Conditioning copulatory behavior to an artificial object: Efficacy of stimulus fading

Transcription

1 Animal Learning & Behavir 199, (), 5-6 Cnditining cpulatry behavir t an artificial bject: Efficacy f stimulus fading MICHAEL DOMJAN, MARILYN HUBER McDONALD, and KEVIN S. HOLLOWAY University f Texas, Austin, Texas Cpulatry behavir rarely ccurs in respnse t an arbitrary inanimate bject. Hwever, such behavir can prvide imprtant infrmatin abut the stimulus cntrl f cpulatry behavir. In the present study, male Japanese quail were administered 15- cnditining trials that included expsure t an inanimate bject and an pprtunity t cpulate with a live female quail Fr sme subjects, the stimulus bject was always entirely cvered with terryclth. Fr ther birds, the stimulus bject cntained a taxidermically prepared head and neck fa quail hen. Fading cnsisted f gradually cvering up the neck and then the head prtins f the stimulus bject ver successive trials. After cnditining, all subjects were tested with the entirely cvered bject. The fading prcedure facilitated the cnditining f cpulatry behavir t the entirely artificial bject. In subjects that received the fading prcedure, learning did nt depend n pairings f the stimulus bject with cpulatry pprtunity. The results are discussed with respect t an assciative mediatin mechanism. Species-typical respnses ccur in a predictable rder. A central issue in the analysis fspecies-typical behavir is whether respnses that ccur early in a behaviral sequence are fundamentally different frm respnses that ccur later in the sequence. In classical ethlgical thery, actins that ccur early in a sequence are referred t as "appetitive" respnses, and actins that ccur at the end f the sequence are referred t as "cnsummatry" respnses. Appetitive respnses are assumed t be invlved in the search fr releasing stimuli and have been characterized as variable, purpsive, and "adaptable t changing situatins" (Eibl-Eibesfeldt, 197, p. 5). In cntrast, cnsummatry respnses are invlved in the cmpletin fthe behaviral sequence and have been characterized as mre steretyped and "autmatically discharged" (Eibl-Eibesfeldt, 197, p. 5). Characterizatins f appetitive and cnsummatry respnses as "adaptable t changing situatins" and "autmatically discharged, " respectively, imply differences in the susceptibility f these respnses t learning. Appetitive respnses are presumed t be mre easily influenced by past experience than are cnsummatry respnses. Tinbergen (1951, p. 15), fr example, nted that appetitive respnses exhibit "plasticity," whereas cnsummatry respnses are "rigid." These presumed differences in the susceptibility fappetitive and cnsummatry behavir t learning r experiential mdificatin may be investigated in sexual behavir systems, in which appetitive behavir cnsists f This research was supprted by Grant MH 99 frm the Natinal Institute f Mental Health. We thank Fawn McDnald, and Chris Fx fr help in running the subjects and Mitch Leben fr help in scring data. Requests fr reprints shuld be addressed t M. Dmjan, Department f Psychlgy, University f Texas, Austin, TX searching fr and appraching a ptential sexual partner and cnsummatry respnses cnsist f munting and cpulatin. Successful systematic demnstratins f the cnditining f appetitive sexual behavir are available in bth fish and avian species. Hllis, Cadieux, and Clbert (1989), fr example, bserved that in blue guramis, the pairing f a cnditined stimulus (a red light) with visual access t a cnspecific f the ppsite sex results in cnditined apprach and display respnses t the red light. Sexually cnditinedapprach respnses tarbitrary visual cnditined stimuli als have been bserved in male Japanese quail (Dmjan, Lyns, Nrth, & BrueU, 1986). Cnsistent with the suggestin that appetitive behavir is mre amenable t cnditining than is cnsummatry behavir, cnditined cpulatry respnses were nt bservedin the studies with guramis and quail nted abve. This may have been because f the type f cnditined stimuli (lcalized visual cues) that were used. Such cnditined stimuli may nt have prvided the supprtive stimulatin that may be necessary fr munting and cpulatry cntact respnses. Cnditining f cnsummatry sexual behavir may be mre likely ifthe cnditined stimulus is a three-dimensinal (-) bject that the subjects can munt and cpulate with mre easily. Sme islated bservatinsfcpulatry behavir directed tward arbitrary -D bjects have been reprted. Fr example, Yung (199) described a male eastern rbin that cpulated with a clump f earth and a piece fcrumpled newspaper. Barraud (195) reprted bserving a yung male huse sparrw cpulating with a dandelin. Ficken and Dilger (196) described a male Fischer's lvebird cpulating with a knt n a wd perch, a wdthrush cpulating with a smth stne, and an American redstart cpulating with a clump fdried drppings. Beach (195) reprted that dgs masturbated by Cpyright 199 Psychnmic Sciety, Inc. 5

2 CONDITIONING COPULATORY BEHAVIOR 51 an experimenter will cme t direct their sexual behavir tward that experimenter, and Michael (1961) described an instance f a male cat cpulating with a ty. These anecdtal bservatins are prvcative; hwever, they invlved very few subjects (ne per species in mst cases) and prvided nly hints abut what factrs might have been respnsible fr the bserved behavir. Dmjan, O'Vary, and Greene (1988, Experiments and ) attempted t cnditin cpulatry behavir t an arbitrary stimulus bject in male Japanese quail by using prcedures that had been fund t be successful in ther frms f sexual cnditining with this species. The cnditined stimulus was a small, bright yellw, stuffed ty dg (a Pund Puppy), prpped up s that its head was abut the height f a squatting female quail's head. The subjects received cnditining trials cnsisting f expsure t the stuffed ty fr sec immediately befre access t a female quail, with which the subjects invariably cpulated. Fr a cntrl grup, cpulatin with a quail hen was prvided abut 9 min befre expsure t the stuffed ty. Cnsistent with ther demnstratins f the cnditining f appetitive sexual behavir, pairings f the stuffed ty with cpulatry pprtunity resulted in a rapid acquisitin f cnditined apprach t the ty. Hwever, the stuffed ty never came t elicit cpulatry behavir. In cntrast t the lack fsystematic evidence fthe cnditining f cpulatry behavir t arbitrary -D bjects, cpulatry behavir has been bserved in respnse t -D bjects that have sign stimulus features. Fr example, male cpulatry behavir has been bserved in respnse t taxidermic mdels f female cnspecifics in a variety f bird species such as chicken, turkey, cwbird, ruffed gruse, and blackbird (Allen, 19; Carbaugh, Schein, & Hale, 196; Nble & Vgt, 195; Schein & Hale, 1965; Schettle & Schein, 1959). These bservatins were derived frm the behavir f sexually experienced male birds. This leaves pen the pssibility that sme f the cpulatry respnding was a prductfprir sexual learning. Cnsistent with this pssibility, studies with male Japanese quail have demnstrated that prir sexual experience increases the likelihd that males will cpulate with a mdel that cntains the head and neck f a female quail (Dmjan, Greene, & Nrth, 1989). Male Japanese quail als can be cnditined t cpulate with a quail hen adrned with bright range feathers by pairing expsure t an adrned hen with the pprtunity t cpulate with a nrmal female quail (Dmjan et al., 1988). Hwever, the cnditined respnding is lst if the range feathers are presented alne, in the absence f sign stimulus features f a female quail. The abve evidence suggests that there are seriuscnstraints n the cnditining f cnsummatry sexual behavir. Studies with taxidermic mdels have shwn that the presence fa live sexually receptive female is nt necessary fr the ccurrence f male cpulatry behavir. Hwever, cpulatry behavir in the absence f sme species-typical female cues has been bserved nly in islated anecdtal reprts. The purpse f the present study was t explre further the pssibility f cnditining cpulatry respnses t an arbitrary stimulus bject. Japanese quail were used in the experiments t take advantage f prir knwledge abut the cnditins that prmte cpulatry behavir in this species. Because previus research had indicated that male quail will cpulate with mdels that cntain female features, ur strategy was t establish respnding t a stimulus bjectthat had quail features in the initial stages f training. The female features then were remved gradually, using a variatin f fading prcedures that have been successfully emplyed in the cnditining f stimulus discriminatins (e.g., Terrace, 1966). The quail features that we emplyed, n the basis f ur previus findings f the imprtance f cues f a hen's head and neck in stimulating male sexual behavir (Dmjan et al., 1989; Dmjan & Nash, 1988; Dmjan et al., 1988) were thse f the head and neck f a female bird. EXPERIMENT 1 Tw grups f subjects were tested in Experiment 1. On each trial, an inanimate bject with which the subjects culd cpulate was presented fr sec, fllwed immediately with access t a live sexually receptive quail hen. Fr birds in the fading grup, the inanimate bject during the first few cnditining trials cnsisted f a taxidermic specimen cntaining the head and neck f a female quail munted vertically in frnt f a sft munting pad cvered with beige terryclth (see Object 1 in Figure 1). Once cpulatin ccurred with the head-and-neck mdel, the neck and then the head were cvered up gradually ver successive trials with beige terryclth. Eventually, n quail features remained, and the inanimate bject cnsisted f a vertical terryclth prtrusin with a terryclth munting pad behind it (Object 6 in Figure 1). Grup received a nnfading prcedure in which the entirely cvered bject (Object 6 in Figure 1) was presented n each trial. At the end f the experiment, bth grups were tested with the entirely artificial bject. Methd Subjects. Frty adult male experimentally naive Japanese quail (Cmmix cmmixjapnica),.5-5 mnths ld, served as subjects. The birds were hatched frm eggs btained frm a clny maintained at the University f Texas at Austin. At -5 weeks f age, they were mved frm mixed-sex brders and hused in metal quail cages (G.Q.F. Manufacturing C., Savannah, GA). Male birds were individually hused, and female birds were hused in grups f up t per cage. Lights in the labratry were n frm 6 a.m. t 1 p.m. daily, which prvided ample phtstimulatin t maintain the birds in reprductive readiness. Fd (turkey grwer) and water were available cntinuusly. Prir t participating in the experiment, all f the subjects were pretested fr cpulatry behavir by having a female quail intrduced int their hme cage fr 5 min. This is usually enugh time fr Japanese quail t cmplete the cpulatry respnse sequence (Schein, Diamnd, & Carter, 197). Only subjects that made clacal cntact with the female bird during the pretest were selected t participate in the experiment. As it turned ut. nt all fthe sub-

3 5 DOMJAN, HUBER-McDONALD, AND HOLLOWAY Head+Neck Head+1jNeck 5 cm Figure 1. Tbe stimulus bjects tbat were used. Objects 1-5 cnsisted f tbe bead and neck f a quail ben tbat bad been taxidermically prepared and munted vertically in frnt fa terrycltb pad filled witb plyester fiber. The neck and bead prtins f Objects -5 were partially cvered witb terrycltb, as indicated by tbe stippled shading. Fr Object 6, tbe quail bead and neck were replaced witb a vertical terrycltb cylinder, whicb was filled witb plyester fiber. jects that cpulated in the hme cages cpulated in the test arenas (see belw). An equal number f female quail f similar age were used during perids f cpulatry pprtunity. Each male bird was paired with a female and encuntered the same quail hen during each perid f cpulatry pprtunity. Apparatus. The experimental prcedures were cducted in large bservatinchambers (9\. cm wide x 16.7 cm high x 1\.9 cm deep; see Figure ). The tw sides and the tp f the chambers were made f sealed plywd; the frnt and back walls and the flr were made f wire mesh. The middle f ne side wall had a small pening (1.x 15.5 cm), which prvided access t a small side cage (1.x 15.5x ll.5 cm). The side cage served as a hlding area fr the birds befre a cnditining trial and was usually blcked ff by a vertically sliding masnite panel that served as a dr. On the wall directly ppsite the side cage, a release bx (1.8 X. X 1.8 cm) rested n brackets 1 cm abve the flr. This bx was used t prvide access t a female quail paired with expsure t a stimulus bject. The sides f the release bx were made f sealed wd, and the tp was wire mesh. The tp was attached t a string passed ver a pulley t allw the experimenter t raise and lwer the bx. The flr f the release bx was hinged, s that when the bx was raised, the flr swung pen, and the quail hen drpped int the test arena. During trials, the inanimate stimulus bject with which subjects culd cpulate was placed directly belw the release bx facing the middle f the chamber at 5 relative t the side wall. The flr f the experimental chamber was marked in nine areas fequal size. One fthese was centered arund the stimulus bject. A series f inanimate stimulus bjects was used (see Figure I). Objects 1-5 cnsisted f the head and neck f a quail hen that had been taxidermically prepared and munted vertically in frnt f a terryclth pad filled with plyester fiber. Fr Object 6, the quail head-and-neck sectin was replaced with a clsed vertical terryclth cylinder, which was als filled with fiber. A black eyespt was painted n bth sides fthis vertical sectin, but infrmal tests with and withut the eyespts at the end f the experiment suggested that they were incnsequential. Prcedure. The experiment was cnducted in tw equal cunterbalanced replicatins. In each replicatin, the subjects were assigned t ne f tw squads f 1 subjects each. Each squad was hused in the experimental chambers during alternate -h perids. The subjects were exchangedarund nn each day, with the birds that had been in the experimental chambers mved t the wire-mesh hme cages and thse in the hme cages mved t the experimental chambers. This trade-ut prcedure was started 18-5 days befre any experimental prcedures and cntinued thrughut the experiment. Trials were cnducted in the mid-mrning and mid-afternn. The use f the alternating husing prcedure resulted in successive trials fr a given bird being alternated between mrning and afternn trials. Figure. A diagram f tbe experimental chamber: a == hlding cmpartment in whicb the male subject was placed befre eacb cnditining trial, b == stimulus bject, c == release bx frm whicb a female quail was released int the experimental chamber n paired trials in Experiments 1-, and d == side dr fr placing a female quail int the experimental chamber, used nly in the unpaired prcedure in Experiment.

4 CONDITIONING COPULATORY BEHAVIOR 5 Befre the start f cnditining trials. the subjects were habituated t being placed in the side cages. On seven t eight ccasins, each subject was mved frm the experimental chambert the side cage, with the dr t the side cage clsed. The dr was then pened. releasing the subject back int the experimental chamber. In additin, n three ccasins. the subjects in the secnd replicatin received access t a live female quail fr 5 min in the experimental chambers. This was expected t facilitate their respnding t the mdels (Dmjan et ai., 1989). Cnditining trials were cnducted after the habituatin phase. At the start f each trial. the male subject was placed int the side cmpartment, with the side dr clsed. A quail hen was then placed int the release bx, and a stimulus bject was placed beneath the bx. After 5-1 min, the male was released int the experimental chamber; sec later. the quail hen was released. and the birds were allwed t interact fr 5 min, during which cpulatin usually ccurred. The quail hen and the stimulus bject were then remved t bring the trial t an end. Thus, the stimulus bject was paired with cpulatry pprtunity. Frthe subjects in Grup NPI (Nnfading. Paired. Experiment I, n = ), Object 6 (see Figure I), which was made entirely fterryclth filled with plyester fiber. was presented n each cnditining trial. Fr the subjects in Grup FPI (Fading, Paired, Experiment I. n = ). a series f different stimulus bjects was presented. Fr the FPI subjects in the first replicatin. the headand-neck bject (Object I in Figure I) served n each f the first 1 trials. After that. the quail head-and-neck cues were gradually cvered up accrding t the perfrmance f each subject. If the subject made a clacal cntact respnse with an bject n cnsecutive trials (e.g., Object ). the next bject in the sequence was presented n the next trial (Object ). Occasinally, if a subject was respnding vigrusly. the stimulus sequence was advanced after nly I trial f cpulatin with an bject. If cpulatin failed t ccur. the sequence was backed up t the last bject with which the subjects cpulated. A ttal f cnditining trials were cnducted fr each grup in the first replicatin. In the secnd replicatin. the fading sequence fr Grup FPI was started after the 5th cnditining trial, and a ttal f 15 cnditining trials were cnducted fr bth the fading and the nnfading subjects. Six f the subjects in Grup FPI in the first replicatin and 5 f them in the secnd replicatin cmpleted the fading sequence by the end f the cnditining trials. By the end f the cnditining trials, the remaining subjects in Grup FPI were making little prgress in the stimulus sequence. Because the tw replicatins prvided similar results, the acquisitin data frm the first 15 trials f each replicatin were pled. After the cnditining phase, each subject was tested with Object 6, which was made entirely f terryclth filled with plyester fiber. This test trial was cnducted in the same manner as were the cnditining trials except that a female hen was nt placed in the release bx abve the stimulus bject, and the subjects were permitted t interact with the bject fr 5 min. Because we were interested in male cpulatry behavir, we nly used data frm the subjects that cpulated with the live quail hens in the experimental chambers during the cnditining trials. Althugh the subjects were pretested fr cpulatry behavir in the hme cages. birds in Grup FPI and in Grup NPI never cpulated during the cnditining trials. In additin. I subject in Grup FPI brke its leg befre the end f the experiment. These lsses left 17 subjects in each grup. Respnse measures. The interactins f the subjects with the stimulus bjects were recrded n videtape fr the first sec f each cnditining trial (befre the live female quail was intrduced) and fr the 5-min test trial with the cmpletely terryclth stimulus at the end fthe experiment. The vide recrds were then scred with respect t five respnse categries. The first f these was time spent in that ninth f the test arena in which the stimulus bject was lcated (see Figure ). This prvided a measure f ap- prach and prximity t the stimulus bject (and the lcatin where the female was released fr the paired grups). The secnd respnse was pecks. and the remaining three respnses invlved cmpnents f cpulatry behavir. Cpulatry behavir in male quail cnsists f the male grabbing the back f the hen's head r neck, munting the hen's back with bth feet, and then making clacal cntact mvements (Wilsn & Bermant. 197). A grab was scred if the subject grabbed the feathers r terryclth surface f the stimulus bject. Grabs were distinguished frm pecks by whether the subject held nt the surface f the stimulus bject. A peck was scred if the subject hit the bject with its beak and quickly withdrew withut hlding nt the terryclth. A munt was scred if the subject gt n tp f the stimulus bject with bth feet. A clacal cntact respnse was scred if the subject arched its back and appeared t bring its claca in cntact with the back fthe stimulus bject. The clacal cntact respnse was ften accmpanied by rhythmic shaking f the clacal area when the bird was in the arched psitin. The cnditining and test trials were scred first by ne f the authrs (M.M. r M.D.). Subsequently, all f the test sessins were scred by an additinal bserver (M.L.), wh was unaware f the grup assignment f the subjects. Crrelatins between the results f the tw bservers wh scred the test data were cmputed fr each replicatin f Experiment I. Fr the first replicatin, these crrelatins were.99,.99,.9.97, and.8 fr pecks. time near the stimulus bjects, grabs. munts, and clacal cntacts, respectively. Fr the secnd replicatin. these crrelatins were.99 fr each respnse. Because fthe high value fthese reliability crrelatins, nly results frm the riginal scring f the videtapes are presented. Results Acquisitin: Nncpulatry respnse measures. The frequency with which the subjects pecked the stimulus bjects during the first 15 cnditining trials is presented in the tp panel f Figure. The subjects that received the fading sequence f stimulus bjects (which included quail features) shwed mre pecking behavir than did Grup NPI [F(l,) = 1.65, p <.1). Hwever, neither the main effect f trials nr the trials X grup interactin was significant (Fs < 1.). These results suggest that the cnditining prcedures did nt influence pecking behavir. Stimulus bjects that cntained quail features were simply mre effective in eliciting pecking than was the entirely terryclth bject that was presented t the subjects in grup NP1. The amunt f time the subjects spent near the stimulus bjects is presented in the lwer panel f Figure. Bth grups shwed an increase in time spent near the stimulus bjects as cnditining prceeded [F(1,8) = 1.66, p <.1). The fading grup (FPI) spent mre time near the stimulus bjects than did the nnfading grup (NPI) [F(I,) = 16.1,p <.1]. Hwever, the grups x trials interactin was nt significant (F < 1.), indicating that the curse f acquisitin f appraching and remaining near the stimulus bjects was nt significantly different in the tw grups. Acquisitin: Cpulatry respnse measures. The cnnected pints in Figure shw the frequency f grab, munt, and clacal cntact respnses directed tward the stimulus bjects that ccurred during the curse f acquisitin. Similar results were btained with each f these respnse measures. The subjects that received the fading

5 5 DaMIAN, HUBER-MCDONALD, AND HOLLOWAY 8 6 >. c Q> :> ~ ---- FP1,.at>:' Pecks,. 'A.a.j; LL NP1.a.... III 'tj C CIJ Zne Time,.,.....a. f---,i""..a=-'-.----,---,---,---, Trials shwn by the uncnnected pints t the right feach acquisitin curve in Figure. The greater levels frespnding that were evident in Grup FPI, as cmpared with Grup NP1, during the training trials were als evident in the final test sessin. The subjects that received the fading sequence fstimulus bjects made mre grab, munt, and clacal cntact respnses during the final test sessin than did the subjects in the nnfading grup. The carryver f respnding frm the end f acquisitin t the test sessin was evaluated fr each respnse measure by separate ANOVAs that included Trial 15 f acquisitin and the test sessin fr each grup. These analyses indicated that the subjects that received the fading prcedure respnded mre than thse that received the nnfading prcedure [Fs(1,) =., 5., and 5., fr the grab, munt, and clacal cntact respnses, respectively, all ps <.5]. The interactin between grups and the shift frm acquisitin t testing was nt significant fr any respnse measure (all Fs < 1.). This latter utcme cnfirms that the grup differences that were evident at the end facquisitin were nt altered significantly Figure. The mean frequency f pecks (tp panel) and mean secnds near the stimulus bjects during the first 15 acquisitin trials f Experiment 1. (Grup FPI received a fading paired prcedure; Grup NPI received a nnfading paired prcedure.) 5 -{}- FP1. NP1 Grabs a sequence fstimulus bjects (Grup FP1) increased their respnding as training prgressed. In cntrast, little change was evident in the respnses f the subjects that received the entirely artificial stimulus bject n each trial (Grup NP1). In additin, the subjects in the nnfading grup were much less likely t make grab, munt, and clacal cntact respnses with their stimulus bject than were subjects in the fading grup. A grups X trials analysis f variance (ANOVA) was calculated fr each respnse measure. Each fthese analyses indicated a significant effect fgrups [Fs(1,) = 16.8, 17.68, and 15.7, fr the grab, munt, and clacal cntact respnses, respectively, all ps <.1]. The analyses als indicated significant effects ftrials fr each respnse measure [Fs(1,8) =.7, 5.19, and.67, fr the grab, munt, and clacal cntact respnses, respectively, all ps <.1]. In additin, the grups X trials interactin was significant fr each respnse measure [Fs(1,8) = 1.95,.78, and.6, all ps <.5]. These latter findings indicate that the subjects expsed tthe fading sequence f mdels increased their cpulatry respnses t the stimulus bjects t a significantly greater extent acrss trials than did the subjects in Grup NPI. Pstcnditining test: Cpulatry respnse measures. During the test trial, bth the fading and the nnfading grups were expsed t the entirely artificial stimulus bject (Object 6, Figure I). This permitted cmparing their perfrmance under identical cnditins and in respnse t an bject lacking the species-typical plumage fa quail hen. The mean frequency f grab, munt, and clacal cntact respnses during the final test sessin are...'. -hil~r---,---, r T Munts...,... O-hll--=r-=-.::..,.---'i' r T Clacal Cntacts...,. O-hll~.----,---, r T Trials Figure. Mean frequencies f grab, munt, and clacal cntact respnses elicited by the stimulus bjects during the rll"st 15 cnditining trials (cnnected pints) and the pstcnditining test (the uncnnected pints n the rigbt f each panel) in Experiment 1. (Grup FP1 received a fading paired prcedure; Grup NPI received a nnfading paired prcedure.)

6 CONDITIONING COPULATORY BEHAVIOR 55 Table I Prprtin f Subjects Making at Least One Grab, Munt, r Clacal Cntact Respnse t the Fully Artificial Mdel During the Pstcnditining Test Respnse Grab Munt Clacal Cntact Experiment I Grup FPI 9/17 1/17 8/17 Grup NPI /17 / Experiment Grup FP 5/1 /1 /1 Grup FU 6/1 6/1 /1 Experiment Grup NP /1 /1 1/1 Overall Fading /7 /7 16/7 Nnfading 6/ 6/ / by the intrductin f the fully artificial stimulus bject fr all subjects during the test sessin. The number f subjects that made at least ne grab, munt, r clacal cntact respnse t the entirely artificial mdel during the final test is summarized in Table I. The subjects that received the fading sequence f mdels during training were times mre likely t make at least ne grab respnse t the artificial stimulus bject than were the subjects that received the nnfading sequence fmdels. Nine fthe 17 subjects in Grup FPl grabbed the mdel, whereas nly fthe 17 subjects in Grup NPI did s. Similar, but smewhat smaller, differences between the grups were evident in the frequency f subjects making munt and clacal cntact respnses t the stimulus bject. Discussin The present fmdings prvide systematic evidence fthe develpment fcpulatry respnding t an inanimate bject that has minimal species-typical features. In cntrast t previus anecdtal accunts f a few unusual subjects that were bserved t cpulate with artificial stimuli, abut 5% f the subjects that received the fading sequence f mdels in the present experiments ended up making grab, munt, and clacal cntact respnses t the artificial stimulus bject. Hwever, the present findings d nt encurage rejectin fthe claim that cnsummatry behavir is less susceptible t mdificatin by learning than is appetitive behavir (e.g., Eibl-Eibesfeldt, 197; Tinbergen, 1951). Cnsistent with that claim, the subjects that were expsed t the entirely artificial stimulus bject n every cnditining trial (Grup NPI) apprached and spent increasing amunts f time near the bject as training prgressed (see Figure ), but they did nt shw substantial increases in grab and clacal cntact respnses (Figure ). The present findings prvide sme suggestins abut factrs that might have prmted cpulatin with a stimulus bject having minimal species-typical cues. As in previus research (e.g., Dmjan et al., 1988), mdels that cntained features fa female quail's head and neck sup- prted mre cpulatry respnding during the training trials than did the fully artificial stimulus bject (Figure ). Cpulatry respnding was maintained t a significant extent as the quail features f the mdels were gradually cvered with terryclth (Grup FPl). As a cnsequence, the subjects in Grup FPl were times mre likely t shw sme cpulatry respnding with the fully artificial mdel during the pstcnditining test than were the subjects in Grup NPI. Smething abut the fading prcedure seemed t prmte cnditining fcpulatry behavir t the fully artificial mdel. The greater efficacy f the fading prcedure may have been due slely t the use during training f mdels that cntained female quail features. Alternatively, gradually cvering thse quail features as training prceeded may have been imprtant fr the develpment fthe behavir. We als d nt knw t what extent the develpment f cpulatry respnding in these prcedures was a functin f expsing subjects t the mdels just befre access t a live sexually receptive female. Experiments and were cnducted t explre these issues. EXPERIMENT Experiment was cnducted t replicate the findings btained in Experiment I with a fading sequence f mdels and t determine whether the cpulatry behavir generated by that prcedure is a result f a direct assciatin between the mdels and cpulatry pprtunity. Tw grups f male quail (paired and unpaired) were tested. Bth received training with a fading sequence f mdels. Fr the paired grup, expsure t a mdel n each trial was fllwed immediately with access t a live sexually receptive quail hen. Fr the unpaired grup, expsure t a mdel and access t a quail hen were prvided n alternate days s that presentatin fthe mdel wuld nt cme t signal impending cpulatry pprtunity. Methd Subjects. Twenty male Japanese quail, -5 mnths ld at the start f the experiment, served as subjects, tgether with an equal number fadultfemale birds. The birds were reared and maintained as in Experiment I. Apparatus. The experimental chambers used in Experiment I were mdified with the additin f a 1 x 16.5 cm side dr thrugh which a female quail culd be placed int the experimental chamber when access t a female was prvided unpaired with expsure t a stimulus bject. The dr was t the right fthe hlding cmpartment in which the male subject was placed at the start f each trial f expsure t a stimulus bject, 1 cm frm the back wall and 15 cm abve the flr (see d in Figure ). Prcedure. As in Experiment I, the subjects were assigned t ne f tw squads f 1 subjects each, and each squad was hused in the experimental chambers during alternate -h perids. The alternating husing prcedure was started 1 days befre the first cnditining trial. During this preliminary phase, the subjects received access t a female quail fr 5 min n each f fur ccasins and were als habituated t being placed in the side cmpartments and released int the test arenas, and t having the female release bxes perated. After the preliminary prcedures, the subjects were assigned t ne f tw grups, each f which received a fading sequence f

7 56 DOMJAN, HUBER-McDONALD, AND HOLLOWAY stimulus bjects. The subjects in Grup FP (Fading, Paired, Experiment, n = 1) were expsed t a stimulus bject fr sec n each cnditining trial, immediately befre receiving access t a quail hen fr 5 min. Cnditining trials were cnducted every ther day. The subjects in Grup FU (Fading Unpaired Experiment, n = 1) received expsure t the stimulus bjects n the same days as did the subjects in Grup FP. Hwever, fr Grup FU, access t a quail hen was prvided fr 5 min 1 day after each expsure t a stimulus bject. The female bird was placed int the test chambers thrugh the side dr (see d in Figure ) fr the unpaired female presentatins. Grups FP and FU received a fading sequence f stimulus bjects similar t what was used with Grup FPI, with tw small exceptins. During the first tw cnditining trials, the stimulus bject cnsisted f the entire bdy f a taxiderrnically preparedquail hen psitined in a squatting psture. In additin, a stimulus bject with 75% f the neck cvered with terryclth was added between Objects and (see Figure I). The decisin rule fr advancing frm ne mdel t the next was the same as fr Grup FPI in Experiment I and was instituted after the first tw cnditining trials. Fur subjects in Grup FP and in Grup FU reached the end f the fading sequence f mdels during the cnditining phase. A test trial with Object 6, as in Experiment I, was cnducted after 15 cnditining trials. Videtaped recrds f the training and test trials were scred as in Experiment I. The interbserver reliability crrelatins fr the test sessin were.97,.99, and.99, fr the grab, munt, and clacal cntact respnses, respectively. Results The frequencies f grab, munt, and clacal cntact respnses bserved with each grup are summarized in Figure 5. (The cnnected pints represent data btained during the cnditining trials, and the uncnnected pints at the right represent data btained during the pstcnditining test.) Respnding t the stimulus mdels started at a much higher level in Experiment than in Experiment I. This was prbably due t the fact that during the first tw trials in Experiment, the stimulus bject cnsisted f the entire bdy f a taxidermically prepared quail hen. Previus research had shwn that the entire bdy fa taxidermically prepared quail hen elicits a higher frequency fcpulatry respnses than des a mdel that nly cntains a hen's head and neck (Dmjan, 199). A head-andneck mdel had been used during the initial trials f Experiment 1. Cpulatry respnding was maintained in the fading paired grup (FP) as cnditining prgressed. The subjectsin the fading unpairedgrup (FU) respnded as frequently as did the subjects in the paired grup thrugh the 1th trial. Hwever, as the quail features fthe stimulus bjects were further cvered up after Trial 1, respnding in Grup FU declined a bit. Separate tw-way (grups X trials) ANOVAs were calculated fr each respnse measure fr the 15 cnditining trials. The analyses failed t reveal any significant main effects ftrials r fgrups (Fs < 1.). Hwever, the interactin between grups and trials was significant fr each respnse measure [Fs(l,5) =.1,.67, and 1.99, fr the grab, munt, and clacal cntact respnses, respectively, aiips <.5]. These results indicate that the divergence f respnding that ccurred between Grups FP and FU tward the end f the cnditining phase was significant. >. c: Ql :> C' Ql u: {}--- FP "" FU 6 Grabs " T Munts T Clacal Cntacts "~...i': 1 +--,...~ ,..--r-- " " T Trials Figure 5. Mean frequencies f grab, munt, and clacal cntact respnses elicited by the stimulus bjects during the 15 cnditining trials (cnnected pints) and the pstcnditining test (the uncnnected pints n the right f each panel) in Experiment. (Grup FP received a fading paired prcedure; Grup FU received a fading unpaired prcedure.) The grup differences that develped tward the end f the cnditining phase were nt evident in the pstcnditining test sessin, when all f the subjects were tested with the stimulus bject that was entirely cvered with terryclth (see uncnnected pints in Figure 5). Althugh there were sme variatins in the mean frequencies f grab, munt, and clacal cntact respnses when the test sessin was intrduced, these variatins were nt statistically significant. The results with the clacal cntact respnse were a bit peculiar because the mean respnse fgrup FU increased frm Cnditining Trial 15 t the test sessin, whereas the respnse fgrup FP decreased. The high frequency fclacal cntacts in Grup FU during the test sessin was primarily the result f 1 unusual subject that respnded 7 times. As in Experiment I, the transfer f respnding t the test sessin was evaluated fr each respnse measure with separate ANOVAs that cmpared Trial 15 f cnditining and the test sessin. These analyses failed t reveal any significant effects f grups, the shift frm cnditining t the test sessin, r interactins between these tw

8 CONDITIONING COPULATORY BEHAVIOR 57 factrs (all Fs <.5, all ps >.1). Separate cmparisns between Grups FP and FU f respnding during the pstcnditining test sessin fr each respnse measure with t tests als failed t reveal any significant differences (all IS < 1.). The prprtin f subjects in each grup that made at least ne grab, munt, and clacal cntact respnse during the pstcnditining test sessin is summarized in Table I. Similar numbers f subjects in each grup made at least ne grab, munt, and clacal cntact respnse during the test trial with the entirely artificial bject. Of the ttal f subjects, II made at least ne grab respnse t the artificial bject, 1 made at least ne munt respnse, and 8 made at least ne clacal cntact respnse. Discussin The present findings cnfirm the bservatin in Experiment I that nearly half f the male quail expsed t a fading sequence f stimulus bjects end up making cpulatry respnses t a stimulus bject that lacks the speciestypical features f a quail hen. The present findings als help t characterize sme f the bundary cnditins fr this phenmenn. There was sme evidence tward the end fthe cnditining phase that the subjects given expsure t stimulus bjects paired with access t a live quail hen (Grup FP) respnded mre vigrusly t the bjects than did the subjects that received access t a quail hen in an unpaired fashin (Grup FU). Hwever, substantial numbers f grab, munt, and clacal cntact respnses were als bserved in the unpaired grup. Furthermre, when all f the subjects were given a standard 5-min test with the entirely cvered stimulus bject at the end f the experiment, there was n evidence that a histry f paired expsure t the bjects significantly increased the likelihd that the subjects wuld cpulate with the fully cvered bject. This finding indicates that a fading sequence f stimulus bjects can result in cpulatry behavir even if the bjects are nt signals fr impending access t a live quail hen. The absence f a clear effect f pairings suggests that cpulatin with the fully cvered mdel did nt develp because fa direct assciatin fthe stimulus bjects with cpulatry reinfrcement. Several factrs may have been respnsible fr this utcme. One pssibility is that a direct assciatin between the stimulus bjects and sexual reinfrcement did nt develp. Expsure t the stimulus bjects was nt uniquely predictive f sexual reinfrcement. The release f the female quail at the end f each cnditining trial was preceded by the subject being released frm the hlding cmpartment and encuntering all fthe stimuli fthe test cage. Rather than the stimulus bjects, varius stimuli, including spatial cues characteristic f the area near where the female was released, culd have becme assciated with access t the female. Anther pssibility is that direct assciatins between the stimulus bjects and sexual reinfrcement develped during the curse fcnditining fr the paired grup. Hw- ever, such assciatins may nt have been manifested in cpulatry behavir. EXPERIMENT The results f Experiments I and indicated that expsure t a fading sequence f stimulus bjects results in nearly half f the subjects displaying cpulatry behavir in respnse t a fully artificial stimulus bject. Experiment 1 prvided suggestive evidence that an imprtant aspect f the fading prcedure invlved expsing subjects t mdels that cntained the shape and plumage f a quail hen's head and neck. The subjects that received nly the fully artificial mdel during training (Grup NPl) were ne third as likely t cpulate with the fully artificial mdel as were the subjects that received the fading sequence f stimulus bjects (Grup FPI). Hwever, we d nt knw whether gradually cvering the quail features during the curse f training was necessary t get the subjects t cpulate with a fully artificial mdel. Perhaps practice in cpulating with an inanimate bject that has quail features was sufficient. Experiment was cnducted t see if expsure t mdels cntaining natural quail features is sufficient fr the develpment f respnding t a fully artificial stimulus bject. In Experiment, the subjects were expsed t mdels cntaining quail features, but thse features were nt cvered up gradually during the curse f training. Methd Subjects. Sixteen male Japanese quail, -5 mnths ld at the start f the experiment, served as subjects, alng with an equal number f sexually receptive adult female quail. The subjects were reared and maintained as in Experiments 1 and. Three f the subjects failed t cpulate with live quail hen in the experimental chambers and were therefre mitted frm the study. Apparatus. The experimental chambers that were used in Experiment 1 were als used in Experiment. Prcedure. As in Experiment I, the subjects were assigned t ne ftw squads (f8 subjects each), and each squad was hused in the experimental chambers during alternate -h perids. The alternating husing prcedure was started 7 days befre the first cnditining trial. During this preliminary habituatin phase, the subjects received access t a female quail fr 5 min n each feight ccasins t facilitate their respnding t inanimate bjects (Dmjan et al., 1989). They were als habituated t being placed in the side cmpartments and released int the test arenas, and t having the female release bxes perated. The cnditining prcedure was similar t that used with the nnfading grup in Experiment 1. Trials cnsistedfpermitting the subject t enter the test arena with a stimulus bject available under the female release bx. Thirty secnds later, a live quail ben was released int the test arena fr 5 min. On Trials 1-6 and 9-18, Stimulus Object 1 (Figure 1) was used, which had a taxidermically prepared female quail head and neck. On Trials 7 and 8, the stimulus bject cnsisted f the entire bdy f a quail hen taxidermically prepared and psitined in a squatting psture. After Trial 18, the standard 5-min test trial with Object 6, which was entirely cvered with terryclth, was cnducted, as in Experiments 1 and. Interbserver reliability crrelatins fr the test sessin were.9,.91, and I., fr the grab, munt, and clacal cntact respnses, respectively.

9 58 DOMJAN, HUBER-McDONALD, AND HOLLOWAY Results The frequencies f grab, munt, and clacal cntact respnses directed tward the stimulus bjects during the training trials are summarized by the cnnected pints in Figure 6. The subjects gradually increased respnding during Trials I-6 when they received expsure t a stimulus bject cntaining just the head and neck f a quail hen. Respnding increased substantially during Trials 7 and 8, when the stimulus bject cnsisted f the entire bdy f a quail hen, but returned t lwer levels when the head-and-neck mdel was returned fr Trials Althugh substantial levels fcpulatry respnding ccurred during the training phase, the cpulatry behavir was nt maintained when the fully artificial mdel was intrduced during the pstcnditining test trial. Only I f the 1 subjects made a clacal cntact respnse with the fully artificial mdel (see Table I). The frequencies f grab, munt, and clacal cntact respnses that ccurred in respnse t the fully artificial mdel are represented by the uncnnected pints in Figure 6. A cmparisn f respnding during the pstcnditining test and the last trial f the training phase indicated that significantly fewer cpulatry respnses ccurred in respnse 5 Grabs T 6 Munts 5 ij' c <ll :J ~ u T 5 Clacal Cntacts T Trials Figure 6. The mean frequencies fgrab, munt, and clacal cntact respnses elicited by the stimulus bjects during the 18 cnditining trials (cnnected pints) and the pstcnditining test (the uncnnected pints n the right f eacb panel) in Experiment. Cl Cl t the fully artificial mdel than were bserved at the end f the training phase, when subjects were expsed t a mdel cntaining the head and neck f a female quail [ts(1) =.58,.9, and.8, fr grab, munt, and clacal cntact respnses, respectively, all ps <.5]. Discussin Experiment was cnducted t explre the pssibility that expsure t the fading sequence f stimulus bjects in Experiments I and resulted in high levels fcpulatin with the fully artificial mdel because, during training, the fading sequence permitted cpulatin with mdels cntaining quail features. The subjects in Experiment were expsed t a mdel cntaining the head and neck f a female quail n Trials 1-6 and 9-18 and received expsure t a full-bdy quail mdel n Trials 7 and 8. Despite cnsiderable experience with and cpulatry respnding t mdels cntaining quail features during training, the subjects in Experiment failed t maintain their respnding when the fully artificial mdel was intrduced during the pstcnditining test sessin. This result cntrasts with the behavirfthe subjects in the fading grups in Experiments 1 and, which maintained their cpulatry respnding withut significant decline during the standard pstcnditining test. Thus, the present results prvide n supprt fr the hypthesis that mere expsure t mdels cntaining quail plumage is sufficient t generate high levels f respnding t a fully artificial stimulus bject. Evidently the fading prcedures were mre successful in stimulating cpulatin with a fully artificial bject because they invlved gradually cvering up the quail features during the curse f training. The present experiment did nt include a replicatin f the fading prcedures that were used in Experiments I and. Hwever, it is unlikely that the lw level fcpulatin bserved during the pstcnditining test was due t a pr set f subjects serving in the experiment. As in Experiments 1 and, nly the subjects that reliably cpulated with the live female quail during the training trials were included in Experiment. In additin, aspects fthe training prcedure in Experiment that were similar t the prcedures tested in Experiments I and yielded similar perfrmance. Fr example, the fading grup f Experiment 1 and the subjects in Experiment were bth expsed t the head-and-neck mdel during the first five training trials. In bth experiments, the subjects made few grab, munt, and clacal cntact respnses n Trial 1 but increased their respnding t the head-andneck mdel during Trials -5 (cf. Figures and 6). A direct cmparisn f the data fr Trials 1-5 fr the fading grup f Experiment 1 and the subjects in Experiment yielded a significant effect ftrials [Fs(, 11) =.99, 9., and 8.7, fr the grab, munt, and clacal cntact respnses, respectively, aiips <.1]. Hwever, the effects fexperiment 1 versus Experiment and the trials x experiment interactin were nt significant (highest F =., all ps >.5). On Training Trials I and f Experiment, the subjects were expsed t a taxiderrnic mdel cnsisting f

10 CONDITIONING COPULATORY BEHAVIOR 59 the entire bdy f a quail hen. A whle-bdy mdel was als used n Training Trials 7 and 8 in Experiment. T check that the subjects in Experiment were just as respnsive t the whle-bdy mdel as were the subjects in Experiment, cpulatry behavir n Trials 7 and 8 f Experiment was cmpared t behavir n Trials 1 and f Experiment. A separate tw-factr ANOVA (experiment X trials) was calculated fr each respnse measure. N significant effects f trials, experiment, r trials X experiment interactins were btained fr the grab r clacal cntact respnses (largest F =.76, all ps >.1). Analyses f the data fr the munt respnse indicated that the subjects in Experiment respnded mre vigrusly t the whle-bdy mdel than did the subjects in Experiment [F(l,1) =.9, P <.5]. Thus, there was n indicatin that the subjects in Experiment were less likely t cpulate with the whle-bdy mdel than were the subjects in Experiment (cf. Trials 7 and 8 ffigure 6 with Trials 1 and ffigure 5). These findings prvide further evidence that the subjects f Experiment were just as sexually respnsive as were the subjects in the earlier experiments. Therefre, the failure f these subjects t shw substantial cpulatry respnding t the fully artificial mdel cannt be attributed t a general lack f sexual respnsiveness. GENERAL DISCUSSION Appetitive cmpnents f sexual behavir have been successfully cnditined t stimuli ranging frm lcalized lights t a small stuffed ty (Dmjan et al., 1986; Dmjan et al., 1988; Hllis et al., 1989). In cntrast, the acquisitin f cnsummatry sexual behavir was nt bserved when an arbitrary stimulus bject served as the cnditined stimulus in cmparable sexual cnditining prcedures (e.g., Dmjan et al., 1988). Sme investigatrs had reprted islated bservatins favian and mammalian species cpulating with artificial stimuli (Barraud, 195; Beach, 195; Ficken & Dilger, 196; Michael, 1961; Yung, 199). Hwever, these reprts invlved small numbers f subjects and did nt identify the training histry that might have been necessary fr the develpment f cpulatin with artificial bjects. The present experiments demnstrated cpulatin with an arbitrary stimulus bject in a sizable number f male Japanese quail and helped t identify a set fexperiential factrs that seem t prmte such behavir. We attempted t cnditin cpulatry behavir t an arbitrary stimulus bject by taking advantage f the fact that sexually experienced male Japanese quail will cpulate with inanimate bjects that include the head and neck f a female quail (e.g., Dmjan et al., 1989). Our strategy was t establish cpulatin with the head-and-neck bject and then gradually cver up the quail features with an arbitrary terryclth material as training prgressed. The fading prcedure was mre successful than the nnfading prcedures in establishing cpulatry behavir t a stimulus bject made entirely f terryclth. Of the 7 subjects that were expsed t the fading prcedure in Ex- periments 1 and, 16 subjects (%) ended up making at least ne clacal cntact respnse when tested with the entirely terryclth bject. In cntrast, nly f (1 %) subjects expsed t a nnfading prcedure (Grups NPI and NP) ended up making at least ne clacal cntact respnse t the fully cvered mdel. The difference between the fading and nnfading prcedures in the prprtin fsubjects cpulating with the fully cvered mdel was significant (Xl = 5.7, p <.5). Several different versins f the fading prcedure were used during the curse f the experiments (Grups FP1, FP, FU). Direct cmparisns fgrups FP1, FP, and FU indicated that these grups shwed similar levels f respnding t the fully cvered mdel during the pstcnditining test in every respnse measure [Fs(,) < 1.]. We als tested tw different nnfading prcedures. In ne (NPl), the subjects were expsed t the fully artificial mdel n every trial; in the ther (NP), the subjects were expsed t mdels cntaining the head and neck f a female quail n every training trial, withut having these quail features gradually remved. The tw nnfading grups (NP1 and NP) shwed similar levels f respnding t the fully cvered mdel during the pstcnditining test in every respnse measure [Fs( 1,8) < 1.9]. Because the fading and nnfading grups did nt differ amng each therduring the pstcnditining test, the test data fr each set f grups were pled.) These pled data are summarized in Figure 7. N significant differences were bserved between the fading and nnfading grups in the frequency f pecking r in the time spent near the stimulus bject during the test sessin [ts(65) =.9 and., respectively, bthps >.7]. Hwever, the subjects that received a fading prcedure made significantly mre grab, munt, and clacal cntact respnses t the fully cvered mdel than did the subjects that received ne f the nnfading prcedures [ts(65) =.,., and.19, allps <.5]. Thus, the advantages prvided by a fading prcedure were limited t the cnsummatry cmpnents f the subjects' cpulatry behavir. The present findings help t rule ut several pssible interpretatins fthe higher level fcpulatry respnding that ccurred in the subjects that received a fading prcedure. Fr example, the superir perfrmance f the fading grups cannt be attributed t sensitizatin effects f cpulatry experience with live female quail because the nnfading grups received cmparable sexual experience with five quail hen. A related interpretatin may be develped n the basis fthe presence fsexually cnditined cntextual r ther stimuli. Studies with avian, rdent, and fish species have shwn that sexually cnditined stimuli increase the effectiveness f female cues in eliciting bth apprach and cpulatry cmpnents f sexual behavir (see Dmjan, 199, fr a review). One pssible interpretatin f these findings is that sexually cnditined stimuli decrease the threshld fr eliciting cpulatry behavir. Dmjan et al. (1989), fr example, demnstrated that male quail are mre likely t cpulate with an inanimate mdel cntaining nly the head and neck f a female if the mdel is

11 6 DaMIAN, HUBER-McDONALD, AND HOLLOWAY 1 >- g 1 Ql ::J CT 8 l!:! ~ 6 "' C ~ F N 1 1 Grab E:I Munt >- 8 c Ql 6 ::J CT Ql u: F 1\7 CI. Cnt Grups Figure 7. Tp panel: Mean secnds spent near the stimulus bject, and frequency f pecks at the bject, during the pstcnditining test trial fr the fading and nnrading grups cmbined (right panel). Bttm panel: Mean frequencies f grab, munt, and clacal cntact respnses during the pstcnditining test trial fr the fading and nfading grups cmbined (right panel). (Vertical bars represent standard errr f the mean.) presented in a sexually cnditined cntext than if the mdel is presented in a familiar, but nnsexual, cntext. In the extreme, the threshld fr eliciting a frm f species-typical behavir may be lwered t such an extent that the behavir ccurs in the absence f its usual eliciting stimulus-what ethlgists have called''vacuum activity" (e.g., Ewert, 198). In the present studies, the cntextual cues f the experimental chambers prbably became assciated with sexual reinfrcement because the subjects received repeated pprtunities t cpulate with quail hen in thse chambers (cf. Dmjan et al., 1989; Dmjan, Akins, & Vandergriff, 199). These cnditined cntextual cues may have lwered the threshld fr eliciting cpulatry behavir. Hwever, the effectiveness f the fading prcedures in prmting cpulatin with the entirely artificial stimulus bject cannt be attributed t such threshld lwering because the nnfading prcedures invlved similar cpulatry experiences in the test chambers and therefre similarpprtunities fr cntextual cnditining. The threshld fr eliciting sexual behavir als may have been lwered by expsure t discrete stimuli that signaled impending cpulatry pprtunity. Fr example, the subjects in the paired grups were placed in the side cage fr abut 5 min befre being released back int the experimental chamber and receiving access t a live quail hen. Therefre, sme aspect f being placed in the side cage and then being let back int the experimental chamber may have becme a cnditined stimulus fr cpulatry pprtunity. Hwever, the presence f such cndi- N tined stimuli cannt explain the facilitating effects fthe fading prcedures because the tw nnfading grups (NPI and NP) als received cpulatry pprtunity paired with release frm the side cages during the cnditining trials. Anther pssible interpretatin is that cpulatin with the artificial bject was a frm f "displacement behavir" r "interruptive activity" (e.g., Baerends, 1988; Ficken & Dilger, 196) that is evident when the executin f an arused activity is thwarted. Fr the subjects in Grups FPl and FP, fr example, cpulatry pprtunity with a live quail hen was always prvided after release frm the side bx and expsure t a stimulus bject, but presentatin f the live hen was delayed fr sec after the start f a trial. The thwarting f sexual behavir during this -sec waiting perid may have caused "displacement" cpulatins directed tward the stimulus bjects. Hwever, such "displacement" cpulatins als shuld have ccurred in the nnfading grups NPI and NP, which als had t wait sec after the start feach cnditining trial t gain access t a live hen. Therefre, interpretatins based n the cncept f displacement behavir als d nt prvide a successful.explanatin f the differences that were btained between the fading and nnfading grups. In additin, a displacement mechanism shuld nt have been perative fr the subjects that received the fading unpaired prcedure in Experiment (Grup FU), because in that prcedure, the live hen was always intrduced int the test chamber unannunced during the cnditining phase, n days that alternated with expsure t the stimulus bjects. Nevertheless, Grup FU did nt make significantly fewer grab, munt, r clacal cntact respnses during the pstcnditining test than did Grup FP. The subjects that received the fading prcedures were mre likely t cpulate with the stimulus bjects during the cnditining trials than were the subjects in Grup NPl, which received the entirely artificial bject n every trial (see Figure ). The fading grups als spent mre time near the stimulus bjects during the cnditining trials than did Grup NP1 (see Figure ). Hwever, these differences prbably were nt respnsible fr the differences between fading and nnfading grups that were bserved during the test sessin. Grup NP, which received access t a stimulus bject cntaining the head and neck f a quail hen n each cnditining trial, als cpulated with the bject much mre ften during the cnditining trials than did Grup NP1 (see Figure 6). Nevertheless, Grup NP did nt shw much cpulatry behavir during the test sessin. The independence ftime spent near a stimulus bject and cpulatin is evident in the fact that the fading and nnfading grups spent cmparable amunts f time near the stimulus bject during the test sessin but shwed significantly different degrees f cpulatry behavir (see Figure 7). The subjects that received the fading prcedures gained mre familiarity with the terryclth cvering during the curse f the cnditining trials than did Grup NP, which never had the quail head and neck cvered with terryclth (even partially) during the cnditining trials.

12 CONDITIONING COPULATORY BEHAVIOR 61 Hwever, the simple hypthesis that familiarity with the terryclth cvering prmtes cpulatin with a terryclth bject cannt explain the btained difference between the fading and nnfading prcedures because ne fthe nnfading grups (NP1) received as much r mre expsure t the terryclth cvering as did the fading grups. Other interpretatins fthe difference between the fading and nnfading grups are based n presumed special prperties f the quail features that were present in the stimulus bjects used in the fading prcedures. Fr example, because f the special significance f quail features in eliciting sexual behavir, the presence f quail features may have enhanced attentin t the stimulus bjects and thereby prmted learning abut the bjects. Thus, the quail features may have enhanced prcessing f the terryclth stimulus. Hwever, fr such an interpretatin t be successful, it has t be elabrated t explain why the presumed increase in attentin enhanced cpulatry respnding but did nt enhance pecking and time spent near the bject during the pstcnditining test. Because Grup FU received access t a live hen n days alternating with expsure t the stimulus bjects, the results btained with Grup FU make unlikely any explanatin that assumes that the fading prcedures smehw enhanced a direct assciatin between the stimulus bjects and reinfrcement btained frm cpulatin with a live hen. The high frequency f cpulatry respnses bserved during the test sessin with Grup FU suggests an assciative mediatinal interpretatin fthe effectiveness f the fading prcedure (Hlland, 1981). This interpretatin assumes the learning ftw assciatins. One is presumably frmed during expsure t a stimulus bject and invlves an assciatin between the quail features f the stimulus bjects and the terryclth cvering. The secnd assciatin is presumably frmed during cpulatry experience with a live quail and invlves the assciatin f visual features f the hen's head and neck with cpulatry reinfrcement. Fr these tw assciatins t be frmed, expsure t the stimulus bjects des nt have t be paired with cpulatry pprtunity. The presence f similar quail features in the stimulus bjects and the live quail hen serves t mediate an assciatin between the terryclth cvering and sexual reinfrcement. All fthe fading prcedures that were used allwed fr the peratin fthe assciative mediatin mechanism. In cntrast, the mechanism culd nt perate with the nnfading prcedure that invlved expsure t a fully cvered mdel n every cnditining trial (Grup NP1). Therefre, the assciative mediatin mechanism is cnsistent with the pr perfrmance f Grup NPI during the test sessin. The mechanism prvides a different accunt fthe pr perfrmance fgrup NP, which was expsed t an bject that included a quail head and neck n every cnditining trial. The stimulus bjects that were used with Grup NP had the quail features that are needed t activate the mediatin mechanism. Hwever, the headand-neck stimuli were nt cvered up during the curse f cnditining. Therefre, the terryclth cvering parts f the neck and head f the stimulus bjects culd nt becme cnditined. The pr perfrmance f Grup NP presumably reflected the lack f pprtunity fr cnditining f the terryclth n the vertical sectin f the entirely artificial stimulus bject (see Figure I). The assciative mediatin interpretatin assumes that cpulatry experience with live female quail is imprtant fr the efficacy fthe fading prcedure. This assumptin was nt tested in the present experiments. Hwever, prir research has shwn that cpulatry experience with live quail hen facilitates cpulatin with a head-and-neck mdel (Dmjan et al., 1989). Cnsistent with that utcme, very little cpulatry behavir was bserved in the present experiments when the subjects were expsed t a headand-neck mdel during the first few cnditining trials, befre they had much cpulatry experience with live quail hen (see Grup FPl in Figure, and Grup NP in Figure 6). Given these findings, it is unlikely that significant cpulatry behavir wuld have develped in the fading grups withut cpulatry experience with live quail hen. The present experiments d nt permit specificatin f the frm f assciative mediatin that might have been perative in the fading grups. Since we intermixed expsures t the stimulus bjects and cpulatin with live female quail, ur prcedures did nt fllw the prtcl fr either sensry precnditining r secnd-rder cnditining. Our fading prcedures may have activated ne r bth f these mechanisms. Any cmplete accunt fthe present fmdings has t prvide an explanatin fthe dissciatin that was bserved between the cpulatry and nncpulatry respnse measures. Althugh the fading grups were mre likely than the nnfading grups t engage in cpulatry behavir during the test sessin, the tw types f grups spent similar amunts ftime near the stimulus bject and shwed similar levels f pecking behavir. Pecking may nt have reflected sexually cnditined behavir (Schlinger, Palter, & Callard, 1987). Cnsistent with that interpretatin, acquisitin effects were nt evident with the pecking respnse (see Experiment 1). In cntrast, time spent near a cnditined stimulus frequently has been used as a measure fsexual cnditining and has been shwn t reflect assciative prcesses (e.g., Dmjan et al., 1986; Dmjan et al., 1988). The nnfading grups may have spent as much time near the stimulus bject as did the fading grups because fr Grups NP1 and NP, the area arund the stimulus bject was als the area where the live female was released int the experimental chamber during cnditining trials (see Figure ). Therefre, the time the nnfading grups spent in this area may have reflected the cnditining f spatial cues rather than the cnditining fthe stimulus bject. Given these cnsideratins, the fading and nnfading grups may have shwn similar time scres during the test sessin fr different reasns. The apprach behavir f the fading grups may have been cntrlled primarily by the stimulus bject, whereas the

13 6 DaMIAN, HUBER-McDONALD, AND HOLLOWAY apprach behavir fthe nnfading grups may have been cntrlled by the place where the female quail had been presented during cnditining trials. Anther pssibility is that the apprach behavir became cnditined t features f the artificial stimulus bject in bth the fading and the nnfading grups but that the cnditining f cpulatry behavir required mre stringent cnditining parameters than did the cnditining f apprach behavir. This alternative is cnsistent with earlier characterizatins fappetitive behavir as being mre flexible than cnsummatry behavir (Eibl-Eibesfeldt, 197; Tinbergen, 1951). Such differences in susceptibility t learning may be related t tempral variables. Timberlake and Lucas (1989), frexample, have suggested that shrter CS-US intervals are required fr the cnditining f cnsummatry cmpnents f behavir sequences rather than fr the cnditining f appetitive respnses. 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Feierman (Ed.), Pedphilia: Biscial dimensins (pp. -7). New Yrk: Springer-Verlag. DMJAN, M. (199). Adult learning and mate chice: Pssibilities and experimental evidence. American Zlgist,, DOMJAN, M., AKINS, C., 8< VANDERGRIFF, D. H. (199). Increased respnding t female stimuli as a result f sexual experience: Tests f mechanisms f learning. Quarterly Jurnal fexperimental Psychlgy, 58, DOMJAN, M., GREENE, P., 8< NORTH, N. C. (1989). Cntextual cnditining and the cntrl fcpulatry behavir by species specific sign stimuli in male Japanese quail. Jurnal fexperimental Psychlgy: Animal Behavir Prcesses, 15, DMJAN, M., LYONS, R., NORTH, N. C., 8< BRUELL, J. (1986). Sexual Pavlvian cnditined apprach behavir in male Japanese quail (Ctumix ctumix japnica). Jurnal f Cmparative Psychlgy, 1, 1-1. DMJAN, M., 8< NASH, S. (1988). Stimulus cntrl f scial behaviur in male Japanese quail (Ctumix ctumixjapnica). Animal Behaviur, 6, DOMJAN, M., O'VARY, D., 8< GREENE, P. (1988). 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Sexual perfrmance levels f male Japanese quail (Ctumix ctumixjapnica). Animal Behaviur,, ScHEIN, M. W., 8< HALE, E. B. (1965). Stimuli eliciting sexual behavir. In F. Beach (Ed.), Sex and behavir (pp. -8). New Yrk: Krieger. ScHLINGER, B. A., PALTER, B., 8< CALLARD, G. V. (1987). A methd t quantify aggressiveness in Japanese quail (Ctumix ctumixjapnica). Physilgy & Behavir,, -8. SCHOETTLE, H. E. T., 8< ScHEIN, M. W. (1959). Sexual reactins f male turkeys t deviatins frm a nrmal female head mdel. Anatmical Recrd, 1, 65. TERRACE, H. s. (1966). Stimulus cntrl. In W. K. Hnig (Ed.), Operant behavir: Areasfresearch and applicatin (pp. 71-). New Yrk: Appletn-Century-Crfts. TIMBERLAKE, W., 8< LUCAS, G. A. (1989). Behavir systems and learning: Frm misbehavir t general principles. In S. B. Klein & R. R. Mwrer (Eds.), Cntemprary leaming theries: Instrumental cnditining thery and the impact fbilgical cnstraints n leaming (pp. 7-75). Hillsdale, NJ: Erlbaum. TINBERGEN, N. (1951). The studyfinstinct. Lndn: Oxfrd University Press. WILSON, M. I., 8< BERMANT, G. (197). An analysis f scial interactin in Japanese quail (Ctumix ctumix japnica). Animal Behaviur,, YOUNG, H. (199). Atypical cpulatry behavir fa rbin. Auk, 66, 9. NOTE I. The three experiments were cnducted cnsecutively, withut a break. Althugh the experiments invlved birds frm different hatchings at slightly different times f year, the subjects were maintained under standard labratry cnditins, which shuld have resulted in cmparable sexual mtivatin. T further insure cmparability f the subjects, the subjects selected fr participatin in the experiments were all pretested fr cpulatry behavir with a live quail hen. All aspects f the experiments that permitted direct assessment f the cmparability f the subjects acrss experiments cnfirmed the absence fsystematic differences. Bth the prcedures and results fthe fading paired prcedure were replicated in Experiments I and (Grups FPI and FPZ, respectively), and the subjects in Experiment respnded similarly t the subjects in Experiments I and that were expsed t the same types f mdels during cnditining (see Results f Experiment ). (Manuscript received July, 1991; revisin accepted fr publicatin April 15, 199.)