After multiple pairings of a cue and a rewarding event, animals will begin to attend to both the reward and the cue. Reports from Brown and Jenkins (1968) first described pigeons that began to track key lights predictive of food reward. Subsequently the phenomenon of conditioned cue approach has been reported across a variety of species including pigeons, quail, rats, monkeys, and stickleback fish (Brown and Jenkins, 1968; Cetinkaya and Domjan, 2006; Holland, 1977; Jenkins and Rowland, 1996; Sidman and Fletcher, 1968). More recently, investigations of individual differences in the expression of these behaviors have begun, as well as exploration into how these differences relate to other cognitive and neurological variations (Lesaint et al., 2014; Lovic et al., 2011; Meyer et al., 2012; Paolone et al., 2013). The objective of this dissertation was to characterize individual differences in rats’ propensity for orienting towards a light-cue predictive of reward. I also aimed to describe how these differences related to the behavior’s vulnerability to memory updating, extinction learning, a variety of cognitive functions, and behavioral and neurological responses to drug challenge. I report that all rats showed conditioned approach toward the site of food-reward delivery, but only a subset also showed robust rearing and/or orienting toward a light predictive of food (Orienters). Those rats that showed only conditioned reward approach were termed Nonorienters. Following memory update procedures, Orienters were more likely than Nonorienters to attenuate conditioned food approach, though conditioned rearing remains unaffected. Orienters were also more likely to make impulsive and risky decisions, enter a novel and risky environment, and be distracted during an attention assay. They also emitted more ultrasonic vocalizations than Nonorienters when exposed to amphetamine. Moreover, while both Orienters and Nonorienters preferred a context previously paired with drug to a context paired with saline, Orienters emitted more ultrasonic vocalizations during the preference test. Finally, while Orienters and Nonorienters showed behavioral differences after amphetamine injection, these differences were not reflected in the activity of the brain regions responsible for the conditioned orienting response. Overall, these findings suggest that Orienters are more apt to memory update, make more impulsive and risky decisions, are more vulnerable to distraction, and that amphetamine has more impact upon the behavior of Orienters. / text

The safety signal hypothesis suggests that during the absence of stimuli predicting impending shock, the organism is not fearful. The stimuli which predict the absence of shock are therefore called safety signals. The purpose of the present study was to investigate some critical properties of safety signals. Such stimuli in an avoidance or escape situation, according to the opponent process model, are expected to acquire hedonic value opposite to shock. This study examined differences in conditioning variables between safety signals predicting different intensities of shock, and between safety signals present in procedures using predicted shock, and procedures using unpredicted shock. Additionally, the effects of inescapable unpredicted shock with no safety signals present were examined. The general procedure involved exposing pigeons to aversive Pavlovian conditioning and subsequently autoshaping these birds to stimuli which had predicted safety in the aversive situation. Dependent measures included trials to acquisition of the autoshaped response and subsequent rate of keypecking. In the six experimental groups, pigeons were repeatedly and inescapably shocked at either 30 or 90 volts. Each individual 0.5 sec shock was (a) predicted by a specific stimulus or (b) not predicted. Additionally and explicitly unpaired with the shock, a safety signal was presented. For each voltage level, a control group was repeatedly shocked with no stimuli presented at any time. Control groups were included which (a) received no aversive conditioning, (b) were autoshaped to a stimulus which had previously predicted shock, (c) received the aversive conditioning, and (4) were exposed to various stimuli but received no aversive reinforcement. The principal finding was that preexposure to strong shock resulted in delays in response acquisition during subsequent autoshaping. This suggests that the learned helplessness hypothesis obtains with classically conditioned responding. Additionally, the importance of shock-alone control groups in the study of transfer effects is critical. Due to the lack of statistical power, the study was not definitive regarding the nature of safety signals or appetitive-to-appetitive transfers. Statistically significant differences were only found on acquisition measures, and no such differences were found on performance measures.

In the autoshaping preparation subjects are exposed to magazine training (US-only trials) prior to the conditioning phase in which a stimulus (conditioned stimulus, CS) predicts the delivery of a response independent reinforcer (unconditioned stimulus, US). Two experiments examined the hypothesis that irrespective of the number of US-only trials administered the magazine training and autoshaping contexts interact to determine conditioning, as measured by contact responses to the CS. The contexts employed were houselight on (light, L) and houselight off (dark, D). In Experiment I pigeons were exposed to 1, 20, 100, or 900 US-only trials in a D, or L, context prior to autoshaping in the D, or L. The results indicated that first, autoshaping in the L was superior to autoshaping in the D. Second, irrespective of the autoshaping context performance was better following magazine training in the different context. Third, the function relating performance to the number of US-only trials was an inverted U if magazine training occurred in the D and biphasic if it occurred in the L, irrespective of the autoshaping context. In Experiment II pigeons were exposed to 900 US-only trials in a D, or L, context. Prior to autoshaping in the D, or L, they were exposed to either the magazine training, or a novel, context; this constituted extinction of the US-only context. The results demonstrated that when magazine training and autoshaping occur in the D extinction in the magazine training context results in superior performance relative to extinction in a novel context. However, extinction in a novel context results in better performance, relative to extinction of the magazine training context, if magazine training and autoshaping proceed in the L. In summary, conditioning in the autoshaping paradigm is determined by the magazine training and autoshaping contexts and their interaction. The development of conditioning is therefore dependent on both the associative value of the CS and the background stimuli.

The purpose of this study was to develop behavior by the pigeon illustrative of S+ and S- rules and to examine if behavior consistent with a concept rule interpretation developed. In order to examine this possibility six groups of pigeons (N=31) were provided different histories of autoshaping. Histories involved the identity of the color of the lighted center key and one side key of three horizontally mounted pigeon keys. Center key onset was followed three seconds later by onset of either outer key. Outer key onset was followed six seconds later by food presentation (explicitly paired) or 45 seconds later, during the inter-trial interval (explicitly unpaired). The foregoing reinforcement conditions were factored into two stimulus conditions, one where the center and side keys were lit by the same hue (identity) and one where the center and side key were lit by different hues (nonidentity). Two groups received identity stimulus sequences with explicitly unpaired food presentation. Two groups were exposed to nonidentity stimulus sequences with explicitly unpaired food presentation. One group received sessions combining exposure to both the explicitly paired identity and explicitly unpaired nonidentity trials. One group received no pretraining. Following pretraining, all birds were placed in a simultaneous matching-to-sample task utilizing the same hues used during pretraining. After reaching criterion on matching-to-sample, on a random ratio 3 schedule of reinforcement, birds were exposed to transfer tests, with a novel hue, to assess for S+ rules, S- rules, and a concept rule. The results indicated that there were no significant differences among groups in terms of their acquisition of matching-to-sample or in terms of their performance on transfer tests. All birds' responding during transfer conditions provided evidence of S+ rules, but neither demonstration of S- rules nor concept rule performance was evidenced. During autoshaping, birds in the identity, explicitly paired groups responded primarily to the center key, suggesting that the stimulus on the outer key was not a salient stimulus for the identity discrimination. For birds in the nonidentity, explicitly unpaired groups neither the center nor outer key controlled responding. For the group combining identity, explicitly paired and nonidentity, explicitly unpaired trials, the birds failed to form a discrimination between types of trials.

A series of five experiments was conducted to determine whether operant or respondent factors controlled the emission of a particular vocalization ( "Q" ) by human infants 16 to 18 months old. Experiment 1 consisted of a pilot investigation of the effects of an autoshaping procedure on three infants' vocal behavior. All three subjects demonstrated increased emission of the target sound during the CR period. Experiments 2 through 4 attempted to replicate the findings of Experiment 1 under controlled conditions, and failed to do so. Experiment 5a presented infant subjects with a discrete-trial operant procedure (having the identical temporal parameters as the autoshaping procedure used in Experiments 1 through 4) , during which subjects received rewards only after emitting the target sound. All three experimentally naive subjects in this condition emitted the target sounds, and each met an acquisition criterion of 15 successive trials with at least one target response (CR) per trial. Subjects in Experiment 5b were exposed to the autoshaping procedure employed in Experiments 1 through 4; in addition, they were rewarded verbally for emitting the target sound at any time during the session. One of these three subjects increased her rate of target sound emission, but never met the acquisition criterion. The results suggest that vocalizations of subjects in this age range are susceptible to response-reinforcer (operant) manipulations and not to stimulus-stimulus (Pavlovian) associations. This conclusion differs from the findings of previous investigations that used younger infant subjects, suggesting that subject age may be important when conditioning vocalizations. Further research is also recommended to determine the utility of employing autoshaping procedures with humans.

This thesis is compromised of three studies in which basic principles of operant conditioning were applied to horses. Autoshaping was examined as a method for horse training. Observational learning was investigated to confirm that naive horses can, in fact, acquire novel behavior by observing experienced horses, and the rate of acquisition with observation is more rapid than spontaneous responding without observation. A third study examined the effect of discriminative stimulus intensity on the acquisition rate of novel behavior. All subjects learned to use an operant conditioning device. Subjects in the first study autoshaped. Observational learning was also demonstrated to be a means by which horses can learn. The rate of learning was significantly improved through observation. Intensity of the discriminative stimulus affects the acquisition of novel behavior. The subject exposed to the higher intensity stimulus acquired sustained manipulandum pressing significantly faster than other subjects. It was concluded that horses acquire behavior in much the same manner as other species.

The attribution of incentive salience to cues that become associated with drugs of abuse is a critical characteristic of individuals who may be vulnerable to drug addiction. Rodents with the propensity to sign track are thought to be vulnerable to drug abuse. The goal of the current work was to investigate whether sign trackers (STs) would acquire cocaine conditioned place preference (CPP) to a discrete cue using an avian species. In Experiment 1, sign and goal trackers (GTs) were first identified using a one third rank order split. Following identification, cocaine-CPP was conducted with a discrete cue in each end chamber. Contrary to previous research, results showed that GTs showed a CPP to the discrete cue but STs did not. Experiment 2 was conducted to determine whether sign and GTs had been misclassified with the rank order split. Experiment 2 compared the rank order method with a t-test method (absolute criterion). Misclassification of both sign and GTs occurred using the rank order split. The findings indicated that use of a more accurate method to identify sign and GTs may have led to different results for Experiment 1. The t-test method may be useful for models that require identification of STs.