Sex Ratios for Selected Behavior and Mental Disorders:

Source:
Gender, Nature, and Nurture
Richard A. Lippa (2005)

The Most Certain Universal Sex Differences (According to Ellis et al. 2008)

 
 

to enlarge: press [Ctrl] and [+]

Source: 

Sex Differences: Summarizing More Than a Century of Scientific Research

Lee Ellis et al. (2008)

The animal nature of spontaneous human laughter

The animal nature of spontaneous human laughter
Gregory A. Bryant, C. Athena Aktipis
Evolution and Human Behavior (Mar 2014)


Abstract

Laughter is a universally produced vocal signal that plays an important role in human social interaction. Researchers have distinguished between spontaneous and volitional laughter, but no empirical work has explored possible acoustic and perceptual differences. If spontaneous laughter is an honest signal of cooperative intent (e.g., derived from play breathing patterns), then the ability to mimic these sounds volitionally could have shaped perceptual systems to be attuned to aspects of spontaneous laughs that are harder to fake—features associated with phylogenetically older vocal control systems. We extracted spontaneous laughs from conversations between friends and volitional laughs elicited by instruction without other provocation. In three perception experiments we found that, 1) participants could distinguish between spontaneous and volitional laughter, 2) when laugh speed was increased (duration decreased 33% and pitch held constant), all laughs were judged as more “real,” with judgment accuracy increasing for spontaneous laughter and decreasing for volitional laughter, and 3) when the laughs were slowed down (duration increased 260% and pitch altered proportionally), participants could not distinguish spontaneous laughs from nonhuman vocalizations but could identify volitional laughs as human-made. These findings and acoustic data suggest that spontaneous and volitional laughs are produced by different vocal systems, and that spontaneous laughter might share features with nonhuman animal vocalizations that volitional laughter does not.

New Book: L.L. Cavalli-Sforza - A bird in a gilded cage

New Book: L.L. Cavalli-Sforza - A bird in a gilded cage
Peter Frost (2014)
http://openpsych.net/forum/attachment.php?aid=39


[Abstract]

Greater male variability in overexcitabilities: Domain-specific patterns

Greater male variability in overexcitabilities: Domain-specific patterns
Wu-jing Hea, Wan-chi Wong
Personality and Individual Differences (Aug 2014)


Highlights

o The greater male variability hypothesis was tested in overexcitability (OE).
o Domain-specific gendered-patterns were found across the five domains of OE.
o The hypothesis was supported in sensual, imaginational, and intellectual OEs.
o Male superiority was found in psychomotor OE.
o Female superiority was found in emotional OE.

Abstract

The greater male variability hypothesis posits that males exhibit greater variability than females in both mental and physical characteristics. The hypothesis has been supported in various giftedness-related constructs (e.g., intelligence, talents, creativity). This study extended this line of research to another giftedness-related psychological construct: overexcitability (OE). The Overexcitability Questionnaire-Two was administered to 836 (51% girls) 7–9th graders in Hong Kong to assess the five domains of OE (i.e., psychomotor, sensual, intellectual, imaginational, and emotional). The results suggested a domain-specific pattern of gender differences in the variability of OE scores. Greater male variability was found in the sensual, imaginational, and intellectual OE domains; male superiority was found in the psychomotor domain; and female superiority was found in the emotional domain. These domain-specific findings enrich the discourse surrounding the greater male variability hypothesis. Theoretical and educational implications regarding the findings are discussed.

(full size: click on the image)

New Book: Smash Chronic Fatigue - A Concise, Science-Based Guide to Help Your Body Heal, and Banish Fatigue Forever

Smash Chronic Fatigue - A Concise, Science-Based Guide to Help Your Body Heal, and Banish Fatigue Forever
P. D. Mangan (2014)

Heritability of Smoking Initiation and Nicotine Dependence

Heritability of Smoking Initiation and Nicotine Dependence
J. M. Vink, G. Willemsen, and D. I. Boomsma (2005)


Abstract

In contrast to other aspects of smoking behavior, little attention has been paid to the genetics of nicotine dependence. In this paper, three models (single liability dimension, independent liability dimension and combined model) have been applied to data on smoking initiation and nicotine dependence (n = 1572 Dutch twin pairs, mean age 30.5). A combined model best described the data. This model postulates a smoking initiation dimension and a nicotine dependence dimension, which are not independent. For both males and females, individual differences in smoking initiation were explained by genetic (44%), shared environmental (51%) and unique environmental (5%) influences. The nicotine dependence dimension was influenced only by genetic (75%) and unique environmental (25%) factors. The substantial impact of genetic factors on nicotine dependence emphasizes the need for further research to localize and identify specific genes and pathways involved in nicotine dependence.

[For those who initiate smoking, 75 % of the variability in the degree of nicotine dependence is caused by genetic reasons. The shared family environment has a strong influence whether someone initiates smoking or not. (?)]

Sex differences in sensation-seeking: a meta-analysis

Sex differences in sensation-seeking: a meta-analysis
Catharine P. Cross, De-Laine M. Cyrenne, and Gillian R. Brown (2013)
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3757272/?report=classic


Abstract

Men score higher than women on measures of sensation-seeking, defined as a willingness to engage in novel or intense activities. This sex difference has been explained in terms of evolved psychological mechanisms or culturally transmitted social norms. We investigated whether sex differences in sensation-seeking have changed over recent years by conducting a meta-analysis of studies using Zuckerman's Sensation Seeking Scale, version V (SSS-V). We found that sex differences in total SSS-V scores have remained stable across years, as have sex differences in Disinhibition and Boredom Susceptibility. In contrast, the sex difference in Thrill and Adventure Seeking has declined, possibly due to changes in social norms or out-dated questions on this sub-scale. Our results support the view that men and women differ in their propensity to report sensation-seeking characteristics, while behavioural manifestations of sensation-seeking vary over time. Sex differences in sensation-seeking could reflect genetically influenced predispositions interacting with socially transmitted information.

Thrill and Adventure Seeking (TAS; interest in physically challenging activities), Disinhibition (Dis; favourable attitudes to uninhibited social interactions), Boredom Susceptibility (BS; dislike for repetition and predictability), Experience Seeking (ES; interest in low-risk, novel experiences)

Reaction Time and Mortality from the Major Causes of Death: The NHANES-III Study

Reaction Time and Mortality from the Major Causes of Death: The NHANES-III Study
G. Hagger-Johnson, I. J. Deary, C. A. Davies, Alexander Weiss, G. David Batty 
(Jan 2014)




Objective

Studies examining the relation of information processing speed, as measured by reaction time, with mortality are scarce. We explored these associations in a representative sample of the US population.

Methods

Participants were 5,134 adults (2,342 men) aged 20–59 years from the Third National Health and Nutrition Examination Survey (NHANES III, 1988–94).

Results

Adjusted for age, sex, and ethnic minority status, a 1 SD slower reaction time was associated with a raised risk of mortality from all-causes (HR = 1.25, 95% CI 1.12, 1.39) and cardiovascular disease (CVD) (HR = 1.36, 95% CI 1.17, 1.58). Having 1 SD more variable reaction time was also associated with greater risk of all-cause (HR = 1.36, 95% CI 1.19, 1.55) and CVD (HR = 1.50, 95% CI 1.33, 1.70) mortality. No associations were observed for cancer mortality. The magnitude of the relationships was comparable in size to established risk factors in this dataset, such as smoking.

Interpretation

Alongside better-established risk factors, reaction time is associated with increased risk of premature death and cardiovascular disease. It is a candidate risk factor for all-cause and cause-specific mortality.

New Book: Evolutionary Perspectives on Human Sexual Psychology and Behavior

Evolutionary Perspectives on Human Sexual Psychology and Behavior
Edited by Viviana A. Weekes-Shackelford and Todd K. Shackelford

Publication Date: March 31, 2014

Seems to be quite interesting (and also a little bit too expensive).

Asexuality: Prevalence and associated factors in a national probability sample

Asexuality: Prevalence and associated factors in a national probability sample
Anthony F Bogaert (2004)
The Journal of Sex Research


Abstract

I used data from a national probability sample (N > 18,000) of British residents to investigate asexuality, defined as having no sexual attraction to a partner of either sex. Approximately 1% (n = 195) of the sample indicated they were asexual. A number of factors were related to asexuality, including gender (i.e., more women than men), religiosity, short stature, low education, low socioeconomic status, and poor health. Asexual women also had a later onset of menarche relative to sexual women. The results suggest that a number of pathways, both biological and psychosocial, contribute to the development of asexuality.

[The female sex drive is lower than the male sex drive and, according to a survey from R. Lippa, more variable. So it's quite plausible that there are more asexual women than men. If a phenomenon like asexuality exists, there is also a phenomenon which we could call hypersexuality. It would be interesting to know the male-female hypersexuality ratio.]

Effects of Sex, Race, Ethnicity and Marital Status on the Relationship between Intelligence and Fertility

Effects of Sex, Race, Ethnicity and Marital Status on the Relationship between Intelligence and Fertility (full download)
G Meisenberg and A Knaul (2010)


Abstract

A negative relationship between intelligence and fertility in the United States has been described repeatedly, but little is known about the mechanisms that are responsible for this effect. Using data from the NLSY79, we investigate this issue separately for Blacks, non-Hispanic Whites and Hispanics. The major findings are: (1) Differential fertility would reduce the average IQ of the American population by up to 1.2 points per generation in the absence of migration and environmental changes; (2) About 0.4 points of the effect is caused by selection within racial and ethnic groups, and the rest is caused by between-group selection; (3) Differential fertility by intelligence is greatest in Hispanics and smallest in non-Hispanic Whites; (4) The fertility-reducing effect of intelligence is greater in females than males; (5) The IQ-fertility relationship is far stronger for unmarried than married people, especially females; (5) High intelligence does not reduce the desire for children; (6) High intelligence does not reduce the likelihood of marriage; (7) Education is the principal mediator of the IQ effect for married women.

Men's perception of women's attractiveness is calibrated to relative mate value and dominance of the women's partner

Men's perception of women's attractiveness is calibrated to relative mate value and dominance of the women's partner
Drew H. Bailey, Kristina M. Durante , and David C. Geary (2011)


Abstract

We tested the hypothesis that men are particularly sensitive to individual differences in the attractiveness of women of the same mate value as themselves and less sensitive to variation among women of lower or higher mate value. We first assessed sensitivity to variation in women's attractiveness by asking men (n=148) to choose the more attractive of two photographs of the same target woman (n=116), photographed once at ovulation, when estrogen—a hormone that has been found to increase women's attractiveness—is known to be high, and once during a nonfertile phase of the cycle. Across all women, men did not rate the picture of the ovulating woman as more attractive (p>0.10), but they did rate this picture as more attractive for women of similar mate value to themselves. When we increased the implicit costs of mate pursuit by presenting a photograph of a boyfriend before presenting the woman's photographs, men showed higher sensitivity to variation in the attractiveness of women of equal and lower mate value, and less sensitivity or preference for the nonovulating photograph for women of higher mate value. Furthermore, experimentally increasing men's self-perceived mate value by providing false “datability” feedback shifted their sensitivity to variation in the attractiveness of women of higher mate value than the men's baseline. The results suggest that men's mate searching is calibrated to the relative mate value of themselves and prospective mates and varies dynamically with the cost–benefit tradeoffs of pursuing such a relationship.

World's top 15 military spenders (2013)

http://en.wikipedia.org/wiki/List_of_countries_by_military_expenditures

All the World's Aircraft Carriers

http://www.globalsecurity.org/military/world/carriers.htm (via Conrad Hackett)

Selective Versus Unselective Romantic Desire - Not All Reciprocity Is Created Equal

Selective Versus Unselective Romantic Desire - Not All Reciprocity Is Created Equal
Paul W. Eastwick, Eli J. Finkel, Daniel Mochon, and Dan Ariely (2007)
http://people.duke.edu/~dandan/Papers/Upside/SpeedDate.pdf

>[The] results suggest that romantic desire comes in two distinct ‘‘flavors’’ depending on whether it is exhibited uniquely toward a particular individual (with positive reciprocal effects) or toward individuals in general (with negative reciprocal effects).<

Mating intelligence: Sex, relationships, and the mind's reproductive system

Mating intelligence: Sex, relationships, and the mind's reproductive system
Edited by Glenn Geher and Geoffrey Miller (2008)

Is Accuracy in Fertility Detection Mediated by Differences in the Mate Value of the Rater and Target?

Is Accuracy in Fertility Detection Mediated by Differences in the Mate Value of the Rater and Target? ( A Master's Thesis)
Drew H Bailey, Thesis Supervisor: David C. Geary; (2009)



Abstract

I propose the existence of a perceptual bias in men toward detecting fertility status in women of similar mate value. To test this hypothesis, 153 male undergraduates (raters) chose which of two photographs of the same woman was more attractive for 116 female undergraduates (targets) photographed once at ovulation and once during a non-fertile phase of their menstrual cycle. Differences between independently determined rankings of women’s physical attractivenesses and the men’s self-perceived mate values were curvilinearly associated. Men’s accuracy at detecting mate value differences peaked for women of modestly higher mate value than themselves, with lower accuracies for women of lower attractiveness and substantially higher attractiveness than themselves. Furthermore, these functions varied with manipulations of apparent target partner status and rater self-perceived mate value. Results suggest that men’s sensitivity to cycle-related changes in women’s attractiveness vary with the fit between the man’s self-perceived mate value and the relative attractiveness of the woman. I discuss how this perceptual bias might have coevolved with a tendency to seek mates with similar mate values.

More than just a pretty face: men's priority shifts toward bodily attractiveness in short-term versus long-term mating contexts

More than just a pretty face: men's priority shifts toward bodily attractiveness in short-term versus long-term mating contexts
Jaime C. Confer, Carin Perilloux, David M. Buss (2010)


Abstract

Studies of physical attractiveness have long emphasized the constituent features that make faces and bodies attractive, such as symmetry, skin texture, and waist-to-hip ratio. Few studies, however, have examined the reproductively relevant cues conveyed by faces and bodies as whole units. Based on the premise that fertility cues are more readily assessed from a woman's body than her face, the present study tested the hypothesis that men evaluating a potential short-term mate would give higher priority to information gleaned from her body, relative to her face, than men evaluating a potential long-term mate. Male and female participants (N=375) were instructed to consider dating an opposite sex individual, whose face was occluded by a “face box” and whose body was occluded by a “body box,” as a short-term or long-term mate. With the instruction that only one box could be removed to make their decision about their willingness to engage in the designated relationship with the occluded individual, significantly more men assigned to the short-term, compared to the long-term, mating condition removed the body box. Women's face versus body information choice, in contrast, was unaffected by the temporal dimension of the mating condition. These results suggest that men, but not women, have a condition-dependent adaptive proclivity to prioritize facial cues in long-term mating contexts, but shift their priorities toward bodily cues in short-term mating contexts.

Economic Decision Biases and Fundamental Motivations: How Mating and Self-Protection Alter Loss Aversion

Economic Decision Biases and Fundamental Motivations: How Mating and Self-Protection Alter Loss Aversion

Y J Li, D T Kenrick, S L Neuberg, and Vladas Griskevicius (2012)

Abstract

Much research shows that people are loss averse, meaning that they weigh losses more heavily than gains. Drawing on an evolutionary perspective, we propose that although loss aversion might have been adaptive for solving challenges in the domain of self-protection, this may not be true for men in the domain of mating. Three experiments examine how loss aversion is influenced by mating and self-protection motives. Findings reveal that mating motives selectively erased loss aversion in men. In contrast, self-protective motives led both men and women to become more loss averse. Overall, loss aversion appears to be sensitive to evolutionarily important motives, suggesting that it may be a domain-specific bias operating according to an adaptive logic of recurring threats and opportunities in different evolutionary domains.

--------------------------------------------------------------------------------

"Much past research shows that humans are loss averse, with the notion that people weigh losses more strongly than gains generally considered to be a domain-general bias. However, an evolutionary perspective suggests that loss aversion might be an adaptive bias in some life domains but not in others. We proposed that loss aversion is likely to have been adaptive for solving challenges in self-protection but not for solving challenges related to mate seeking, especially for men.

Our findings support this proposal. Across three studies, activating a mating motivation selectively erased loss aversion for men. Mating motivation had no such effect on women’s gain–loss preferences."

"An interesting note is that, across the three studies, there was a trend for women to become slightly more loss averse in mating compared to a neutral control condition."

From the Bedroom to the Budget Deficit: Mate Competition Changes Men’s Attitudes Toward Economic Redistribution

From the Bedroom to the Budget Deficit: Mate Competition Changes Men’s Attitudes Toward Economic Redistribution
Andrew E. White, Douglas T. Kenrick, Rebecca Neel, and Steven L. Neuberg (2013)
http://neelpsychlab.files.wordpress.com/2013/09/2013-26501-001.pdf



Abstract

How do economic recessions influence attitudes toward redistribution of wealth? From a traditional economic self-interest perspective, attitudes toward redistribution should be affected by one’s financial standing. A functional evolutionary approach suggests another possible form of self-interest: That during periods of economic threat, attitudes toward redistribution should be influenced by one’s mate-value—especially for men. Using both lab-based experiments and real-world data on voting behavior, we consistently find that economic threats lead low mate-value men to become more prosocial and supportive of redistribution policies, but that the same threats lead high mate-value men to do the opposite. Economic threats do not affect women’s attitudes toward redistribution in the same way, and, across studies, financial standing is only weakly associated with attitudes toward redistribution. These findings suggest that during tough economic times, men’s attitudes toward redistribution are influenced by something that has seemingly little to do with economic self-interest—their mating psychology.

Menstrual cycle shifts in attentional bias for courtship language

Menstrual cycle shifts in attentional bias for courtship language
Maya L. Rosen, Hassan H. López (2009)


Abstract

The current study investigated whether women show an attentional bias toward courtship language during the fertile phase of their menstrual cycle. Thirty heterosexual women (17 naturally cycling, 13 using hormonal contraceptives) completed a dichotic listening task on both a high and low fertility day of their menstrual cycle. Participants were asked to verbally repeat (shadow) an emotionally neutral target passage played in one ear while either a neutral or courtship distracter was played in the other ear. Courtship distracters were flirtatious in content but not overtly sexual. Shadowing errors were coded as a measure of attentional bias toward the distracter. Saliva samples were taken to determine whether levels of estradiol, progesterone and/or testosterone correlated with task performance. As predicted, naturally cycling women made more shadowing errors when listening to a courtship distracter during the fertile phase of their cycle than during the nonfertile phase. This effect was moderated by relationship status, such that fertile, mated women showed an attentional bias for courtship language but
fertile single women did not. However, because of small sample sizes in the analysis, this relationship should be viewed as preliminary. Hormonal analysis revealed that higher levels of salivary estradiol predicted greater attentional bias toward courtship language in naturally cycling women. These results suggest that women's attention is drawn to verbal courtship signals when they are fertile, and that this shift is linked to increased estradiol release during the periovulatory phase.

[Small sample size.]

Evidence of a latitudinal gradient in the age at onset of schizophrenia

Evidence of a latitudinal gradient in the age at onset of schizophrenia (full download)
Andrew Shaner, Geoffrey Miller, Jim Mintz  (2007)


Abstract

Variation in the age at onset of a multifactorial disease often reflects variation in cause. Here we show a linear latitudinal gradient in the mean age at onset of schizophrenia in 13 northern hemisphere cities, ranging from 25 years old in Cali, Columbia (at 4° north) to 35 years old in Moscow, Russia (at 56° north). To our knowledge, this striking association has not been previously reported. We consider several explanations, including the effects of pathogen stress, natural selection, sexual selection, migration, life-history profiles, or some combination of these factors, and we propose a test of competing causal hypotheses.

[Later onsets of schizophrenia generally lead to better (social) outcomes than early onsets. - Other stats show different (earlier) ages of onset. But maybe these other stats use other criteria. E.g. occurrence of first negative symptoms.]

Symmetry and sexual dimorphism in human faces: interrelated preferences suggest both signal quality

Symmetry and sexual dimorphism in human faces: interrelated preferences suggest both signal quality
A. C. Little, Benedict C. Jones, Lisa M. DeBruine, and David R. Feinberg (2008)
Behavioral Ecology


Abstract

Symmetry and masculinity in human faces have been proposed to be cues to the quality of the owner. Accordingly, symmetry is generally found attractive in male and female faces, and femininity is attractive in female faces. Women's preferences for male facial masculinity vary in ways that may maximize genetic benefits to women's offspring. Here we examine same- and opposite-sex preferences for both traits (Study 1) and intercorrelations between preferences for symmetry and sexual dimorphism in faces (Study 1 and Study 2) using computer-manipulated faces. For symmetry, we found that male and female judges preferred symmetric faces more when judging faces of the opposite-sex than when judging same-sex faces. A similar pattern was seen for sexual dimorphism (i.e., women preferred more masculine male faces than men did), but women also showed stronger preferences for femininity in female faces than men reported. This suggests that women are more concerned with female femininity than are men. We also found that in women, preferences for symmetry were positively correlated with preferences for masculinity in male faces and that in men preferences for symmetry were positively correlated with preferences for femininity in female faces. These latter findings suggest that symmetry and sexual dimorphism advertise a common quality in faces or that preferences for these facial cues are dependent on a common quality in the judges. Collectively, our findings support the view that preferences for symmetry and sexual dimorphism are related to mechanisms involved in sexual selection and mate choice rather than functionless by-products of other perceptual mechanisms.

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For women, "a significant positive relationship between preferences for symmetry and for masculinity in male faces (r = 0.18, P = 0.015)" was found. "For men, a significant negative relationship was observed between preferences for symmetry and for masculinity in female faces (r = −0.26, P = 0.003, i.e., a positive correlation between preferences for femininity and symmetry)."

Does the contraceptive pill alter mate choice in humans?

Does the contraceptive pill alter mate choice in humans?
Alexandra Alvergne and Virpi Lummaa (2010)
http://sites.google.com/site/droptone/contraceptive_pill.PDF


Abstract

Female and male mate choice preferences in humans both vary according to the menstrual cycle. Women prefer more masculine, symmetrical and genetically unrelated men during ovulation compared with other phases of their cycle, and recent evidence suggests that men prefer ovulating women to others. Such monthly shifts in mate preference have been suggested to bring evolutionary benefits in terms of reproductive success. New evidence is now emerging that taking the oral contraceptive pill might significantly alter both female and male mate choice by removing the mid-cycle change
in preferences. Here, we review support for such conclusions and speculate on the consequences of pill-induced choice of otherwise less-preferred partners for relationship satisfaction, durability and, ultimately, reproductive outcomes.


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A few quotes:

"Cycling preferences in women are likely to enable discriminative mate choice at peak fertility for mate genetic quality and/or compatibility."

"All ovulatory-cycle effects are potentially modified by oral contraceptives. The impact of such oestrous disruption on reproductive success is currently unknown although it is likely that if oestrus is adaptive, then any drug specifically designed to eliminate ovulation and the associated oestrus psychological and physical changes will have maladaptive side-effects."

"We can ... predict that: (i) the use of the pill when choosing a partner for reproduction has consequences for actual mate choice ... and (ii) commencement or cessation of the pill influences the quality and stability of pre-existing long-term relationships."

"There is emerging evidence that the use of the pill by women can disrupt: (i) the variation in mate preferences across their menstrual cycle; (ii) their attractiveness to men; and (iii) their ability to compete with normally cycling women for access to mates."

"It is worthy of note that since the approval of the pill as a contraceptive method by the US Food and Drug Administration (FDA) in 1960 and the subsequent rapid export, for example, to Canada (1961), Australia (1961) and Europe (West Germany, 1961, UK, 1961, France, 1967), the potential side-effects on a range of women’s psychological attributes and behaviour have never been investigated by FDA or drug companies. Given the centrality of relationship satisfaction and offspring quality in the subjective well-being of women and mothers, drug companies marketing hormonal contraception should be encouraged to institute large-scale clinical trials investigating behavioural and psychological side-effects potentially associated with oral contraceptives, and any possible maladaptive side-effects of pill use on mate choice, attractiveness, relationship satisfaction, divorce probability and offspring health."

U.S. Women: Age of Sexual Initiation and Number of Lifetime Sexual Partners

Source: CDC, National Center for Health Statistics, National Survey of Family Growth, 1995. -> A Book of Charts

Chinese Sex-Ratio Imbalance

Source:
Zhu, W. X. et al. BMJ 2009

Sex Ratio in 1-4 year age group;
(2005)

(2010?)

Sexual Selection and Human Geographic Variation

Sexual Selection and Human Geographic Variation
Peter Frost (2008)


Abstract

Among early modern humans, a woman would face stronger competition for a mate the further away she was from the equator. Men were less available because they 1) hunted over longer distances that increased male mortality proportionately and 2) were less able to offset the resulting man shortage through polygyny. The longer the winter, the costlier it became to provision a second wife and her children, since women could not gather food in winter. Women competed the most for mates in the 'continental Arctic,' where wandering herds were the main food source. Conversely, men competed the most for mates in the Tropics, particularly after year-round agriculture emerged. This means of subsistence allowed women to become primary food producers, thereby freeing men to take more wives. Because mate competition has varied in intensity among human populations, sexual selection has correspondingly varied in intensity for certain traits, often highly visible and colorful ones. Intense female-female competition may explain an unusual convergence of color traits in northern and eastern Europeans. Intense male-male competition may explain increased masculinization of body build in highly polygynous agricultural populations of sub-Saharan Africa.


[Publications of Peter Frost: http://evoandproud.blogspot.co.at/p/my-publications.html]

European hair and eye color A case of frequency-dependent sexual selection?

European hair and eye color A case of frequency-dependent sexual selection?
Peter Frost (2006)
http://www.ceacb.ucl.ac.uk/cultureclub/files/CC2006-03-07_Frost.pdf


Abstract

Human hair and eye color is unusually diverse in northern and eastern Europe. The many alleles involved (at least seven for hair color) and their independent origin over a short span of evolutionary time indicate some kind of selection. Sexual selection is particularly indicated because it is known to favor color traits and color polymorphisms. In addition, hair and eye color is most diverse in what used to be, when first peopled by hunter-gatherers, a unique ecozone of low-latitude continental tundra. This type of environment skews the operational sex ratio (OSR) of hunter-gatherers toward a male shortage in two ways: (1) men have to hunt highly mobile and spatially concentrated herbivores over longer distances, with no alternate food sources in case of failure, the result being more deaths among young men; (2) women have fewer opportunities for food gathering and thus require more male provisioning, the result being less polygyny. These two factors combine to leave more women than men unmated at any one time. Such an OSR imbalance would have increased the pressures of sexual selection on early European women, one possible outcome being an unusual complex of color traits: hair- and eye-color diversity and, possibly, extreme skin depigmentation.

How Clever-sillies Might Thwart the Singularity, Michael A. Woodley, Part 2/2 (Jan 2011)

How Clever-sillies Might Thwart the Singularity, Michael A. Woodley, Part 1/2 (Jan 2011)

[The sound is not great but ok.]

Sex Differences in Reading Facial Expressions

>Men's sensitivity to negative cues signaled by other men, such as an angry facial expression, is an intriguing exception to women's overall advantage in reading nonverbal cues; men are more sensitive to these cues than to the same ones signaled by women (N. G. Rotter & Rotter, 1988; Wagner et al., 1993; M. A. Williams & Mattingley, 2006). In two large-scale studies involving more than 1,100 people, N. G. Rotter and Rotter found that women are more accurate than men in judging disgust, fear, or sadness in the facial expressions of other women and of men. Women are also more accurate than men in detecting an angry expression on the face of other women. Men, in contrast, are more accurate in detecting an angry expression on the face of other men (N. G. Rotter & Rotter, 1988). Dimberg and Öhman (1996) concluded that men are more sensitive to the angry expressions of other men than they are to the angry expressions of women, especially when these anger-signaling cues are expressed in adult men as contrasted with adolescents and when the expressions are directed toward the individual (e.g. with eye contact). Women, in contrast, appear to be equally senstive to angry expressions in men and other women. At the same time, men are less accurate in detecting disgust, fear, and sadness in other men's facial expressions than in detecting these cues in women's facial expressions.<

Male, Female - The Evolution of Human Sex Differences

David C. Geary (2010)

Incremental Validity of Spatial and Psychomotor Aptitudes

>The factors that provide the largest incremental validity over and above the criterion vari­ance predicted by g are spatial and psychomotor abilities, which often contribute to the validity for predicting success in jobs requiring technical or motor skills. Physical scientists, for example, are well above average not only in g but also in spatial ability. Although most spatial tests are also quite g loaded, they can significantly enhance predictive validity for certain job categories. 

Tests of psychomotor abilities also enhance validity for some jobs that depend on manual dexterity and muscular coordination. Considering how very different in form and content psychomotor tests are from the paper-and-pencil tests typ­ically used to measure cognitive ability, it may seem surprising how relatively small the incremental validity contributed by psychomotor tests actually is, compared to the g validity even for jobs where psychomotor ability is relevant. The apparent reason for this is that the psychomotor tests are themselves largely tests of g, showing true-score correlations with g even as high as .70 after correction for range restriction in Air Force samples. Usually g accounts for most of the validity of psychomotor tests, thus allowing comparatively little incremental validity. (The expectation that a test’s appearance necessarily in­dicates what latent traits it measures has been called the “ topographical fal­lacy.” )

Major efforts to discover other psychometric variables that add appreciable increments over and above g to predictive validity for “core job performance” have not proved fruitful. Of course there are many other aspects of success in life besides g or spatial and psychomotor factors, such as physical and mental energy level, effort, conscientiousness, dependability, personal integrity, emo­tional stability, self-discipline, leadership, and creativity. These characteristics, however, fall into the personality domain and can be assessed to some extent by personality inventories. A person’s interests have little incremental validity over g or other cognitive abilities, largely because a person’s interests are to some degree related to the person’s abilities. People generally do not develop an interest in subjects or activities requiring a level of cognitive complexity that overtaxes their level of g. Specialized talents, when highly developed, may be crucial for success in certain fields, such as music, art, and creative writ­ing. The individual’s level of g, however, is an important threshold variable for the socially and economically significant expression of such talents. Probably very few, if any, successful professionals in these fields have a below-average IQ.<

The g Factor

Arthur R. Jensen (1998)

Everyday Life as an Intelligence Test

>We all make mistakes in life, and Alexander Pope’s “To err is human” is a familiar refrain. There is good reason, however, for supposing that the probabilities of making a mistake in any given situation, independent of experience, vary from individual to individual according to IQ or score on any good test of g, the general intelligence factor. This would help explain why “some people make more errors than other people” ... . Full recognition of this probability differential is blunted by the fact that, although life in some ways resembles a test of general intelligence, life departs in many ways from the formal requirements of a well-designed psychometric instrument. Combined with age differences in experience (which can easily be mistaken for differences in intelligence) and with age differences in cumulative lifetime risk (which can let the histories of younger and hence less exposed persons seem more error free than those of older, more exposed ones of equal intelligence), such departures from psychometric rigor obscure the role of g but do not negate it. ...<

Source:
Everyday Life as an Intelligence Test: Effects of Intelligence and Intelligence Context
Robert A. Gordon (1997)

Sociosexuality in Mainland China

Sociosexuality in Mainland China

Wei Jun Zheng, Xu Dong Zhou, Xiao Lei Wang, Therese Hesketh

Archives of Sexual Behavior (April 2014)

Abstract

The construct of sociosexuality or sociosexual orientation describes the extent to which people will have casual, uncommitted sexual relationships. The Sociosexual Orientation Inventory (SOI) has been used to measure sociosexuality in many countries, but not in China. The aims of this study were to explore sociosexuality in a cross-section of the Chinese adult population, to quantify sex differences in sociosexuality, and to examine the sociodemographic correlates and the impact of the high sex ratio. The study consisted of a cross-sectional survey using a self-completion questionnaire. It was administered to adults of reproductive age in three provinces: Zhejiang, Guizhou, and Yunnan. While questionnaires were received from 7,424 participants, total SOI scores could be computed only for the 4,645 (63 %) who completed all seven items of the SOI. The mean score for men and women combined was 21.0, very low compared with most other countries, indicating restricted sociosexuality. The men (n = 2,048) had a mean of 27, showing more restricted sociosexuality than in all other countries where the SOI has been used. Wealth was the strongest independent correlate of high (unrestricted) sociosexuality in men and women. The effect size for the difference between the sexes was moderate (Cohen’s d = .64), and comparable to more developed countries, perhaps reflecting relative gender equality in contemporary China. Despite the very high sex ratio, which is theorized to lead to restricted sexuality, its influence was difficult to determine, since differences in sociosexuality between high and low sex ratio areas within this population were inconsistent.

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For comparison:

Source:

Sociosexuality from Argentina to Zimbabwe: a 48-nation study of sex, culture, and strategies of human mating, D.P Schmitt (2005)

Functional Literacy and Daily Self-Maintenance

"Citizens of literate societies take for granted that they are routinely called upon to read instructions, fill out forms, determine best buys, decipher bus schedules, and otherwise read and write to cope with the myriad details of everyday life. But such tasks are difficult for many people. The problem is seldom that they cannot read or write the words, but usually that they are unable to carry out the mental operations the task calls for—to compare two items, grasp an abstract concept, provide comprehensible and accurate information about themselves, follow a set of instructions, and so on. This is what it means to have poor “functional literacy.”

Functional literacy has been a major public policy concern, as illustrated by the U.S. Department of Education’s various efforts to gauge its level in different segments of the American population. Tests of functional literacy essentially mimic individually-administered intelligence tests, except that all their items come from everyday life, such as calculating a tip (see extended discussion in Gottfredson, 1997b). As on intelligence tests, differences in item difficulty rest on the items’ cognitive complexity (their abstractness, amount of distracting irrelevant information, and degree of inference required), not on their readability per se or the level of education test takers have completed. Literacy researchers have concluded, with some surprise, that functional literacy represents a general capacity to learn, reason, and solve problems—a veritable description of g.

The National Adult Literacy Survey (NALS; Kirsch, Jungeblut, Jenkins, & Kolstad, 1993) groups literacy scores into five levels. Individuals scoring in Level 1 have an 80% chance of successfully performing tasks similar in difficulty to locating an expiration date on a driver’s license and totaling a bank deposit slip. They are not routinely able to perform Level 2 tasks, such as determining the price difference between two show tickets or filling in background information on an application for a social security card. Level 3 difficulty includes writing a brief letter explaining an error in a credit card bill and using a flight schedule to plan travel. Level 4 tasks include restating an argument made in a lengthy news article and calculating the money needed to raise a child based on information in a news article. Only at Level 5 are individuals routinely able to perform mental tasks as complex as summarizing two ways that lawyers challenge prospective jurors (based on a passage discussing such practices) and, with a calculator, determining the total cost of carpet to cover a room.

Although these tasks might seem to represent only the inconsequential minutiae of everyday life, they sample the large universe of mostly untutored tasks that modern life demands of adults. Consistently failing them is not just a daily inconvenience, but a compounding problem. Likening functional literacy to money—it always helps to have more—, literacy researchers point out that rates of socioeconomic distress and pathology (unemployment, adult poverty, etc.) rise steadily at successively lower levels of functional literacy (as is the pattern for IQ too; Gottfredson, 2002a). Weaker learning, reasoning, and problem solving ability translates into poorer life chances. The cumulative disadvantage can be large, because individuals at literacy Levels 1 or 2 “are not likely to be able to perform the range of complex literacy tasks that the National Education Goals Panel considers important for competing successfully in a global economy and exercising fully the rights and responsibilities of citizenship” (Baldwin et al., 1995, p. 16). Such disadvantage is common, too, because 40% of the adult white population and 80% of the adult black population cannot routinely perform above Level 2. Fully 14% and 40%, respectively, cannot routinely perform even above Level 1 (Kirsch et al., 1993, pp. 119-121). To claim that lower-ability citizens will only be victimized by the public knowing that differences in intelligence are real, stubborn, and important is to ignore the practical hurdles they face."

Source:

Suppressing intelligence research: Hurting those we intend to help

Linda S. Gottfredson (2005)

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->The adults who performed in Levels 1 and 2 did not necessarily perceive themselves as being "at risk." 66 to 75 percent of the adults in the lowest level and 93 to 97 percent in the second lowest level described themselves as being able to read or write English "well" or "very well."

Cocaine:

2007/2008: "North America accounts for more than 40% of global cocaine consumption (the total is estimated at around 470 tons); whereas the 27 EU and four EFTA countries were responsible for more than a quarter of global cocaine consumption. These two regions comprise more than 80% of the value of the global cocaine market, estimated at US$88 billion in 2008."

Source:
The Globalization of Crime - A Transnational Organized Crime Threat Assessment (p. 81-105)
UNODC (2010)

A common neurobiology for pain and pleasure

A common neurobiology for pain and pleasure
Siri Leknes and Irene Tracey (2008)


Abstract

Pain and pleasure are powerful motivators of behaviour and have historically been considered opposites. Emerging evidence from the pain and reward research fields points to extensive similarities in the anatomical substrates of painful and pleasant sensations. Recent molecular-imaging and animal studies have demonstrated the important role of the opioid and dopamine systems in modulating both pain and pleasure. Understanding the mutually inhibitory effects that pain and reward processing have on each other, and the neural mechanisms that underpin such modulation, is important for alleviating unnecessary suffering and improving well-being.

Genotypic IQ of European Populations (1455-1995)

Fig.1: Two-axis graph illustrating the relationship between change in genotypic IQ (using Meisenberg’s dysgenesis rate estimates) and innovation rate over time (r = .876, N = 56 decades, P < .01). Nyborg’s dysgenesis rate estimates (not shown) correlated at r = .866, N = 56 decades, P < .01.


Source:
Woodley, M.A., The social and scientific temporal correlates of genotypic intelligence and the Flynn effect, Intelligence (2012)

[Thanks @ Elijah.]

INEQUITY IN EQUITY: How "Equity" Can Lead to Inequity for High-Potential Students

INEQUITY IN EQUITY: How "Equity" Can Lead to Inequity for High-Potential Students
Camilla P. Benbow and Julian C Stanley (1996)


Abstract

Over the past three decades, the achievement of waves of American students with high intellectual potential has declined as a result of inequity in educational treatment. This inequity is the result of an extreme form of egalitarianism within American society and schools, which involves the pitting of equity against excellence rather than promoting both equity and excellence, anti-intellectualism, the "dumbing-down" of the curriculum, equating aptitude and achievement testing with elitism, the attraction to fads by schools, and the insistence of schools to teach all students from the same curriculum at the same level. In this article we provide recommendations for creating positive change—recommendations that emphasize excellence for all, that call for responsiveness to individual differences, and that suggest basing educational policies on well-grounded research findings in psychology and education. Educational policies that fail to take into account the vast range of individual differences among students—as do many that are currently in use—are doomed to be ineffective.

The Relation between Intelligence and Unemployment at the Individual and National Level

The Relation between Intelligence and Unemployment at the Individual and National Level
Richard Lynn and Garth Zietsman (Summer 2013)
Journal of Social, Political, and Economic Studies


Abstract

It has been shown that there is an association between low intelligence and unemployment among individuals within nations. We explore the question of whether this relationship is present across nations. We find that national rates of unemployment for 107 nations, averaged for the years 2001 and 2008, are correlated with national IQs at r = -0.66, and national IQ therefore explains 43.5% of the national variance in unemployment. Corrected for unreliability of both variables, the correlation between national IQ and rates of unemployment is r = -0.756 and national IQ explains 57.2% of the national differences in unemployment. Variations in economic freedom independently account for another 12.9% of national rates of unemployment.

Sex Roles and Mutual Mate Choice Matter during Mate Sampling

Sex Roles and Mutual Mate Choice Matter during Mate Sampling
L. C. Myhre, K. de Jong, E. Forsgren, and T.Amundsen (June 2012)
http://jong1234.home.xs4all.nl/files/paper%20mate%20sampling.pdf


Abstract

The roles of females and males in mating competition and mate choice have lately proven more variable, between and within species, than previously thought. In nature, mating competition occurs during mate search and is expected to be regulated by the numbers of potential mates and same-sex competitors. Here, we present the first study to test how a temporal change in sex roles affects mating competition and mate choice during mate sampling. Our model system (the marine fish Gobiusculus flavescens) is uniquely suitable because of its change in sex roles, from conventional to reversed, over the breeding season. As predicted from sex role theory, courtship was typically initiated by males and terminated by females early in the breeding season. The opposite pattern was observed late in the season, at which time several females often simultaneously courted the same male. Mate-searching females visited more males early than late in the breeding season. Our study shows that mutual mate choice and mating competition can have profound effects on female and male behavior. Future work needs to consider the dynamic nature of mating competition and mate choice if we aim to fully understand sexual selection in the wild.

(full size: click at the image)

Ethnic Conflict and Violence in Heterogeneous Societies

Ethnic Conflict and Violence in Heterogeneous Societies 
Tatu Vanhanen (Spring 2012)
Journal of Social, Political, and Economic Studies


Abstract

Ethnic groups have tended to conflict since the beginning of the known human history, and the intensity of violent conflicts does not seem to have decreased during the last centuries. Why are ethnic conflicts so common across all civilizational boundaries and over time? Researchers have explained particular ethnic conflicts as being due to various political, cultural, and other environmental factors, but they have not yet been able to produce any theoretical explanation that could be tested by global empirical evidence. It will be argued in this paper that the universality of ethnic conflict can be traced to our common human nature, to our evolved disposition to ethnic nepotism. This hypothesis is tested by empirical evidence on a scale of institutionalized ethnic interest conflict (IC) and on a scale of ethnic violence (EV), which are intended to measure the degree of ethnic conflict from two different perspectives, and by the degree of ethnic heterogeneity (EH), which is used to measure ethnic nepotism, in a group of 176 contemporary countries. The results show that EH explains approximately 70 percent of the global variation in IC and nearly half of the variation in EV. These results leads to the conclusion that ethnic nepotism provides the most powerful theoretical explanation for the persistance of ethnic conflicts.

Cognitive Abilities of Emirati and German Engineering University Students

Cognitive Abilities of Emirati and German Engineering University Students
H. Rindermann, A. E. E. Baumeister, and A. Gröper (March 2014)
Journal of Biosocial Science


Abstract

According to human capital theory, individual competences and personality attributes are relevant for individual productivity and income. Within human capital, intelligence is crucial. To study engineering and work successfully as an engineer, high cognitive abilities are necessary, especially for work in research and development. In a study of 30 German and 30 Emirati engineering students (mean age: 22 years), both groups were tested with mathematical and figural intelligence scales (CogAT). German engineering students achieved a mean IQ of 116, and Emirati students 104 (in converted UK norms). In both groups male students achieved better results than females (2 to 4 IQ point difference). The results are compared with those from PISA and TIMSS. The possible causes of these results, their consequences and strategies for improvement are discussed.



[I always thought the IQ-scores of German engineering students are higher (around 125). It would be interesting to know the scores of a bigger sample.]


See also: 
Performance on Raven’s Advanced Progressive Matrices by African, East Indian, and White engineering students in South Africa; J. P. Rushton et al. (2003)