Men's attraction to women's bodies changes seasonally

Humans exhibit seasonal variation in hormone levels, behaviour, and perception. Here we show that men's assessments of women's attractiveness change also seasonally. In five seasons (from winter 2004 to winter 2005) 114 heterosexual men were asked to assess the attractiveness of the same stimuli: photos of a female with three different waist-to-hip ratios; photos of female breasts, and photos of average-looking faces of young women. For each season, the scores given to the stimuli of the same category (body shape, breast, and face) were combined. Friedman's test revealed significant changes for body shape and breast attractiveness assessments across the seasons, but no changes for face ratings. The highest scores for attractiveness were given in winter and the lowest in summer. We suggest that the observed seasonality is related to the well-known 'contrast effect'. More frequent exposure to women's bodies in warmer seasons might increase men's attractiveness criteria for women's body shape and breasts.     

A multipurpose voltage controlled oscillator

This report describes a multipurpose voltage controlled oscillator that is inexpensive, flexible, and adaptable to a variety of experimental purposes. Design features include the capability to (1) select a wide range of frequencies for experimental use, and (2) use the output to drive other digital circuits.     

Food wrenching and dodging: Eating time estimates influence dodge probability and amplitude

Eating rats dodge conspecifics, who are trying to steal their food, by making a somewhat stereotyped 180° turn and step movement to block the robber's approach. This experiment examined the effect of food features on the form and vigor of the dodging movement. Dodge probability and its amplitude were measured as a function of food size, elapsed eating time, food hardness, and the way in which food theft was attempted. Under all conditions dodge probability and its amplitude were directly related to the time necessary to complete eating. Thus, rats estimated the time required to complete eating and adjusted the size of their evasive movements to gain this time. The results show that although dodging has the appearance of a fixed-action pattern, it is influenced by cognitive processes that may be similar to those that direct other aspects of foraging behavior. © 1994 Wiley-Liss, Inc.     

Variable preferences for sexual dimorphism in stature (SDS): Further evidence for an adjustment in relation to own height

In contemporary Western populations, some physical characteristics are sexually dimorphic, and it is known that these traits also affect human mate preferences. Height is one such characteristic, and evidence suggests that females prefer taller over shorter males, indeed, taller males have been found to have greater reproductive success. However, relative height is also important with ‘Sexual Dimorphism in Stature’ (SDS) calculated as male height/female height. Pawlowski (2003) showed that people adjust their preferences for SDS in relation to their own height in order to increase their potential pool of partners. The aim of the present study was to replicate Pawlowski’s study on a larger sample of participants, and to investigate the universality of the reported preference adjustment within European societies. We present data of 1102 men and women from three countries (Germany, Austria, and the UK) that confirm Pawlowski’s original data on a Polish sample. Moreover, the mechanism of an adjustment of SDS preferences in relation to own height was found in all three countries, suggesting that height dependent partner preference is a genuine feature in Western societies.     

Alcohol and nicotine intake and prenatal level of androgens measured by digit ratio

The purpose of this study was to examine the associations between using unhealthy substances and the digit ratio (2nd to 4th digit length ratio, 2D:4D) which is supposed to indicate the prenatal testosterone level. The subjects were 455 students, 225 women and 230 men. Participants declared their frequency of smoking and alcohol drinking. There was no significant difference in digit ratios between subjects regularly using both nicotine and alcohol and those who took none of them. When analyzing the two substances separately, there was no relationship between 2D:4D and alcohol drinking, whereas left hand 2D:4D was positively related to smoking only for women (nonsignificant trend was observed for right hand). Contrary to the previous study, our results indicate that there is no relationship between 2D:4D and alcohol drinking. There is, however, a subtle influence of prenatal testosterone levels for cigarette smoking habits in the case of women.     

Eye-mouth-eye angle as a good indicator of face masculinization, asymmetry, and attractiveness (Homo sapiens)

Past research on male facial attractiveness has been limited by the reliance on facialmetric measures that are less than ideal. In particular, some of these measures are face size dependent and show only weak sexual dimorphism, which limits the ability to identify the relationship between masculinization and attractiveness. Here, the authors show that eye-mouth-eye (EME) angle is a quantitative and face size independent trait that is sexually dimorphic and a good indicator of masculinity and face symmetry. Using frontal photographs of female and male faces, the authors first confirmed that the EME angle (measured with the vertex in the middle of the mouth and the arms crossing the centers of pupils) was highly sexually dimorphic. Then, using pictures of young male faces whose attractiveness was assessed on a 7-point scale by young women, the authors showed that attractiveness rate was negatively correlated with EME angle and with the angle asymmetry. The results are compared with those that could be obtained with interpupilary or upper face height measurements. The authors discuss the relationship between attractiveness and both EME angle and its symmetry in the light of evolutionary psychology.