Effect of visual surrounding motion on body sway in a three-dimensional environment

Unidirectional motion of a uniplanar background induces a codirectional postural sway. It has been shown recently that fixation of a stationary foreground object induces a sway response in the opposite direction (Bronstein & Buckwell, 1997) when the background moves transiently. The present study investigated factors determining this contradirectional postural response. In the experiments presented, center of foot pressure and head displacements were recorded from normal subjects. The subjects faced a visual background of 2 x 3 m, at a distance of 1.5 m, which could be moved parallel to the interaural axis. Results showed that when the visual scene consisted solely of a moving background, the conventional codirectional postural response was elicited. When subjects were asked to fixate an earth-fixed foreground (window frame) placed between them and the moving background, a consistent postural response in the opposite direction to background motion was observed. In addition, we showed that this contradirectional postural response was not transient but was sustained for the 11 sec of background motion. We investigated whether this contradirectional postural response was the consequence of the induced movement of the foreground by background motion. Although induced movement was verbally reported by subjects when viewing an earth-fixed target projected onto the moving background, the contradirectional sway did not occur. These results indicate that foreground-background separation in depth was necessary for the contradirectional postural response to occur rather than induced movement. Another experiment showed that, when the fixated foreground was attached to the head of the observer, the contradirectional sway was not observed and was therefore unrelated to vergence. Finally, results showed that the contradirectional postural response was, in the main, monocularly mediated. We conclude that the direction of the postural sway produced by a moving background in a three-dimensional environment is determined primarily by motion parallax.     

Judging body weight from faces: the height-weight illusion

Being able to exploit features of the human face to predict health and fitness can serve as an evolutionary advantage. Surface features such as facial symmetry, averageness, and skin colour are known to influence attractiveness. We sought to determine whether observers are able to extract more complex features, namely body weight. If possible, it could be used as a predictor for health and fitness. For instance, facial adiposity could be taken to indicate a cardiovascular challenge or proneness to infections. Observers seem to be able to glean body weight information from frontal views of a face. Is weight estimation robust across different viewing angles? We showed that participants strongly overestimated body weight for faces photographed from a lower vantage point while underestimating it for faces photographed from a higher vantage point. The perspective distortions of simple facial measures (e.g., width-to-height ratio) that accompany changes in vantage point do not suffice to predict body weight. Instead, more complex patterns must be involved in the height-weight illusion.     

Relations among media influence,body image,eating concerns,and sexual orientation in men: A preliminary investigation

The current study explored the relation between sexual orientation, media persuasion, and eating and body image concerns among 78 college men (39 gay; 39 straight). Participants completed measures of sexual orientation, eating disorder symptoms, appearance-related anxiety, perceived importance of physical attractiveness, perceptions of media influence, and media exposure. Gay men scored significantly higher on drive for thinness, body dissatisfaction, and body image-related anxiety than their straight counterparts. Additionally, perceptions of media influence were higher for gay men, and significantly mediated the relation between sexual orientation and eating and body image concerns. Sexual orientation also moderated the relation between perceived media influence and beliefs regarding the importance of physical attractiveness, as this relation was significant for gay men, but not straight men. The current findings suggest that gay men's increased vulnerability to media influence partially accounts for the relatively high rate of eating pathology observed in this population.     

Sex-role orientation and stereotypes about male-female sexuality

An experiment was conducted to examine the stereotypes about human sexuality held by persons of different sex-role orientations. Sex-typed and androgynous subjects were given bogus information about the sexual experience of another person. This other person was either a male or a female and either high or low in sexual experience. The subjects were then shown some erotic slides and asked to predict how sexually aroused the target person would be by viewing these stimuli. Additionally, the subjects were asked to rate the target person on traits of a sexual and evaluative nature. The results showed, as predicted, that the sexual experience of a female target influences how much sexual arousal is attributed to her. Female targets of high experience were attributed more arousal than inexperienced female targets. For male targets, no such difference was found. Ratings of the targets on an evaluative dimension revealed a double standard: Sexually experienced females were rated lower than were inexperienced females; no difference was found for male targets. In addition, sex-typed subjects tended to express more traditional stereotypes of sexuality than androgynous subjects. The influence that these stereotypes may have in guiding malefemale interactions is discussed.This article is based on the author's doctoral dissertation, submitted to Kansas State University. The author gratefully acknowledges the assistance of William Giffitt, and his helpful comments and suggestions.     

Gender,sexual orientation,and disordered eating

Abstract

While most patients with bulimia nervosa are heterosexual women, a significant number of men with bulimia nervosa are gay males, suggesting that gay men, more than heterosexual men, may be at risk for developing eating disorders. This study compared the food-related attitudes and behaviors of heterosexual men and women in contrast with those of lesbians and gay men, attempting to find whether one's sexual orientation may contribute to differential risk. Two thousand employees were randomly selected from a large health care corporation, of whom 805 returned a completed questionnaire including Stunkard and Messick's (1985) Dietary Restraint and Disinhibition Scales. A stratified random sample was drawn to include demographically comparable groups of 25 lesbians, 50 gay men, 75 heterosexual women, and 75 heterosexual men. Women were less satisfied with their appearance at their present weight and expressed more restraint and more negative feelings after bingeing than did men. Heterosexual women were most dissatisfied with their weight, although heterosexual men were more objectively overweight. Gay men and heterosexual women were similar in disordered eating patterns and disinhibition, contrasting with lesbians and heterosexual men.     

Religion, genetics, and sexual orientation: the Jewish tradition

This paper probes the implications of a genetic basis for sexual orientation for traditional branches of Judaism, which are struggling with how accepting to be of noncelibate gays and lesbians in their communities. The paper looks at the current attitudes toward homosexuality across the different branches of Judaism; social and cultural factors that work against acceptance; attitudes toward science in Jewish culture; and the likelihood that scientific evidence that sexual orientation is at least partly genetically determined will influence Jewish scholars' and leaders' thinking on this issue.     

Shape, orientation, and apparent rotational motion

Apparent rotational motion was investigated in polygonal shapes ranging in rotational symmetry from random to self-identical under 180 degrees rotation. Observers adjusted the rate of alternation between two computer-displayed orientations of any given polygon to determine the point of breakdown of perceived rigid rotation between those two orientations. For asymmetric polygons, the minimum stimulus-onset asynchrony yielding apparent rigid rotation increased approximately linearly with orientational disparity, as anticipated on the basis of the extension of Korte's third law to rotational motion by Shepard and Judd. For nearly symmetric polygons, however, the critical time increased markedly as the disparities approached 180 degrees, owing to the availability of a shorter, nonrigid rotation in the opposite direction. The results demonstrate the existence of competing mental tendencies to preserve the rigid structure of an object and to traverse a minimum transformational path.     

Preference for human body odors is influenced by gender and sexual orientation

Human body odor may contribute to selection of partners. If so, sexual orientation may influence preference for and perhaps production of human body odors. In a test of these hypotheses, heterosexual and homosexual males and females made two-alternative forced-choice preference judgments for body odors obtained from other heterosexual and homosexual males and females. Subjects chose between odors from (a) heterosexual males and gay males, (b) heterosexual males and heterosexual females, (c) heterosexual females and lesbians, and (d) gay males and lesbians. Results indicate that differences in body odor are detected and responded to on the basis of, in part, an individual's gender and sexual orientation. Possible mechanisms underlying these findings are discussed.     

Mexican-American adolescent sexuality and sexual knowledge: an exploratory study

This article reports the findings of a study designed to examine the sexual knowledge, attitudes, and practices of low-income Mexican- American adolescents. The participants in the study were all about to begin a sex education program in a community health organization in East Los Angeles. The study involved 84 adolescents aged 14-19, 97% of who identified themselves as Mexican-American (the remainder identified themselves as Latino). 51 of the subjects were female and 33 male. The participants completed a 43-item questionnaire concerning demographics, sexual experience and contraceptive use, knowledge of birth control methods, and attitudes towards sexuality and birth control. Only 18 (21%) of the subjects indicated ever having sex. But among this group, 83% reported not using contraception during their last intercourse, and 61% reported never using contraception. Only 22% reported using contraception regularly. Concerning the knowledge of different birth control methods,many of the participants were able to list several methods, but their responses indicated a lack of accurate and specific knowledge about contraceptive methods. In addition to the 43-item questionnaire, 27 of the subjects also completed a sexual and contraceptive knowledge questionnaire. The topics included contraceptive effectiveness, the menstrual cycle, and fertilization. The scores on the questionnaire were low, with an average score of 33% of correct answers. Finally, all 84 participants responded to a sexual attitude questionnaire, which revealed a generally traditional attitude toward the importance of have children, virginity, and the relationship between sex and love.     

Televised sexual content and parental mediation: Influences on adolescent sexuality

Little research has been conducted to examine the influence of exposure to televised sexual content on adolescent sexuality or how parental intervention may reduce negative effects of viewing such content. This study uses self-report data from 1,012 adolescents to investigate the relations among exposure to sexually suggestive programming, parental mediation strategies, and three types of adolescent sexuality outcomes: participation in oral sex and sexual intercourse, future intentions to engage in these behaviors, and sex expectancies. As predicted, exposure to sexual content was associated with an increased likelihood of engaging in sexual behaviors, increased intentions to do so in the future, and more positive sex expectancies. Often, parental mediation strategies were a significant factor in moderating these potential media influences.     

Sex-role acquisition,parental behavior,and sexual orientation: Some tentative hypotheses

It was hypothesized that sexual orientation is not an aspect of sex-role socialization, but is acquired during a sensitive period from birth to 3 years through physical contact with adults. This is tentatively supported by evidence suggesting that (a) sexual orientation is highly resistant to change after adolescence; (b) infants respond to sexual stimulation and discriminate between the sexes; (c) gender identity is fixed between birth and 3 years of age; (d) during their infancy, homosexuals were psychosocially and presumably physically responded to as children of the opposite sex; (e) parents touch boys and girls differently. Stronger support for the hypothesis must be gained from longitudinal observation of parent-infant physical and social interaction and the infant's eventual sexual orientation.     

Race/ethnicity and sexual orientation: intersecting identities

Racial/ethnic minority women who come to identify as lesbian must confront the norms and expectations of both the majority and minority cultures in which they live. This article reports findings from a diverse sample of nearly 450 women and examines the effects of race/ethnicity on sexual identity development in African American, Latina, and White lesbians. African American and Latina respondents differed little in the timing and disclosure of lesbian identity; comparisons between women of color and White women revealed substantial variability. Findings are discussed in terms of their implications for practice with lesbians of color.     

Resolving ambiguities in orientation, motion, and depth domains.

Three different perceptual systems--orientation, motion, and depth--can recover a global perceptual organization from spatially correlated random multielement patterns. In all three cases the global structure composed of random elements is evaluated by mechanisms performing measurements in the energy domain within appropriately defined local space-time areas. The selective increase in energy of one fraction of the elements may dramatically change the whole perceptual organization of the stimulus. In specially devised patterns one and the same element can belong to two or more separate perceptual organizations, the perceptual salience of one of which can be reinforced by a luminance increment of the elements comprising it. If a stimulus provides two different perceptual organizations to which each element could potentially belong, one of four possible solutions of the existing ambiguity will occur: suppression, rivalry, mixture, or parity. Two superimposed global orientation patterns either suppress or dominate over each other but cannot be seen simultaneously or in a mixed form. Characteristic of the depth system is that it allows multiple binocular matchings and parity of possible perceptual solutions. Finally, if a stimulus provides two or more paths along which each element may appear to move, the perceived global motion direction is determined by a mixture of directions of these competing motion paths. Dissimilarities in these ways of resolving ambiguities may be based on different principles defining regularity and coherence of an object in the orientation, motion, and depth domains.     

Youth suicide risk and sexual orientation

Using a broad suicide risk assessment (suicidal ideation, hopelessness, hostility) with 100 youth ages 17 to 19, this study examined the relationship between sexual orientation and youth suicide risk. Participants were compared across sexual orientation, as well as level of perceived external support, which may be a mitigating variable in suicide risk. The suicide risk demonstrated by sexual minorities in this study was no greater than that of their heterosexual peers. Youth who reported more external support demonstrated lower overall suicide risk and, specifically, lower levels of hostility, hopelessness, and suicidal ideation. The results indicated that suicide risk is not determined by demographic criteria alone, and may be influenced by psychosocial variables, such as support.     

Female sexual orientation is perceived accurately, rapidly, and automatically from the face and its features

Whereas previous work has shown that male sexual orientation can be accurately and rapidly perceived from the human face and its individual features, no study has examined the judgment of female sexual orientation. To fill this gap, the current work examined the accuracy, speed, and automaticity of judgments of female sexual orientation from the face and from facial features. Study 1 showed that female sexual orientation could be accurately judged from the face and from just eyes without brows and limited to the outer canthi. Study 2 then examined the speed and efficiency of these judgments, showing that judgments of the faces following very brief, near subliminal (40 ms) exposures were significantly better than chance guessing. Finally, Study 3 tested the automaticity of judgments of female sexual orientation by examining the effects of deliberation on accuracy. Participants who made snap judgments of female sexual orientation were significantly more accurate than participants who made thoughtful and deliberated judgments. These data therefore evidence a robust, reliable, and automatic capacity for extracting information about female sexual orientation from nonverbal cues in the face.     

Self-objectification,body self-consciousness during sexual activities,and sexual satisfaction in college women

Few studies examine the mechanisms that link body image to sexual satisfaction in women. Using the tenets of objectification theory, this study investigated the relationships between body surveillance, body shame, body self-consciousness during sexual activities, and sexual satisfaction in an ethnically diverse sample of American female college students (N = 368), while controlling for relationship status and body mass index. Results based on self-report measures of these constructs suggested that body shame and body self-consciousness during sexual activity were negatively correlated with sexual satisfaction. Additionally, path analysis indicated that body surveillance predicted increased body self-consciousness during sexual activity, partially mediated by body shame. Body self-consciousness, in turn, predicted decreased sexual satisfaction. Overall, study findings highlight the negative consequences of body image concerns for women's sexual satisfaction.     

Sex, sexual orientation, and identification of positive and negative facial affect

Sex and sexual orientation related differences in processing of happy and sad facial emotions were examined using an experimental facial emotion recognition paradigm with a large sample (N = 240). Analysis of covariance (controlling for age and IQ) revealed that women (irrespective of sexual orientation) had faster reaction times than men for accurate identification of facial emotion and were more accurate in identifying male faces than female ones, whereas men performed the same regardless of the sex of the face. However, there were no overall sex differences in accuracy. These findings suggest a limited role for sex in the perception of facial affect.     

Aggressive behavioral characteristics,hormones, and sexual orientation in men and women

Aggressive behavioral characteristics were assessed in groups of men and women by a self-report instrument, the Aggression Inventory, in which adult males reported more physical and verbal aggression than did females. Furthermore, males had higher scores on measures of impulsiveness and lack of frustration tolerance than did females, while women were more likely to avoid confrontation. In a second study, groups of male and female homosexuals and heterosexuals completed this Aggression Inventory after having blood samples taken to assay resting levels of testosterone (T) and estradiol (E). Groups of subjects within each gender were closely matched in terms of age, education, and vocational interests. Women were matched for the same time in their menstrual cycle (early follicular phase). Among men, homosexuals were indistinguishable from heterosexuals on all measures of aggression. Lesbians did not differ from heterosexual women on any aggression subscale except physical aggression, in which the homosexual women had lower scores. T and E were positively correlated with several indices of aggressive behavioral characteristics in men but were negatively correlated with those same measures in women.