Stroke damages attentional maintenance in working memory

Stroke is the main cause of acquired disability in adults, and specific deficits in working memory (WM) are among the most common cognitive consequences. In neuropsychological routine, WM is most of the time investigated in the framework of the multicomponent model (Baddeley & Hitch, 1974, The psychology of learning and motivation, 47). Using a more recent theoretical WM model, the time-based resource-sharing (TBRS) model (Barrouillet et al., 2011, Psychol. Rev., 118, 175), the aim of the present study was to investigate in young post-stroke patients to which extent attentional maintenance is impaired in WM. To address this question, we discarded other factors known to directly influence WM performance, that is processing speed and short-term memory span. We proposed to 53 post-stroke patients and to 63 healthy controls a complex span paradigm in which participants were asked to alternate between the memorization of a series of images and a concurrent parity judgement task of a series of digits. To investigate the attentional maintenance processes, we manipulated the cognitive load (CL) of the concurrent task. CL effect is typically interpreted as the involvement of attentional maintenance processes. The task was adapted to each participant according to their processing speed and memory span. As expected, the results showed higher recall performance in healthy controls compared with post-stroke patients. Consistent with the literature, we also observed higher performance when the CL was low compared with high. However, the improvement in recall at low CL was smaller for post-stroke patients compared with controls, suggesting that post-stroke WM deficit could be in part due to a deficit of the attentional maintenance processes.     

Pain in the eye of the beholder: Variations in pain visual representations as a function of face ethnicity and culture

Pain experienced by Black individuals is systematically underestimated, and recent studies have shown that part of this bias is rooted in perceptual factors. We used Reverse Correlation to estimate visual representations of the pain expression in Black and White faces, in participants originating from both Western and African countries. Groups of raters were then asked to evaluate the presence of pain and other emotions in these representations. A second group of White raters then evaluated those same representations placed over a neutral background face (50% White; 50% Black). Image-based analyses show significant effects of culture and face ethnicity, but no interaction between the two factors. Western representations were more likely to be judged as expressing pain than African representations. For both cultural groups, raters also perceived more pain in White face representations than in Black face representations. However, when changing the background stimulus to the neutral background face, this effect of face ethnic profile disappeared. Overall, these results suggest that individuals have different expectations of how pain is expressed by Black and White individuals, and that cultural factors may explain a part of this phenomenon     

Some comments in connection with Rozeboom's linear correlation theory

It is shown that certain correlation measures suggested by information theory are simple functions of the determinants of the correlation matrices involved, if multivariate normality is assumed. This illuminates and in a sense strengthens Rozeboom's point in [3], that information theoretical statistics have classical correlational counterparts.     

Une hypothèse sur l'extension des relations finies et sa vérification dans certaines classes particulières

Sans résumé