Metabolic energy expenditure and the regulation of movement economy

Over the years, various psychological theories have embraced notions ofeconomy, efficiency, orleast effort to explain how complex movement sequences are organized and modified. The purpose of the present paper was to synthesize various perspectives on this issue, to identify a common hypothesis, and to propose a conceptual framework that explains how movement economy is regulated. The framework presented here postulates that adaptive movement patterns emerge as a function of the organism’s propensity to minimize metabolic energy expenditure with respect to task, environment, and organism constraints to action. An important role is also proposed for interoceptive sensory information in guiding motor skill learning and control. The paper concludes by suggesting future directions in four areas of movement economy research that contribute to understanding the learning and control of movement in both human and nonhuman organisms.     

A Light Theory of Color

Traditional theories locate color in primary qualities of objects, indispositional properties of objects, in visual fields, or nowhere. Incontrast, we argue that color is located in properties of light. Morespecifically, light is red iff there is a property P of the lightthat typically interacts with normal human perceivers to give thesensation of red. This is an error theory, because objects and visualfields that appear red are not really red, since they lack theproperties that make light red. We show how this light theory solvesor avoids problems that afflict its competitors.     

Family-supportive organization perceptions, multiple dimensions of work-family conflict, and employee satisfaction: A test of model across five samples

Using samples of managers drawn from five Western countries, we tested a theoretical model linking employees’ perceptions of their work environment’s family-supportiveness to six different dimensions of work-family conflict (WFC), and to their job satisfaction, family satisfaction, and life satisfaction. Our results are consistent with a causal process whereby employees working in an environment viewed as more family-supportive experience lower levels of WFC. Reduced WFC then translates into greater job and family satisfaction, followed by greater overall life satisfaction. These findings were generalizable across the five samples.     

Distinct contributions of the basolateral amygdala and the medial prefrontal cortex to learning and relearning extinction of context conditioned fear

We studied the roles of the basolateral amygdala (BLA) and the medial prefrontal cortex (mPFC) in learning and relearning to inhibit context conditioned fear (freezing) in extinction. In Experiment 1, pre-extinction BLA infusion of the NMDA receptor (NMDAr) antagonist, ifenprodil, impaired the development and retention of inhibition but post-extinction infusion spared retention. Pre-extinction infusion of the GABA(A) agonist, muscimol, depressed freezing and impaired retention as did post-extinction infusion. In Experiment 2, pre-extinction mPFC infusion of ifenprodil spared the development of inhibition whereas muscimol depressed freezing. Both impaired retention when infused pre- or post-extinction. Thus, the development of inhibition involves NMDAr activation in the BLA, whereas its consolidation involves both NMDAr activation in the mPFC and NMDAr-independent mechanisms in the BLA. In Experiment 3, BLA infusion of ifenprodil impaired relearning and retention of inhibition when infused before but did not impair retention when infused after re-extinction. BLA infusion of muscimol depressed freezing but did not impair retention when infused before or after re-extinction. In Experiment 4, mPFC infusion of ifenprodil impaired relearning when infused before re-extinction, whereas muscimol depressed responses. Both drugs impaired retention when infused into the mPFC before or after re-extinction. Thus, relearning to inhibit fear responses involves NMDAr activation in both the BLA and mPFC and consolidation of the inhibitory memory involves NMDAr activation in the mPFC. However, relearning and consolidation occur in the absence of neuronal activity within the BLA. We propose that NMDAr in the mPFC supports relearning inhibition when the BLA is inactivated.     

A message in a bottle: Extrapharmacological effects of alcohol on aggression

The physiological and expectancy effects of alcohol consumption on the aggressive behavior of 116 general-population males aged 18-45 years were analyzed separately in a naturalistic field experiment using a 3 × 3 Balanced Placebo Design (BPD). Participants were given a non-alcoholic drink, a drink targeting a Blood Alcohol Concentration (BAC) of .05%, or a drink targeting a BAC of .1%. Within these three groups, three expectancy levels were induced regarding the quantity of alcohol ingested. Aggressive behavior was measured as retaliation against an aggressive confederate, in the form of amounts of hot sauce and salt administered in a taste test. Expectancies significantly increased aggressive behavior, whereas actual quantity of alcohol ingested was unrelated to aggression. Aggressive dispositions also predicted aggressive behavior.     

Are autistic traits autistic?

According to the extreme male brain theory of autism ( Baron‐Cohen, 2002 ), autistic traits would be extreme manifestations of typical male behaviours. The Auyeung et al. (2009) paper establishes a link between autistic traits and higher fetal testosterone (fT) levels in typically developing children. We argue that the construct behind this relationship needs further investigation. First, the link between fT levels and sexually dimorphic traits, that are for example, associated with empathizing and systemizing, is controversial. Likewise, describing autistic behaviours as being extreme male‐like is debatable. The cerebral hemisphere laterality pattern of individuals with autism also seems to differ from the pattern typically observed in males. Moreover, the parallel that should exist, according to the fT theory, between individuals with autism and individuals with congenital adrenal hyperplasia (CAH), because of their high fT levels, is unclear. The theory implying fT levels in autism fails to account for a big part of autism, and the link between fT and normal ‘autistic traits’ hardly demonstrates the causal link between fT and autism.     

Building a Better WarBot: Ethical Issues in the Design of Unmanned Systems for Military Applications

Unmanned systems in military applications will often play a role in determining the success or failure of combat missions and thus in determining who lives and dies in times of war. Designers of UMS must therefore consider ethical, as well as operational, requirements and limits when developing UMS. I group the ethical issues involved in UMS design under two broad headings, Building Safe Systems and Designing for the Law of Armed Conflict, and identify and discuss a number of issues under each of these headings. As well as identifying issues, I offer some analysis of their implications and how they might be addressed.

Influence of typical size of objects in a categorization task]

This study explores the influence of typical size during a categorization task. The specificity of this experimental work is based on the homogeneity of the graphic stimuli size. We have created a typical size standard of our stimuli, that concerns the real size of the objects represented by the drawings of homogeneous sizes. Then, a priming experiment was performed in which the prime and target drawings had two types of relations: a typical size, and a categorial. The participants are na?ve as to the typical size relation between prime and target. The results show a positive priming effect of the typical size but not of the category. The results are discussed in term of theoretical approach developed by Barsalou and his colleagues (1999, 2003). In this theoretical framework, the typical size can be considered as a perceptual knowledge. In that way, we propose that participants could automatically simulate the typical size as soon as they perceived the drawings of objects with homegenous sizes.     

A dynamical framework to understand performance trade-offs and interference in dual tasks.

This study demonstrated that the dynamic pattern approach may reconcile resource and outcome conflict theories to explain performance in dual tasks. Participants performed a bimanual coordination task and a reaction time task with different conditions of attentional priority. Results showed a trade-off between pattern variability and reaction time when priority was given to the coordination task. Such a trade-off was indicative of resource allocation. An analysis of perturbation in the bimanual coordination revealed interference, a reputed sign of outcome conflict. Moreover, interference diminished substantially when priority was given to the bimanual task. The coexistence of performance trade-off and outcome conflict suggests that these two phenomena are not mutually exclusive. Rather, both may follow from modifying the coupling between the limbs through attention.     

Cross-cultural examination of the tripartite model with children: data from the Barretstown studies.

The Positive and Negative Affect Scale for Children (PANAS-C) and the Physiological Hyperarousal Scale for Children (PH-C) were administered to a group of 240 children from European countries to determine their utility in examining the tripartite model of anxiety and depression in a cross-cultural sample. Most of the children (n = 196) had been diagnosed with a medical illness; the remainder were siblings of these youngsters (n = 44). Only slight variations were noted in items between this sample and samples from the United States. Despite these minor differences, 3 distinct scales measuring the positive affect, negative affect, and physiological hyperarousal constructs of the tripartite model were identified. These findings illustrate that the PH-PANAS-C provides a useful measure of the tripartite model in a cross-cultural sample of youth. The findings also demonstrate that the tripartite model is generalizable to a cross-cultural milieu.