Representation at different levels in a conceptual hierarchy

The present study examines the influence of hierarchical level on category representation. Three computational models of representation – an exemplar model, a prototype model and an ideal representation model – were evaluated in their ability to account for the typicality gradient of categories at two hierarchical levels in the conceptual domain of clothes. The domain contains 20 subordinate categories (e.g., trousers, stockings and underwear) and an encompassing superordinate category (CLOTHES). The models were evaluated both in terms of their ability to fit the empirical data and their generalizability through marginal likelihood. The hierarchical level was found to clearly influence the type of representation: For concepts at the subordinate level, exemplar representations were supported. At the superordinate level, however, an ideal representation was overwhelmingly preferred over exemplar and prototype representations. This finding contributes to the increasingly dominant view that the human conceptual apparatus adopts both exemplar representations and more abstract representations, contradicting unitary approaches to categorization.     

Retroactive interference in short-term memory and the word-length effect

Two experiments investigated the possibility that the word-length effect in short-term memory (STM) is a consequence of long words generating a greater level of retroactive interference than shorter words. In Experiment 1, six-word lists were auditorily presented under articulatory suppression for immediate serial reconstruction of only the first three words. These three words were always drawn from a single set of middle-length words, whereas the last three positions were occupied by either short or long interfering words. The results showed worse memory performance when the to-be-remembered words were followed by long words. In Experiment 2, a recent-probes task was used, in which recent negative probes matched a target word in trial n-2. The results showed lower levels of proactive interference when trial n-1 involved long words instead of short words, suggesting that long words displaced previous STM content to a greater extent. By two different experimental approaches, therefore, this study shows that long words produce more retroactive interference than short words, supporting an interference-based account for the word-length effect.     

Depression is not an inevitable outcome of disclosure avoidance: HIV stigma and mental health in a cohort of HIV-infected individuals from Southern India

Previous research has shown that HIV stigma in India can be characterized by a framework dividing manifestations into enacted (discrimination), vicarious (hearing stories of discrimination), felt normative (perceptions of stigma's prevalence), and internalized stigma (personal endorsement of stigma beliefs). We examined whether this framework could explain associations among stigma, efforts to avoid HIV serostatus disclosure, and depression symptoms in a cohort of 198 HIV-infected individuals from Southern India who were followed up for one year as part of a study of antiretroviral adherence. Prior studies had suggested that disclosure avoidance was a primary outcome of stigma and that impaired well-being was a primary outcome of disclosure avoidance. Analyses from our longitudinal research revealed that the pattern of associations among stigma, disclosure avoidance, and depression symptoms remained consistent over time. Enacted and vicarious stigmas were correlated with felt normative stigma beliefs. In turn, felt normative stigma was correlated with disclosure avoidance. And, enacted stigma, internalized stigma, and disclosure avoidance were all associated with depression symptoms. However, even though the overall framework held together, internalized stigma and depression symptoms dropped significantly over time while other components remained unchanged. These findings suggest that, although HIV stigma may limit disclosure, it does not invariably lead to psychological maladjustment. Amidst ongoing perceptions and experiences of stigma, HIV-positive individuals can achieve significant improvements in their acceptance of the disease and in mental well-being.     

Acceptance of sexual aggression myths in a representative sample of German residents

A representative sample of German residents (N = 5397) was surveyed with the aim of studying their acceptance of contemporary rape myths (RMA), using items from the Acceptance of Modern Myths About Sexual Aggression Scale [AMMSA; Gerger et al., 2007] in relation to demographic variables (e.g., gender, age), intolerant belief systems (e.g., sexism, islamophobia), the ideologies of rightwing authoritarianism (RWA), and social dominance orientation (SDO), as well as gender identification. Age showed a U-shaped relationship with RMA, whereas gender was unrelated to RMA. For men (women), greater identification with their gender was associated with higher (lower) RMA. Substantial correlations of RMA with intolerant belief systems support the idea of a schema of intolerance. Although RWA and SDO were both related to RMA, only RWA explained unique variance beyond the effects of intolerant belief systems. Results are discussed in comparison to prior studies using mainly student samples.     

Individual differences in chronically defeated male mice: behavioral, endocrine, immune, and neurotrophic changes as markers of vulnerability to the effects of stress

This study aimed to analyze different behavioral profiles in response to chronic social defeat using the sensorial contact model. We hypothesized that a passive profile, unlike an active one, would be associated with behavioral and physiological characteristics related to depression. Six-week-old OF1 male mice were subjected to defeat for 21 consecutive days. A combination of cluster and discriminant analyses of the behavior exhibited during confrontation on Day 21 established two behavioral profiles: active (n?=?22) and passive (n?=?34). Passive mice, with a high level of immobility and low non-social exploration, had higher plasma corticosterone concentrations than active mice after 21 days of defeat. Three days after the last defeat, passive mice had lower corticosterone levels than manipulated-control mice (n?=?11). Higher levels of interleukin-6 and tumor necrosis factor-α (TNF-α) in the spleen and lower hippocampal brain-derived neurotrophic factor levels were observed in passive mice in comparison with those in active mice and the manipulated controls. The only differences observed in active mice in relation to the manipulated control were higher plasma corticosterone (Day 21) and TNF-α levels. The results show that different behavioral profiles in response to chronic defeat are associated with different physiological profiles, and that the passive profile presents physiological characteristics previously associated with depression.     

Re-locating colors in the OSA space

A monolexemic color-naming experiment in the Italian language was performed on a sample of 1,014 colors obtained extending the OSA-UCS color system (E-OSA). Colors were rendered on a Mitsubishi Diamond pro 2070 monitor as patches subtending 10° of visual angle in a completely dark room. The 11 universal categories proposed by Berlin and Kay (Basic color terms: Their universality and evolution, 1969) were considered. Consensus, consistency and focal colors were determined for each category. Comparisons were performed among the results obtained using Boynton & Olson (B&O), the extended OSA (E-OSA), a subset of it covering almost all the B&O sample (R-OSA) and the Sturges & Whitfield (S&W) sample sets. A good overlap could be observed among the locations of the consensus colors in the {L, j, g} color model between B&O and R-OSA, as well as a close proximity among the centroids of homologue regions for the majority of the classes. The analysis of the location of focal colors versus the centroids suggests that an additional basic term could be missing for the Italian language in the blue category.     

Signals of threat do not capture, but prioritize, attention: a conditioning approach

Research suggests that threatening information captures attention more rapidly than neutral information. However, in most studies threat stimuli differ perceptually from neutral stimuli and are instrumental to perform the task, leaving the question unanswered whether threat is sufficient to capture attention. In experiment 1, we designed a visual search task with stimuli of equal salience (colored circles) that have the potential to lead to efficient search (10 ms/item). In experiment 2, one of the colors (conditioned stimulus, CS+) was made threatening by means of fear conditioning. Participants responded to a target presented in one of the circles. Overall, the search was faster on congruent trials (where the target was presented in the CS+) than on baseline trials (where the CS + was absent). Furthermore, the search was slower on incongruent trials (where the target was presented in another color than the CS+) than on baseline trials. The search on congruent trials was affected by set size (90 ms/item), but to a lesser extent than on baseline trials (105 ms/item). We conclude that threat prioritizes, but does not capture attention.     

Bimanual reaching across the hemispace: Which hand is yoked to which?

When both hands perform concurrent goal-directed reaches, they become yoked to one another. To investigate the direction of this coupling (i.e., which hand is yoked to which), the temporal dynamics of bimanual reaches were compared with equivalent-amplitude unimanual reaches. These reaches were to target pairs located on either the left or right sides of space; meaning that in the bimanual condition, one hand's contralateral (more difficult) reach accompanied by the other hand's ipsilateral (easier) reach. By comparing which hand's difficult reach was improved more by the presence of the other hand's easier ipsilateral reach, we were able to demonstrate asymmetries in the coupling. When the cost of bimanual reaching was controlled for the contralateral reaching left hand's performance was improved, suggesting that the left hand is yoked to the right during motor output. In contrast, the right hand showed the greatest improvements for contralateral reaching in terms of reaction time, pointing toward a dominant role for the left hand in the processes prior to movement onset. The results may point toward a mechanism for integrating the unitary system of attention with bimanual coordination.