Stability in the metamemory realism of eyewitness confidence judgments

The stability of eyewitness confidence judgments over time in regard to their reported memory and accuracy of these judgments is of interest in forensic contexts because witnesses are often interviewed many times. The present study investigated the stability of the confidence judgments of memory reports of a witnessed event and of the accuracy of these judgments over three occasions, each separated by 1 week. Three age groups were studied: younger children (8–9 years), older children (10–11 years), and adults (19–31 years). A total of 93 participants viewed a short film clip and were asked to answer directed two-alternative forced-choice questions about the film clip and to confidence judge each answer. Different questions about details in the film clip were used on each of the three test occasions. Confidence as such did not exhibit stability over time on an individual basis. However, the difference between confidence and proportion correct did exhibit stability across time, in terms of both over/underconfidence and calibration. With respect to age, the adults and older children exhibited more stability than the younger children for calibration. Furthermore, some support for instability was found with respect to the difference between the average confidence level for correct and incorrect answers (slope). Unexpectedly, however, the younger children’s slope was found to be more stable than the adults. Compared to the previous research, the present study’s use of more advanced statistical methods provides a more nuanced understanding of the stability of confidence judgments in the eyewitness reports of children and adults.     

The holistic presumptions of the indispensability argument

The indispensability argument is sometimes seen as weakened by its reliance on a controversial premise of confirmation holism. Recently, some philosophers working on the indispensability argument have developed versions of the argument which, they claim, do not rely on holism. Some of these writers even claim to have strengthened the argument by eliminating the controversial premise. I argue that the apparent removal of holism leaves a lacuna in the argument. Without the holistic premise, or some other premise which facilitates the transfer of evidence to mathematical portions of scientific theories, the argument is implausible.     

Do positive children become positive adults? Evidence from a longitudinal birth cohort study

BACKGROUND: Little is known about the long-term consequences of positive wellbeing in childhood in the general population. We used the MRC National Survey of Health and Development (the British 1946 birth cohort) to test associations between adolescent positive wellbeing and social functioning in midlife. METHOD: Temperament and behaviour at ages 13 and 15 years were rated by school teachers on a range of criteria. These mostly referred to absence or presence of conduct and emotional problems, but four items allowed positive ratings: 'very popular with other children', 'unusually happy and contented', 'makes friends extremely easily' and 'extremely energetic, never tired'. In addition, at age 16 years survey members self-completed the Maudsley Personality Inventory, from which a summary measure of extraversion was derived, as this was previously found to be associated with midlife positive wellbeing in this cohort. RESULTS: Being a happy child, defined as receiving at least two of the above teacher ratings, was positively associated with midlife functioning and wellbeing, specifically a low probability of lifetime emotional problems, a high frequency of contact with friends or relatives, engagement in social activities, and to a lesser extent feeling satisfied with accomplishments in working life. These associations were independent of father's social class, childhood cognition, educational attainment, and midlife occupational social class. There were no independent associations between being a happy child and educational or occupational attainment, being married, engagement in prosocial activities, taking leadership in community activities, and with life satisfaction in general or with family life. Extraversion was associated with a low probability of lifetime emotional problems, high engagement in social activities, being married, general midlife life satisfaction, and satisfaction with family life, but not with social contact, prosocial activity, leadership activity, or work satisfaction. While childhood conduct and emotional problems were associated with few of the social and life satisfaction outcomes, the former were negatively associated with educational and occupational attainment, and positively with divorce, whereas the latter were negatively associated with being married. CONCLUSIONS: Prospectively rated childhood wellbeing has long-term beneficial links to adult functioning; our results also support the view that positive wellbeing has a unique impact on these outcomes, and does not merely represent the absence of mental ill-health.     

Visuospatial over verbal demands in predicting Tower of London planning tasks

The role of verbal and visuospatial information processing in Tower of London (TOL) tasks was investigated. The first part of the investigation examined the verbal and visuospatial abilities and preferred cognitive style (visualizer vs. verbalizer) of 79 participants, in an inter-individual differences approach. Visuospatial abilities significantly predicted TOL performance, but the impact of cognitive style was negligible. The second part applied a dual-task manipulation of concurrent interference of TOL planning tasks on verbal and visuospatial memory, using the same participants. Concurrent processing of the TOL tasks diminished visuospatial memory performance considerably but had no effect on verbal memory, and there was no interaction between cognitive style and memory. These findings clearly underscore the role of visuospatial information processing in TOL tasks and indicate little bearing of verbal or visual cognitive style on TOL problem solving. These results have important implications for TOL and cognitive style in clinical application and cognitive neuroimaging research.     

Microstructural organization of corpus callosum projections to prefrontal cortex predicts bimanual motor learning

The corpus callosum (CC) is the largest white matter tract in the brain. It enables interhemispheric communication, particularly with respect to bimanual coordination. Here, we use diffusion tensor imaging (DTI) in healthy humans to determine the extent to which structural organization of subregions within the CC would predict how well subjects learn a novel bimanual task. A single DTI scan was taken prior to training. Participants then practiced a bimanual visuomotor task over the course of 2 wk, consisting of multiple coordination patterns. Findings revealed that the predictive power of fractional anisotropy (FA) was a function of CC subregion and practice. That is, FA of the anterior CC, which projects to the prefrontal cortex, predicted bimanual learning rather than the middle CC regions, which connect primary motor cortex. This correlation was specific in that FA correlated significantly with performance of the most difficult frequency ratios tested and not the innately preferred, isochronous frequency ratio. Moreover, the effect was only evident after training and not at initiation of practice. This is the first DTI study in healthy adults which demonstrates that white matter organization of the interhemispheric connections between the prefrontal structures is strongly correlated with motor learning capability.     

Organization, development and function of complex brain networks

Recent research has revealed general principles in the structural and functional organization of complex networks which are shared by various natural, social and technological systems. This review examines these principles as applied to the organization, development and function of complex brain networks. Specifically, we examine the structural properties of large-scale anatomical and functional brain networks and discuss how they might arise in the course of network growth and rewiring. Moreover, we examine the relationship between the structural substrate of neuroanatomy and more dynamic functional and effective connectivity patterns that underlie human cognition. We suggest that network analysis offers new fundamental insights into global and integrative aspects of brain function, including the origin of flexible and coherent cognitive states within the neural architecture.