Ontogeny of passive avoidance learning in domestic chicks: Punishment of key-peck and running responses.

Determined the effect of the number of prepunishment acquisition trials on the age dependency of passive avoidance (PA) learning of the chick in keypeck and runway tests. In 9 experiments, 1- and 4-day-old Ss were first trained to respond for heat reward. After a variable number of reinforced acquisition trials (ATs), Ss' responses were punished with aversive wing shocks. Results show that the age dependency of PA learning of the young S is related specifically to the number of reinforced training trials given prior to PA testing. When several prepunishment ATs were given, 1-day-old Ss learned as quickly as 4-day-old Ss to withhold responding when punished. However, when only a few ATs preceded PA testing, 1-day-old Ss showed significantly less response suppression than 4-day-old Ss. Rather, results suggest that the 1-day-old chick, compared with the 4-day-old chick, is deficient in learning or detecting changes in stimulus– and/or response–reinforcement contingencies. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Activation of domestic chicks.

Given prior results showing reinforcement effects for contingent light onset in day-old Leghorn chicks, the present series of studies examined effects of noncontingent light presentation using the same operant as an index of activity. Ss were a total of 641 White Leghorn cockerel chicks between 24-36 hrs old. Results show a strong, consistent topography of activity which depended upon the same parameters known to influence reinforcement effects in these Ss. Activation is suggested as a process and a means for prediction or reinforcement effects-particularly when the topography of activation is compatible with behavioral requirements of a reinforcement contingency. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ontogeny of eyeblink conditioned response timing in rats.

Eyeblink conditioned response (CR) timing was assessed in adult and infant rats. In Experiment 1, adult rats were trained with a 150-ms tone conditioned stimulus (CS) paired with a periorbital shock unconditioned stimulus (US; presented at 200- or 500-ms interstimulus intervals [ISIs]). The rats acquired CRs with 2 distinct peaks that occurred just before the US onset times. Experiments 2 and 3 examined developmental changes in CR timing in pups trained on Postnatal Days 24-26 or 32-34. Experiment 3 used a delay conditioning procedure in which the tone CS continued throughout the ISIs. Pups of both ages exhibited robust conditioning. However, there were age-related increases in the percentage of double-peaked CRs and in CR timing precision. Ontogenetic changes in eyeblink CR timing may be related to developmental changes in cerebellar cortical or hippocampal function. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pavlovian conditioned inhibition.

Examined the notion of conditioned inhibition and suggests a definition in terms of the learned ability of a stimulus to control a response tendency opposed to excitation. 2 techniques of measuring inhibition are outlined: (1) the summation procedure in which an inhibitor reduces the response that would normally be elicited by another stimulus, and (2) the retardation of acquisition procedure in which an inhibitor is retarded in the acquisition of an excitatory CR. Examples of the use of these procedures are given for a variety of UCS modalities. Several possible operations for generating conditioned inhibitors are reviewed: extinction following excitatory conditioning, discriminative conditioning, arrangement of a negative correlation between CS and a UCS, use of an extended CS-UCS interval, and presentation of a stimulus in conjunction with UCS termination. These operations suggest that conditioned inhibitors are not generated either by simple extinction procedures or by pairing a stimulus with UCS termination. By contrast, for both salivary and fear conditioning the other procedures do appear to generate inhibitors. Most of the procedures generating conditioned inhibitors can be described as arranging a negatively correlated CS and UCS. (2 p. ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of multiple peer separation in domestic chicks.

Determined if domestic chicks respond to multiple social separations with the cumulative disruption of social development seen in other species. 12 pairs of White Leghorn chicks were separated and reunited 15 times over 7 wks. The 1st 3 separations were 72 hrs each; the remaining 12 each lasted 24 hrs. Reunions were of the same length as the corresponding separations. Daily observations were supplemented with measures of Ss' reactions to unfamiliar conspecifies and environments. As a group, the separates were sensitive to every separation and every reunion. One facet of the separates' social behavior was apparently affected by these separation–reunion episodes: There was a reduction in the degree to which the separates matched one another's food-peck responses, indicating a possible deficit in their social propensities. However, the separates' behavior tended toward control levels within the 72-hr separation periods, across the series of day-long separations, and in the supplemental tests. In sum, no broadly debilitating effect comparable to that found in primates was seen. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stimulus relevance in the control of drinking and conditioned fear responses in domestic chicks (Gallus gallus).

Trained groups of young domestic chicks (N = 310) to reject selectively quinine-flavored or electrified water distinguished by 1 of several visual and auditory stimuli. With visual discriminative stimuli, Ss learned within a few trials, but with sounds they learned poorly, although they could hear the sounds. When a compound of flashing light and clicks signaled footshocks for drinking or shock through the water, drinking was completely controlled by the flashing light. In contrast, when the same compound was paired with footshock in a CER paradigm, Ss' behavior was controlled primarily by the clicks. Results constitute a demonstration of stimulus relevance or belongingness, but differ in important ways from other examples of the nonequivalence of stimuli, responses, or reinforcers. (35 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Social discrimination and aggressive pecking in domestic chicks.

Free interaction among 192 White Leghorn chicks involved inter-S pecking. During tests as early as 1 day after hatching, socially reared Ss showed reliable social discriminations by pecking more at strangers than at cage mates. Compared with socially reared birds, Ss reared in isolation exhibited certain exaggerated or atypical response patterns. Patterns included heightened rates of inter-S pecking, a pronounced tendency to peck at the head, elevated emotionality as reflected in the distress call, and the failure of pair-mates to show matched rates of environmental pecking. Inferences are drawn from these patterns, with the conclusion that infantile inter-S pecking in chicks may be based on aggressive rather than strictly exploratory tendencies. Findings are discussed in terms of the development of a basic tolerance for conspecifics and early social orderings. (52 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Extinction of Pavlovian conditioned inhibition.

Examined 2 procedures with potential for reducing Pavlovian conditioned inhibition in 4 experiments with 72 male Sprague-Dawley rats. The 1st, simple nonreinforced presentation, was suggested by a theory which has been successful with data from the acquisition of conditioned inhibition. However, nonreinforced presentation of a stimulus, either after conditioned inhibition training or intermixed with such training, failed to produce any loss of the inhibition controlled by that stimulus. The 2nd procedure involved removing the negative correlation between inhibitor and reinforcement. When this correlation was altered, in such a way as to continue UCS presentation, loss of inhibition occurred. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Learning in domestic chicks after exposure to both discriminanda.

P. P. Bateson and D. F. Chantrey (see record 1972-30989-001) have suggested that the characteristics of complex objects may be learned by young animals by sequential exposure to parts or views of the object. The various component stimuli are said to be "classified together" as the animal learns to perceive its world. Consequently, domestic chicks given the opportunity to classifty together color stimuli are subsequently less able to discriminate between them than are controls. Nine experiments with 171 Shaver Starcross Leghorn and Vantress broiler chicks were designed to investigate this phenomenon further. Ss were exposed either to colors or to shapes and subsequently trained to discriminate between them, and their discrimination performance was compared with that of nonexposed controls. In only 2 experiments, one of them a near replication of Bateson and Chantrey's work, were their findings reproduced. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Enhancement of effectiveness of learning by testosterone in domestic chicks.

In 4 experiments with 20 2–3 day old male Warren Sex-link chicks, the presentation of a nonaversive colored bead to be pecked (pretraining) interfered with subsequent avoidance training in which the bead presented tasted unpleasant, when only 2 conditions were fulfilled: (a) Beads used at pretraining and training were of similar appearance, and (b) testosterone was injected either before or shortly after pretraining. This effect of the hormone was not a consequence of changes in behavior at training or at test. Rather, it appeared to reflect changes during the consolidation of the pretraining memory trace that made it more effective in subsequent competition with training. Beads that were blue in color were unusual in evoking high levels of avoidance in naive Ss and, when used in pretraining in the presence of testosterone, in failing to oppose subsequent training on the blue bead. Such pretraining became effective when paired with avoidance training with a bead of different color, apparently by changing the information stored about pretraining. (37 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of social isolation and social separation in domestic chicks.

Conducted 2 experiments with 60 white Leghorn chicks, with subsamples of 24 and 36 animals tested in 2 independent replications, to assess the impact of early social isolation and social separation on the behavior of domestic chicks. In Exp I, a 3-wk longitudinal study, the day-to-day behavior of isolated chicks was compared to the behavior of birds housed in pairs. Ss in a 3rd group were reared in pairs for 2 wks, and then were permanently separated. The daily observations of all Ss recorded disturbance reactions, exploratory activities, consummatory behavior, grooming, and inactivity. In Exp II, 36 Ss from the 3 experimental conditions were tested in the 4th posthatch week for general social responsiveness in the presence of unfamiliar conspecifics. Results show that (a) both isolation and separation produced behavioral anomalies; (b) separated Ss' reactions indicated patterns analogous to post-separation patterns seen in other species; and (c) the effects of isolation and separation were not qualitatively equivalent--exposure to conspecifics revealed antisocial behavior in the isolates, relative to the responses of their socially reared and separated counterparts. Results are discussed in terms of a model for differences in the essence and consequences of early social isolation and social separation. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Food-reinforced inhibition of conditioned salivation in dogs.

12 mongrel dogs salivated to a tone that was followed by food, but not to a noise for which there was an added response dependency. The noise was followed by food if and only if they did not salivate. The addition of this response dependency vitiated the classically conditioned response to the noise. A yoked-control group of 6 Ss receiving the same sequences of stimuli and food salivated to both the tone and noise stimuli. It is generally concluded that neither the effects of stimulus-dependent reinforcement nor the effects of response-dependent reinforcement are restricted to either skeletal or autonomic responses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Latent inhibition in the conditioned electrodermal response.

Measured the effects of preexposure to the CS, amount of pre-exposure, and delay between pre-exposure and conditioning in a classical electrodermal conditioning experiment with 139 female nursing students. 3 conditions were investigated: no delay, 1-hr delay, and 24-hr delay. In each of these delay conditions Ss were pre-exposed to either 100 or 50 presentations of the to-be-conditioned stimulus or 100 or 50 presentations of an irrelevant stimulus. Results were analyzed separately for long and short latency responses in terms of amplitude, magnitude, latency, recruitment, and frequency. It was found that CS pre-exposure reduced the frequency of responding regardless of delay or number of pre-exposures. There was a significant CS Pre-exposure main effect for short latency responses and a significant Trial Blocks * CS Pre-exposure interaction effect for long latency responses. Theoretical and methodological implications are discussed. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of conditioned fear on tonic immobility in domestic chickens.

Conducted 2 conditioned fear experiments with 36 and 14 Production Red chickens. Ss given brief exposure to a compound stimulus which had been previously paired with intense electric shock remained immobile significantly longer following manual restraint than Ss which received either shock only or the compound stimulus only during training. The administration of a tranquilizer (metoserpate hydrochloride, pacitran) reduced the effect of conditioned fear on the resulting duration of immobility. Results provide strong support for the notion that fear underlies the tonic immobility reaction in domestic fowl. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparator mechanisms and conditioned inhibition: Conditioned stimulus preexposure disrupts Pavlovian conditioned inhibition but not explicitly unpaired inhibition.

Three conditioned lick-suppression experiments with rats examined the effects of pretraining exposure to the conditioned stimulus (CS) on behavior indicative of conditioned inhibition. After CS-preexposure treatment, subjects received either Pavlovian conditioned inhibition training or explicitly impaired inhibition training with the preexposed CS. The inhibitory status of the CS was then assessed with a retardation (Experiment 1) or a summation (Experiment 2) test. Experiment 3 controlled for the unconditioned stimulus-preexposure effect being a potential confound in Experiments 1 and 2. As predicted by the comparator hypothesis (R. R. Miller & L. D. Matzel, 1988), the CS–context association that developed during the CS-preexposure phase disrupted the expression of Pavlovian conditioned inhibition but not the expression of explicitly impaired inhibition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ontogeny of serotonergic inhibition of behavioral arousal in the rat.

Tested the effects of para-chlorophenylalanine (P-CPA), which depletes brain serotonin, in 3 experiments with 10-25 day old albino Sprague-Dawley rats. Experimental Ss were tested for locomotor effects 0, 24, 48, and 72 hrs after P-CPA injection. Depletion of serotonin increased behavior arousal in 15-, 20-, and 25-day-old Ss, but not in those 10 days old. P-CPA potentiated the locomotor activity induced by amphetamine, but again 10-day-old Ss did not show the effect. These results are interpreted as evidence for the delayed maturation of a serotonergic inhibitory system that modulates behavioral arousal. (53 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Septal correlates of conditioned inhibition and excitation in rats.

Recorded multiple-unit activity in the lateral septum of rats during Pavlovian differential conditioning. In Exp I, 14 male Sprague-Dawley rats received a classical aversive discrimination paradigm, while 11 Ss were presented with a control procedure in which the UCS (shocks) was administered randomly with regard to the CS. Septal unit activity increased during presentations of the conditioned inhibitor and was markedly suppressed during presentations of the conditioned excitor in the conditioning-group Ss and not in controls. Baseline activity remained unchanged in the conditioning group but was suppressed in the random control group. Furthermore, termination of the aversive stimuli was marked by a burst of firing in the conditioning group, but no such rebound was seen in the control group. In Exp II (6 Ss), a classical appetitive discrimination paradigm was given, in which septal unit activity increased in the presence of the conditioned excitor and was suppressed in the presence of the conditioned inhibitor. Results indicate a role for the septum in the relief of aversive states. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Simultaneous backward conditioned inhibition and mediated conditioning.

Demonstrations of retrospective revaluation suggest that remembered stimuli undergo a reduction in association with the unconditioned stimulus (US) present during learning. Conversely, demonstrations of mediated conditioning in flavor-conditioning experiments with rats suggest that remembered stimuli undergo an increase in association with the US present during learning. In a food allergy prediction task with 23 undergraduates, we demonstrated simultaneous backward conditioned inhibition and mediated conditioning effects. These results are compatible with the hypothesis that the direction of change (decrease or increase) in associative strength depends on whether the remembered stimulus was of a different category (conditioned stimulus/antecedent) or the same category (US/outcome) as the presented US. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Radiosensitive period of pecking response during embryological development of domestic chicks.

Gave gamma irradiation to 174 cross-bred chick embryos on Days 2-12 of incubation in 2-day steps. A 5-fold increase in between-Ss variance and a 3-fold increase in within-Ss variance resulted when Ss were tested with induced pecking responses, but only in groups treated on Days 6 and 8. There were no difference in variances between groups treated on any other day nor in the controls. It is claimed that comparison of means is an inappropriate and misleading test for treatment effects. Results are discussed in terms of both raised thresholds and loss of negative feedback in the response system. (24 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Transfer of negative occasion setting and conditioned inhibition across conditioned and unconditioned stimuli.

The transfer of negative occasion setting and conditioned inhibition across conditioned stimuli (CSs) and unconditioned stimuli (USs) was examined in four experiments that used Pavlovian appetitive feature negative discrimination training procedures with rats. After training with simultaneous compounds (A+, XA–), X inhibited conditioned responding (CRs) elicited by other CSs and CRs supported by other appetitive USs that had not been involved in discrimination training. After training with serial compounds (A+, X→A–), X's power to set the occasion for nonresponding transferred across CSs and USs only if those events had also been involved in serial feature negative discrimination training. The results supported the suggestion that the acquisition of negative occasion setting involves the representation of individual events in a higher order memory system, separate from that involved in simple association, and that negative occasion setters act only on events that are represented in that system. (PsycINFO Database Record (c) 2010 APA, all rights reserved)