A distributd mmory modl of contxt ffcts in word idntification. In D. Bsnr & G. W. Humphrys (Eds.), Basic procsss in rading: Visual word rcognition (pp ). Hillsdal, NJ: Erlbaum. asson,. E. J. (1995). A distributd mmory modl of smantic priming. Journal of Exprimntal Psychology: Larning, mory, and Cognition, 21, ccllland, J. L., & Rumlhart, D. E. (1981). An intractiv activation modl of contxt ffcts in lttr prcption: Part 1. An account of basic findings. Psychological Rviw, 88, ckoon, G., & Ratcliff, R. (1988). Contractually rlvant aspcts of maning. Journal of Exprimntal Psychology: Larning, mory, and Cognition, 14, ckoon, G., & Ratcliff, R. (1992). Sprading activation vrsus compound cu accounts of priming: diatd priming rvisitd. Journal of Exprimntal Psychology: Larning, mory, and Cognition, 18, cnamara, T. P. (1992). Thoris of priming: I. Associativ distanc and lag. Journal of Exprimntal Psychology: Larning, mory, and Cognition, 18, cnamara, T. P., & Altarriba, J. (1988). Dpth of sprading activation rvisitd: Smantic mdiatd priming occurs in lxical dcisions. Journal of mory and Languag, 27, cnamara, T. P., & Diwadkr, V. A. (in prss). Th contxt of mmory rtrival. Journal of mory and Languag. yr, D. E., & Schvanvldt, R. W. (1971). Facilitation in rcognizing pairs of words: Evidnc of a dpndnc btwn rtrival oprations. Journal of Exprimntal Psychology, 90, yr, D. E., Schvanvldt, R. W., & Ruddy,. G. (1975). Loci of contxtual ffcts on visual word rcognition. In P.. A. Rabbitt & S. Dornic (Eds.), Attntion and Prformanc V (pp ). Nw York: Acadmic Prss. orton, J. (1969). Intraction of information in word rcognition. Psychological Rviw, 76, oss, H. E., Ostrin, R. K., Tylr, L. K., & arsln-wilson, W. D. (1995). Accssing diffrnt typs of lxical smantic information: Evidnc from priming. Journal of Exprimntal Psychology, Larning, mory, and Cognition, 21, Nly, J. H. (1977). Smantic priming and rtrival from lxical mmory: Rols of inhibitionlss sprading activation and limitd capacity attntion. Journal of Exprimntal Psychology: Gnral, 106, Nly, J. H. (1991). Smantic priming ffcts in visual word rcognition. In D. Bsnr & G. Humphrys (Eds.), Basic procsss in rading: Visual word rcognition (pp ). Hillsdal, NJ: Erlbaum. Nly, J. H., Kf, D. E., & Ross, K. L. (1989). Smantic priming in th lxical dcision task: Rols of prospctiv prim-gnratd

19 SUATION OF ACTIVATION 845 xpctancis and rtrospctiv smantic matching. Journal of Exprimntal Psychology: Larning, mory, and Cognition, 14, Paul, S. T., Kllas, G., artin,., & Clark,. B. (1992). Influnc of contxtual faturs on th activation of ambiguous word manings. Journal of Exprimntal Psychology: Larning, mory, and Cognition, 18, Ratcliff, R., & ckoon, G. (1988). A rtrival thory of priming. Psychological Rviw, 95, Ratcliff, R., & ckoon, G. (1995). Squntial ffcts in lxical dcision: Tsts of compound-cu rtrival thory. Journal of Exprimntal Psychology: Larning, mory, and Cognition, 21, Rdr, L.. (1983). What kind of pitchr can a catchr fill? Effcts of priming in sntnc comprhnsion. Journal of Vrbal Larning and Vrbal Bhavior, 22, Rubnstin, H., Garfild, L., & illikan, J. A. (1970). Homographic ntris in th intrnal lxicon. Journal of Vrbal Larning and Vrbal Bhavior, 9, Rubnstin, H., Lwis, S., & Rubnstin,. (1971). Evidnc for phonmic rcoding in visual word rcognition. Journal of Vrbal Larning and Vrbal Bhavior, 10, Schmidt, R. (1976). On th sprad of smantic xcitation. Psychological Rsarch, 38, Schvanvldt, R. W., yr, D. E., & Bckr, C. A. (1976). Lxical ambiguity, smantic contxt, and visual word rcognition. Journal of Exprimntal Psychology: Human Prcption and Prformanc, 2, Sidnbrg,. S., Tannhaus,. K., Liman, J.., & Binkowski,. (1982). Automatic accss of th manings of ambiguous words in contxt: Som limitations of knowldg-basd procssing. Cognitiv Psychology, 14, Sidnbrg,. S., Watrs, G. S., Sandrs,., & Langr, P. (1984). Pr- and post-lxical loci of contxtual ffcts on word rcognition. mory & Cognition, 12, Sharky, N. E. (1990). A connctionist modl of txt comprhnsion. In D. A. Balota, G. B. Flors d'arcais, & K. Raynr (Eds.), Comprhnsion procsss in rading (pp ). Hillsdal, NJ: Erlbaum. Shlton, J. R., & artin, R. C. (1992). How smantic is smantic priming? Journal of Exprimntal Psychology: Larning, mory, and Cognition, 18, Simpson, G. B., & Kang, H. (1994). Inhibitory procsss in th rcognition of homograph manings. In D. Dagnbach & T. H. Carr (Eds.), Inhibitory mchanisms in attntion, mmory and languag (pp ). Nw York: Acadmic Prss. Simpson, G. B., & Kllas, G. (1989). Dynamic contxtual procsss and lxical accss. In D. S. Gorfin (Ed.), Rsolving smantic ambiguity (pp ). Nw York: Springr-Vrlag. Smith,. C. (1979). Contxtual facilitation in a lttr sarch task dpnds on how th prim is procssd. Journal of Exprimntal Psychology: Human Prcption and Prformanc, 5, Smith,. C, Bsnr, D., & iyoshi, H. (1994). Nw limits to automatic! ty: Contxt modulats smantic priming. Journal of Exprimntal Psychology: Larning, mory, and Cognition, 20, Smith,. C, Thodor, L., & Franklin, P. E. (1983). On th rlationship btwn contxtual facilitation and dpth of procssing. Journal of Exprimntal Psychology: Larning, mory, and Cognition, 9, Stanovich, K. E., & Wst, R. F. (1981). Th ffct of sntnc contxt on ongoing word rcognition: Tsts of a two-procss thory. Journal of Exprimntal Psychology: Human Prcption and Prformanc, 7, Stanovich, K. E., & Wst, R. F. (1983). On priming by a sntnc contxt. Journal of Exprimntal Psychology: Gnral, 112, Stolz, J. A., & Nly, J. H. (1995). Whn targt dgradation dos and dos not nhanc smantic contxt ffcts in word rcognition. Journal of Exprimntal Psychology: Larning, mory, and Cognition, 21, Swinny, D. A. (1979). Lxical accss during sntnc comprhnsion: (R)considration of contxt ffcts. Journal of Vrbal Larning and Vrbal Bhavior, 18, Tabossi, P. (1988). Accssing lxical ambiguity in diffrnt typs of sntntial contxts. Journal of mory and Languag, 27, Rcivd January 24,1995 Rvision rcivd Sptmbr 19,1995 Accptd Octobr 4,1995