The role of central and peripheral vision in postural control duringwalking

Three hypotheses have been proposed for the roles of central and peripheral vision in the perception and control of self-motion: (1) peripheral dominance, (2) retinal invariance, and (3) differential sensitivity to radial flow. We investigated postural responses to optic flow patterns presented at different retinal eccentricities during walking in two experiments. Oscillating displays of radial flow (0° driver direction), lamellar flow (90°), and intermediate flow (30°, 45°) patterns were presented at retinal eccentricities of 0°, 30°, 45°, 60°, or 90° to participants walking on a treadmill, while compensatory body sway was measured. In general, postural responses were directionally specific, of comparable amplitude, and strongly coupled to the display for all flow patterns at all retinal eccentricities. One intermediate flow pattern (45°) yielded a bias in sway direction that was consistent with triangulation errors in locating the focus of expansion from visible flow vectors. The results demonstrate functionally specific postural responses in both central and peripheral vision, contrary to the peripheral dominance and differential sensitivity hypotheses, but consistent with retinal invariance. This finding emphasizes the importance of optic flow structure for postural control regardless of the retinal locus of stimulation.     

What is an “appropriate” migrant? Impact of the adoption of meritocratic worldviews by potential newcomers on their perceived ability to integrate into a Western society

The acceptance of migrant populations and the definition of an “appropriate” migrant are controversial issues in many countries. The present research focuses on the ideological determinants of how newcomers are evaluated by a host population in a Western country with a strongly rooted meritocratic ideology. We carried out two studies to examine how the expression of meritocratic beliefs by a male potential migrant affects the way he is evaluated by the host population. We measured the host population's perception of the potential migrant's ability to integrate into society, his tendency to adopt the host country's culture, and the general desirability of his world vision for all newcomers. We also noted the host population's judgments of the target's agency and communality. The results showed that a potential newcomer who expresses a strong (vs. weak) belief in a just world (Study 1) or an internal (vs. external) locus of control (Study 2) is evaluated more favorably by the host population. In addition, judgments of the target's integration capacity were only mediated by his perceived agency. We discuss these results in the light of work on the meritocratic ideology and intercultural relations. Copyright © 2012 John Wiley & Sons, Ltd.     

Asymmetric switch-costs and ERPs reveal facial identity dominance over expression

Previous studies on face processing have revealed an asymmetric overlap between identity and expression, as identity is processed irrespective of expression while expression processing partly depends on identity. To investigate whether this relative interaction is caused by dominance of identity over expression, participants performed familiarity and expression judgments during task switching. This paradigm reveals task-set dominance with a paradoxical asymmetric switch-cost (i.e., greater difference between switch and repeat trials when switching toward the dominant task). Event-related potentials (ERPs) were recorded to find the neural signature of the asymmetric cost. As expected, greater switch-cost was shown in the familiarity task with respect to response times, indicating its dominance over the expression task. Moreover, a left-sided ERP correlate of this effect was observed at the level of the frontal N2 component, interpreted as an index of modulations in endogenous executive control. Altogether, these results confirm the overlap between identity and expression during face processing and further indicate their relative dominance.     

Dynamics of learning new postural patterns: influence on preexisting spontaneous behaviors

In stance, rotations around the hips and ankles typically exhibit a relative phase close to 20 degrees or 180 degrees . In 2 experiments, the authors studied the reciprocal influence of those coordination tendencies with learning an ankle-hip relative phase of 135 degrees . Before, during, and after learning a new mode of coordination, they assessed participants' (N = 24 in each experiment) spontaneous postural patterns with a tracking task in which no specific coordination was required. Learning the 135 degrees phase relation led to persistent modifications of the spontaneous in-phase and antiphase modes. Contrary to the theoretical predictions of the dynamical approach, the initial stability of the preexisting patterns did not influence the difficulty of producing the new mode or the improvement in performance during learning. Initial stability did, however, influence the rate and type of modification of spontaneous patterns. The authors discuss the results in relation to conclusions drawn from bimanual studies.     

Stance Width Influences Postural Stability and Motion Sickness

We examined the influence of stance width (the distance between the feet) on postural sway and visually induced motion sickness. Stance width influences the magnitude of body sway, and changes in sway precede the subjective symptoms of motion sickness. Thus, manipulation of stance width may influence motion sickness incidence. Participants (healthy young adults) were exposed to complex, low-frequency oscillation of a moving room. Participants stood with their feet 5 cm, 17 cm, or 30 cm apart. During exposure to visual motion, the widest stance (30 cm) was associated with reduced incidence of motion sickness. For all stance widths, motion sickness was preceded by significant changes in motion of the head and torso. The results support the postural instability theory of motion sickness and suggest practical implications for the prevention of motion sickness. Adoption of wider stance may decrease the risk of motion sickness in operational situations.     

Punitive emotions and norm violations

The recent literature on social norms has stressed the centrality of emotions in explaining punishment and norm enforcement. This article discusses four negative emotions (righteous anger, indignation, contempt, and disgust) and examines their relationship to punitive behavior. I argue that righteous anger and indignation are both punitive emotions strictly speaking, but induce punishments of different intensity and have distinct elicitors. Contempt and disgust, for their part, cannot be straightforwardly considered punitive emotions, although they often blend with a colder form of indignation to favor low-cost, indirect, and collective forms of punishment such as mockery, exclusion, and ostracism.     

Development of a fully automated system for delivering odors in an MRI environment

We describe the development and evaluation of a computer-controlled system for delivering odors in a magnetic resonance imaging (MRI) environment. The system allows a timely presentation of different odors in synchrony with MRI sequences and participant’s inspiration phase. The rise/fall time of odor deliverance has been optimized to generate prompt and strong stimulations. Equipped with a user-friendly programming interface, the system can be used reliably in a wide range of experimental paradigms. We have paid particular attention to developing a portable system that is relatively easy, rapid, and inexpensive to replicate. The equipment has been tested in a 3-Tesla MRI in a boxcar paradigm, in which stimulation conditions alternated with rest periods (no stimulation). The experiment demonstrated the good functioning of the device and its efficiency in producing the expected activation in the olfactory cortex; it also revealed some methodological and technical aspects to be improved.     

A computational model for simulating text comprehension

In the present article, we outline the architecture of a computer program for simulating the process by which humans comprehend texts. The program is based on psycholinguistic theories about human memory and text comprehension processes, such as the construction-integration model (Kintsch, 1998), the latent semantic analysis theory of knowledge representation (Landauer & Dumais, 1997), and the predication algorithms (Kintsch, 2001; Lemaire & Bianco, 2003), and it is intended to help psycholinguists investigate the way humans comprehend texts.