Working memory: Trouble in mind

AbstractVisual working memory has been found to depend on interactions between the prefrontal cortex and visual association areas; the neurons involved can be modulated by dopamine. These new findings have relevance for the treatment of Parkinson's disease and schizophrenia

Cultural Predictors of Facial Ethnicity Preference in the Miskitu and Mestizos of Rural Nicaragua

Both basic visual experience and cultural associations with race and ethnicity may contribute to the extent observers do or do not favor some facial ethnicity cues over others. Given that visual media contain a highly biased selection of faces, with Whiteness both over-represented and strongly privileged in film and television, communities for whom visual media are relatively novel may experience an additional, pervasive source of attitudes to facial ethnicity markers. In the current research, we compared individuals of Mestizo and Miskitu identities living in communities on the Caribbean Coast of Nicaragua with, and without, regular access to television on their relative preference for facial stimuli manipulated to look more or less White (Black vs White, Black vs Mestizo, Mestizo vs White). Results showed that all communities showed an overall preference for images with lighter skin, although changes in facial shape did not affect preferences. Those who had attended more years of education preferred whiter faces than those with less education, and those who watched more television preferred whiter faces more only where color (rather than shape) had been manipulated. Results are discussed in terms of the broader relations around ethnicity, status, and technological transition in this area

BMI Not WHR Modulates BOLD fMRI Responses in a Sub-Cortical Reward Network When Participants Judge the Attractiveness of Human Female Bodies

In perceptual terms, the human body is a complex 3d shape which has to be interpreted by the observer to judge its attractiveness. Both body mass and shape have been suggested as strong predictors of female attractiveness. Normally body mass and shape co-vary, and it is difficult to differentiate their separate effects. A recent study suggested that altering body mass does not modulate activity in the reward mechanisms of the brain, but shape does. However, using computer generated female body-shaped greyscale images, based on a Principal Component Analysis of female bodies, we were able to construct images which covary with real female body mass (indexed with BMI) and not with body shape (indexed with WHR), and vice versa. Twelve observers (6 male and 6 female) rated these images for attractiveness during an fMRI study. The attractiveness ratings were correlated with changes in BMI and not WHR. Our primary fMRI results demonstrated that in addition to activation in higher visual areas (such as the extrastriate body area), changing BMI also modulated activity in the caudate nucleus, and other parts of the brain reward system. This shows that BMI, not WHR, modulates reward mechanisms in the brain and we infer that this may have important implications for judgements of ideal body size in eating disordered individuals

Cultural Predictors of Facial Ethnicity Preference in the Miskitu and Mestizos of Rural Nicaragua

Both basic visual experience and cultural associations with race and ethnicity may contribute to the extent observers do or do not favor some facial ethnicity cues over others. Given that visual media contain a highly biased selection of faces, with Whiteness both over-represented and strongly privileged in film and television, communities for whom visual media are relatively novel may experience an additional, pervasive source of attitudes to facial ethnicity markers. In the current research, we compared individuals of Mestizo and Miskitu identities living in communities on the Caribbean Coast of Nicaragua with, and without, regular access to television on their relative preference for facial stimuli manipulated to look more or less White (Black vs White, Black vs Mestizo, Mestizo vs White). Results showed that all communities showed an overall preference for images with lighter skin, although changes in facial shape did not affect preferences. Those who had attended more years of education preferred whiter faces than those with less education, and those who watched more television preferred whiter faces more only where color (rather than shape) had been manipulated. Results are discussed in terms of the broader relations around ethnicity, status, and technological transition in this area

Representational capacity of a set of independent neurons

The capacity with which a system of independent neuron-like units represents a given set of stimuli is studied by calculating the mutual information between the stimuli and the neural responses. Both discrete noiseless and continuous noisy neurons are analyzed. In both cases, the information grows monotonically with the number of neurons considered. Under the assumption that neurons are independent, the mutual information rises linearly from zero, and approaches exponentially its maximum value. We find the dependence of the initial slope on the number of stimuli and on the sparseness of the representation.Comment: 19 pages, 6 figures, Phys. Rev. E, vol 63, 11910 - 11924 (2000

Judging the difference between attractiveness and health: does exposure to model images influence the judgments made by men and women?

Recent research has shown facial adiposity (apparent weight in the face) to be a significant predictor of both attractiveness and health, thus making it an important determinant of mate selection. Studies looking at the relationship between attractiveness and health have shown that individuals differentiate between the two by preferring a lower weight for attractiveness than for health in female faces. However, these studies have either been correlational studies, or have investigated weight perceived from only the face. These differences have been discussed with regard to sociocultural factors such as pressure from parents, peers and also media, which has been seen to have the highest influence. While exposure to media images has been shown to influence women’s own body image, no study has yet directly tested the influence of these factors on people’s preferred weight in other women’s bodies. Here we examine how a short exposure to images of models influences men’s and women’s judgments of the most healthy looking and attractive BMI in Malaysian Chinese women’s bodies by comparing differences in preferences (for attractiveness and health) between groups exposed to images of models of varying attractiveness and body weight. Results indicated that participants preferred a lower weight for attractiveness than for health. Further, women’s but not men’s preferred BMI for attractiveness, but not health, was influenced by the type of media images to which they were exposed, suggesting that short term exposure to model images affect women’s perceptions of attractiveness but not health

UV-Deprived Coloration Reduces Success in Mate Acquisition in Male Sand Lizards (Lacerta agilis)

Background: Recent work on animal signals has revealed a wide occurrence of UV signals in tetrapods, in particular birds, but also in lizards (and perhaps other Squamate reptiles). Our previous work on the Swedish sand lizard (Lacerta agilis) has verified, both in correlative selection analyses in the wild and with laboratory and field experiments, the importance of the green ‘badge ’ on the body sides of adult males for securing mating opportunities, probably mostly through deterring rival males rather than attracting females. The role of UV in communication has, however, never been examined. Methodology/Principal Findings: Here we show that when measured immediately after spring skin shedding, there is also signaling in the UV. By UV-depriving the signal (reflectance) with sun block chemicals fixated with permeable, harmless spray dressing, we show that males in the control group (spray dressing only) had significantly higher success in mate acquisition than UV-deprived males. Conclusions/Significance: These results suggest that at least two colour traits in sand lizards, badge area and UV, contribute to rival deterrence and/or female choice on UV characters, which elevates success in mate acquisition in UV intact male sand lizards

Body size estimation in women with anorexia nervosa and healthy controls using 3D avatars

A core feature of anorexia nervosa is an over-estimation of body size. However, quantifying this over-estimation has been problematic as existing methodologies introduce a series of artefacts and inaccuracies in the stimuli used for judgements of body size. To overcome these problems, we have: (i) taken 3D scans of 15 women who have symptoms of anorexia (referred to henceforth as anorexia spectrum disorders, ANSD) and 15 healthy control women, (ii) used a 3D modelling package to build avatars from the scans, (iii) manipulated the body shapes of these avatars to reflect biometrically accurate, continuous changes in body mass index (BMI), (iv) used these personalized avatars as stimuli to allow the women to estimate their body size. The results show that women who are currently receiving treatment for ANSD show an over-estimation of body size which rapidly increases as their own BMI increases. By contrast, the women acting as healthy controls can accurately estimate their body size irrespective of their own BMI. This study demonstrates the viability of combining 3D scanning and CGI techniques to create personalised realistic avatars of individual patients to directly assess their body image perception