The Default Mode Network and Recurrent Depression: A Neurobiological Model of Cognitive Risk Factors

A neurobiological account of cognitive vulnerability for recurrent depression is presented based on recent developments of resting state neural networks. We propose that alterations in the interplay between task positive (TP) and task negative (TN) elements of the Default Mode Network (DMN) act as a neurobiological risk factor for recurrent depression mediated by cognitive mechanisms. In the framework, depression is characterized by an imbalance between TN-TP components leading to an overpowering of TP by TN activity. The TN-TP imbalance is associated with a dysfunctional internally-focused cognitive style as well as a failure to attenuate TN activity in the transition from rest to task. Thus we propose the TN-TP imbalance as overarching neural mechanism involved in crucial cognitive risk factors for recurrent depression, namely rumination, impaired attentional control, and cognitive reactivity. During remission the TN-TP imbalance persists predisposing to vulnerability of recurrent depression. Empirical data to support this model is reviewed. Finally, we specify how this framework can guide future research efforts.     

Assessment of the learning curve from the California Verbal Learning Test—Children's Version with the first-order system transfer function

A mathematical model is proposed to measure the learning curve in the California Verbal Learning Test–Children's Version. The model is based on the first-order system transfer function in the form Y = B3*exp[-B2*(X-1)]+B4*{1-exp[-B2*(X-1)]}, where X is the trial number, Y is the number of recalled correct words, B2 is the learning rate, B3 is interpreted as readiness to learn and B4 as the ability to learn. Children's readiness to learn and ability to learn were lower than adults. Modeling revealed that girls had greater readiness to learn and ability to learn than boys.     

Coalescence of the Fermi-surface-related diffuse-intensity peaks in disordered alloys

The theoretical possibility of the disappearance of the diffuse-intensity peak splitting induced by the Fermi surface in disordered alloys with decreasing temperature is predicted. The underlying mechanism is the compensation of the reciprocal-space curvatures of the self-energy and the interaction. The theory also describes similar results obtained earlier for two low-dimensional models with competing interactions. The coalescence is compared with the recently observed 'thermal' splitting in Pt-V which can be explained in the same way.     

Blind(fold)ed by science: A constant target-heading angle is used in visual and nonvisual pursuit

Previous work investigating the strategies that observers use to intercept moving targets has shown that observers maintain a constant target-heading angle (CTHA) to achieve interception. Most of this work has concluded or indirectly assumed that vision is necessary to do this. We investigated whether blindfolded pursuers chasing a ball carrier holding a beeping football would utilize the same strategy that sighted observers use to chase a ball carrier. Results confirm that both blindfolded and sighted pursuers use a CTHA strategy in order to intercept targets, whether jogging or walking and irrespective of football experience and path and speed deviations of the ball carrier during the course of the pursuit. This work shows that the mechanisms involved in intercepting moving targets may be designed to use different sensory mechanisms in order to drive behavior that leads to the same end result. This has potential implications for the supramodal representation of motion perception in the human brain.     

Prevalence-based decisions undermine visual search

In visual search, observers make decisions about the presence or absence of a target based on their perception of a target during search. The present study investigated whether decisions can be based on observers’ expectation rather than perception of a target. In Experiment 1, participants were allowed to make target-present responses by clicking on the target or, if the target was not perceived, a target-present button. Participants used the target-present button option more frequently in difficult search trials and when target prevalence was high. Experiment 2 and 3 employed a difficult search task that encouraged the use of prevalence-based decisions. Target presence was reported faster when target prevalence was high, indicating that decisions were, in part, cognitive, and not strictly perceptual. A similar pattern of responses were made even when no targets appeared in the search (Experiment 3). The implication of these prevalence-based decisions for visual search models is discussed.     

Wisdom in a complex world: A situated account of wise reasoning and its development

Social issues (e.g., partisan politics, economic decisions, and interpersonal conflicts) often involve trade‐offs, necessitating the consideration of multiple interests. Such issues do not have simple answers and benefit from wise reasoning—a set of metacognitive strategies that guide people toward managing complexity and balancing different interests. We review recent advances in research on wise reasoning, including evidence pertinent to the question of wisdom's trait‐like and state‐specific features, how it varies across situations, and how one can develop it. Overall, empirical studies suggest that researchers can understand wisdom better by paying attention to its situated nature across time and contexts.     

Idealizations and Concretizations in Laws and Explanations in Physics

The paper tries to provide an alternative to Hempel’s approach to scientific laws and scientific explanation as given in his D-N model. It starts with a brief exposition of the main characteristics of Hempel’s approach to deductive explanations based on universal scientific laws and analyzes the problems and paradoxes inherent in this approach. By way of solution, it analyzes the scientific laws and explanations in classical mechanics and then reconstructs the corresponding models of explanation, as well as the types of scientific laws appearing in it. Finally, it compares this reconstruction with the approaches of J. Woodward and C. Hitchcock, C. Liu and with the views of M. Thalos on analytic mechanics.