Right-handers' reaching in contralateral hemispace: a kinematic observation

C. Gabbard and C. Helbig (2004) found, when examining seated participants' limb selection for reaching and grasping in hemispace, that right-handers preferred to switch to the nondominant left arm for objects located approximately 20 degrees horizontally from body midline (90 degrees) in left hemispace. In the present study, the authors examined 13 strongly lateralized seated right-handers' kinematics of reaching to object positions ranging from body midline to 40 degrees horizontally in left hemispace. Participants executed faster reaches with the left arm than with the right arm to objects placed 20 degrees-40 degrees from midline, whereas they did not change the proportion of time they spent accelerating the hands when the position of the object changed. A 2nd main finding was an increase in the left hand's trajectory curvature as object position moved farther from midline, with a corresponding decrease in the contribution of upper-arm motion to the reach. Those observations suggest that the switch from dominant right-arm reaching to nondominant left-arm reaching in left hemispace reported in the aforementioned study may have emerged from a shift from a shoulder-driven reach to an elbow-driven action.     

Detection of visual stimuli in correlated noise

The hypothesis of detection by temporal probability summation (TPS) as characterised in Mortensen [(2007). An analysis of visual detection by temporal probability summation, submitted for publication] is critically evaluated, considering data from an experiment of Roufs and Blommaert [(1981). Temporal impulses and step responses of the human eye obtained psychophysically by means of a drift-correcting perturbation technique. Vision Research, 21, 1203-1221], who derived the impulse and the step response for a sustained type of channel. The assumed approximate linearity of the channel is discussed with respect to recent findings from neurophysiological investigations. The data are shown not to be compatible with the TPS-postulate. Further, a model of a cell assembly, consisting of a homogeneous set of neurons, is presented that allows for a natural interpretation of random fluctuations in case of temporal peak detection (TPD). The model may be discussed with respect to TPS as well as to TPD; in any case, the model allows to integrate some results concerning the effects of attentional focussing on the detection process.     

Motivation gains of inferior group members: a meta-analytical review

In recent years, a growing number of studies have demonstrated that individuals can exert higher motivation when working in a group compared to working individually. This is particularly true for less capable, inferior group members. To aggregate these findings and to examine preconditions as well as moderating influences on motivation gains of inferior group members, the authors conducted a meta-analysis (17 studies, N=2,240). Results indicated that the overall motivation gain effect of inferior group members observed is moderate and significant (g=.60). Moderator analyses revealed substantial influences of task structure, performance information, physical presence, gender, and task type.     

Efficiently checking propositional refutations in HOL theorem provers

This paper describes the integration of zChaff and MiniSat, currently two leading SAT solvers, with Higher Order Logic (HOL) theorem provers. Both SAT solvers generate resolution-style proofs for (instances of) propositional tautologies. These proofs are verified by the theorem provers. The presented approach significantly improves the provers' performance on propositional problems, and exhibits counterexamples for unprovable conjectures. It is also shown that LCF-style theorem provers can serve as viable proof checkers even for large SAT problems. An efficient representation of the propositional problem in the theorem prover turns out to be crucial; several possible solutions are discussed.     

A New Solution to the Recovered Memory Debate

ABSTRACT— The controversy regarding recovered memories of childhood sexual abuse (CSA) has been characterized by two perspectives. According to one perspective, some people repress their memories of abuse because these experiences have been so emotionally traumatic, and they become capable of recalling the CSA only when it is psychologically safe to do so many years later. According to the other perspective, many reports of recovered memories of sexual abuse are false memories, often inadvertently fostered by therapists. In this article, we provide evidence for a third interpretation that applies to a subset of people reporting recollections of CSA; it does not require the concepts of repression, trauma, or false memory. These people did not experience their CSA as traumatic; they either failed to think about their abuse for years or forgot their previous recollections, and they recalled their CSA spontaneously after encountering reminders outside of psychotherapy. Their recovered memories are corroborated at the same rate as those of people who never forgot their abuse. Hence, recalling CSA after many years is not the same thing as having recalled a previously repressed memory of trauma.     

The effects of wording on the understanding and use of uncertainty information in a threshold forecasting decision

Many believe that information about small chances of severe weather would be useful to the general public for precautionary action. What is the best way to explain this kind of information to a non‐expert audience? The studies reported here investigated effects of framing (negative vs. positive), format (frequency vs. probability), likelihood (low vs. high) and compatibility (task‐match) on interpretation of verbal expressions of forecast uncertainty and on subsequent forecasting decisions. The crucial factor was the match between the verbal expression and the overall task goal. Errors increased when there was a mismatch between the expression (e.g. winds less than 20 knots) and the task (e.g. post an advisory when winds will exceed 20 knots). However, framing and format had little impact. We conclude that consideration of user expectations arising from the overall task goal is crucial in explaining uncertainty information to a naïve audience. Global expectations overpower other potential effects. Copyright © 2008 John Wiley & Sons, Ltd.     

What coping tells about personality

In this study, 123 participants (non‐psychology students) who responded to an interpersonal stress situation staged in the laboratory were judged by unacquainted observers in terms of the Big Five dimensions, intelligence and social attractiveness. Coping behaviour appeared to predict personality impressions in a way that mirrors the relations between personality and coping observed in previous research: Overall, higher levels of Extraversion (E), Agreeableness (A), Conscientiousness (C) and Openness to experience (O) (as well as intelligence and social attractiveness) were predicted by problem‐focussed behaviour and cognitive restructuring, whereas higher levels of Neuroticism (N) were predicted by withdrawal/passivity. The interpersonal impact of the particular coping reactions, as indicated by a positive personality impression, were largely inconsistent with their impact on affect following the stress induction. Copyright © 2009 John Wiley & Sons, Ltd.     

Analysis of the Talmudic Argumentum A Fortiori Inference Rule (Kal Vachomer) using Matrix Abduction

We motivate and introduce a new method of abduction, Matrix Abduction, and apply it to modelling the use of non-deductive inferences in the Talmud such as Analogy and the rule of Argumentum A Fortiori. Given a matrix \({\mathbb {A}}\) with entries in {0, 1}, we allow for one or more blank squares in the matrix, say a _i,j =?. The method allows us to decide whether to declare a _i,j = 0 or a _i,j = 1 or a _i,j =? undecided. This algorithmic method is then applied to modelling several legal and practical reasoning situations including the Talmudic rule of Kal-Vachomer. We add an Appendix showing that this new rule of Matrix Abduction, arising from the Talmud, can also be applied to the analysis of paradoxes in voting and judgement aggregation. In fact we have here a general method for executing non-deductive inferences.     

Fathers' parenting hassles and coping: associations with emotional expressiveness and their sons' socioemotional competence

The present study examined fathers' daily parenting hassles and coping strategies to (a) determine their association with fathers' emotional expressiveness and (b) predict their sons' development of socioemotional competence. Fathers of 148 preschool‐aged boys reported on their parenting hassles, coping strategies, and emotional expressiveness; mothers also reported on fathers' emotional expressiveness; and teachers reported on boys' socioemotional competence. Parenting hassles were associated with less rational, more emotional, and more avoidance coping as well as negative emotional expressiveness. More emotional and less rational coping responses were related to more negative expressiveness, whereas more rational, more emotional, and less coping were related to more positive expressiveness. Fathers' negative expressiveness was predictive of their sons being rated as more aggressive and disruptive by their teachers. In addition, fathers' parenting hassles and coping both predicted teacher ratings of their sons' aggressiveness. Implications of the findings are discussed. Copyright © 2007 John Wiley & Sons, Ltd.     

The aftermath of 9/11: effect of intensity and recency of trauma on outcome

Does trauma exposure have a long-term impact on the brain and behavior of healthy individuals? The authors used functional magnetic resonance imaging to assess the impact of proximity to the disaster of September 11, 2001, on amygdala function in 22 healthy adults. More than three years after the terrorist attacks, bilateral amygdala activity in response to viewing fearful faces compared to calm ones was higher in people who were within 1.5 miles of the World Trade Center on 9/11, relative to those who were living more than 200 miles away (all were living in the New York metropolitan area at time of scan). This activity mediated the relationship between group status and current symptoms of posttraumatic stress disorder. In turn, the effect of group status on both amygdala activation (fearful vs. calm faces) and current symptoms was statistically explained by time since worst trauma in lifetime and intensity of worst trauma, as indicated by reported symptoms at time of the trauma. These data are consistent with a model of heightened amygdala reactivity following high-intensity trauma exposure, with relatively slow recovery.