changes used to indicate the aversiveness of

Transcription

1 JOURNL OF THE EXPERIMENTL NLYSIS OF BEHVIOR SUPPRESSION OF BEHVIOR BY TIMEOUT PUNISHMENT WHEN SUPPRESSION RESULTS IN LOSS OF POSITIVE REINFORCEMENT' RNOLD KUFMN ND LN BRON UNIVERSITY OF WISCONSIN-MILWUKEE 1968, 11, NUMBER 5 (SEPTEMBER) This investigtion, using rts s subjects nd punishment by timeout for responses mintined on rtio schedule, sought to determine whether behvior would be suppressed by timeout punishment when such suppression lso reduced reinforcement density or frequency. series of experiments indicted tht timeout punishment suppressed responding, with the degree of suppression incresing s function of the durtion of the timeout period. Suppressive effects were found to decrese s function of increses in deprivtion (body weight) nd were eliminted when the punished response lso ws reinforced. It ws concluded tht timeout cn produce versive effects even when loss of reinforcement results. n lterntive interprettion of the findings, bsed on the effects of extinction periods nd dely of reinforcement on chined behvior, ws discussed. CONTENTS Generl Method Experiment 1. Punishment of responding by response-dependent timeout. Experiment 2. Punishment by timeouts of different durtions. Experiment 3. Timeout punishment of reinforced response. Experiment 4. Deprivtion nd timeout punishment. Generl Discussion nd Conclusions. Studies with both niml nd humn subjects hve used timeout from positive reinforcement s the versive event in conjunction with voidnce, escpe, nd punishment procedures. These studies hve indicted tht timeout hs influences on behvior similr to those observed when versive events such s electric shock re used with these procedures. Thus, Ferster (1958) nd Thoms (1965), using free-opernt voidnce procedures, trined 'This reserch ws supported by Grnt MH 843 from the Ntionl Institute of Mentl Helth nd by Grnt GB 44 from the Ntionl Science Foundtion. The uthors grtefully cknowledge the creful ssistnce of Stnley Scobie nd Brbr cqu who helped to mintin equipment nd collect dt. The dt from Exp. I were presented, in prt, t the September 1967 meetings of the mericn Psychologicl ssocition, Wshington, D.C. Reprints my be obtined from rnold Kufmn, Deprtment of Psychology, University of Wisconsin-Milwukee, Milwukee, Wisconsin chimpnzees nd pigeons to void periods of timeout from food reinforcement. Similr results were obtined with humn subjects by Ber (196) who demonstrted tht preschool children will void interruption of crtoon movie, nd by Bron nd Kufmn (1966) who observed voidnce of timeout from monetry reinforcement by young dults. Kufmn nd Bron (1966) used discriminted escpevoidnce procedure nd found tht rts could be trined to escpe periods of timeout from food reinforcement, but not to void such periods consistently. Using punishment procedures nd mentl ptients s subjects, Holz, zrin, nd yllon (1963) showed tht punishment of vrible-intervl reinforced behvior by periods of timeout from reinforcement led subjects to switch to second key producing reinforcement but not timeout. More recently, McMilln (1967) punished the VI-reinforced responding of monkeys with timeout in single key sitution nd found tht responding ws suppressed. In considering the question of whether timeout is n versive event, Leitenberg (1965) pointed out tht the bove procedures, conventionlly used to ssess the versive properties of electric shock, do not necessrily provide definitive evidence tht timeout is versive. The problem is tht the behvior chnges used to indicte the versiveness of timeout when voidnce, escpe, nd punishment procedures re used my hve the consequence of incresing the reltive density of re- 595

2 596 RNOLD KUFMN nd LN BRON inforcement. By voiding or escping periods of timeout, s ws the cse in studies by Ferster (1958), Ber (196), Thoms (1965), nd Bron nd Kufmn (1966), the subject replces periods of timeout with periods when reinforcement cn be obtined, nd, s consequence, obtins higher density of reinforcement over time, or possibly greter numbers of reinforcers thn if timeout hd occurred. Similr reltive increses in reinforcement my occur in situtions where orgnisms cn switch from the response punished by timeout to n lterntive unpunished response (Holz et l., 1963) or through rte reductions in situtions with single response key nd VI reinforcement (Holz et l., 1963; McMilln, 1967). Thus, the results of the bove nd similr studies of timeout effects my be interpreted in terms of incresed positive reinforcement, lthough, s Leitenberg pointed out, this interprettion in no wy negtes the lterntive possibility tht timeout is n versive event. The purpose of the present study ws to observe the effects of timeout under circumstnces where its behviorl influences could not result in incresed reinforcement densities or frequencies. This ws ccomplished by studying the effects of timeout punishment on response mintined by rtio schedule of reinforcement, i.e., schedule in which reinforcement density decreses with decreses in response rtes. Response suppression under these conditions could not be explined in terms of incresed reinforcement, nd would provide support for the hypothesis tht timeout from reinforcement is versive. t lest two investigtions hve been published in which rtio-reinforced behvior ws punished by timeout, thus providing the possibility of reinforcement loss if behvior ws suppressed. Ferster nd Skinner (1957, pp ) scheduled timeout following fixed-rtio reinforcements nd observed in some instnces pusing fter the timeouts, lihough ccelertion of responding lso ws noted. The effects of timeout were not investigted in sufficient detil to permit sttement to be mde bout the vribles leding to one or the other of these two consequences. Using mtching-to-smple procedures, Ferster nd ppel (1961) nd Zimmermn nd Ferster (1963) observed pusing prior to the mtching response when incorrect responses were punished by timeout durtions rnging from 2 to 1 min. Pusing nd consequent reinforcement loss did not occur when shorter timeout durtions were used. GENERL METHOD Subjects Six femle lbino rts, 9 dys old t the strt of the experiment, were obtined from the Holtzmn Co., Mdison, Wisconsin. With the exception of Exp. IV, in which body weight ws vried, subjects were mintined t 8% of the medin weight of control group of sme-ged non-deprived nimls following the method of Dvenport nd Goulet (1964). Mintennce feeding with dry food lwys followed dily trining by t lest 3 min. nimls were housed in individul cges where wter lwys ws vilble. pprtus Trining ws conducted in two stndrd lever-pressing units (Grson-Stdler, E 3125). The chmber of ech unit ws plstic except for the front wll nd grid floor, which were metl. The response lever ws centered on the front wll directly bove circulr enclosure into which.1-cc dipper could be rised. Throughout the series of experiments, fullstrength evported milk (Pet Milk Co.) ws presented in the dipper. djcent to the chmber ws speker for delivering uditory stimuli nd lmp for illumintion. Ech chmber ws enclosed within sound-ttenuting ventilted chest. Scheduling nd recording equipment were locted in n djcent room. Preliminry Trining Lever-press trining. fter two 45-min dipper-trining sessions, when the dipper operted independently of the subject's behvior, ech 2-sec opertion of the dipper ws mde dependent upon lever-press response. Fifteen dily sessions were conducted on this bsis (continuous reinforcement [CRF] schedule) during which the response ws cquired nd the rte stbilized. Ech session ws terminted fter 9 reinforcements or 45 min, whichever cme first. The stndrd procedure for strting ech session ws to plce the subject in the drk, silent chmber with the lever inopertive. With the strt of the session, the response lever becme opertive, the chmber ws illuminted, nd white noise, the SD or discrimintive stimulus correlted with rein-

3 SUPPRESSION BY TIMEOUT PUNISHMENT 597 forcement, ws continuously presented. During certin phses of the experiments, described below, 5-cps pure tone, rther thn white noise, ws used s the SD. When the session ws over, the lever ws mde inopertive, nd the chmber remined drk nd silent until the subject could be returned to its home cge. Discrimintion trining. fter lever-press trining, discrimintion trining procedure ws introduced in which every response ws reinforced (CRF) in the presence of white noise (SD) nd no responses were reinforced in the presence of 5-cps tone (S). The S periods lwys lsted for t lest 2 min nd ech response during the lst 1 sec prolonged the period for 1 more sec. This procedure ws used to fcilitte cquisition of the discrimintion nd to eliminte dventitious reinforcement of responses t the end of ech S period. The S periods were scheduled to occur irregulrly throughout the session, every 15 sec on the verge. Onset of the S periods lwys occurred s the dipper strted to retrct so tht S ws seprted by 2 sec from the lst lever press, nd ws concurrent with the subject's feeding behvior. Dily sessions were terminted fter 9 reinforcements or 2 hr, whichever cme first. totl of 2 sessions were conducted with the discrimintion trining procedure, by which time S responding ws miniml, nd SD responding ws stble from dy to dy. EXPERIMENT I: PUNISHMENT OF RESPONDING BY RESPONSE- DEPENDENT TIMEOUT Experiment I investigted the effects of mking the S period, i.e., period of timeout from positive reinforcement, dependent upon responding. Subsequently, the roles of the specific stimuli used to define the S nd SD periods were evluted by reversing the functions of the white noise nd tone s used originlly during discrimintion trining. METHOD Subjects nimls 1, 3, nd 5 were used. No punishment control. fter discrimintion trining, the procedure used during subsequent punishment trining ws introduced. Sessions were conducted with the white noise SD present throughout nd with dipper opertion scheduled in sequences of three responses. The first two responses in ech sequence (R1 nd R2) were followed by opertion of the dipper but R3 ws not. Thus, R3 ws not reinforced, nor ws it followed by timeout, s ws the cse during subsequent punishment trining. Dily sessions were continued until 9 reinforcements hd been received. Trining ws continued for 15 sessions, by which time response rtes hd stbilized. Punishment trining. The procedure ws similr to the preceding no-punishment procedure, with R1 nd R2 reinforced nd R3 not reinforced in the presence of the white noise SD. But, in ddition, timeout punishment ws now mde dependent upon R3 of ech cycle. Thus, R3 immeditely terminted the white noise SD, nd produced the 5-cps S for 2 min, during which time responses went unreinforced. s in the discrimintion trining procedure, ny responses occurring during the lst 1 sec of the timeout period prolonged the period for 1 sec. Dily sessions were terminted fter 9 reinforcements or 2 hr, whichever cme first. totl of nine sessions ws conducted on this bsis, by which time the effects of punishment trining were relibly seen in ll three nimls. Reversl of stimuli. To determine whether rections to response-dependent timeout were ssocited with the specific stimuli used to define the periods, the functions of the white noise nd tone were reversed. This ws ccomplished by retrining the subjects in the previously described CRF lever-press, discrimintion, nd no-punishment phses with the tone defining the SD periods nd the white noise the S periods. The number of retrining sessions in ech of the three phses ws 2, 15, nd 11, respectively, nd performnce ws stble when discrimintion nd no-punishment trining were terminted. Punishment trining sessions were then resumed with the third, unreinforced response now terminting the tone SD nd producing the white noise S concurrently with 2 min of timeout. Punishment trining ws continued on this bsis for 82 sessions for Subject 1 nd for 4 sessions for Subject 3 nd Subject 5. RESULTS Dt nlyzed during the no-punishment nd punishment phses were the men interre-

4 598 RNOLD KUFMN nd LN BRON sponse times (IRTs) between the three responses of ech sequence of two reinforced nd one unreinforced responses. Not included in these vlues were the 2-sec periods when the dipper operted or the timeout periods. Thus, during punishment trining the IRT between the third response of one cycle (the punished response) nd the first response of the next cycle represented the intervl between re-onset of the SD nd R1. verge dily IRTs re presented in Fig. 1 for ech of the three subjects. The first pnel shows terminl performnces during the nopunishment control phse when white noise ws the SD. It is pprent tht IRTs in ll cses were quite brief (under 5 sec), nd tht IRTs between the second, reinforced response, nd the third non-reinforced response (R2-R3) were of bout the sme durtions s the R3-R, nd R1-R2 IRTs. The second pnel of Fig. 1 shows performnces during the punishment trining phse when R3 terminted the white noise SD nd produced the timeout period. By the fourth session of punishment trining for ll three subjects, nd s erly s Session 2 for Subject 5, considerble suppression of R3 ws mnifested. When trining ws terminted fter nine sessions, the verge puse prior to R3 ws 66 sec for Subject 1, 77 sec for Subject 3, nd 95 sec for Subject 5. These vlues re to be compred with the R2-R3 IRTs during the prior, no-punishment phse when, for ll three nimls, the verge intervls were 5 sec or less. Figure 1 lso shows tht punishment trining hd little or no effect on the IRTs of the first nd second responses. The third nd fourth pnels of Fig. 1 show performnces when the discrimintive functions of the SD nd S stimuli were reversed, tht is, when the tone ws the SD nd the white noise the S. Performnces during the no-punishment phse'(pnel 3) were bout the sme s during prior no-punishment trining, lthough Subject 5's performnce ws not s efficient or s regulr s before reversl. The fourth pnel shows tht when punishment trining ws reintroduced with the reversed stimuli, suppression of the third response reppered. Suppressive effects incresed in ll three subjects over the erly punishment-trining session to level tht ws mintined with some vribility but without systemtic chnge during subsequent punishment trining sessions. Terminl R3 ltencies for Subject 3 nd Subject 5, fter 4 sessions, were bout 215 sec nd 55 sec respectively. For Subject 1, trined for 82 dys on the punishment procedure, the terminl R3 ltency ws bout 3 sec. Figure 2 presents cumultive records of performnces during the vrious phses of Exp. I. The records to the left show terminl rtes when responding ws not punished by timeout. To the right my be seen the extent of suppression with the noise SD nd the tone S (top curves) nd when the stimuli were reversed (bottom curves). The top curves for ech subject, obtined during initil exposure to timeout, illustrte instnces of the most extreme suppression observed. The bottom curves show performnces fter extended exposure to timeout punishment with the reversed stimuli. lthough somewht reduced in the cses of Subjects 1 nd 5, suppression ws stble spect of intr-session performnce for ll three subjects over n extended series of sessions (see lso Fig. 1). Figure 3 shows enlrged portions of cumultive records of Subject 1 tken during Sessions 3 nd 82 with the tone SD nd noise S. These records mke cler the rpidity of the two reinforced responses nd the long puses preceding the third, punished response. Figure 3 lso shows tht the intervening 79 sessions did not reduce the extent of response suppression. If nything, the durtion of pusing ws greter during the segment chosen from Session 82 thn for Session 3, lthough the verge puse lengths for both sessions were pproximtely equl, s my be seen by compring the points plotted in Fig. 1. DISCUSSION Response-dependent timeout punishment mrkedly suppressed behvior in ll three subjects. During the no-punishment control phse, R3, lthough not reinforced, lwys ws rpidly executed with IRTs of 5 sec or less, bout the sme durtions ssocited with R1 nd R2. By comprison, timeout punishment of R3 produced long puses prior to R3 with verge IRTs in the rnge 1 to 3 sec for the subject showing most extreme suppression, nd 25 to 4 sec in the subject whose suppression ws lest. possible bsis for suppression of responding by timeout punishment is tht the stimuli

5 SUPPRESSION BY TIMEOUT PUNISHMENT S 'I TIMEOUT PUNISHMENT SO Noise SI Tone 1 j..,4 _F. 4 NO. PUN. SD Tone TIMEOUT PUNISHMENT St Tone S Noise IRT %RI * IRT RI- IRT %J-% & 6 "164 i2 * 4 i2 F' 2 24 '16' 14' 78 O 86 os3 ol! b ^ ^ o,\ S ^, z 2 t) U * NO. PUN. Sr' Noise SS 4 12 X ML SX ~_ &.& & &&& - --I, smod"88 38o38B3 ow3ow836swo owo888 w 1 ~12 4 w T 1-w w4w wwdw wlkw wf6w w2br I w w w wgw wv& 'W 1 ww w4i.d W w w w SESSIONS Fig. 1. Dily men interresponse times (IRTs) in Exp. I. R3-R1 is the time from the third response of one cycle to the first response in the next cycle in the no-punishment procedure, nd the time from termintion of timeout to the first response in the next three-response cycle in the punishment procedure. R1-R2 is the time from the first response to the second response of the cycle, nd R,-R. is the time from the second response to the third response of the cycle. In both the punishment nd no-punishment procedures, R1 nd R& were reinforced nd R, ws not reinforced. During the punishment procedure, R, produced 2 min of timeout. Throughout the sessions depicted in the two left-hnd pnels the SD nd S stimuli were white noise nd tone respectively; during the sessions depicted in the two right-hnd pnels, the SD ws tone nd the S white noise. used to define the timeout period possessed in- socition with other versive events, cn supdependent versive properties. Severl studies press the behvior of rts nd mice when mde (Bron, 1959; Bron nd Kish, 1962) hve in- response dependent. Such n explntion dicted tht pure tones, without history of s- clerly does not pply to the present results

6 6 RNOLD KUFMN nd LN BRON No Punishment Timeout Punishment noise SD tone c S1I noise SD tone S rr- TTV = ~~~~r-l st tone SD noise S4 1 MIN. nolnsoenolise SD tone tone tone SD noises / ~II I I II WI % nol se noise SDXS5 SD tone S tone :1... ~~tone SD noise S5 Fig. 2. Cumultive records from terminl sessions of the vrious procedures of Exp. I. In the no-punishment procedure, reinforcements (not mrked on the record) followed the first two responses of ech three-response cycle. In the punishment procedure, in ddition, the third response produced timeout. During the 2-min timeout period, the response pen deflected but responses were not recorded nd the chrt drive did not operte. becuse response suppression occurred regrdless of whether responding terminted the white noise SD nd produced the pure tone S, or vice vers. The second possibility, nd the one providing the mjor rtionle for the present series of experiments, concerns whether suppression ws mintined by positive reinforcement, rther thn by ny versive properties possessed by timeout. lthough severl other studies hve shown tht behvior cn be suppressed by timeout punishment (e.g., Holz et l., 1963; McMilln, 1967), the procedures of these studies were such tht response suppression usully served to increse positive reinforcement bove levels tht otherwise would hve occurred, nd on this bsis their results do not provide conclusive evidence bout versiveness of timeout. The present results, however, cnnot be explined in terms of suppression incresing positive reinforcement. The procedure excluded this possibility since responding ws reinforced on rtio schedule nd the sessions ended fter 9 or fewer reinforcements. Not only ws response suppression ineffectul in incresing the reltive density of positive reinforcement but suppression, if sufficiently extreme, ctully resulted in loss of reinforcement. In the cse of Subject 3, for exmple, one-third of the 9 reinforcements potentilly vilble were consistently lost during punishment trining.

7 Timeout Si sess 3 I. SUPPRESSION BY TIMEOUT PUNISHMENT Punishment tone SD noise S 5 MINUTES Fig. 3. Enlrged sections of cumultive records of Subject 1 during Sessions 3 nd 82 of the second punishment procedure in Exp. I. The records begin with the sixteenth timeout in the session. The recorder operted s described for Fig. 2. The results, then, offer strong evidence for the contention tht timeout is versive, insofr s timeout punishment suppressed behvior without incresing positive reinforcement, nd often t the cost of some reinforcement. Loss of reinforcement is common outcome, of course, when responding is punished by the versive events of electric shock nd loud sound. EXPERIMENT II: PUNISHMENT BY TIMEOUTS OF DIFFERING DURTIONS Experiment II studied the durtion of timeout s vrible potentilly ffecting suppression of responding by timeout punishment. It ws hypothesized tht versiveness of timeout would be n incresing function of its durtion. METHOD Subjects nimls 2, 4, nd 6 served. 61 Procedure The initil procedures were identicl to the no-punishment nd punishment trining phses of Exp. I with white noise the SD, tone the S, nd timeout durtion of 12 sec. fter totl of 26 punishment trining sessions with the 12-sec durtion, subsequent sessions were conducted first with durtion of 1 sec, then 6 sec, nd finlly 9 sec. Trining ws continued with ech durtion until ll three nimls showed stble performnces. This required 24, 31, nd 38 sessions. RESULTS During the no-punishment phse, nd when the 12-sec timeout durtion ws studied, performnces were within the rnge of IRTs observed in Exp. I. Figure 4 summrizes the effects of the vrious timeout durtions on the verge IRT between R2 nd R3. Plotted vlues for ech subject re bsed on the lst eight dys of trining with ech timeout durtion. Figure 4 shows tht suppression of R3 generlly ws n incresing function of the durtion of timeout within the rnge from sec (no-punishment trining) to 12 sec. The only devition from this reltionship occurred with Subject 4, where somewht more suppression occurred with 6 sec thn with 9 sec. The individul curves ll show substntil increses in the rnge from to 1 sec, reltively little chnge from 1 to 6 sec, nd increses gin between 6 nd 12 sec. s in Exp. I, the IRTs preceding the first nd second response were generlly less thn 3 to 4 sec when R3 ws punished with the vrious timeout durtions. DISCUSSION Timeout durtion ws found to be significnt vrible influencing the effectiveness of timeout punishment, with degree of suppression of R3 incresing s function of incresed timeout durtion. These findings, in sitution in which simple opernt response ws punished by timeout, re similr in generl outline to the effects of punishing mtchingto-smple errors of pigeons (Ferster nd ppel, 1961; Zimmermn nd Ferster, 1963) where suppression of incorrect responses progressively incresed with increses in the dur-

8 62 RNOLD KUFMN nd LN BRON LLJ 5 _- S2 95 * * ~~~S6I c4 L c" 3 w 2 I TIMEOUT DURTION (IN SECONDS) Fig. 4. Interresponse times between the second nd third response (R2-R.) in ech cycle s function of timeout durtion in the punishment procedure of Exp. II. Plotted points represent the medin of the lst eight dys with ech durtion. Vlues for the -sec durtion were obtined from the no-punishment procedure of Exp. I. tion of timeout punishment within the rnge to 6 sec. Worth noting, however, is tht when mtching errors re suppressed by timeout, behviorl chnges serve to increse positive reinforcement. In the present study, by comprison, suppression of behvior could only hve the consequence of reducing positive reinforcement. EXPERIMENT III: TIMEOUT PUNISHMENT OF REINFORCED RESPONSE Experiment III exmined the effects of reinforcing the third, previously unreinforced, response in ech cycle of three responses. It ws expected tht strengthening of R3 by reinforcement would reduce suppressive effects ssocited with response-dependent timeout. METHOD Subjects nimls 3 nd 5, previously exposed to the procedures of Exp. I, served. Procedure fter the fortieth dy of punishment trining in Exp. I, reinforcement ws introduced for the third s well s the first two responses in ech cycle. Thus, R3 terminted the tone SD, produced the noise S, nd lso produced the dipper for the first 2 sec of the timeout period. s ws the cse for these subjects in Exp. I, the durtion of the timeout period ws 12 sec, nd responses during the lst 1 sec of the period prolonged it for n dditionl 1 sec. Fifteen sessions were conducted with R3 reinforced, followed by 26 (Subject 5) or 27 (Subject 3) sessions when R3 gin ws not reinforced. Dily sessions were terminted fter 9 reinforcements or 2 hr, whichever cme first. RESULTS Figure 5 presents men dily IRTs for Subject 3 nd Subject 5. The first pnel shows these vlues during the lst 15 dys of punishment trining in Exp. I when R3 ws not reinforced. With introduction of reinforcement for R3 (second pnel), the verge R2-R3 IRT decresed mrkedly, from 215 to 4 sec for Subject 3 nd from 55 sec to 5 sec for Subject 5. In both cses, suppressive effects of timeout were eliminted, since R2-R3 IRTs decresed R3 R3 UNREINFORCED REINFORCED 4 S3 3-2 l I '6 R3 UNREINFORCED %-I Ph- so ti~- ~ MSs ~~ 4 ll _ S U _,.~~ ~ ~5~ O *w Fig. 5. Dily men interresponse times in Exp. III. During ll sessions, R1 nd R, were reinforced nd R. produced 2 min of timeout. During Sessions 46-6, R. lso ws reinforced. Interresponse times were determined s described for Fig. 1.

9 SUPPRESSION BY TIMEOUT PUNISHMENT 63 to the levels of the no-punishment control phse, s well s to the levels chrcteristiclly obtined for the R1-R2 nd R3-R1 IRTs in the sme nd previous phses of the experiment. The third pnel of Fig. 5 shows effects of the punishment trining procedure when reinforcement gin ws withheld following R3. verge R2-R3 IRTs incresed substntilly for both subjects, nd were mintined throughout subsequent trining. There ws however, substntil residul effect of R3 reinforcement when it ws no longer provided. When terminl performnces re compred for sessions, before nd fter R3 ws reinforced (pnels 1 nd 3), it my be seen tht suppressive effects were substntilly reduced: from 215 sec to 75 sec for Subject 3 nd from 55 sec to 26 sec for Subject 5. lso noteworthy is the tendency for Subject 3's IRTs to continue to decrese during the 27 punishment trining sessions with R3 unreinforced. _- n dditionl consequence of reinforcing the punished response ws trnsitory increse in response rtes during the timeout period itself. Prior to reinforcing R3, s well s during previous experiments, timeout rtes were quite low, rrely exceeding dily verge of bout one response per timeout period. During the first session when R3 ws reinforced, rtes incresed shrply to bout five responses per period for both subjects. During subsequent sessions, rtes declined nd by Session 7 nd therefter were well within the previous rnge shown by both subjects. DISCUSSION The net effect of reinforcing R3 ws to eliminte the puses chrcterizing performnces when R3 ws not reinforced. Holz et l. (1963) suggested tht timeout is not n exceptionlly versive event, when compred with shock, for exmple. The present findings re consistent with this interprettion since suppression by timeout punishment ws not mintined with concurrent reinforcement of the punished response. Worth emphsizing, however, is tht suppression by shock punishment lso cn be mrkedly reduced, if not eliminted, by incresing the strength of the punished response through reinforcement. recent study of this question (Church nd Rymond, 1967) compred the effects of shock punishment on performnce of response mintined either by VI 5-min or VI.2-min reinforcement. In mnner similr to the present findings, punishment mrkedly suppressed behvior on the VI 5-min schedule but hd considerbly less effect on behvior mintined by the VI.2- min schedule, which provided considerbly more positive reinforcement. The present findings, together with those of previous experiments in this series, suggest the circumstnces under which timeout punishment might suppress reinforced behvior. Presumbly such effects would be mnifested when reinforcement of R3 is either weker thn ws the cse in the present experiment (e.g., with lesser mounts of reinforcement) nd/or when the versiveness of timeout is greter (e.g., with longer durtions of timeout). Reinforcement of R3, side from eliminting concurrent suppressive effects, lso reduced subsequent suppressive effects when reinforcement of R3 gin ws withheld. This finding is of some significnce since extended punishment trining with R3 unreinforced (4 previous sessions) did not systemticlly reduce the suppressive effects of punishment for either niml. EXPERIMENT IV: DEPRIVTION ND TIMEOUT PUNISHMENT The purpose of Exp. IV ws to study the effects of food deprivtion upon the suppressive effects of timeout punishment. Deprivtion ws vried by mnipulting subjects' body weights. Procedure ll six nimls served fter prticipting in Exp. I to III. The sme punishment trining procedure used in the immeditely preceding phse for ech niml ws employed in Exp. IV. Thus, in the cses of Subjects 1, 3, nd 5, the 5-cps tone continued to serve s the SD nd the white noise s the S; timeout durtion ws 12 sec. In the cses of Subjects 2, 4, nd 6, the white noise ws the SD, the tone the S, nd timeout durtion ws 9 sec. Following trining with body weights djusted to 8% of the medin weights of smeged control subjects, punishment trining ws conducted when subjects were either 7%

10 64 RNOLD KUFMN nd LN BRON of norml weights (Subjects 3, 4, nd 6) or 9% (Subjects 1, 2, nd 5). Subjects were trined dily, including the periods when body weights were incresed or decresed. Weight reduction from 8% to 7% ws chieved over n 11-dy period by withholding ll food except tht vilble during trining sessions. Weight increse to the 9% criterion ws ccomplished in four (lys by providing 2 g of dry food per dy in the home cge. Trining ws continued for t lest 16 sessions fter body weight hd stbilized t the pproprite level. RESULTS Figure 6 presents dily IRTs for the three subjects whose weights were incresed from soi 61 v 4 ṅi , 25 BODY WEIGHT 8% Si BODY WEIGHT. 9% R3_ Ml Ml - "2 * R2-R3 & & ~~~~~~~ :L * 5 - L.4^9t99D&i9 4. E I bo S2 io ~ I o ^~~.E SO 35;-s ^ I1 Is SESSINS Fig. 6. Dily men interresponse times in Exp. IV s function of incresed body weight. During ll sessions, R1 nd R2 were reinforced nd R. produced 2 min of timeout (Subjects 1 nd 5) or 9 sec of timeout (Subject 2). The left pnel represents terminl performnces t 8% body weight during the previous phse of the experiment for ech subject. The right pnel shows performnces when body weight ws incresed from 8% nd reched 9% in ll nimls by the fourth session of incresed feeding. Dotted lines indicte chnges in the scle of the ordinte with points t or below the line corresponding to the lower scle. Interresponse times were determined s described for Fig. 1. 8% to 9% of norml weight; the left pnel shows terminl performnces t 8% nd the right pnel subsequent performnces t 9% from the point t which dditionl food ws provided. It is pprent tht for ll three subjects, body weight increses were ccompnied by substntil increses in R2-R3 IRTs. For Subjects 1, 2, nd 5, terminl R2-R3 IRTs t 8% of norml weights were 28 sec, 18 sec, nd 26 sec (medin of lst 1 dys); by the end of trining t 9% of norml weight, these vlues hd incresed to 273, 149, nd 178 sec respectively. Figure 6 lso shows tht weight increses were not ccompnied by consistent chnges of ny gret mgnitude for R3-R1 or R1-R2 IRTs, lthough occsionl long puses, not seen t 8% of norml weight, did occur. Figure 7 presents comprble dt for the three subjects whose weights were reduced from 8% to 7% of norml. Two of the three (Subject 3 nd Subject 6) showed relible decreses in R2-R3 IRTs when the lst 1 dys' performnce t ech weight re compred. In the cse of Subject 3, the decrese ws from 83 sec to 38 sec, on the verge, while Subject 6 decresed from 25 sec to 15 sec. The performnce of the remining subject whose weight ws decresed (Subject 4) did not chnge relibly s consequence; terminl R2-R3 IRTs t the two levels were 1 nd 11 sec respectively. This discrepnt performnce my be relted to unusully short IRTs t 8% (trining ws with 9-sec timeout), leving reltively little opportunity for further reductions when body weight ws reduced to 7%. Figure 7 lso shows tht, s ws the cse with weight increses, weight reductions did not result in systemtic chnges in the IRTs ssocited with R1 nd R2. dditionlly, it my be noted tht chnges in the R2-R3 IRT were considerbly more rpid when weights were incresed thn when weights were decresed. This difference in rte of chnge undoubtedly ws relted to the fct tht more time ws required to reduce weights from 8% to 7% thn to increse weights from 8% to 9%. DISCUSSION The influence of deprivtion level on punished behvior hs not been studied t ll with timeout punishment, nd only in limited wy with shock punishment. fter reviewing

11 SUPPRESSION BY TIMEOUT PUNISHMENT 65 the limited evidence with respect to shock punishment, zrin nd Holz (1966) concluded tht incresed deprivtion reduces the effectiveness of given level of shock punishment. Perhps the strongest support for this conclusion is study by zrin, Holz, nd Hke (1963) in which the VI-reinforced behvior of pigeons ws completely suppressed by shock punishment when the nimls were t 85% of their norml weights, but reductions nd eventul elimintion of suppression occurred when weights were progressively reduced to 6% of norml weight. The present results re consistent with those obtined with shock punishment, since response suppression by timeout punishment incresed when body weights were incresed from 8% to 9% of norml weights nd suppression decresed when body weights were reduced from 8% to 7%. BODY WEIGHT 8% 15 5 S3 1 SO o 4' 3 2' h BODY WEIGHT 7% %-III 't -,o f,-3 2 I ~ ~ & 1' see se s86esee sjjeje JeeJJe68662 sj*8es 82.s If Is I; SESSIS Ieee...e....e...G I! Io So 1 J & so is le ~~ & Fig. 7. Dily men interresponse times in Exp. IV s function of decresed body weight. During ll sessions, R1 nd R, were reinforced, nd R. produced 2 min of timeout (Subject 3) or 9 sec of timeout (Subjects 4 nd 6). The left pnel represents terminl performnces t 8% body weight during the previous experiment for ech subject. The right pnel shows performnces when body weight ws reduced from 8% nd reched 7% in ll nimls by the eleventh session of reduced feeding. Interresponse times were determined s described for Fig. 1. Thus, it my be concluded tht vritions in motivtion to perform punished response hve generlly similr effects regrdless of whether punishment is by shock or by timeout Ȧlthough the results of mnipultion of deprivtion levels in the present study seem consistent with the conception of timeout s n versive event, they rise one puzzling question. Reductions in the effectiveness of electric shock punishment with incresed deprivtion cn be understood in terms of the direct influence of deprivtion on the punished response: the strengthening effects of deprivtion on free-opernt behvior re well-estblished, but there is little or no evidence to indicte tht deprivtion directly influences rections to electric shock. When timeout punishment is used, incresed deprivtion lso would be expected to strengthen the punished response. But unlike the cse with shock, it might be expected tht vritions in deprivtion would lso hve some direct influences on the versiveness of timeout, with incresed deprivtion incresing versiveness nd decresed deprivtion decresing versiveness. t the extreme, for exmple, completely stited orgnism should not find timeout from food reinforcement t ll versive. This resoning with respect to the direct influence of deprivtion on the versiveness of timeout leds to the prediction tht incresed deprivtion should produce incresed suppression by timeout punishment, prediction exctly the opposite of the present results. The conclusion must be reched, then, tht vritions in deprivtion hve greter influences on the strength of the punished response thn upon the versiveness of timeout punishment. GENERL DISCUSSION ND CONCLUSIONS The results demonstrted tht timeout punishment cn suppress behvior under circumstnces in which suppression could not increse reinforcement density or frequency. From the stndpoint of the two hypotheses offered by Leitenberg (1966) bout timeout effects, the present results support the hypothesis tht timeout is n versive event, nd rgue ginst the hypothesis tht the influences of timeout stem from incresed positive reinforcement.

12 66 RNOLD KUFMN nd LN BRON Worth considering re the possible roles of other vribles in determining the outcome of the present experiments. One wy of viewing the procedure is in terms of response chin in which R3, the punished response, constituted one element. When timeout ws mde dependent upon R3, considerble dely ensued before the next response element in the chin, R1 (nd its ssocited SD nd primry reinforcer), becme vilble. Thus, wekening of R3 by timeout punishment my hve been due to the disruptive influences of delyed reinforcement (zzi, Fix, Keller, nd Roch e Silv, 1964; Ferster, 1953) rther thn to the versive influences of the timeout period itself. The dditionl findings tht suppression decresed s the timeout period ws shortened (Exp. II), nd tht suppression ws eliminted when R3 ws reinforced by immedite dipper opertion (Exp. III) lso suggest the contribution of delyed reinforcement to response suppression. nother fctor which my hve produced suppression of R3 ws discrimintive control by stimuli ssocited with non-reinforcement. Since timeout punishment resulted in incresed R3 times without chnge in R1 nd R2 times, it is cler tht the period initited by the second dipper opertion ws effectively discriminted. During this period, s well s during the timeout period following R3, responses were never reinforced. Thus, suppression of R3 my be ttributed to the wekening of behvior in the presence of stimuli systemticlly ssocited with extinction. In considering such n ccount, the complex nd presumbly interoceptive nture of these stimuli should be noted; suppression of R3 occurred regulrly in the presence of the SD otherwise ssocited with reinforcement of R1 nd R2. The bove considertions suggest, then, tht conclusions bout the'versiveness of timeout punishment must be dopted with cution. lthough the present results hve estblished tht versive effects occur even when reinforcement is lost, it remins uncler to wht extent the present results my hve been due to the influences of such dditionl fctors s delyed reinforcement nd control by stimuli ssocited with extinction. It is instructive to compre the present conclusions with those reched in the studies of delyed reinforcement mentioned previously. zzi et l. (1964) found tht with fixed dely of primry reinforcement, the presence of n exteroceptive stimulus during the dely period reduced the disruptive effects of the dely. To ccount for this finding they ppeled to n explntion previously offered by Ferster (1953), nmely, "... the br-press is presumbly reinforced immeditely by the new stimulus sitution,... which is t once n S for br-pressing nd n SD for the occurrence of the mediting behvior..." (zzi et l., 1964, p. 161). Thus, zzi et l., fced with the need to ccount for incresed response strength when the response produced stimulus ssocited with period of timeout, concluded tht the stimulus possessed the properties of conditioned reinforcer. By comprison, the present results indicted response suppression when the response produced stimulus ssocited with period of timeout, thus suggesting the conclusion tht the timeout stimulus ws conditioned versive stimulus. Since there is empiricl support for either view, nd since timeout periods my occur in vrying reltionships to mny other events, it my well be tht the pproprite question is not whether timeout is n versive event, but rther under wht conditions does timeout ssume versive properties? It my be noted in this connection tht the dynmic properties of electric shock punishment were mde cler only fter experimentl evidence indicted tht shocks could serve either discrimintive, reinforcing, or punishing functions (Holz nd zrin, 1962), depending upon the nture of the ssocition of shock with the response nd with the schedule of positive reinforcement. REFERENCES zrin, N. H. nd Holz, W. C. Punishment. In W. K. Honig (Ed.), Opernt behvior: res of reserch nd ppliction. New York: ppleton-century- Crofts, Pp zrin, N. H., Holz, W. C., nd Hke, D. F. Fixed-rtio punishment. Journl of the Experimentl nlysis of Behvior, 1965, 6, zzi, R., Fix, Dor S. R., Keller, F. S., nd Roch e Silv, Mri Ignez. Exteroceptive control of response under delyed reinforcement. Journl of the Experimentl nlysis of Behvior, 1964, 7, Ber, D. M. Escpe nd voidnce responses of preschool children to two schedules of reinforcement withdrwl. Journl of the Experimentl nlysis of Behvior, 196, 3, Bron,. Functions of CS nd US in fer condition-

13 SUPPRESSION BY TIMEOUT PUNISHMENT 67 ing. Journl of Comprtive nd Physiologicl Psychology, 1959, 52, Bron,. nd Kufmn,. Humn, free-opernt voidnce of "time out" from monetry reinforcement. Journl of thte Experimentl nlysis of Behvior, 1966, 9, Bron,. nd Kish, G. B. Low-intensity uditory nd visul stimuli s reinforcers for the mouse. Journl of Comprtive nd Physiologicl Psychology, 1962, 55, Church, R. M. nd Rymond, G.. Influence of the schedule of positivc reinforcement on punished behvior. Jouirnl of Coinprtive nd Physiologicl Psychology, 1967, 63, Dvenport, D. G. nd Goulet, L. R. Motivtion rtifct in stndrd food-deprivtion schedules. Journl of Comprtive nd Physiologicl Psychology, 1964, 57, Ferster, C. B. Sustined behvior under delyed reinforcement. Journl of Experimentl Psychology, 1953, 45, Ferster, C. B. Control of behvior in chimpnzees n(d pigeons by timeout from positive reinforcement. Psychologicl Monogrms, 1958, 72 (8, Whole No. 461). Ferster, C. B. nd ppel, J. B. Punishment of S responding in mtching to smple by time out from positive reinforcement. Journl of the Experimentl nlysis of Behvior, 1961, 4, Ferster, C. B. nd Skinner, B. F. Schedules of reinforcement. New York: ppleton-century-crofts, Holz, W. C. nd zrin, N. H. Interctions between the discrimintive nd versive properties of punishmenit. Journl of the Experimentl nlysis of Behvior, 1962, 5, Holz, W. C., zrin, N. H., nd yllon, T. Elimintion of behvior of mentl ptients by response-pro- (luced extinction. Journl of the Experimentl nlysis of Behvior, 1963, 6, Kufmn,. nd Bron,. Use of withdrwl of reinforcement within the escpe-voidnce prdigm. Psychologicl Reports, 1966, 19, Leitenberg, H. Is time-out from positive reinforcement n versive event? Psychologicl Bulletin, 1965, 64, McMilln, D. E. comprison of the punishing effects of response-produced shock nd response-produced time out. Journl of the Experimentl nlysis of Behvior, 1967, 1, Thoms, J. R. Time-out voidnce from behviorindependent contingency. Psychonomic Science, 1965, 3, Zimmermn, J. nd Ferster, C. B. Intermittent punishment of S responding in mtching to smple. Journl of the Experimentl nlysis of Behvior, 1963, 6, Received 22 Jnury 1968.