Falk's pivotal 1961 study showed that rats would drink excessive amounts of water when exposed to a time based schedule of reinforcement. Since then, schedule-induced drinking or polydipsia, has been demonstrated with several species and with a variety of different behaviors. Rats, the most commonly used animal, have been shown to drink excessive amounts of water under a variety of different time based schedules of reinforcement; exclusively during a free operant procedure. The current study shows that water drinking can be induced during a discrete trial procedure, and instead of using a time-based schedule of reinforcement, this study used a variable-ratio schedule of reinforcement. The results showed that excessive water drinking was induced under these conditions with a canine.

Behavioral momentum theory (BMT) has become a prominent method of studying the effects of reinforcement on operant behavior. BMT represents a departure from the Skinnerian tradition in that it identifies the strength of responding with its resistance to change. Like in many other operant research paradigms, however, responses are considered to be momentary phenomena and so little attention has been paid to non-rate dimensions of responding. The current study takes up the question of whether or not the degree of effort defining a discriminated operant class has any meaningful effect on its resistance to change. Using a force transducer, rats responded on a two-component multiple VI 60-s VI 60-s schedule where each component was correlated with a different force requirement. Resistance to change was tested through prefeeding and extinction. Proportional declines in response rate were equal across components during all disruption tests. Differentiated response classes remained intact throughout. The negative result suggests several future research directions.

Evaluating our environment by deciding what is beneficial or harmful, pleasant or punishing is a part of our daily lives. Seeking pleasure and avoiding pain is a common trait all mobile organisms exhibit and understanding how rewarding stimuli are represented in the brain remains a major goal of neuroscience. Studying reward learning in the fruit fly, Drosophila melanogaster has enabled us to better understand the complex neural circuit mechanisms involved in reward processing in the brain. By conditioning flies with sugars of differing nutritional properties, we determined that flies trained with sweet but non-nutritive sugars formed robust short-term memory (STM), but not long-term memory (LTM). However, flies conditioned with a sweet and nutritious sugar or a sweet non-nutritious sugar supplemented with a tasteless nutritious compound, formed robust 24 hour LTM. These findings led us to propose a model of parallel reinforcement pathways for appetitive olfactory conditioning in the fly, in which both sweet taste and nutrient value contribute to appetitive long-term memory. We followed this line of research by examining the neural circuitry in the fly brain that represents these parallel reward pathways. We found that the biogenic amine octopamine (OA) only represents the reinforcing effects of sweet taste. Stimulation of OA neurons could replace sugar in olfactory conditioning to form appetitive STM. Surprisingly, implanting memory with OA was dependent on dopamine (DA) signaling, which although being long associated with reward in mammals, was previously linked with punishment in flies. We found that OA-reinforced memory functions through the α-adrenergic OAMB receptor in a novel subset of rewarding DA neurons that innervate the mushroom body (MB). The rewarding population of DA neurons is required for sweet and nutrient reinforced memory suggesting they may integrate both signals to drive appetitive LTM formation. In addition, OA implanted memory requires concurrent modulation of negatively reinforcing DA neurons through the β-adrenergic OCTβ2R receptor. These data provide a new layered reward model in Drosophila in which OA modulates distinct populations of both positive and negative coding DA neurons. Therefore, the reinforcement system in flies is more similar to that of mammals than previously thought.

Aversive tasks and activities are commonly encountered in the everyday routines of most individuals. For individuals with intellectual disabilities, a means to assess individual sensitivities to aversive stimulation could allow caregivers to avoid unnecessary contact with aversive events, teach appropriate ways to avoid or escape aversive situations, and condition tolerance to unavoidable aversive tasks and activities. The current study, conducted at a large, state-operated residential facility for adults with intellectual disabilities, used an anecdotal assessment, the Sensitivities to Aversive Stimulation Survey (SASS), to evaluate the relative aversiveness of an array of commonly encountered tasks and activities for each participant. Five caregivers complete the 25-question assessment, using Likert-type scales to rate individual participants' affect, compliance or tolerance, and severity of problem behavior related to each item. The mean scores of the raters were used to estimate the aversiveness of each task, condition, or activity. The outcomes from the SASS were then compared with outcomes of an experimental analysis in which participants could emit responses to escape situations that were ranked either high or low using the SASS. Relative aversiveness was evaluated by comparing the percentage of trials with escape behavior and duration of exposure for each stimulus. Preliminary results indicate that the SASS may be useful in identifying aversive tasks and stimuli.

Two groups of eleven retarded adults each were used as subjects. An individually consequated token economy was in effect during baseline-1 for both groups. The treatment phase of the experiment consisted of group consequation, the first group receiving a high rate of reinforcement and the second group receiving a low rate. The individual token system was reinstated for both groups during baseline-2 measures. Attending behavior and work output were measured during each phase of the experiment. Significant differences were found between group versus individually contingent reinforcement treatments on attending behaviors, and between high and low contingency groups on performance behaviors. Differences between the high contingency and low contingency groups were found to be non-significant in regard to attending behaviors.

The purposes of this study are: (1) to make a contribution to the increasingly urgent evaluation of an appropriate measure of the intellectual potential of South Texas Mexican-American children as studied through the community of Charlotte, Texas; (2) to gain some insight into the intellectual abilities of Mexican-American children of Charlotte, Texas when compared to the national norm; (3) to appraise the effects of bilingualism as it relates to the mental development of first through fourth grade children of Mexican- American parentage, particularly through the WISC from the standpoint of the language in which the test is given; (4) to ascertain the value of tangible (candy) and intangible (praise) reinforcement for each correct response yielded during the testing session.

Operant conditioning using positive reinforcement techniques has been used extensively in the management of nonhuman primates in both zoological and laboratory settings. Based on a large body of previous research that demonstrates the utility of such techniques in reducing stress, abnormal behavior, and aggression, this research project was intended to develop and test the usefulness of habituation and counter-conditioning techniques in reducing the fear-responses of singly-housed male rhesus macaques living in the laboratory environment. Additionally, we investigated the variable of temperament as it relates to the reduction of fear-responsivity and overall training success. Based on a Wilcoxon Matched-Pairs Sign Test, we found that animals exposed to desensitization training were significantly likely to show a reduction in the rate at which they engaged in cringing toward humans (exact significance = .016, one-tailed, N ties = 6), cringing in general (exact significance = .016, one-tailed, N ties = 6), and in stress-related behaviors (exact significance = .016, one-tailed, N ties = 6). Animals exposed to basic husbandry training or exposed to no training at all were not significantly likely to show a reduction in the rates of these behaviors. When these same behaviors were analyzed in terms of duration of behavior, desensitization-exposed animals were significantly likely to show reduction in the amount of time spent cringing toward humans (exact significance = .016, one-tailed, N ties = 6), but not in cringing behaviors in general or in stress-related behaviors. Neither the husbandry-exposed group nor the group exposed to no training showed a significant number of subjects exhibiting a reduction in duration of any of these behaviors. Additionally, initial temperament assessments were found to significantly predict the relative ability of subjects exposed to training to acquire trained behaviors such that animals generally ranked as more inhibited in terms of temperament also ranked as slower learners based on a Wilcoxon Matched-Pairs Signed-Ranks test, z = -.316, p = .752 (two-tailed). Results of this study could enhance both laboratory animal welfare and laboratory animal research, and could be a first step in developing techniques for reducing fearful behavior in rhesus monkeys in the laboratory environment.

published_or_final_version / Public Administration / Master / Master of Public Administration

The differential outcomes effect (DOE) refers to an observed increase in rates of acquisition of simple or conditional relations when the contingencies of reinforcement arrange for reinforcers to be uniquely correlated with a particular stimulus or response relative to conditions where the reinforcers are not uniquely correlated with either stimulus or response. This effect has been robustly documented in the literature with nonhuman subjects. This study asked whether the DOE would be observed with children with autism spectrum disorder (ASD) learning audio-visual conditional relations. Two participants learned two sets of 3 audio-visual conditional relations. For one set, the training conditions arranged for each of the three conditional relations to be uniquely correlated with a particular reinforcing stimulus (the DO condition). For the second set, the training conditions arranged for the same reinforcer to be used for all three audio-visual conditional relations (the NDO condition). Early results show that audio-visual conditional relations were acquired faster under the DO condition relative to the NDO outcomes condition (accuracy in DO condition was 30.8% higher on average than in NDO condition). These data suggest that differential outcomes should be more thoroughly investigated with children with diagnoses of ASD.

Reinforcer assessments have largely relied on the use of progressive ratio (PR) schedules to identify stimuli that function as reinforcers. PR schedules evaluate the reinforcing efficacy of a stimulus by measuring the number of responses produced in order to access a stimulus as the number of required responses increases. The current evaluation extends the literature on reinforcer assessments by measuring responding under a progressive force (PF) schedule, in addition to progressive ratio requirements. We compared responding under PR and PF schedules with two children with autism using a multielement design embedded within a reversal experimental design. Results were mixed and implications for further development of reinforcer assessment methods (particularly PF schedules) are discussed.