Treating excessively slow responding of a young man with Asperger syndrome using differential reinforcement of short response latencies

Fjellstedt and Sulzer-Azaroff (1973) used differential reinforcement of short latencies to decrease a child's latency to comply with instructions. We replicated this contingency with a young man diagnosed with Asperger syndrome across two tasks (question answering and math problem solving). We added a differential reinforcement contingency to teach the participant to discriminate between math problems that could be answered rapidly and those that required more time for accurate performance.     

The effects of reinforcer pairing and fading on preschoolers' snack selections

The effects of reinforcement pairing and fading on preschoolers' snack selections were evaluated in a multiple baseline design. Baseline preferences for snack options were assessed via repeated paired-item preference assessments. Edible, social, and activity-based reinforcers were then exclusively paired with a less preferred snack option. Once the snack paired with reinforcement was selected most frequently, the three types of reinforcement were systematically faded. Frequent selections of the previously less preferred snack option were produced with paired reinforcement, but were disrupted for all children as the paired reinforcement was reduced to low levels. These data showed that paired reinforcement was initially effective in increasing preference for the originally less preferred snack options, but more permanent changes in the value of the snack options were not achieved. Conditions for producing persistent changes in children's snack choices are discussed.     

Assessing and treating vocal stereotypy in children with autism

Previous research implies that stereotypic behavior tends to be maintained by the sensory consequences produced by engaging in the response. Few investigations, however, have focused on vocal stereotypy. The current study examined the noncommunicative vocalizations of 4 children with an autism spectrum disorder. First, functional analyses were conducted in an attempt to identify the function of each child's behavior. For each of the participants, it was found that vocal stereotypy was likely not maintained by the social consequences. Following assessment, response interruption and redirection (RIRD) was implemented in an ABAB design to determine whether vocal stereotypy could be successfully redirected. RIRD involved a teacher issuing a series of vocal demands the child readily complied with during regular academic programming. Vocal demands were presented contingent on the occurrence of vocal stereotypy and were continuously presented until the child complied with three consecutively issued demands without emitting vocal stereotypy. For each child, RIRD produced levels of vocal stereotypy substantially lower than those observed in baseline. For 3 of the children, an increase in appropriate communication was also observed. The children's teachers were trained to implement RIRD. Brief follow-up probes and anecdotal information implied that the treatment had a positive impact in the natural environment.     

The effect of conditioned reinforcement rate on choice: a review

We review the nature of conditioned reinforcement, including evidence that conditioned reinforcers maintain choice behavior in concurrent schedules and that they elevate responding in the terminal links of concurrent‐chains schedules. A question has resurfaced recently: Do theories of choice in concurrent‐chains schedules need to include a term reflecting greater preference for higher rates of conditioned reinforcement? The review of several studies addressing this point suggests that such a term is inappropriate. Elevated rates of conditioned reinforcement (and responding) in the terminal links of concurrent‐chains schedules do not lead to greater preference in the initial link leading to the higher rate of conditioned reinforcement. If anything, the opposite preference is likely to occur. This result is not surprising, since the additional putative conditioned reinforcers in the terminal link are not correlated with a reduction in time to primary reinforcement nor with an increase in value.     

Stochastic matching and the voluntary nature of choice

Attempts to characterize voluntary behavior have been ongoing for thousands of years. We provide experimental evidence that judgments of volition are based upon distributions of responses in relation to obtained rewards. Participants watched as responses, said to be made by "actors," appeared on a computer screen. The participant's task was to estimate how well each actor represented the voluntary choices emitted by a real person. In actuality, all actors' responses were generated by algorithms based on Baum's (1979) generalized matching function. We systematically varied the exponent values (sensitivity parameter) of these algorithms: some actors matched response proportions to received reinforcer proportions, others overmatched (predominantly chose the highest-valued alternative), and yet others undermatched (chose relatively equally among the alternatives). In each of five experiments, we found that the matchingactor's responses were judged most closely to approximate voluntary choice. We found also that judgments of high volition depended upon stochastic (or probabilistic) generation. Thus, stochastic responses that match reinforcer proportions best represent voluntary human choice.     

Response induction during the acquisition and maintenance of lever pressing with delayed reinforcement

The acquisition of lever pressing by rats and the occurrence of unreinforced presses at a location different from that of the reinforced response were studied using different delays of reinforcement. An experimental chamber containing seven identical adjoining levers was used. Only presses on the central (operative) lever produced food pellets. Groups of 3 rats were exposed to one of seven different tandem random-interval (RI) fixed-time (FT) schedules. The average RI duration was the complement of the FT duration such that their sum yielded a nominal 32-s interreinforcement interval on average. Response rate on the operative lever decreased as the FT value was lengthened. The spatial distribution of responses on the seven levers converged on the operative lever when the FT was 0 or 2 s and spread across the seven levers as the FT value was lengthened to 16 or 32 s. Presses on the seven levers were infrequent during the FT schedule. Both operative- and inoperative-lever pressing intertwined in repetitive patterns that were consistent within subjects but differed between subjects. These findings suggest that reinforcer delay determined the response-induction gradient.     

IS MATCHING INNATE?

Experimentally naive mice matched the proportions of their temporal investments (visit durations) in two feeding hoppers to the proportions of the food income (pellets per unit session time) derived from them in three experiments that varied the coupling between the behavioral investment and food income, from no coupling to strict coupling. Matching was observed from the outset; it did not improve with training. When the numbers of pellets received were proportional to time invested, investment was unstable, swinging abruptly from sustained, almost complete investment in one hopper, to sustained, almost complete investment in the other-in the absence of appropriate local fluctuations in returns (pellets obtained per time invested). The abruptness of the swings strongly constrains possible models. We suggest that matching reflects an innate (unconditioned) program that matches the ratio of expected visit durations to the ratio between the current estimates of expected incomes. A model that processes the income stream looking for changes in the income and generates discontinuous income estimates when a change is detected is shown to account for salient features of the data.     

Effects of post-session wheel running on within-session changes in operant responding

This study tested the effects of post-session wheel running on within-session changes in operant responding. Lever-pressing by six rats was reinforced by a food pellet under a continuous reinforcement (CRF) schedule in 30-min sessions. Two different flavored food pellets were used as reinforcers. In the wheel conditions, 30-min operant-sessions with one of the flavored pellets were followed by 30-min free-wheel running sessions. Meanwhile, in the home conditions, rats’ operant responding was reinforced by the other flavored pellets during 30-min operant-sessions, and the rats were then returned to their homecages. All rats were exposed to 4 wheel and 4 homecage sessions. Operant responding was lowered during the wheel conditions. However, post-session running did not alter the within-session pattern of operant responding. These effects were practically identical to the effects of drug-induced taste-aversion learning on within-session changes in operant responding, suggesting similar mechanisms in both taste-aversion preparations.     

Extinction-induced "despair" in the water maze, exploratory behavior and fear: effects of chronic antidepressant treatment

In former studies, we found evidence for the hypothesis that withdrawal of negative reinforcement presents a major source for stress and despair. Specifically, the removal of a hidden platform in the water maze induced extinction of previously reinforced escape behavior and behavioral immobility, indicative of "despair", which also correlated with indices of fear. Here, we tested the effects of antidepressants on extinction in the water maze, and expected that such drugs would attenuate the rate of extinction of a conditioned place preference (CPP) and also any emotionally relevant behavior that is induced by the loss of reinforcement, such as immobility. Adult male Wistar rats were trained to escape onto a hidden platform for 10 days. Daily treatment with desipramine hydrochloride (DMI, 10mg/kg) or fluoxetine (FLX, 10 mg/kg) commenced 1 day before the first of 11 extinction trials without the platform, administered 48 h apart, and continued thereafter, as the rats were tested in an open field and elevated-plus maze. As compared to controls, DMI increased the resistance-to-extinction of CPP, attenuated immobility, and increased wall climbing behavior. In the open field, DMI reduced activity levels, but was without effect on traditional fear parameters in the elevated-plus maze. FLX, by contrast, increased immobility during the extinction trials and fear in the elevated-plus maze. The withdrawal of reinforcement induced "despair" that was alleviated by the noradrenaline reuptake inhibitor DMI. The effects of the selective serotonin reuptake inhibitor FLX on immobility and fear may be explained in terms of its side effect profile.     

不同教师群体激励因素的比较研究

本研究选择云南曲靖和浙江宁波的两所师范学校作为研究对象,以教育人种学研究方法为基本方法,通过现象分析、个案访谈、问卷调查、文献分析等途径,对不同地区教师群体的工作积极性状态及其原因进行了实证性对比研究,得出以下结论:竞争压力和相对报酬之间的相互关系是决定不同教师群体工作积极性大小的两个关键因素。其中竞争因素的激励功能相对较强。竞争压力大小与相对报酬高低之间的相互关系影响着群体激励力量的大小。