Inhibition, interference, and conflict in task switching

The role of inhibition in the task-switching process has received increased empirical and theoretical attention in the literature on cognitive control. Many accounts have suggested that inhibition occurs when a conflict must be resolved—for example, when a target stimulus contains features of more than one task. In the two experiments reported here, we used variants of backward inhibition, or N – 2 repetition, designs to examine (1) whether inhibition occurs in the absence of conflict at the stimulus or response level, (2) when in the task-switching process such inhibition may occur, and (3) the potential consequences of inhibition. In Experiment 1, we demonstrate that neither stimulus- nor response-level conflict is necessary for inhibition to occur, while the results of Experiment 2 suggest that inhibition may be associated with a reduction of proactive interference (PI) from a previously performed task. Evidence of inhibition and the reduction of PI both occurred at the task-set level. However, inhibition of specific stimulus values can also occur, but this is clearly separable from task-set inhibition. Both experiments also provided evidence that task-set inhibition can be applied at the time of the new task cue, as opposed to at the onset of the target or at the response stage of the trial. Taken together, the results from these experiments provide insight into when and where in the task-switching process inhibition may occur, as well as into the potential functional benefits that inhibition of task sets may provide.     

Lesbian, Gay, and Bisexual Identity Scale (LGBIS): construct validation, sensitivity analyses and other psychometric properties

According to Mohr and Fassinger (2006), identity is seen as both self-identification and collective identification with values, beliefs, traits or behaviours and attachments. Their Lesbian, Gay, and Bisexual (LGB) multidimensional identity model accounts for important variables regarding the constitution of identities. This model not only accesses numerous dimensions of the lives of LGB individuals, but is also based on a body of research that recognizes how LGB difficulties are caused by societal intolerance and marginalization (Mohr & Fassinger, 2000). The Lesbian, Gay, and Bisexual Identity Scale (LGBIS; Kendra & Mohr, 2008) constitutes an operationalization of this multidimensional model, and the aim of this article is to present its construct validity by analysing its factor structure using a sample of Portuguese lesbian, gay and bisexual participants. Results from exploratory and confirmatory factor analyses, as well as from factor invariance analysis across sub-samples are presented. In a general way, the factor structure obtained in this study follows the original proposal of Kendra and Mohr's (2008) LGBIS. Moreover, scale sensitivity analyses are presented in order to check for eventual differences in the factor structure and/or factor intercorrelations regarding participant gender and sexual orientation. These results are then discussed in the light of LGB identity models.     

An explanatory model of academic achievement based on aptitudes, goal orientations, self-concept and learning strategies

As a result of studies examining factors involved in the learning process, various structural models have been developed to explain the direct and indirect effects that occur between the variables in these models. The objective was to evaluate a structural model of cognitive and motivational variables predicting academic achievement, including general intelligence, academic self-concept, goal orientations, effort and learning strategies. The sample comprised of 341 Spanish students in the first year of compulsory secondary education. Different tests and questionnaires were used to evaluate each variable, and Structural Equation Modelling (SEM) was applied to contrast the relationships of the initial model. The model proposed had a satisfactory fit, and all the hypothesised relationships were significant. General intelligence was the variable most able to explain academic achievement. Also important was the direct influence of academic self-concept on achievement, goal orientations and effort, as well as the mediating ability of effort and learning strategies between academic goals and final achievement.     

Self-recognition and self-regulation: the relationship with socialization trajectories and children's sex

The initial process of self development involves interaction with others and the establishment of relationships taking different paths depending on the socio-cultural context. Self-recognition and self-regulation are considered manifestations of this development between 18 and 24 months of age. This study aimed at analyzing the relationship between these two aspects, maternal beliefs about autonomy and relatedness, as well as identifying differences between boys and girls in this developmental stage. Participants were 94 mothers of different educational levels and their children of 17-22 months of age in two Brazilian cities. Socialization Goals Inventory and Parental Practices in the First Year Inventory were used to collect data on mothers' beliefs. Children performed tasks related to self-recognition (the mirror test) and self-regulation (compliance to requests). The group of mothers studied valued both autonomy and interdependence. Children's responses are consistent with a perspective of relational autonomy, which value both independence and interdependence. Differences were found in relation to sex in both self-recognition and self-regulation, and baby girls showed superior performance than boys in both tasks.     

A randomized wait-list controlled analysis of the implementation integrity of team-initiated problem solving processes

Members of Positive Behavior Interventions and Supports (PBIS) teams from 34 elementary schools participated in a Team-Initiated Problem Solving (TIPS) Workshop and follow-up technical assistance. Within the context of a randomized wait-list controlled trial, team members who were the first recipients of the TIPS intervention demonstrated greater implementation integrity in using the problem-solving processes during their team meetings than did members of PBIS Teams in the Wait-List Control group. The success of TIPS at improving implementation integrity of the problem-solving processes is encouraging and suggests the value of conducting additional research focused on determining whether there is a functional relation between use of these problem-solving processes and actual resolution of targeted student academic and social problems.     

Effects of speed of word processing on semantic access: the case of bilingualism

Bilingual speakers generally manifest slower word recognition than monolinguals. We investigated the consequences of the word processing speed on semantic access in bilinguals. The paradigm involved a stream of English words and pseudowords presented in succession at a constant rate. English-Welsh bilinguals and English monolinguals were asked to count the number of letters in pseudowords and actively disregard words. They were not explicitly told that pairs of words in immediate succession were embedded and could either be semantically related or not. We expected that slower word processing in bilinguals would result in semantic access indexed by semantic priming. As expected, bilinguals showed significant semantic priming, indexed by an N400 modulation, whilst monolinguals did not. Moreover, bilinguals were slower in performing the task. The results suggest that bilinguals cannot discriminate between pseudowords and words without accessing semantic information whereas monolinguals can dismiss English words on the basis of subsemantic information.     

Asymmetric switch-costs and ERPs reveal facial identity dominance over expression

Previous studies on face processing have revealed an asymmetric overlap between identity and expression, as identity is processed irrespective of expression while expression processing partly depends on identity. To investigate whether this relative interaction is caused by dominance of identity over expression, participants performed familiarity and expression judgments during task switching. This paradigm reveals task-set dominance with a paradoxical asymmetric switch-cost (i.e., greater difference between switch and repeat trials when switching toward the dominant task). Event-related potentials (ERPs) were recorded to find the neural signature of the asymmetric cost. As expected, greater switch-cost was shown in the familiarity task with respect to response times, indicating its dominance over the expression task. Moreover, a left-sided ERP correlate of this effect was observed at the level of the frontal N2 component, interpreted as an index of modulations in endogenous executive control. Altogether, these results confirm the overlap between identity and expression during face processing and further indicate their relative dominance.     

Transitional and steady-state choice behavior under an adjusting-delay schedule

Twelve rats made repeated choices on an adjusting-delay schedule between a smaller reinforcer (A) that was delivered immediately after a response and a larger reinforcer (B) that was delivered after a delay which increased or decreased by 20% depending on the subject's choices in successive blocks of trials. In two phases of the experiment (100 sessions and 40 sessions), reinforcer sizes were selected which enabled theoretical parameters expressing the rate of delay discounting and sensitivity to reinforcer size to be estimated from the ratio of the indifference delays obtained in the two phases. Indifference delays, calculated from adjusting delays in the last 10 sessions of each phase, were shorter when the sizes of A and B were 14 and 25 μl of a 0.6 M sucrose solution than when they were 25 and 100 μl of the same solution. The ratio of the indifference delays was significantly smaller than that predicted on the basis of an assumed linear relation between reinforcer size and instantaneous reinforcer value, consistent with a previous proposal that this relation may be hyperbolic in form. Estimates of the rate of delay discounting based on the ratio of the two indifference delays (mean, 0.08 s(-1)) were similar to values obtained previously using different intertemporal choice protocols. Estimates of the size-sensitivity parameter (mean 113 μl) were similar to estimates recently derived from performance on progressive-ratio schedules. In both phases of the experiment, adjusting delays in successive blocks of trials were analyzed using the Fourier transform. The power spectrum obtained from individual rats had a dominant frequency that corresponded to a period of oscillation of the adjusting delay between 30 and 100 trial blocks (mean, 78). Power in the dominant frequency band was highest in the early sessions of the first phase and declined with extended training. It is suggested that this experimental protocol may have utility in neurobehavioral studies of intertemporal choice.