TESTS FOR CONTROL BY EXCLUSION AND NEGATIVE STIMULUS RELATIONS OF ARBITRARY MATCHING TO SAMPLE IN A “SYMMETRY-EMERGENT” CHIMPANZEE

In the present experiments, controlling relations in arbitrary matching-to-sample performance were tested in a 9-year-old female chimpanzee who showed statistically significant emergence of symmetry in previous two-choice conditional discrimination experiments. In Experiment 1, a novel (undefined) sample stimulus was followed by a pair of trained (defined) and undefined comparison stimuli to assess the control by exclusion in arbitrary matching. The chimpanzee selected the undefined shape comparison, excluding the defined one, in color-sample-to-shape-comparison probe trials, although stimulus preferences were relatively stronger than control by exclusion in shape-sample trials. An additional test for control by relations of the sample to the positive comparison (S+ control) showed that her behavior was also under the control of relations of the sample to the positive comparison. In Experiment 2, a defined sample was followed by a pair of negatively defined and undefined comparisons to test control by the relations of the sample to the negative comparison. (S- control). The subject selected undefined comparisons in both color-shape and shape-color test trials. These results clearly indicate that the conditional discrimination behavior of this “symmetry-emergent” chimpanzee was under both S+ and S- control. Furthermore, her performance was also under control by exclusion in color-shape arbitrary matching, unlike other chimpanzees who showed no evidence of symmetry but only S+ control of arbitrary matching.     

“TRANSITIVE INFERENCE” IN MULTIPLE CONDITIONAL DISCRIMINATIONS

We used multiple conditional discriminations to study the inferential abilities of pigeons. Using a five-term stimulus series, pigeons were trained to respond differentially to four overlapping pairs of concurrently presented stimuli: A+B?, B+C?, C+D?, and D+E?, where plus and minus indicate the stimulus associated with reinforcement and extinction, respectively. Transitive inference in such situations has been defined as a preference for Stimulus B over Stimulus D in a transfer test. We measured this and other untrained preferences (A vs. C, A vs. D, B vs. E, etc.) during nonreinforced test trials. In three experiments using a novel, rapid training procedure (termed autorun), we attempted to identify the necessary and sufficient conditions for transitive inference. We used two versions of autorun: response-based, in which the subject was repeatedly presented with the least well-discriminated stimulus pair; and time-based, in which the subject was repeatedly presented with the least-experienced stimulus pair. In Experiment 1, using response-based autorun, we showed that subjects learned the four stimulus pairs faster than, but at a level comparable to, a previous study on transitive inference in pigeons (Fersen, Wynne, Delius, & Staddon, 1991), but our animals failed to show transitive inference. Experiments 2 and 3 compared time- and response-based autorun. Discrimination performance was maintained, but transitive inference was observed only on the second exposure to the response-based procedure. These results show that inferential behavior in pigeons is not a reliable concomitant of good performance on a series of overlapping discriminations. The necessary and sufficient conditions for transitive inference in pigeons remain to be fully defined.     

Conditional discrimination in mentally retarded subjects: programming acquisition and learning set.

In Experiment 1, 3 subjects with retardation were exposed to two visual-visual arbitrary matching-to-sample problems each day. One conditional discrimination was presented under trial-and-error conditions, and the other was presented under a component training procedure. The latter began by establishing the comparison discrimination and its rapid reversal. The successive discrimination between the sample stimuli was established through differential naming. Then, sample naming was maintained in conditional discrimination sessions in which the same sample was presented in blocks of consecutive trials. Block size was decreased across sessions until sample presentation was randomized as in trial-and-error training (but with naming maintained). Two subjects initially learned only with component training. The performance of the 3rd subject was inconsistent across conditional discriminations. One of the successful subjects ultimately learned rapidly and consistently with trial-and-error procedures. Experiment 2 sought to demonstrate learning set in the other 2 subjects. Elements of the component training procedure were withdrawn over successive conditional discriminations. Ultimately, 1 subject nearly always learned under trial-and-error conditions, and the other learned under trial-and-error conditions combined with differential sample naming.     

Bilaterally recorded multiple-unit activity of the cingulate cortex during head turning conditioning with unilateral medial forebrain bundle stimulation

Cats were conditioned to turn their heads using a tone conditioned stimulus (CS) and medial forebrain bundle stimulation (MFB) unconditioned stimulus (US). The CS+ was delivered to one ear at a time, in random order, followed by the US. A tone of a different frequency was used as a CS-. The cats learned to respond differentially to the CSs showing head movements of greater acceleration to the CS+ than CS- over sessions. Bilateral recordings of cingulate cortex multiple-unit activity showed increased response amplitudes over sessions and larger responses in the hemisphere ipsilateral to the US. Since ipsilateral multiple-unit responses did not differ for the CSs, the asymmetry was probably due to the sensitizing effect of the unilateral US. Although increases in cingulate cortex neural activity coincided with increases in conditioned head movements, larger activation of the cingulate cortex ipsilateral to the US suggests that the neural changes were independent of these movements.     

Discrimination and liberal neutrality

This paper examines the political philosophy of Liberalism with particular focus on the principles of liberal neutrality and value pluralism. These principles, which are advocated by the most prominent contemporary liberal theorists mark a significant departure from classical liberalism and its monistic approach to seeking truth and the good. I argue that the shift to neutrality and pluralism have done a disservice to liberalism and that the cultivation of discrimination skills is needed to deal with the complex tasks of making decisions intelligently and effectively.     

Comparison of extra- and within-stimulus prompting to teach prepositional discriminations to preschool children with developmental disabilities

This study compared extra-stimulus to within-stimulus prompts in teaching children with developmental disabilities to discriminate the prepositional concepts In and On. Five preschool-aged children who had difficulty discriminating verbal instructions participated. Extra-stimulus prompts involved modeling, gestures, positioning, and auditory cues which did not form part of the target discrimination. Within-stimulus prompts manipulated the volume and intonational pattern of the verbal stimuli. Four children did not learn the discrimination with extra-stimulus prompting. All four of these children, plus a fifth child who did not have prior experience with extra-stimulus prompting, reached criterion in the within-stimulus prompting condition. The success of the within-stimulus prompts may be related to their enhancing phonetic differences between the verbal stimuli.     

Effects of schedule of reinforcement on a pentobarbital discrimination in rats.

The purpose of this study was to determine the effects of the schedule of reinforcement on a pentobarbital discrimination in rats. Five rats were trained to discriminate 10 mg/kg pentobarbital from saline under a multiple fixed-interval 180-s fixed-ratio 20 schedule of reinforcement. During both saline and pentobarbital training sessions, subjects emitted a higher percentage of correct responses under the fixed-ratio component as compared to the fixed-interval component of the multiple schedule. Determination of the pentobarbital dose-response curve under the fixed-ratio component resulted in a steep curve characterized by responding on the saline lever at low doses and on the drug lever at higher doses. Under the fixed-interval component, a graded dose-effect curve was produced, with considerable responding on both levers after intermediate doses of pentobarbital. The administration of phencyclidine and MK-801 resulted in an intermediate level of drug-lever responding for some subjects. Administration of d-amphetamine resulted in saline (nondrug) appropriate responding. The results of this study demonstrate that the schedule of reinforcement is a determinant of drug stimulus control, just as it is a determinant of other drug effects.     

嗓声鉴别的脑事件相关电位研究

该项工作研究了21名女大学生和研究生鉴别两个陌生人的噪声时,六个脑区的事件相关电位(ERPs)。结果表明,双音节语义嗓声的鉴别更易引起明显的ERPs变化;两个陌生人嗓声不等概率呈现,较等概率呈现更易引起明显的ERPs变化。在单音节嗓声鉴别中,在左额区引起N200波波幅增高;而在右颞区引起P300波潜伏期的增长。在双音节语义嗓声鉴别中,除右顶叶外在其它五个脑区引起P300波波幅增高,在右额区引起P300波潜伏期明显缩短。     

Haitian and Haitian American experiences of racism and socioethnic discrimination in Miami-Dade county: At-risk and court-involved youth

We examine how juvenile justice-involved youth of Haitian descent in Miami-Dade County cope with structural racism and its impact on their mental health. Drawing on longitudinal ethnography, psychosocial assessment data, and a family-based clinical intervention funded by the National Institute on Drug Abuse, this article explores youth narratives of discrimination prior to and during the COVID-19 pandemic. We use critical race theory and theory of practice to understand youths’ perceptions as racialized bodies and stigmatized selves, highlighting the experiences and perspectives of a particular black immigrant group, ethnic beings caught up in the everyday practices of racialization, sociocultural marginalization, and racism. We frame these experiences as a variation of the complex continuum of structural racism and racial domination in the US. These experiences have caused anger, fear, anxiety, chronic anticipatory distress, and hopelessness among youth of Haitian descent. We conclude with some recommendations for therapeutic support that encourages youth to process their experiences, promotes their development of a positive self-concept, and provides them with mind-body techniques to attenuate the physical impacts of discriminatory events. The clinical trial registration number for this study intervention is NCT03876171.     

The Relationship between Workplace Status and Workplace Religious Expression

A growing body of literature explores religious expression in workplaces, but comparatively little research examines how religious expression might be shaped by inequality in workplace status. We hypothesize that perceived work autonomy and socioeconomic status (SES) both function as mediating links between organizational status and religious expression. Drawing on a sample of employed adults from a nationally-representative survey in the United States (n = 8611), we examine three modes of religious expression at work: displaying faith, feeling comfortable talking about faith, and expressing views when observing unfair work practices that conflict with faith. Results revealed that workers at the bottom of their organizations express their religiosity less than those at the top. Religious expression in the workplace is thus not simply a reflection of individual religiosity or religious identity, but also workplace power. Although perceived work autonomy mediated the relationship, SES buffered the relationship. Findings have important implications for workplace policy.