The neuroscience of perceptual categorization in pigeons: A mechanistic hypothesis

We are surrounded by an endless variation of objects. The ability to categorize these objects represents a core cognitive competence of humans and possibly all vertebrates. Research on category learning in nonhuman animals started with the seminal studies of Richard Herrnstein on the category “human” in pigeons. Since then, we have learned that pigeons are able to categorize a large number of stimulus sets, ranging from Cubist paintings to English orthography. Strangely, this prolific field has largely neglected to also study the avian neurobiology of categorization. Here, we present a hypothesis that combines experimental results and theories from categorization research in pigeons with neurobiological insights on visual processing and dopamine-mediated learning in primates. We conclude that in both fields, similar conclusions on the mechanisms of perceptual categorization have been drawn, despite very little cross-reference or communication between these two areas to date. We hypothesize that perceptual categorization is a two-component process in which stimulus features are first rapidly extracted in a feed-forward process, thereby enabling a fast subdivision along multiple category borders. In primates this seems to happen in the inferotemporal cortex, while pigeons may primarily use a cluster of associative visual forebrain areas. The second process rests on dopaminergic error-prediction learning that enables prefrontal areas to connect top down the relevant visual category dimension to the appropriate action dimension.     

Teacher sensitivity in interaction with individual students: the role of teachers’ daily negative emotions

ABSTRACT

Research stresses the importance of teacher sensitivity for the development of special needs students, including students with attachment problems. However, little is known about the antecedents of teacher sensitivity. This study investigated associations between teachers’ daily negative emotions and teacher sensitivity towards individual students. Data were collected from 71 teacher-student dyads in special education primary schools and included students with mild to severe attachment problems (6 to 10 years old). Teachers reported their daily negative activating (e.g. anger) and deactivating (e.g. sadness) emotions in relation to individual students during a three-week period. Teacher sensitivity was observed in interaction with the target student in a cognitively challenging and an emotionally challenging task. Teachers’ higher but decreasing negative activating emotions were associated with higher levels of observed teacher sensitivity in the cognitively challenging task. In addition, heightened levels of negative deactivating emotions were associated with lower levels of observed teacher sensitivity but only in the emotionally challenging task.     

Caregiving and 5‐HTTLPR Genotype Predict Adolescent Physiological Stress Reactivity: Confirmatory Tests of Gene × Environment Interactions

A theory‐driven confirmatory approach comparing diathesis–stress and differential susceptibility models of Gene × Environment (G × E) interactions was applied to examine whether 5‐HTTLPR genotype moderated the effect of early maternal caregiving on autonomic nervous system (ANS) stress reactivity in 113 adolescents aged 13–17 years. Findings supported a differential susceptibility, rather than diathesis–stress, framework. Carriers of one or more 5‐HTTLPR short alleles (SS/SL carriers) reporting higher quality caregiving exhibited approach ANS responses to a speech task, whereas those reporting lower quality caregiving exhibited withdrawal ANS responses. Carriers of two 5‐HTTLPR long alleles (LL carriers) were unaffected by caregiving. Findings suggest that 5‐HTTLPR genotype and early caregiving in interaction are associated with ANS stress reactivity in adolescents in a “for better and for worse” fashion, and they demonstrate the promise of confirmatory methods for testing G × E interactions.     

Dissociation predicts later attention problems in sexually abused children

OBJECTIVE: The goals of this research are to develop and test a prospective model of attention problems in sexually abused children that includes fixed variables (e.g., gender), trauma, and disclosure-related pathways. METHODS: At Time 1, fixed variables, trauma variables, and stress reactions upon disclosure were assessed in 156 children aged 8-13 years. At the Time 2 follow-up (8-36 months following the initial interview), 56 of the children were assessed for attention problems. RESULTS: A path analysis involving a series of hierarchically nested, ordinary least squares multiple regression analyses indicated two direct paths to attention problems including the child's relationship to the perpetrator (beta=.23) and dissociation measured immediately after disclosure (beta=.53), while controlling for concurrent externalizing behavior (beta=.43). Post-traumatic stress symptoms were only indirectly associated with attention problems via dissociation. Taken together, these pathways accounted for approximately 52% of the variance in attention problems and provided an excellent fit to the data. CONCLUSIONS: Children who report dissociative symptoms upon disclosure of CSA and/or were sexually abused by someone within their family are at an increased risk of developing attention problems. PRACTICE IMPLICATIONS: Findings from this study indicate that children who experienced sexual abuse at an earlier age, by someone within their family, and/or report symptoms of dissociation during disclosure are especially likely to benefit from intervention. Effective interventions should involve (1) providing emotion regulation and coping skills; and (2) helping children to process traumatic aspects of the abuse to reduce the cyclic nature of traumatic reminders leading to unmanageable stress and dissociation.     

The impact of childhood abuse on inpatient substance users: Specific links with risky sex,aggression, and emotion dysregulation

Adults with substance use disorders (SUDs) report a high prevalence of childhood abuse. Research in the general population suggests specific types of abuse lead to particular negative outcomes; it is not known whether this pattern holds for adults with SUDs. We hypothesized that specific types of abuse would be associated with particular behavioral and emotional outcomes among substance users. That is, childhood sexual abuse would be associated with risky sex behaviors, childhood physical abuse with aggression, and childhood emotional abuse with emotion dysregulation. 280 inpatients (M age = 43.3; 69.7% male; 88.4% African American) in substance use treatment completed the Childhood Trauma Questionnaire (CTQ), HIV Risk-Taking Behavior Scale, Addiction Severity Index, Difficulties with Emotion Regulation Scale (DERS), Distress Tolerance Scale (DTS), and Affect Intensity and Dimensions of Affiliation Motivation (AIM). Consistent with our hypotheses, the CTQ sexual abuse subscale uniquely predicted exchanging sex for cocaine and heroin, number of arrests for prostitution, engaging in unprotected sex with a casual partner during the prior year, and experiencing low sexual arousal when sober. The physical abuse subscale uniquely predicted number of arrests for assault and weapons offenses. The emotional abuse subscale uniquely predicted the DERS total score, AIM score, and DTS score. Among substance users, different types of abuse are uniquely associated with specific negative effects. Assessment of specific abuse types among substance users may be informative in treatment planning and relapse prevention.