Spatial Conceptual Influences on the Coordination of Bimanual Actions: When a Dual Task Becomes a Single Task

When the left and right hands produce 2 different rhythms simultaneously, coordination of the hands is difficult unless the rhythms can be integrated into a unified temporal pattern. In the present study, the authors investigated whether a similar account can be applied to the spatial domain. Participants (N = 8) produced a movement trajectory of semicircular form in single-limb and bimanual conditions. In the bimanual tasks, 1 limb moved above the other in the frontal plane. Bimanual unified tasks were constructed so that the spatial paths to be produced by the 2 limbs could be easily conceptualized as parts of a unified circle pattern. Bimanual distinct tasks availed a less obvious spatial pattern that would unify the 2 tasks. Performance of the spatial patterns was more accurate in the unified task, despite similar demands placed on the coordination dynamics between the limbs in the 2 cases (e.g., the phase relations). The authors conclude that a dual task becomes a single task, and interlimb interference is reduced, when the spatial patterns produced by the 2 hands form a geometric arrangement that can be conceptualized as a unified representation.     

Motor Performance of Stutterers and Nonstutterers on Timing and Force Control Tasks

Recently it has been suggested that speech and manual timing tasks share a common central process (Franz, Zelaznik, & Smith, 1992). Because stuttering is thought to be related to deficits in motoric processes such as timing, stutterers (n = 15) were compared with a set of age-, education-, and sex-matched nonstutterers on timing and isometric force-production tasks. In the timing tasks, subjects flexed and extended the right index finger at the metacarpophalangeal joint at cycle durations of 600, 500, 400, 300, and 200 ms. In the force-production tasks, subjects generated isometric forces to match target force levels displayed on a cathode-ray tube (CRT) screen. There were five levels of force, ranging from .11 to 7.85 newtons. Overall, there were no differences in timing and force-production performance between stutterers and nonstutterers. These results are similar to those obtained recently by Hulstijn, Summers, van Lieshout, and Peters (1992). We suggest that stuttering is not characterized by a general deficit in rhythmic timing. Instead, the motor deficit associated with stuttering should be viewed as speech specific.     

Reasons for (prior) belief in Bayesian epistemology

Bayesian epistemology tells us with great precision how we should move from prior to posterior beliefs in light of new evidence or information, but says little about where our prior beliefs come from. It offers few resources to describe some prior beliefs as rational or well-justified, and others as irrational or unreasonable. A different strand of epistemology takes the central epistemological question to be not how to change one’s beliefs in light of new evidence, but what reasons justify a given set of beliefs in the first place. We offer an account of rational belief formation that closes some of the gap between Bayesianism and its reason-based alternative, formalizing the idea that an agent can have reasons for his or her (prior) beliefs, in addition to evidence or information in the ordinary Bayesian sense. Our analysis of reasons for belief is part of a larger programme of research on the role of reasons in rational agency (Dietrich and List, Nous, 2012a, in press; Int J Game Theory, 2012b, in press).     

Observational Context of Mother-Child Interaction: Impact of a stress Context on Emotional Availability

Previous studies have found that a stressful observational context challenges the mother-child relationship, thus highlighting negative interactive behavior. However, the impact of observational context has only been investigated in infants and preschoolers without specifically using the Emotional Availability Scales. Nor have they explored whether the association of mother-child interaction with children’s emotional or behavioral problems depends on the observational context. We observed 140 mothers and their five to 12-year-old children in non-stressful free play and in a stressful task context. In general, dyads showed higher emotional availability in the task context compared to the free play. Specifically, mothers showed higher levels of Sensitivity, Structuring and Nonhostility, but lower levels of Nonintrusiveness during the task compared to the free play context; children showed higher levels of Responsiveness during the task than during free play. After controlling for dyadic stress, contextual effects decreased for all dimensions of emotional availability. The association of mother-child interaction with child problem behavior depended on the observational context. Specifically, we found maternal emotional availability during free play to be more strongly associated with child problem behavior than during the stressful task; however, emotional availability of the child was more strongly associated with problem behavior when obtained during the task. We conclude that context impacts on mother-child interactive behavior and also on the association of mother-child-interaction and child behavior. Stress is a relevant contextual factor influencing mother-child interactive behavior.     

Long‐Term Effects of Social Investment: The Case of Partnering in Young Adulthood

ABSTRACT On the basis of the assumptions of the dynamic transactional paradigm, the current study investigates the effects of success and failure of social investment on personality development across young adulthood. Using longitudinal data from the Michigan Study of Adolescent and Adult Life Transitions (MSALT), the authors demonstrate that entering into the first long‐term romantic relationship was accompanied by decreases in facets of neuroticism, thereby fully replicating findings by Neyer and Lehnart (2007) based on a German longitudinal study. In addition, remaining single over 8 years was related to decreasing self‐esteem, especially for men. These results demonstrate long‐term effects of investment and lack of investment in social roles and provide further evidence of the interrelatedness of social or relationship experiences and personality development.     

Contrasting the Theory of Planned Behavior With the Value‐Belief‐Norm Model in Explaining Conservation Behavior1

In this paper, we contrast the value‐belief‐norm (VBN) model and the theory of planned behavior (TPB) for the first time regarding their ability to explain conservation behavior. The participants represent a convenience sample of 468 university students. Using survey data and adopting previously established compound measures, structural equation analyses revealed a remarkable explanatory power for both theories: TPB's intention accounted for 95% of people's conservation behavior and VBN's personal norms accounted for 64%. Compared to the VBN model, the TPB covered its concepts more fully in terms of proportions of explained variance. More importantly, the fit statistics revealed that only the TPB depicts the relations among its concepts appropriately, whereas the VBN model does not.     

关于上帝存在问题的理论及其实践的意义

一、任何人在开始作一个系列讲座的时候,都一定会首先阐明讲座主题的重要性,以引起读者对这项探索性研究的兴趣.有时候这是需要的,但就我们目前的讲座而言,这一点肯定是不必要的.     

Effects of unilateral distractors: A comparison of eye movement and key press responses

We compared the effects of a unilateral distractor on the latencies of voluntary eye movements and key press responses in order to elucidate some of the differences between these two types of response with respect to processing distractors. On each trial, participants indicated the colour of a central patch by making a left or a right response. The colour of the distractor either matched the target colour or matched the colour associated with the incorrect response. Similarly, the side of the distractor corresponded to the side of either the correct or the incorrect response. The results showed that side congruency exerted a main effect only on eye movement responses, but colour congruency affected eye movement and key press responses similarly. Moreover, when we made the target more distinct from the distractor, only distractors that appeared on the same side as the response elicited a colour congruency effect, for both response modalities. Wepropose that (1) the appearance of the distractor activates oculomotor cells, which facilitate a subsequent eye movement with the same direction vector, (2) the distinctiveness of the target determines whether colour and side congruency interact, and (3) spatial codes mediate the interaction between colour and side congruency that occurs when the target is sufficiently distinct from the distractor.