Theories and models of consumer information

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1 Hemispherically Laeralized EEG as a Response o Television Commercials MICHAEL L. ROTHSCHILD YONGJ.HYUN YRON REEVES ESTHER THORSON ROERT GOLDSTEIN* EEG was recorde<j from 21 righ-handed women as hey wached commerciai elevision. A significan amoun of variance in hemispheric dominance shifs of laeraiized EEG was explained as a funcion oj he onse of easily idenifiable v^ables in he simulus. There were hemispheric differences in EEG due o he verbal and nonverbal componens of he simulus. Lags beween simulus onse and change in EEG also were observabie. The daa were fourxj o be reliable wihin his sudy, beween his sudy and a prior one. and beween his sudy and ohers in he EEG lieraure ha uses less complex simuli. Theories and models of consumer informaion processing of adverising have changed dramaically in he pas few years, leading o new insighs for researchers. Alhough much is known reroacively abou how informaion in general was processed and learned when a consumer was exposed o an adverising message, lile is known abou how informaion is processed a any poin during is acual presenaion. One direcion for sudying on-line processing comes from psychophysiologic variables such as elecroderma! (EDA), hear-rae (EKG), and elecromyographic (EMG) measures. This sudy considers he elecroencephalograph (EEG), which aids in he sudy of brain waves. Hemispheric laeralizaion, he sudy ofhe respecive roles ofhe righ and lef hemispheres of he brain in informaion processing, is a useful area of sudy wihin he EEG field. Popularis wriers have speculaed ha he righ hemisphere is specialized o process picures and mu- MichaeJ L. Rohschild is Professor of usiness and Yong J, Hyun is a Ph.D. candidae, boh a he School of usiness, Universiy of Wisconsin, Madison, Wl yron Reeves is Professor of Communicaion, School of Humaniies and Sciences. Sanford Universiy, Sanford, CA Esher Thorson is Associae Professor, School of Journalism and Mass Communicaion, College of Leers and Sciences, and Rober Goldsein is Professor of Communicaive Disorders. College of Medicine, boh a he Universiy of Wisconsin, Madison. Wl The auhors hank Judy Hirsch, Marian Friesad, and Joan Schieuder for echnical assisance and Gilber Churchill. Richard Davidson, and Seven Shapiro for criical feedback. This projec was funded by grans from he American roadcasing Company and he Universiy of Wisconsin. 185 sic whereas he lef is beer suied o process words and numbers. Unforunaely, much ofhe basis for his conjecure comes from research ha used subjecs damaged in one hemisphere or wih surgically separaed hemispheres, or ha used exremely simple simuli (picure ofa ca versus he word CAT). Few hemispheric daa ses are available based on normal subjecs viewing elevised adverising or oher naurally occurring complex simuli. The purpose of his sudy was o examine hemispheric differences in he EEG of normal subjecs waching elevision commercials o obain a physiologic parallel o he processing of informaion. Hemispheric differences daa relaing o raional and emolional commercials, and he verbal, nonverbal, audio, and visual componens of hese commercials were examined. Wihin recen years, several major sudies have been done o evaluae he poenial of EEG as an index of response o elevision commercials. Two of hese sudies (Olson and Ray 1983; Rus, Price, and Kumar J 985) did no show a srong relaion beween elevision commercial simuli and changes in he EEG. (Alwi's 1985 reanalysis of Olson and Ray's daa is discussed in he Lieraure Review secion under Adverising-Relaed EEG Issues.) The laes resuls ofhe EEG index and elevision commercials are repored here, beginning wih a review of prior work and concluding wiih a discussion ofa relaion ha is reliable, replicable, and consisen wih EEG findings repored for less complex simuli. In addiion, we discuss in his aricle possible reasons why his sudy suc- JOURL OF CONSUMER RESEARCH Vol 15«Seplcmber 1988

2 186 THE JOURL OF CONSUMER RESEARCH cessfully uncovered wha oher sudies failed o find. The discussion also summarizes and inegraes oher previously repored findings ha have emerged from his curren sream of research. LITERATURE REVIEW EEG poenially is useful in elevision commerciai esing because i can provide a coninuous record ha reflecs corical arousal in response o a message simulus (Walker 1980). Alhough self-repor measures provide rerospecive saic informaion, a selfrepor measure is less useful for assessing he impac on memory ofa paricular scene, a line of scrip, camera movemen, or a piece of music from a commercial. Nonphysiologic, coninuous measures such as hand-held poeniomeers used in heare ess yield coninuous daa, bu may disurb he cogniive processes of he subjec by requiring a houghful response. Passive physiologic measures in general have he advanage of no disurbing cogniive processes. asic EEG Issues If EEG is o be used appropriaely, i firs is necessary o undersand EEG and he difficulies in measuring and inerpreing i. For an inroducion o EEG, he reader is referred o Greenfield and Sernbach (1972) or Sern, Ray, and Davis (1980); for an inroducion o hemispheric laeraliy, refer o Springer and Deusch (1981); a shorer review direced oward markeers and hose reviewing he work relaed o adverising can be found in Hansen (1981), Olson and Ray (1983), Rohschild and Thorson (1983), and Rohschild e al. (1986). A synhesis of hese reviews would lead a researcher who waned o sudy elevision (a medium ha observers feel consiss primarily of visual simuli) o a range of frequencies (8 Hz o 13 Hz) ha are mos prominen in he occipial region ofhe brain. This so-called alpha frequency is useful because i covaries srongly (and inversely) wih arousal and cogniive aciviy; also, i is more prominen and seems o be more sensiive o exernal simuli han oher frequency ranges. The occipial lobe is appropriae because his area of he brain shows he cleares reacions o visual simuli. Occipial alpha has been he dominan choice in basic EG sudies as wel! as in more recen adverising relaed EEG sudies;' arousal can be observed by a rapid (wihin 300 milliseconds) reducion ' The occipu is he primary visual recepor ofhe brain, bu he parieal and emporal corices also process complex visual simuli. Alhough he occipu shows he cleares response o basic visual simuli, he parieal corex may show greaer laeraliy responses o complex simuli such as elevision commercials and may uuimaely be he locaion of choice for sudying laeraliy. of elecrical aciviy in he alpha frequency (alpha blocking). Alpha blocking occurs when subjecs acively respond o a wide variey of simuli (e.g., Doyle, Ornsein, and Galin 1974; Spydell and Sheer 1982) and when hey passively receive hese simuli (e.g., Morgan, Macdonald, and Hilgard 1974; Mulholland e al. 1971). For example, alpha blocking occurs when subjecs are exposed o simple simuli such as ones and ligh flashes, moderaely complex simuli such as verbal analogies and block designs (e.g., Gevins e al. 1979; Warren, Pelz, and Hauer 1976), and exremely complex simuli such as elevision scenes and sophisicaed musical rhyhms (e.g., McKee, Humphrey, and McAdam 1973; Schafer 1978). These observaions are encouraging for he sudy of elevision commercial viewing where complex simuli are received passively. Very few ess have examined EEG and memory in he psychophysiology lieraure. Typical of hese ess is he work of Seamon (1974) and Madden and Nebes (1980). oh of hese sudies examined memory for words or figures ha had been presened in he righ or lef visual field. Resuls showed ha memory was sronger and responses were faser when hese verbal and numerical simuli were presened in he righ visual field and herefore firs were received for processing in he lef hemisphere. We have found no sudies ha deal wih simuli nearly as complex as a elevision commercial. Adverising-Relaed EEG Issues In adverising sudies, Rohschild e al. (1986), Reeves e al. (1985), and Weinsein, Appel, and Weinsein (Appel, Weinsein, and Weinsein 1979; Weinsein, Appel, and Weinsein 1980) have shown ha here is an inverse relaion beween he elecric power of occipial alpha and elevision commercial simuli. The work presened in his aricle describes daa colleced in he second ofa series of sudies. The major findings of he firs sudy were repored in Rohschild e al. (1986) and Reeves e al. (1985). Tha sudy examined he power of occipial alpha collapsed across he hemispheres. The findings included he following; A srong negaive correlaion was found beween he mean level of alpha across an enire commercial and recall and recogniion ess. This finding confirms Appel e al and is consisen wih he exensive psychophysiology lieraure ha shows alpha blocking o relae o an increase in arousal. Definable paerns of alpha change occurred across periods (epochs) of hree o eigh seconds, during which aipha dropped in response o definable changes in he commercial such as

3 EEG AS A RESPONSE TO TV COMMERCIALS edis and movemens. These decreases in alpha were followed by a period of alpha increase (aenuaion of blocking). Regression analyses showed ha alpha decreased mos sharply wihin one-half second of an edi or he onse of movemen. Thiry-seven percen ofhe variance in alpha was accouned for by changes in hese wo variables. Anoher 20 percen of he variance was accouned for by auocorrelaion. In a reanalysis of Olson and Ray's (1983) daa, Alwi (1985) used ime-series analysis and found a negaive relaion beween several elemens ofhe elevision commercial simulus and alpha in he same period (she used wo-second periods), bu many posiive relaions beween he simulus and alpha in following periods. This finding is consisen wih Rohschild e al. (1986) where processing epochs were shown o occur. In hese epochs, alpha dropped a he onse ofa simulus (such as a scene change) and hen slowly recovered over several seconds unil here was anoher simulus change or onse. Alwili's finding also is consisen wih he ime series analysis of Reeves el al. (1985). bu Reeves' daa were aggregaed in half-second incremens and, herefore, showed more deail abou he presence and lengh of lagged responses o elevised simuli. A more complee review of adverising-relaed EEG sudies can be found in Rohschild e al. (1986). Oher sudies ha have employed EHG o examine adverising effecs on memory show a mixed se of resuls. Alhough Appel e al. (1979) demonsraed a relaion beween hese wo variables, Weinsein e al. (1980) did no replicae his finding and found no relaion beween EEG and memory. Rus e al. (1985) also showed no consisen relaion beween EEG and recall; Rockey, Greene, and Perold (1980) showed no difference in EEG paerns beween high- and low-recall commercials. Alhough some sudies have found a relaion beween EEG and memory for commercials, mos sudies have no shown his relaion. Hemispheric Laeraliy Issues The effec of he reducion of alpha is disincly differen beween he lef and righ hemispheres ofhe brain (e.g., Galin and Ornsein 1972; Osaka 1984; Walker 1980). This firs was observed during World War II when clinicians found ha peopie damaged in he lef hemisphere ofhe brain showed abnormaliies in heir verbal, audio, and piecemeal-like analyic skills, whereas hose damaged in he righ hemisphere showed abnormaliies in heir nonverbal, visual, and holisic (spaial) analyic skills. These resuls were inerpreed o mean ha he lef hemisphere specializes in verbal and audio skills, whereas he righ hemisphere specializes in nonverbal and visual skills (Corballis 1980; see Allen 1983 and Sergen 1983 for reviews). More recenly, much research on hemispheric laeralizaion has been conduced wih normal subjecs. This research generally revealed significan hemispheric differences, alhough he effec sizes ended o be smaller han ha in he research using samples of abnormal people (e.g., Kinsbourne 1982; Sperry 1968, 1973). Wheher a paricular hemisphere can or canno do a paricular ask afer injury or surgery does no speak direcly o he abiliies ofhe normal brain; alhough here is some dominance of skills, each hemisphere can do he asks of he opposie hemisphere well (Kinsbourne 1982), even hough execuional sraegies may differ. In normal subjecs, he difference in EEG power beween hemispheres ends o be in he 10 o 15 percen range (Andreassi 1980). Galin (1979) reached a similar conclusion; here is more likely lo be a bihemispheric response han an asymmeric response o complex simuli. oh hemispheres are doing heir own asks and boh are performing a he same ime. Therefore, i is difficul o deermine ifhe hemispheres are cooperaing, inerfering, or operaing in an independen manner. Currenly, he mos popular heory of laeraliy is ha boh hemispheres ofhe normal person's brain process simuli in parallel; however, depending on he naure of he simulus or ask, one hemisphere is more likely o dominae. Parallel processing is less likely o be found in an abnormal person's brain if one of he hemispheres is damaged or he hemispheres have been separaed. Therefore, he effec size forhemisphericlaeralizaion mus be smaller in normal subjecs simply because parallel processing is able o occur. Oher hemispheric findings relevan o his aricle include he following: For audio simuli, language is more likely o be processed in he lef hemisphere; nonverbal sounds are more likely o be processed in he righ hemisphere (Springer and Deusch 1981). No heory of hemispheric laeraliy and informaion processing is universally acceped. There are five major models based on correlaional daa ha are relaed o ypes of simuli, asks, and subjecs; he models are no all muually exclusive. These models sugges unilaeral specializaion (a hemisphere is oally responsible for processing or compleing a ask), bilaeralizaion (boh hemispheres can perform a ask), ineracion (he hemispheres perform simulaneously or inerac o suppress each oher), parallelism (he hemispheres eiher duplicae each oher or share funcions), and allocaion (asks are allocaed o hemispheres so here is neiher ineracion nor parallelism; Allen 1983; Donchin, Kuas, and Me-

4 !88 THE JOURL OF CONSUMER RESEARCH Carhy 1977; Janiszewski 1987). This lack of unanimiy is quie differen from he lay view of unilaeral specializaion ha currenly is leas favored by sudens of EEG. Alhough laeralizaion has been reponed in he ways previously discussed, laeralizaion has no been found using complex elevision simuli. Weinsein e al. (1980) did no find laeralizaion; Olson and Ray (1983) and Alwi (1985) also were unsuccessful in heir search. Rus e al. (1985) found laeralizaion ha had a difficul-o-inerpre paern. Hansen (1981), in a summary review, also was negaive in his prognosis for finding laeralizaion effecs in response o elevision commercials. Oher Relevan Issues Nonhemispheric findings of relevance o his aricle include: Eye movemen and muscle arifac are weakes a he occipu {Galin 1979). In he occipial region, audio simuli produce less change in alpha han do visual simuli (Mulholland 1978) because he occipu specializes in processing visual simuli. The response laency ofhe suppression of al= pha o a simple simulus such as a one or a flash of ligh is abou 300 milliseconds (Sern eal. 1980); acivaion in response o a longer, more complex visual simulus persiss for up o 15 or 20 seconds (owers and Heilman 1980). EEG has high variance across subjecs, bu findings are mixed for wihin-subjec designs. Wihin subjecs, a laeraliy advanage may shif over ime in response o he same simulus, alhough more recen sudies show srong es-rees reliabiliy. eween subjecs, EEG may have high variance because of differences in age, gender, handedness, an undiagnosed pahologic condiion, eye movemen and muscle arifacs, differences in skull hicknesses, and idiosyncraic differences in processing speeds (Davidson 1986; Gasser, acher, and Mocks 1982). These findings provide background for daa and discussion abou mehodologic issues o be presened nex. Mehod Issues Two mehod issues in he exan EHG lieraure need o be inroduced. Firs, EEG researchers generally choose o aggregae raher han use individual daa. The aggregae measure is derived from an averaging process across individual subjecs' EEGs. An individual subjec's EEG reflecs many idiosyncraic facors, and hus he individual measure does no capure sensiively he sysemaic variance in response o he impac ofa paricular simulus (e.g., Gasser e al. 1981; Hansen 1980). Variances due o such idiosyncraic facors can be reduced significanly by aggregaing EEG across individuals, or by exposing each subjec o he same simulus many imes and hen averaging across he exposures. The laer mehod is impracical for adverising research where here is ofen ineres in repeiion effecs. Second, a variey of arihmeic manipulaions of hemispheric laeralizaion can be considered o show asymmery or dominance. For example, hese measures include "Righ - Lef" (R - L), "Righ/Lef" {RID and "Righ - Lef/Righ + Lef" {R - L)/(R + L) (McKee e al 1973; Suer 1982). The choice among hese measures does no always affec significanly he resuls of EEG research (Donchin e al. 1977); amoun of variance in he daa will affec he choice. Empirical evidence indicaes ha {R - L)/(R + L) ends o capure he change in hemispheric laeralizaion more sensiively han does oher measures, and, hus, EEG researchers generally seem o prefer his measure (Ehriichman and Weiner 1980; Galin e al. 1982). These dominance measures are used in addiion o measures ha examine one hemisphere independenly ofhe oher. OJECTIVES AND HYPOTHESES The following daa are from he second EEG sudy, which was designed o expand he findings ofhe firs sudy (repored in Rohschild e al and Reeves eal. 1985) and o coninue he examinaion of EEG as a viable echnique in he assessmen ofhe processing of elevision commercials. There were wo specific objecives: (1) hemispheric laeraliy and lagged effecs and (2) reliabiliy, replicabiiiy, and consisency. A synhesis ofhe lieraure review shows ha EEG manifesaions of processing differ for he lef and righ hemispheres ofhe brain and show simulus-response lags. Alhough hese are well-documened findings in he EEO lieraure, hey have no been shown in adverising-relaed EEG sudies. One objecive ofhis sudy was o invesigae hemispheric laeraiiy and lags as responses o elevision commercial simuli. This exension was necessary because elevision commercials are more complex and are changing more rapidiy han simuli ypically sudied using EEG. The second objecive was o seek signs of regulariy hrough reliabiliy wihin he sudy, replicaion ofhe resuls ofhe firs sudy, and consisency wih he basic lieraure from which he mehod was drawn.

5 EEG AS A RESPONSE TO TV COMMERCIALS These objecives led o a number of hypoheses. The firs hypohesis gives an overview ofhe daa and is viabiliy. Hypohesis 2 hrough Hypohesis 4 deal wih specific issues of informaion processing of ineres o boh heoreicians and praciioners. Hypohesis 5 summarizes wha is learned in he earlier hypoheses, and Hypohesis 6 examines he reliabiliy issues. HI: A significan amoun of variance in he hemispheric EEG daa can be explained as a funcion ofhe changing commercial simuli. Variance can be explained in he absolue level of EEG in each hemisphere and in he relaive level across he hemispheres. The sudy ofhe explanaion of variance is an exension of a nonhemispheric finding from Reeves eal. (1985). H2: Evidence of processing verbal simuli will be sronger in he lef hemisphere and evidence of processing nonverbal simuli will be sronger in he righ hemisphere. A basic EEG finding concerns he processing differences of he wo hemispheres f"or verbal and nonverbal simuli. This is empered, hough, by findings ha show only sligh laeraliy effecs in response o complex simuli. H3; Evidence of processing emoional commercials will be sronger in he righ hemisphere and evidence ofprocessing raional commercials will be sronger in he lef hemisphere. Alhough here is no lieraure direcly driving his hypohesis, i would seem ha raional commercials end o be more verbal and emoional commercials end o be more nonverbal. H4; There are observable lags beween he onse of a simulus variable and a responsive hemispheric shif in EEG. Differen ypes of simuli will elici differen lags. No EEG lieraure deals wih lagged effecs. In prior work using elevision commercials (Reeves eal 1985), he average lag beween he onse of a simulus variable and a change in EEG was 1100 milliseconds, H5: Television commercial simuli are processed in a bilaeral fashion wih significan dominance endencies exhibied. Alhough i has been shown ha simple simuli are processed primarily in one hemisphere and ha pahologic subjecs wih hemispheric damage or surgically severed hemispheres process in a single hemisphere, hese findings have no been generalized o normal subjecs receiving complex simuli. In normal subjecs, i has been shown ha boh hemispheres process ogeher and only sligh dominance paerns are exhibied. H6: Paerns in EEG are consisen. This will be examined in a reliabiliy es wihin his sudy, in a replicaion es across our wo daa ses, and in comparison wih some of he basic EEG findings presened earlier in hisaricle= METHOD Procedures The righ- and lef-hemisphere occipial alpha EEGs of 21 righ-handed women were recorded individually during he viewing ofa elevision videoape. One a a ime, subjecs sa in a comforable reclining chair in a dimly li sound-aenuaing chamber, six fee from a 19-inch color elevision. They lef he chamber o complee quesionnaires and were allowed o ake a shor break beween an acclimaion videoape and he acual simulus videoape. efore viewing, subjecs were asked o find a comforable posiion in he chair and hen o move as lile as possible. They were moniored for movemen hrough an observaion window behind hem. Afer having elecrodes placed on heir scalp, subjecs viewed an acciimaion/disracor videoape for abou 10 minues. The purpose of his ape was o allow subjecs o ge used o he aached elecrodes and o become comforable wih heir srange surroundings. A second purpose ofhis videoape was o confirm our cover sory. Subjecs had been old ha hey would be evaluaing program conen only; by showing hem he firs ape and hen asking hem for program evaluaions, he cover appeared o be confirmed. The acciimaion/disracor videoape consised of wo, five-minue segmens of feaure sories, spors, and commercials. Simulus The simulus was a 27.5-minue videoape. The simulus ape consised of nine commercials (4.5 minues in oal), wo minues of TV black, and 21 minues of programming. The programming included approximaely seven minues each of comedic, violen, and sexual scenes from wo elevision shows and wo movies. The simulus videoape began and ended wih one minue of TV black. The sevenminue violen segmen was an edied version of "The A Team," he comedic porion was from an episode of "Happy Days," and he sexual scenes were excerps from he movies Peer Proud and Shampoo. The program segmens were separaed by hree pods of hree commercials each. The es commercials were seieced from a group of 200, 30-second color producions. Each adverised

6 190 THE JOURL OF CONSUMER RESEARCH produc was inuiively judged o be low involvemen; none ofhe brands were markeed in he es area. The commercials were chosen by having suden subjecs (no he EEG subjecs previously described) rank subses of he 200 on a scale ranging from 0 (purely emoional) o 50 (a mixure of emoional and raional) o 100 (purely raional); commercials wih means neares o eiher 0, 50, or ioo, and wih he leas variance were chosen as he simulus se. Nine commercials were used; hree were raional (referred o as RATl, RAT2, and RAT3), hree emoional (EMOTl, EM0T2, and EMOT3) and hree balanced (MIXl, M1X2, and MIX3). One commercial from each caegory had been used in he firs sudy. This overlap allowed for reliabiliy esing. Three videoapes were consruced o balance he order of programming and he order of commercials wihin and beween he commercial pods. Muliple apes permied furher reliabiliy esing. Subjecs were assigned randomly o one ofhe hree apes. Apparaus EEG daa were colleced during he viewing ofhe simulus videoape, alhough elecrodes were in place for he disracor and simulus apes. Elecronic pulses placed on an unused audio rack riggered he EEG recording device so ha daa were colleced a regular inervals and so ha reference marks would appear on he recordings. The EEG daa were recorded from occipial locaions (01, 02, according o he Inernaional Sysem locaions). 01 was referenced o A2 (a neural locaion on he righ earlobe), and 02 was referenced o Al (a neural locaion on he lef eariobe). The EEG was recorded wih silver-cup elecrodes (Grass E5SH). Amplifiers (Hewle-Packard 881 la) were se a a gain of 20,000, wih a bandpass of 1,5 Hz- 100 Hz. Filer slopes were 6 d/ocave. The amplified daa were furher lowpassed a 50 Hz by filers (Krohn-Hie 3342R) wih a 48 d/ocave slope. All amplifiers were calibraed each morning before esing began. Daa collecion ook place during a hree-week period. Afer he firs week, he inpus o he amplifiers were swiched, hereby avoiding amplifier bias. AnipUfied and filered daa were led o an analogo-digial converer (Nicole MED-80) where hey were sampled every milliseconds. The daa were aggregaed every half-second and ransformed by Fourier specra! analysis across he alpha frequency band (8 Hz o 13 Hz) o show power unis for each period. Memory Response Variables Alhough his aricle deals primarily wih he relaion beween he simulus and he EEG, he mehod also inciuded a es designed o replicae he linkage beween EEG and memory found in Rohschild e al. (1986). In his es, respondens were given recall and recogniion ess afer a half-hour delay. The recall es asked subjecs o lis he produc caegory, brand name, and claims for as many of he nine commercials as possible. Afer compleing he recall quesionnaire, subjecs received a four-disracor recogniion quesionnaire ha lised produc, brand, and claim choices on consecuive pages for each of he nine commercials. Subjecs were asked no o reurn o a page afer compleing i and were moniored for compliance. The es order of he commercials in he quesionnaire was randomized across subjecs. Daa Transformaions The EEG daa were Fourier ransformed (Thompson and Paerson 1974) separaely for he lef and righ occipial locaions in he alpha frequency range for each half-second. These daa were hen sandardized o a mean of zero and variance of one (Z ransformaion; see Ehriichman and Wiener 1980) using a mean calculaed across all program and commercial daa wihin each individual. The normalizaion was necessary because ofhe variance in EEG ha occurs across individuals, and because he daa were bounded a he lower end by a zero levei of EEG. The raw daa, herefore, were unduly influenced by subjecs wih high variance or high means. Finally, he median for each half-second of normalized daa across all subjecs was calculaed. The median was seleced as he bes measure of aggregaion because of he occasional high EEG values (over en sandard deviaions above he mean) caused by muscle or eye blink arifac and he skew caused by a Iower boundary. The following daa, hen, consis of medians compued across subjecs for each half-second afer normalizaion wihin each subjec. Consrucion ofhe Time Series Independen and dependen variable series were consruced for each commerciai. Nine differen independen simulus variables were idenified wihin he commercials; a ime series was creaed for each commercial based on he half-second during which each simulus firs appeared. In hese series, dummy variable values for each variable were placed in he firs half-second of each appearance of eacb variable. The Appendix liss he nine variables and heir codes. These variables were seleced so ha he hypoheses could be esed and were influenced by earlier daa analysis on he prior daa se (Reeves e al. 1985); in rerospec, he variables also were similar o hose seleced by Alwi (1985) and Thorson, Papas Heide, and Page (1988). Ulimaely, he variables used in his sudy were seleced arbirarily o represen a

7 EEG AS A RESPONSE TO TV COMMERCIALS number of simulus condiions ha could influence EEG. Clearly, many oher such variables could be consruced, and, indeed, should be consruced in fuure work. The variables in his sudy were seleced o represen he four racks of a elevision commercial. These were verbal video (VERVIS, PKG), verbal audio (VERAUD), nonverbal audio (NONVER), and nonverbal video. Nonverbal video was represened by person movemen (ODY, HEAD, and STARE) and camera movemen / producion (EDIT and ZOOMS). VERAUD, VERVIS, and PKG were verbal simuli; he oher six variables were nonverbal. VER- AUD and NONVER were audiory; he oher seven were visual. Of he visual simuli, ODY, HEAD, and STARE deal wih he movemen ofhe acors, EDIT and ZOOM deal wih camera and echnical changes, and VERVIS and PKG represened verbally-oriened visual simuli. In Reeves e al. (1985), he independen variables were MOVE- MENT (a composie of ODY, HEAD, and STARE) and EDIT (a composie of EDIT and ZOOM); auocorrelaion was also considered. Dependen variable ime series also were consruced for each commercial. These consised ofhe values of {R ~ L)/iR + L) for each half-second, where R and L were he value of EEG for ha halfsecond in he righ and Jef occipial locaion. This series was used o examine relaive EEG changes across he hemispheres. Each series consised of 60 half-second periods for each commercial RESULTS As saed earlier, wo specific goals were addressed in his sudy: (1) examinaion of hemispheric differences and lagged effecs in response o elevision commercial simuli; and (2) examinaion ofhe consisency of he EEG daa wihin his sudy, across he wo sudies, and in relaion o he basic EEG lieraure. This secion considers he daa for each of hese goals and hen examines he six hypoheses. Hemispheric Laeraliy Each 30-second commercial was analyzed as a ime series of 60 half-second periods where he dependen variable was (R ~ L)/(R + L), The daa, herefore, refleced he shif in hemispheric dominance over ime as a funcion ofhe nine independen simulus variables. As a conservaive analysis sance, he regression models were consruced o include all nine simulus variables raher han o include only significan variables. The effec of his decision was o lower he adjused i?^, bu o presen daa analysis ha sricly conformed o he a priori model of commercial impac on EEG. In his way, he nine-variable model shows he impac of each variable in compeiion wih each ofhe oher eigh variables. Noe also ha some cells of Table 1 show (insufficien observaions). The occurrence of indicaes eiher ha a paricular simulus variable did no occur in a paricular commercial or ha a paricular simulus variable suffered from an exreme level of mulicollineariy wih some oher independen variable. Auocorrelaion variables were inroduced when ime series residuals were significan in esimaing regression models wihou hem. Table 1 shows he dominance regression models for each of he nine commercials. For example, he regression model for hemispheric dominance in commercial RAT 1 shows ha he model explained 36 percen ofhe variance in EEG (adjused R^ = 0.23). The model was significan (F = 2.68; p < 0.05). All simulus variables were enered ino he equaion; significan conribuions came from he verbal audio rack (VERAUD) wih a wo half-second lag ( = 0.095; / = 2.01; p < 0.05). zooms and pans (ZOOM) wih a five half-second lag { = ; / = -2.36; ;?< 0,05) and he appearance of he package (PKG) wih no lag { = 0.152; = 1.83; p < 0.1). VERAUD showed significan posiive, indicaing lef hemisphere dominance; ZOOM showed a significan negaive, indicaing righ hemispheric dominance. Eigh of hese models explained significan amouns of variance in EEG; only one had a marginally significan {p <0.l) auocorrelaion componen. The Durbin-Wason saisic generally was in he accepable range. The conribuion of he hree verbally-oriened variables (VERAUD, VERVIS, and PKG) was in he expeced direcion, showing lefi-hemisphere dominance in 23 of 26 cells; in all nine cells where his conribuion was significan, i was o lef-hemisphere dominance. The conribuion of he six nonverbal variables also was in he expeced direcion, bu in his case was o righ-hemisphere dominance in 44 of 48 cells; in al! 17 cells where his conribuion was significan, i was o righ-hemisphere dominance. The conribuion was in he heoreically expeced direcion in 67 ofhe 74 cells of Table 1 where a value could be calculaed. The median value of he remaining seven cells was The regression models of he emoional and raional commercials did no differ in erms of he mix of verbal and nonverbal independen variables. Individuai simulus variables did no make consisen conribuions across he commerciai regression models. This was o be expeced because each commercial was unique and employed a unique combinaion of simulus variables. ZOOM was he mos consisen simulus variable; i made a significan conri-

8 192 THE JOURL OF CONSUMER RESEARCH TALE 1 DOMINCE REGRESSION MODELS Commercial ype Verbaud Verbvis Pkg ody Head Sare Nonverb Edi Zcxjm R^ (Adj. F RAT1 RAT2 RAT3 MIXl MIX2 M1X3 EMOTl EM0T2 EMOT3 i ' ^095 (2,01") V06Q (1.64') \076 (1^19) ^071 (1.99") *.O48 {1.05) *.O56 ( 94) =.021 ( 51) *.139 (1,68') - -,007 (- 12) '.102 (1,47) \001 (.02) ^.066 (1-01) ^.086 (1.10) ^.080 {.44) *.O75 (1.66') => (-.28) '.016 (-16) M52 (1.83') (2,86=) ^-.018 (-.20) *.115 (1.76-) ^078 {1.78') =.011 (-07) ^.069 (92) ^322 (1.16) ^.035 ( 29) ^001 {.03) (-1.53) *~.123 (-2-17") ' (-1.97") (-.62) ' (-.60) = {-2.19^) '-.045 (--65) "-.191 (-1.85') = {-.47) Voii ( 28) -.i95 (-2.41") ' (-88) ' -040 (- 52) ^-,290 (-3,24=) '-.069 (-.58) * {-1,69') (-1,47) ^-.170 (-2,38") ' (-.10) = (-3 31=) ^-.059 (-.37) ''-.183 (-,86) ''-,111 (-1.41) (-.50) ^.144 (.84) ''-.065 (-1.17) ^-.159 (-1.12) ' (-.65) ^-,103 {-.73) ^ ,78') * (-1,83') ' (-.45) ^ {-.75) ' (- 63) ^ {-1,88') V003 (07) "-.010 (- 14) * {- 65} ^-,119 (-1.29) = -,215 (-2,36") ''-,159 (-1.75') = (-1.10) (-.68) ' (-2.64") ^-.557 (-2,54'') ^-.150 (-1.69').359 ( 23).312 ( 21).314 ( 16).463 (-35).226 ( 11),107 (- 07).416 ( 31).321 ( 18).267 (.13) 2,681^ 2,985" 2.087^ 4,216'' 1.943", '^ 2.310" 1 956* 'p<0.10 "p < ^p < NOTE: = insufficien observaions. Lag effecs are shown as superscrips o he lef of values. Posiive S values indicae lef hemisphere dominance; negaive values indicae righ hemisphere dominance. buion o five ofhe models and hree oher simulus variables conribued o four models. Lagged Effecs ofhe Independen Variables The daa showed lags beween he onse ofhe simulus variable and he observable hemispheric change in EEG. Across he dominance models, he average lag was 2,36 half-second periods (or 1.18 seconds). In looking a he lags beween he significan simuli and EEG responses (regardless of model ype), EEG lagged he verbal simuli by a greaer amoun han i lagged nonverbal simuli (2.99 versus 2.27 periods; = 3.04; df = 213; p < 0.01), and lagged in he lef hemisphere more han in he righ (2.72 versus 2.40 periods; / = 1.34; p < 0.1). Across ail significan simuli and all models, he average lag was 2.57 periods (or 1.28 seconds). Correlaions Across Hemispheres Alhough a subsanial body of lieraure shows laeralized specializaion of occipial alpha, daa also show ha he hemispheres covary, ha is, normal subjecs' hemispheres work ogeher rauch more han hey compee. Correlaion of he ime-series daa across hemispheres ranged from 0.48 o 0.79 across he nine commercials; he average correlaion was Consisen wih he EEG lieraure, his level of correlaion showed some level of independence beween hemispheres ye also showed a srong level of covariance. The cross-hemispheric correlaions also showed differences by commercial ype. The raional commercials implied greaes bilaeral processing (r = 0.70) followed by he mixed commercials (r = 0.62); he emoional commercials had he lowes correlaion across he hemispheres (r = 0.54), This difference in level of bilaeral processing beween he raional and emoional commercials was significan { = 2.59;df= 16;/7<0.0l). Relaing he Daa o he Firs Five The daa now are reviewed in ligh ofhe hypoheses. The firs hypohesis deal wih he general inroducory issue, ha a significan amoun of variance in he EEG daa can be explained as a funcion ofhe changing commercial simuli,!n six ofhe nine commercial models, he i?^ was significan a p <0.05. Hypohesis 2 hrough Hypohesis 5 deal wih specific issues of informaion processing. All significan

9 EEG AS A RESPONSE TO TV COMMERCIALS 193 conribuions o dominan processing of verbal simuli in he lef hemisphere and nonverbal simuli in he righ hemisphere were in he hypohesized direcion for Hypohesis 2. The verbal simuli conribued o he lef dominance in all nine cases where he conribuion was significan; he nonverbal variables conribued o righ dominance in all 17 cells showing significance. The daa did no suppor Hypohesis 3, ha here would be evidence of sronger processing in he righ hemisphere for emoional commercials and in he lef hemisphere for raional commercials. The daa did suppor Hypohesis 4: he average lag beween he onse of he simulus and he change in EEG was 2.57 periods (1.28 seconds); here also was a greaer lag afer a verbal han a nonverbal simulus ip < 0.01) and a marginally greaer lag in he lef hemisphere han in he righ {p < 0.01). The fifh hypohesis ies he earlier findings ogeher wih curren hemispheric laeraliy views ha elevision commercial simuli are processed in a bilaeral fashion wih significan dominance endencies exhibied. Firs, he average across-hemisphere correlaion over all nine commercials was 0.62 {p < 0.001); here was greaer correlaion beween he hemispheres during raional commercials (0.70) han emoional commercials (0.54; p < 0.01). Second, as seen in he es of Hypohesis 2 in Table 1, here were also clear paerns of dominance of one hemisphere over he oher ha suppor one or more ofhe bilaeral models o he exclusion ofhe unilaeral model Consisency ofhe EEG Daa The findings presened in he previous secion provide suppor for four ofhe firs five hypoheses, bu are hey reliable? Consisency can be shown beween subses ofhis daa se (reliabiliy), in comparison wih prior daa colleced using he same mehod (replicabiiiy), and in comparison wih earlier EEG lieraure (face validiy). The firs wo of hese issues are deal wih here; he hird is considered in he discussion. In addiion, reliabiliy ess could be considered for he relaion beween he simulus and EEG, and beween EEG and memory. Each of hese will be considered. Reliabiliy of Correlaions Across Subsampies. Consisen wih he EEG lieraure, here were no significan beween-subjec correlaions. However, because here were hree videoapes, a convenien reliabiliy es could assess he correlaion ofhe aggregae ime series across he hree apes. Given he insabiliy of EEG, a low-level of reliabiliy would be expeced; in addiion, because he commercial conex also differed for he viewers of each ofhe hree videoapes, one would expec even lower correlaions. Murry (1987) has shown conexual effecs on memory and persuasion, and Thorson and Reeves (1986) have shown ha program conex influences laer recall. Given hese and oher recen findings ha show a srong conex effec, one would expec he reliabiliy es o yield quie low correlaions beween he spli hird samples. In considering all pairs of comparisons across he hree apes (A-; A-C; -C), he wo hemispheres, and he nine commercials, here were 54 correlaions. More han 75 percen of hese pairs had a significan relaion(/7 < 0.05). This showed ha EEG did vary reliably across subjecs in response o elevision commercial simuli. ecause ofhe poenial for significan conex effecs on EEG paerns, he acual significan correlaions are even more meaningful Replicaions of Earlier Findings. A second form of reliabiliy can be found in he replicaions beween his sudy and he firs sudy, which used a similar mehod. For example, his sudy showed correlaions across hemispheres of 0.62; he firs sudy yielded a correlaion of 0.68 for he same examinaion. The regression models also were similar beween he firs and second sudies. Alhough here were more complexiies in he models in his sudy (nine independen variables versus wo; hemispheric dominance versus aggregaed power across hemispheres), here were similariies. Theoverall/J's were higher in he firs sudy (Reeves e al 1985) probably because of greaer auocorrelaion in he aggregaed power daa; he incremen in R' due lo he simulus variables was greaer in his sudy. These changes may be due. a leas in par, o he inpu of more simulus variables in he second sudy and lo he laeralizaion, raher han power, analysis. The variables ofhe firs sudy were included here as ODY and HEAD and as EDIT and ZOOM; hese variables were similar in impac in boh sudies. The average lag across all variables was 2.57 halfseconds in his sudy versus 2.20 in he firs sudy. This difference of 185 milliseconds was oo large o imply consisen findings across sudies {p < 0.1). Comparing similar variables across he sudies showed lags of 2.35 and 2.20 half-seconds in he wo ses of regression models. When comparing only similar variables, he lags were consisen (ns). The amoun of lag also was similar o ha found by Alwi (1985) in her aggregae power daa. Her daa were colleced in wo-second incremens and she found ha for 14 of 17 variables, he bes relaions were eiher in he curren or firs lagged periods. In anoher replicaion, he ime series of hree commercials ha appeared in boh sudies were examined. The correlaions ofhe wo 60-poin ime series plos for each ofhe hree commercials were 0.33 {p < 0.01) (p < 0.001)and 0.29 (p < 0.02), respecively. Again, his provides srong evidence for reliabiliy because i occurred despie he inheren unre-

10 194 THE JOURL OF CONSUMER RESEARCH liabiliy of EEG and he fac ha he program and oher commercial conexs were differen in he wo sudies. The final replicaion considered he relaion beween aggregae mean EEG and aggregae memory. In Rohschild e al (1986), here were significan relaions beween EEG and boh recall and recogniion across he nine commercials. Neiher of hese relaions was found o be significan in he replicaion alhough boh showed consisen direcional endencies. The ess of memory in he wo sudies were idenical. Relaing he Reliabiliy Daa o Hypohesis 6 We hypohesized ha paerns in EEG are consisen. Resuls show ha significan similariy exised among he variables ha conribue o he dominance models (p < 0.05). They also show ha significan correlaions of ime series daa were found across hree subsamples of subjecs (78 percen of 54 pairs of correlaions are significan; p < 0.05). Across sudies, he across-hemisphere correlaions were sable (0-68 versus 0.62), and he average lag of similar variables was consisen (2.35 periods versus 2.20 periods). The correlaions ofhe ime series plos of he hree commercials ha appeared in boh sudies were significan (p <O.Ol;p < 0.001; p < 0.02). Alhough he simulus-eeg relaion showed many consisen paerns, he EEG-memory relaion was no replicaed. DISCUSSION There are few EEG sudies ha have considered simuli such as elevision commercials; hose ha have generally have aggregaed daa over long periods of ime (from 30 seconds up o several minues). We know of no EEG sudies ha have aken as deailed a view of such a complex simulus; he closes has been Alwi's analysis (1985), which used a wo-second uni of ime. Given he complexiy of elevision as a simulus, his sudy is more han a mere ransference of mehod or echnology from anoher field o consumer behavior. A Summary of Findings Across he Two Sudies Table 2 summarizes he issues sudied, he relevan findings in he EEG lieraure, and he findings in he wo repored sudies. Despie he simulus complexiy, he daa were quie consisen wih prior EEG work, showed inernal reliabiliy, and were replicable. This sabiliy occurred for overall occipial alpha power as well as for he righ versus lef hemispheres wihin he occipial region. The wo sudies hus far have been concerned wih examining EEG ha occurs during he viewing of elevision commercials, ha is, during he following simulus-response relaion: S (ADVERTISING) -* R (MEMORY). To ha end, he sudies have examined he inermediae linkages of: S (ADVERTISING) -* R (AROUSAL MEASURED VIA EEG) and R (AROUSAL) -*R(MEMORY). STIMULUS -* EEG. oh sudies have shown a clear relaion beween elevision simuli and changes in occipial alpha. EEG responded rapidly (during a period ofa half-second), wihin 1.5 seconds from he onse of an easily idenifiable change in he elevision commercial Afer EEG dropped, i slowly recovered for a period of up o 15 seconds, alhough he ime beween sharp drops seemed o average abou five o six seconds, and was a funcion ofhe individual commercial srucure (Rohschild e al 1986). In addiion, each commercial influenced EEG in a unique manner, again based on is own producion syle. This can be seen in aggregae elecrical power across hemispheres (Reeves e al 1985) and in hemisphere dominance (his sudy). Processing also was influenced by he commercial: verbal componens were more likely o be processed in he lef hemisphere; nonverbal componens were more likely o be processed in he righ hemisphere. Alhough here has been speculaion abou he differen processing characerisics ofhe wo hemispheres, he daa were mos consisen wih basic EEG findings ha have shown weak bu predicable hemispheric differences. The presen sudy showed ha he lef hemisphere was more responsive o verbal variables and he righ was more responsive o nonverbal variables. These endencies were quie suble and have no been repored previously in response o elevision simuli. The daa are consisen wih bilaeral models, such as ha proposed by Janiszewski (1987), where boh hemispheres work ogeher bu show some specializaion. The pop psychology view of unilaeral processes has no been suppored by he work presened in his aricle. EEG MEMORY. The replicaions of he STIMULUS -* EEG linkage generally were successful, and he comparisons ofhe aggregae power analysis and he hemispheric laeralizaion analysis showed similar resuls. The replicaion ofhe EEG - MEMORY linkage was no successful However, he failure o replicae he EEG -» MEMORY linkage found in Rohschild e al. (1986) is a replicaion ofa wider se of sudies dealing wih EEG as a mechanism for assessing memory response o adverising. This linkage has been nooriously unreliable as discussed in he lieraure review earlier in his aricle. Jus as we were no able o replicae his linkage, Weinsein, Appel, and Weinsein (Appel e al 1979; Weinsein e al. 1980) also found a iinkage in one

11 EEG AS A RESPONSE TO TV COMMERCIALS 195 TALE 2 SUMMARY OF KEY FINDINGS IN CURRENT STREAM OF RESEARCH Issue asic EEG lieraure Sudy 1 (repored in Rohschild e al and Reeves eal. 1985) Sudy 2 (sudy repored in his aricle) R^aion of alpha power o arousal Relaion of aipha o cogniive ess Relaion of alpha o simulus changes Hemispheric laeralizaion Changes in alpha due o raional/emoionai messages Auocorrelaion in EEG Lags beween simulus onse and drop in alpha Reiiabiiiy Alpha drop indicaes arouse Negaive correlaion beween alpha and recall/recogniion for brief simuli Changes in alpha can be explained due o changes in simulus Righ hemisphere more responsive o visual/ music/absrac cues Lef hemisphere more responsive o verbal/ concree cues ilaeral processing across hemispheres No daa No daa No daa Reliabiliy of EEG is robus in response o simple simuli Same finding Same finding Same finding (power as dependen variawe) No daa No daa No daa No daa Afer responding o a simulus, here is a period during which aenuaon occurs (power as dependen variable) 1100 milfisecond delay {power as dependen vanable) No daa No esed No repjiicaed a p<0.1 Same firming (dominance as dependen variable) Same firvding as basic lieraure Same firxjing as basic lieraure Same finding as basic lieraure No significan findings No significan findings (doitiinance as deperkjen variable) 280m(H(second delay (dominance as dependen vanable) Reiiabiiiy o EEG is robus in response o complex simuli Sudy bu no in he oher. Oher researchers have found weak or no relaions beween hese variables (Rus eal 1985; Rockey e al 1980). Perhaps he difference in he success rae of replicabiiiy beween he wo linkages is a funcion of wheher he linkage considers wha precedes or follows he observaion of EEG. We feel ha here is a beer explanaion. The daa repored in his sudy ha examined STIMULUS -* EEG used half-second incremens of ime as he uni of measuremen, and capured he imporance of EEG in describing micro informaion processing. However, he EEG -^ MEM- ORY linkage was examined across an aggregaion of hiry seconds of EEG and across memory responses o he enire commercial To clearly observe he relaion beween EEG and memor>', i may be necessary o consider shor ime periods of EEG and memory ess for componen pars ofhe overall commercial simulus. There is a less heoreical reason o believe he aggregae EEG should correlae wih aggregae memory han ha shor periods of EG should correlae wih memory ess of appropriae message componens. ecause each componen generaes is own variance, i is naural ha pooling hese variances would lead o less clear resuls. U is his issue ha we feel is mos likely o have led o a lack of replicabiiiy in he EEG - MEMORY linkage. Mehod Differences eween This Sudy and Oher Research Concerning EEG and Adverising Adverisers have become ineresed in considering EEG measures as a se of responses o commercial

12 196 THE JOURL OF CONSUMER RESEARCH Simuli. This ineres has been piqued by a psychophysiology lieraure ha indicaes a srong relaion beween cerain ypes of simuli and cerain ypes of EEG responses. However, hese EEG findings will only ransfer wih difficuly o he relaion beween commercial adverising simuli and learning response measures. As noed in he psychophysiology lieraure, effecs become more difficul o observe as simui become more complex. This complexiy has been overlooked in many of he earlier adverising-relaed sudies and may have been a major conribuor o a lack of posiive findings. In he curren work, he cleares findings have emerged when he complex simulus was broken down ino simpler pars; using he complex simulus in is enirey has been more likely o resul in insignifican findings. Anoher advanage ofhe half-second ime incremen appears in sudying lag effecs. As noed, longer ime periods smooh over paerns in he daa; he Alwi (1985) daa discussed previously show ha longer periods also miss lagged effecs. Alwi, using a similar mehod o ours, aggregaed all daa o he neares wo seconds and was unable o observe as many differences in lags; in her analysis, nine of 17 cases were lagged zero periods and anoher five were lagged one period (wo seconds). In addiion o he problems of analyzing complex simuli, here are oher complexiies ha need o be avoided. These include concern for a homogenous sample of respondens ha conrols for gender, handedness and age, and concern for homogeneiy in he simuli ha conrols for involvedness ofhe producs and prior exposure ;o he messages, in Rohschild e al. (1986), we discussed hese issues in more deph and recommended showing previously unseen commercials for low involvemen producs lo righhanded women beween he ages of 20 and 50. Alhough hese consrains are desirable for reducing variance, hey limi he generalizabiliy of resuls and exernal validiy. y being concerned wih homogeneiy of subjecs and simuli, by creaing an experimenal siuaion ha minimizes unnecessary variance, by considering lag effecs, and by ransforming daa o conrol for individual variance, analysis of he wo daa ses colleced o dae have been able o show ha relaions exis beween adverising simuli and EEG responses. Furhermore, he sudies have shown ha hese relaions, which previously had been shown o exis for simpler simuli^ also exis for complex simuli. Implicaions for Informaion Processing Theory and Research The word "processing" implies somehing ha is dynamic, proceeding, marked by change. Alhough he field of informaion processing examines changes ha occur over long periods of ime or over he repeiion of messages, here is very lile work ha considers his process wihin he scope ofa 30-second commercial. People coninually process, bu researchers evaluae in erms of large discree ime periods. Evaluaing in he same coninuous manner in which people process may provide more informaion. Indeed, he daa repored in his sudy indicae ha here is a dynamic process occurring over shor periods of ime, which can be seen in he lagged effecs and auocorrelaions ha differ across simuli and across hemispheres. Perhaps messages need o be consruced wih an eye o wha precedes and follows each simulus componen. Will informaion be processed more effecively if key ideas follow componens, such as edis, by a cerain period of ime? Should a verbal idea follow a verbal or nonverbal componen? These quesions need o be pursued. A rend exiss among adverisers oward more visual and emoional messages, ye much ofhe informaion processing lieraure is based on verbal and raional messages. This sudy has shown differences in processing for differen message componens. A leas hree ypes of variance can be considered in assessing message impac; hese ypes of variance are due o he medium, he overall message, and he message componens. Pas informaion processing work has considered primarily he firs wo; his sream of research has examined he las wo. Fuure Research In sudies o dae, he examinaion of EEG was an end uno iself; i was necessary o learn how EEG would respond o complex simuli before researchers could use i as a reliable ool. This ask has progressed grealy, and EEG now becomes a means o pursue a differen end. Fuure work needs o sudy micro levels of informaion processing. For exampie, EEG can be used o examine order effecs on informaion processing. Will memory or persuasion be enhanced if key message poins are preceded by elemens ha enhance learning? Can an experimenal design paradigm be used o observe a commercial consruced wih several differen orderings? In a more macro environmen, he issue of conex effecs has become imporan in informaion processing research; similarly, scene by scene conex effecs may prove o be equally imporan. Anoher imporan area of informaion processing is ha of cogniive versus affecive processing. EEG can conribue in his area as well. y examining alpha a he fronal and parieal lobes, one may be able o learn wha ype ofprocessing is occurring a any insan during he message. (I is fel ha fronal alpha shows affec [ Davidson 1984 ], and parieal aciviy bes indicaes higher level cogniive processing [Moscovich 1979].)

13 EEG AS A RESPONSE TO TV COMMERCIALS A hird issue o be sudied migh consider he quesion of cenral versus peripheral processing (Pey and Cacioppo 1986). If^ cenral processing is higher order and peripheral is a response o basic changes in simuli, hen parieal versus occipial differences migh be insighful as EEG measures of hese respecive levels ofprocessing. Finally, a weak link in he STIMULUS -> AROUSAL--MEMORY/PERSUASION relaion is he one hai ies EEG o self-repored measures of learning and affec. To improve his work, he selfrepor measures will need o es wha has happened a he scene or epoch level ofhe message. Lile research has been done in his area, alhough Young and Robinson (1987) and Thorson e al. (1988) have made ineresing moves in his direcion. Wheher EEG is a viable research ool for consumer researchers is no longer a legiimae debae. The nex sep is o se a research agenda o use his ool in he sudy of informaion processing a a micro level. In his way, we will give a richer meaning o he word process. APPENDIX Lis of Independen Simulus Variables VERAUD: verbal audio any words on he audio rack VERVIS: verbal visual any superimposed words on he visual rack PKG: appearance ofhe words on he produc or package ODY: any below-he-neck movemen of a person HEAD: any above-he-neck movemen of a person STARE: saring a he camera by he spokesperson NONVER: nonverbal audio any oher sound on he audio rack EDIT: edis, scene changes, dissolves ZOOMS: zooms, pans [Received July Revised April 1988.] REFERENCES Allen, Max (1983), "Models of Hemispheric Specializa-- ion," Psychological ullein, 93 (1), Alwi, Linda F. (1985), "EEG Aciviy Reflecs he Conen of Commercials," in Psychological Processes and Adreriising Effecs, eds. Linda F. Alwi and Andrew A. Michell, New York: Lawrence Erlbaum Associaes, Andreassi, John L. (1980), Psychophysiology. New York'. Oxford Universiy Press. Appel, Valenine, Sidney Weinsiein, and Cur Weinsiein (1979), "rain Aciviy and Recall of TV Adverising," Journal ofadverising Research, 19 (4) , Dawn and Kenneh Heilman (1980), "Maerial- Specific Hemispheric Acivaion," Neuropsychologia, 18 (3), Corbaiiis. Michael C. (1980). "Laeraliy and Myh," American Psychologis. 35 (3), Davidson, Richard J. (1984). "Affec, Cogniion and Hemispheric Specializaion," in Emoions. Cogniions and ehavior, eds. Carroll E. Izard e al.. New York: Cambridge Universiy Press, (1986), Personal communicaions. Donchin, Emanue!, Mara Kuas, and Gregory McCanhy (1977), "Elecrocorical Indices of Hemispheric Uilizaion," in Laeralizaiion in he Nervous Sysem, eds. Seven Harnard e al.. New York; Academic Press, Doyle, Joseph C, Rober Ornsein, and David Galin (3974). "Laeral Specializaion of Cogniive Mode: IL EEG Frequency Analysis," Psychophysiology. U (5), Ehriichman, Howard and Marjorie Weiner (1980), "EEG Asymmery During Cover Menal Aciviy," Psychophysiology. 17 (May), Galin, David (1979), "EEG Sudies of Laeralizaion a Verbal Processes," in The Neurological ases of Language Disorders in Children: Mehods and Direcions for Research, eds. Chrisy L. Ludlow and Mar>' Ellen Doran-Quine, ehesda. MD: Naional Insiue of Healh and Rober Ornsein (1972). "Laeral Specializaion of Cogniive Mode: An EEG Sudy," Psychophysiology. 9(4), 412-4iS., Rober Ornsein, Jeannine Herron, and Jack Johnsone (1982). "Sex and Handedness Differences in EEG Measures of Hemispheric Specializaion," rain and Language. I6(May), Gasser, Theo, Pera acher, and Joachim Mocks (1982), "Transformaions Towards he Normal Disribuion ofroad and Specra] Parameers of he EEG," /ecroencephalography and Clinical Neurophysiology, 53 (January-), Gevins, Alan S., G.M. Zeilin, Charles D. Yingling, Joseph C. Doyle, M.F. Dedon, Rober E. Schaffer. J.T. Roumasse, and Charles L. Yeager (1979). "EEG Paerns During "Cogniive* Tasks. I. Mehodology and Analysis of Complex ehaviors," Elecroencephalography and ClinicalNeurophysiology. 47 (May), Greenfield, Norman S. and Richard A. Sernbach (1972), Handbook of Psychophysiology. New York: Hol, Rinehar & Winson. Hansen, Flemming (1981), "Hemispheric Laeralizaion: Implicaions for Undersanding Consumer ehavior," Journal of Consumer Research. 8(1), Janiszewski, Chrisopher (1987), Implicaions of Hemispheric Organizaion and Processing on Placing and Developing Prim Adveriisemens, unpublished docoral disseraion. Deparmen of Markeing, Norhwesern Universiy, Evanson, IL Kinsbourne, Marcel (1982), "Hemispheric Specializaion and he Growh of Human Undersanding," ylmen'can Psychologis. 37 (4), Madden, David J. and Rober D= Nebes (1980). "Hemispheric Differences in Memory Search/' Neuropsvcho- 18(6)

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