Differentiated forgetting rates of spatial knowledge in humans in the absence of repeated testing

Spatial knowledge, necessary for efficient navigation, comprises route knowledge (memory of the landmarks along a route) and survey knowledge (map-like). Available data on the retention in humans of spatial knowledge show that this does not decline systematically over months or years. Here, two groups of participants elaborated route and survey knowledge during navigation in a complex virtual environment before performing route and survey tasks. Both groups were tested 5 minutes after learning and 3 months later, while one group was also tested 1 week and 1 month later (repeated testing). Performance was similar in both groups on the first testing session, remained stable in the repeated tested group, but decreased in the non-repeated tested group, especially on route tasks. These results are the first to reveal a substantial and selective decline of spatial knowledge, occurring only if there is no possibility of reactivating knowledge along repeated testing.     

Emotion-cognition interaction in people at familial high risk for schizophrenia: the impact of sex differences

Cognitive deficits are fundamental to schizophrenia, and research suggests that negative emotion abnormally interferes with certain cognitive processes in those with the illness. To a lesser extent, cognitive impairment is found in persons at risk for schizophrenia, but there is limited research on the impact of emotion on cognitive processing in at-risk groups. It is unknown whether interference of negative emotion precedes illness and contributes to vulnerability for the disorder. We studied the extent to which negative emotional information interferes with working memory in 21 adolescent and young adult first-degree relatives of people with schizophrenia and 22 community controls. Groups were comparable in age, sex, education, ethnicity, and socioeconomic status. Primary measures were n-back tasks varying in cognitive load (1-back, 2-back, 3-back) with emotional faces (neutral, happy, fearful) as stimuli. The control group's response times (RTs) and the women's RTs, regardless of group, differed depending on the emotion condition. In contrast, the RTs of the relatives and of the men, regardless of group, did not differ by emotion. This study is the first to examine emotion-cognition interactions in relatives of individuals with schizophrenia. Reduced efficiency in processing emotional information may contribute to a greater vulnerability for schizophrenia that may be heightened in men. Additional research with larger samples of men and women is needed to test these preliminary findings.     

The Invisible Thin Red Line

The aim of this paper is to argue that the adoption of an unrestricted principle of bivalence is compatible with a metaphysics that (i) denies that the future is real, (ii) adopts nomological indeterminism and (iii) exploits a branching structure to provide a semantics for future contingent claims. To this end, we elaborate what we call Flow Fragmentalism, a view inspired by Kit Fine's non-standard tense realism, according to which reality is divided up into maximally coherent collections of tensed facts. In this way, we show how to reconcile a genuinely A-theoretic branching time model with the idea that there is a branch corresponding to the thin red line, that is, the branch that will turn out to be the actual future history of the world.