Richard A. Lippa

Are 2D:4D Finger-Length Ratios Related to Sexual Orientation? Yes for Men, No for Women

The ratio of index and ring finger lengths (2D:4D) is thought to be a marker of prenatal androgen exposure. In a sample of over 2,000 participants, men had significantly lower 2D:4D ratios than women (d = .36 and .23 for right and left hands, respectively), and these results were consistent across ethnic groups. Heterosexual men had significantly lower (more male typical) 2D:4D ratios than gay men (d = .32 and .31 for right and left hands, respectively), and these results tended to be consistent across ethnic groups. Heterosexual and lesbian women showed no significant differences in 2D:4D ratios, after ethnicity was taken into account. The current findings add to evidence that prenatal hormonal factors may be linked to mens sexual orientation.

Sex Differences in Mental Rotation and Line Angle Judgments Are Positively Associated with Gender Equality and Economic Development Across 53 Nations

Mental rotation and line angle judgment performance were assessed in more than 90,000 women and 111,000 men from 53 nations. In all nations, men’s mean performance exceeded women’s on these two visuospatial tasks. Gender equality (as assessed by United Nations indices) and economic development (as assessed by per capita income and life expectancy) were significantly associated, across nations, with larger sex differences, contrary to the predictions of social role theory. For both men and women, across nations, gender equality and economic development were significantly associated with better performance on the two visuospatial tasks. However, these associations were stronger for the mental rotation task than for the line angle judgment task, and they were stronger for men than for women. Results were discussed in terms of evolutionary, social role, and stereotype threat theories of sex differences.

Some psychometric characteristics of gender diagnosticity measures: reliability, validity, consistency across domains, and relationship to the big five.

Preferences for various occupations, school subjects, everyday activities, and hobbies and amusements were rated by 119 male and 145 female Ss. Discriminant analyses were conducted to compute gender diagnostic probabilities. Ss also rated themselves on Big Five traits and completed the Bem Sex-Role Inventory (BSRI) and the Personal Attributes Questionnaire (PAQ). Results indicated that (a) gender diagnosticity measures showed high reliability, (b) gender diagnosticity predicted sex of S and self-ascribed masculinity (M) and femininity (F) better than contrasted-groups M-F scales, (c) gender diagnosticity measures displayed substantial consistency across domains both within and across the sexes, and (d) gender diagnosticity measures were independent of the Big Five and PAQ and BSRI scales both within and across the sexes, whereas PAQ and BSRI scales loaded highly on Big Five dimensions.

Gender-related traits of heterosexual and homosexual men and women.

Two studies investigated the relation between sexual orientation and gender-related traits. Analyzing data from an Internet survey, Study 1 found that gay men and lesbians differed from same-sex heterosexuals most strongly on gender diagnosticity (GD) measures, which assess male- versus female-typicality of occupational preferences (effect sizes were 1.14 for men and 0.53 for women) and least strongly on instrumentality (I) and expressiveness (E). Study 2 found that GD measures showed large differences between 289 gay and 200 heterosexual men (d = 0.95) and between 296 lesbian and 435 heterosexual women (d = 1.32), whereas I and E showed much smaller differences. In Study 2 homosexual–heterosexual diagnosticity measures, computed from mens and womens occupational preferences, correlated very strongly with GD measures (r = 0.88 for men and 0.89 for women), indicating that occupational preference items that distinguished men from women also tended to distinguish heterosexual from homosexual individuals. LISREL 8 analyses showed that self-ascribed masculinity–femininity did not mediate the strong relation between sexual orientation and GD for men or for women.

Finger lengths, 2D:4D ratios, and their relation to gender-related personality traits and the Big Five.

Finger lengths and the ratio of index finger to ring finger length (2D:4D) may be markers of gonadal hormone exposure. The current study investigated possible associations between absolute finger lengths, 2D:4D ratios, and gender-related personality traits in over 2000 participants. Regression analyses showed no associations between mens 2D:4D ratios and gender-related personality traits and weak associations between womens 2D:4D ratios and gender-related occupational preferences. Mens absolute finger lengths were weakly associated with self-ascribed masculinity, and womens absolute finger lengths were weakly associated with masculine occupational preferences. Big Five personality traits were assessed in a subsample of over 1000 participants. Analyses showed a weak positive association between 2D:4D and extraversion and a weak negative association between 2D:4D and openness to experience. Absolute finger lengths showed a weak negative association with agreeableness and a tendency to be associated with womens but not mens openness. Overall, associations between finger-length measures and personality were weak and inconsistent.

Is High Sex Drive Associated With Increased Sexual Attraction to Both Sexes? It Depends on Whether You Are Male or Female

If sex drive is a generalized energizer of sexual behaviors, then high sex drive should increase an individuals sexual attraction to both men and women. If sex drive energizes only dominant sexual responses, however, then high sex drive should selectively increase attraction to men or to women, but not to both, depending on the individuals sexual orientation. Data from three studies assessing a total of 3,645 participants show that for most women, high sex drive is associated with increased sexual attraction to both men and women. For men, however, high sex drive is associated with increased sexual attraction to only one sex or the other, depending on the individuals sexual orientation. These results suggest that the correlates of sex drive and the organization of sexual orientation are different for women and men.

The effects of a large destructive local earthquake on earthquake preparedness as assessed by an earthquake preparedness scale

A multi-act scale for measuring the earthquake preparedness of individuals and small businesses was developed and used to assess the earthquake preparedness and the perceived difficulty of becoming prepared for earthquakes of 291 University of Southern California undergraduate students approximately 3 weeks prior to the 5.9 magnitude Whittier Narrows earthquake on 1 October 1987. These data were then compared with similar information collected over a 2 1/2 month period following the earthquake from randomly selected samples of subjects that had participated in the original survey. In one case, levels of preparedness of a single group were measured at approximately 2 week intervals (the repeated measures study). In a second case, this information was collected at different points in time following the earthquake from different groups of subjects (the between groups study). Results indicated an initial increase in earthquake preparedness which was significant for subjects in the repeated measures group and which approached significance for subjects in the between groups. This increase in preparedness was maintained for subjects in the repeated measure study but gradually declined to pre-earthquake levels for subjects in the between subjects study. Subjects in the repeated measures study also perceived earthquake preparedness as a significantly less difficult task following the earthquake. Level of perceived difficulty continued to decline over the 2 1/2 month study period. Declines in perceived difficulty for the between subjects study were more erratic, and were only approximately 1/3 of that for the repeated measures group at the end of 2 1/2 months.

Handedness, Sexual Orientation, and Gender-Related Personality Traits in Men and Women

This study assessed large numbers of heterosexual and homosexual men and women on handedness and gender-related personality traits. Initial analyses employed a dichotomous measure of handedness (right-handed vs. non–right-handed). For men and women combined, homosexual participants had 50% greater odds of being non–right-handed than heterosexual participants, a statistically significant difference. Homosexual men had 82% greater odds of being non–right-handed than heterosexual men, a statistically significant difference, whereas homosexual women had 22% greater odds of being non–right-handed than heterosexual women, a nonsignificant difference. When participants were classified into five graduated categories of handedness, both men and women showed significant homosexual–heterosexual differences in handedness distributions. Within groups, handedness showed a number of weak but statistically significant associations with sex-typed occupational preferences, self-ascribed masculinity, and self-ascribed femininity, but not with instrumentality or expressiveness. Rates of non–right-handedness were virtually identical for heterosexual men and women, suggesting that sex differences in handedness may result from higher rates of homosexuality in men.

Does Culture Moderate the Relationship Between Sexual Orientation and Gender-Related Personality Traits?:

Do cultural factors moderate the relationship between sexual orientation and gender-related personality traits? To answer this question, the authors assessed gender-related traits in 90 gay men, 82 lesbians, 71 heterosexual men, and 95 heterosexual women from three cultural groups: Asian Americans, Hispanic Americans, and White Americans. Among the gender-related traits measured were gender diagnosticity (GD), which assesses maleversus female-typicality of occupational and hobby preferences; self-ascribed masculinity and femininity; masculine instrumentality; and feminine expressiveness. We found strong homosexual-heterosexual differences on GD measures, moderate to strong differences in self-ascribed masculinity and femininity, and weak and inconsistent differences on instrumentality and expressiveness. Participants from traditional, gender-polarized cultures (Asians and Hispanics) tended to show larger heterosexual-homosexual differences in gender-related traits than participants from a nontraditional and gendernonpolarized culture (American Whites).

The Structure of Sexual Orientation and its Relation to Masculinity, Femininity, and Gender Diagnosticity: Different for Men and Women

Three hundred ninety-four college students (148 men and 246 women; 42% White, 25% Hispanic, and 23% Asian) were assessed on masculine instrumentality (M), feminine expressiveness (F), gender diagnosticity (GD), and the Big Five personality traits (Extraversion, Agreeableness, Conscientiousness, Neuroticism, and Openness). Participants completed a 16-item sexual behavior and attitude questionnaire that asked about their attraction to men, their attraction to women, their degree of emotional commitment in sexual relationships, their level of sex drive, and their interest in visual sexual stimuli and fantasy. Factor analysis of sexual behavior and attitude items for men showed four factors: Bipolar Sexual Orientation, Emotional Commitment, Sex Drive, and Sexual Fantasy. Factor analysis of items for women showed four somewhat different factors: Homosexuality, Heterosexuality, Emotional Commitment, and Sex Drive. Thus, sexual orientation proved to be bipolar for men, but two-dimensional for women. For men, Sexual Orientation correlated most strongly with GD, less with M, and not at all with F. Among women, there were few significant correlations between personality measures and Homosexuality or Heterosexuality.