Habituation under stress: shocked mice show nonassociative learning in a T-maze

Conflicting predictions of reinforcement and neophobia-arousal theories were evaluated in a simple choice task. Four groups of C57BL/6J mice were administered daily two-trial tests in a uniform T-maze for 10 consecutive days. For three groups, the contingencies of footshock treatments were manipulated to reinforce alternation, perseveration, or both. A control group that was not administered footshock alternated, but all three groups that were stressed perseverated more and more across tests, despite the differences in reinforcement contingencies. These results are inconsistent with the predictions of reinforcement theory but consistent with the view that stressed or aroused animals are neophobic and use nonassociative learning (habituation) to distinguish between novel and familiar alternatives.     

ADHD and Working Memory: The Impact of Central Executive Deficits and Exceeding Storage/Rehearsal Capacity on Observed Inattentive Behavior

Inattentive behavior is considered a core and pervasive feature of ADHD; however, an alternative model challenges this premise and hypothesizes a functional relationship between working memory deficits and inattentive behavior. The current study investigated whether inattentive behavior in children with ADHD is functionally related to the domain-general central executive and/or subsidiary storage/rehearsal components of working memory. Objective observations of children’s attentive behavior by independent observers were conducted while children with ADHD (n?=?15) and typically developing children (n?=?14) completed counterbalanced tasks that differentially manipulated central executive, phonological storage/rehearsal, and visuospatial storage/rehearsal demands. Results of latent variable and effect size confidence interval analyses revealed two conditions that completely accounted for the attentive behavior deficits in children with ADHD: (a) placing demands on central executive processing, the effect of which is evident under even low cognitive loads, and (b) exceeding storage/rehearsal capacity, which has similar effects on children with ADHD and typically developing children but occurs at lower cognitive loads for children with ADHD.     

A review of social disinhibition after traumatic brain injury

Acquired social disinhibition refers to a debilitating behavioural syndrome commonly reported after a severe traumatic brain injury (TBI) and is characterized by inappropriate social behaviour, often described as immaturity and insensitivity towards others. These behaviours can have enduring effects on the social capability of the individual and their relationships with others. However, research into socially disinhibited behaviour after TBI has been thwarted by a lack of consensus in the literature on definition and measurement. This review provides an overview of our current understanding of the definition, measurement, prevalence, associated outcomes, neuropathology, and underlying mechanisms of social disinhibition after TBI. In addition, suggestions are made for future research to further our understanding of this syndrome with the eventual aim of rehabilitating problematic behaviours. It is concluded that an improved understanding of what causes disinhibited behaviour after TBI will be necessary for the development of effective treatment strategies aimed at the rehabilitation of underlying impairments.     

System-justifying ideologies and academic outcomes among first-year Latino college students

The present study examines the relationship between system-justifying ideologies and academic outcomes among 78 first-year Latino college students (21 men, 57 women, mean age = 18.1 years) attending a moderately selective West Coast university. Endorsement of system-justifying ideologies was negatively associated with grade point average (GPA); however it was positively associated with feelings of belonging at the university. In addition, system-justifying ideologies were negatively associated with perceptions of personal discrimination. In contrast, ethnic identity centrality was unrelated to GPA, feelings of belonging, and perceptions of personal discrimination once the relationship between system-justifying ideologies and these outcomes was statistically taken into account. The results of the present study suggest that endorsement of system-justifying ideologies may be a double-edged sword for Latino college students, involving trade-offs between academic success and feelings of belonging.     

Control of behavior by an establishing stimulus

Seventeen pigeons were exposed to a three-key discrete-trial procedure in which a peck on the lit center key produced food if, and only if, the left keylight was lit. The center key was illuminated by a peck on the lit right key. Of interest was whether subjects pecked the right key before or after the response-independent onset of the left keylight. Pecks on the right key after left-keylight onset suggest control of behavior by the left keylight—an establishing stimulus. In three experiments, the strength of center-keylight onset as conditioned reinforcer for a response on the right key was manipulated by altering the size of the reduction in time to food delivery correlated with its onset. Control of pigeons' key pecks by onset of the left keylight occurred on more trials per session when the center keylight was a relatively weak conditioned reinforcer and on fewer trials per session when the center keylight was a relatively strong condtioned reinforcer. Differences across conditions in the degree of control by onset of the establishing stimulus were greatest when changes in conditioned reinforcer strength occurred relatively frequently and were signaled. The results provide evidence of the function of an establishing stimulus.     

The affective consequences of cognitive inhibition: devaluation or neutralization?

Affective evaluations of previously ignored visual stimuli are more negative than those of novel items or prior targets of attention or response. This has been taken as evidence that inhibition has negative affective consequences. But inhibition could act instead to attenuate or "neutralize" preexisting affective salience, predicting opposite effects for stimuli that were initially positive or negative in valence. We tested this hypothesis by presenting trustworthy and untrustworthy faces (Experiment 1), strongly positive and negative photographs (Experiment 2), and monetary gain- and loss-associated patterns (Experiment 3) in a Go/No-Go task and assessing subsequent affective ratings. Evaluations of prior No-Go (inhibited) stimuli were more negative than of prior Go (noninhibited) stimuli, regardless of a priori affective valence. Ratings of No-Go stimuli also became increasingly negative (vs. increasingly neutral) when preexisting salience was increased via stimulus repetition (Experiment 4). Our results suggest inhibition leads to affective devaluation, not affective neutralization.