The role of spatial integration in the perception of surface orientation with active touch

Vision research has shown that perception of line orientation, in the fovea area, improves with line length (Westheimer & Ley, 1997). This suggests that the visual system may use spatial integration to improve perception of orientation. In the present experiments, we investigated the role of spatial integration in the perception of surface orientation using kinesthetic and proprioceptive information from shoulder and elbow. With their left index fingers, participants actively explored virtual slanted surfaces of different lengths and orientations, and were asked to reproduce an orientation or discriminate between two orientations. Results showed that reproduction errors and discrimination thresholds improve with surface length. This suggests that the proprioceptive shoulder-elbow system may integrate redundant spatial information resulting from extended arm movements to improve orientation judgments.     

Global versus local image expansion in estimating time-to-contact from complex optic flow

Previous work (Harris and Giachritsis 2000, Vision Research 40 601-611) has shown that, when global and local image expansion are placed in conflict, estimates of time-to-contact (TTC) are based almost exclusively upon global expansion. Here we extend this finding by demonstrating that global image expansion continues to predominate even under conditions that seem more favourable to a local analysis. We added a global rotation to the stimulus so that the global pattern of expansion was distorted while leaving the local expansion unaffected. Even under relatively high rotation rates (30 degrees s(-1)), local expansion continued to have little systematic effect upon estimates of TTC.     

People,State and Civic Responses to Immigration,Xenophobia and Racism in the New South Africa

As a result of its political transformation, South Africa has become a victim of its own success, in that the shift in political power brought about a range of new discriminatory practices and victims. South Africa became a magnet for nationals from African countries who came to ‘the rainbow nation’ to share in the fruits of more stable governance and enjoy the benefits of a larger more dynamic economy, instead find themselves faced with xenophobia and racism. The aim of this paper is to analyse the development of immigration policy in post-apartheid South Africa in terms of the vulnerabilities and protections it has afforded migrants, as well as ways in which it has informed the behaviour of state officials from 1994 to 2008. It highlights trends and tensions surrounding immigration reform in the new South Africa and argues that legislation has made significant strides in informing the behaviour of high- and low-ranking officials in government and state departments but still has a long way to go.     

The unit size effect of indulgent food: How eating smaller sized items signals impulsivity and makes consumers eat less

In deciding how much to eat, people are influenced by environmental cues. The unit size of food (i.e. the number of units in which a given amount of food is divided) provides such a cue. Previous research showed that given equal caloric and volumetric content, smaller units of food tend to reduce food consumption. We propose that the unit size of food impacts intake as it influences perceptions of impulsiveness and appropriateness. Our analysis is based on three experimental studies, all employing between subject designs. When consuming similar amounts of chocolates in studies 1 (n?=?118) and 2 (n?=?124), both studies show that consumption of five small units of chocolates is considered to be more impulsive, excessive and less appropriate than consuming one large unit of chocolate. Results of a third study (n?=?165) indicate that about 23% less chocolate is eaten when it is presented in small unit size vs. a large unit size and this effect is mediated by perceptions of impulsivity. All three studies suggest that perceptions of impulsivity and excess eating while eating several smaller units of food compared to one large unit might be a key factor explaining consumption effects in earlier studies on this bias.     

Converging Technologies: A Critical Analysis of Cognitive Enhancement for Public Policy Application

This paper investigates cognitive enhancement, specifically biological cognitive enhancement (BCE), as a converging technology, and its implications for public policy. With an increasing rate of technological advancements, the legal, social, and economic frameworks lag behind the scientific advancements that they support. This lag poses significant challenges for policymakers if it is not dealt with sufficiently within the right analytical context. Therefore, the driving question behind this paper is, “What contingencies inform the advancement of biological cognitive enhancement, and what would society look like under this set of assumptions?” The paper is divided into five components: (1) defining the current policy context for BCEs, (2) analyzing the current social and economic outcomes to BCEs, (3) investigating the context of cost-benefit arguments in relation to BCEs, (4) proposing an analytical model for evaluating contingencies for BCE development, and (5) evaluating a simulated policy, social, technological, and economic context given the contingencies. In order to manage the risk and uncertainty inherent in technological change, BCEs’ drivers must be scrutinized and evaluated.     

Effects of mental workload and caffeine on catecholamines and blood pressure compared to performance variations

Caffeine is characterised as a central nervous system stimulant, also affecting metabolic and cardiovascular functions. A number of studies have demonstrated an effect of caffeine on the excretion of catecholamines and their metabolites. Urinary epinephrine and norepinephrine have been shown to increase after caffeine administration. Similar trends were observed in our study in adrenaline (ADR) and noradrenaline (NORADR) levels and additionally a dose dependent effect of caffeine. The effect of caffeine on cognitive performance, blood pressure, and catecholamines was tested under resting conditions and under mental workload. Each subject performed the test after oral administration of 1 cup and then 3 cups of coffee. Root mean square error (RMSE) for the tracking task was continuously monitored. Blood pressure was also recorded before and after each stage of the experiment. Catecholamines were collected and measured for three different conditions as: at rest, after mental stress alone, after one dose of caffeine under stress, and after triple dose of caffeine under stress. Comparison of the performance of each stage with the resting conditions revealed statistically significant differences between group of smokers/coffee drinkers compared with the other two groups of non-coffee drinkers/non-smokers and non-smokers/coffee drinkers. There was no statistically significant difference between the last two groups. There was an increase of urine adrenaline with 1 cup of coffee and statistically significant increase of urine noradrenaline. Both catecholamines were significantly increased with triple dose of caffeine. Mental workload increased catecholamines. There was a dose dependent effect of caffeine on catecholamines.     

Effects of video modeling on social initiations by children with autism

We examined the effects of a video modeling intervention on social initiation and play behaviors with 3 children with autism using a multiple baseline across subjects design. Each child watched a videotape showing a typically developing peer, and the experimenter engaged in a simple social interactive play using one toy. For all children, social initiation and reciprocal play skills were enhanced, and these effects were maintained at 1- and 3-month follow-up periods.