Global social identity and global cooperation.

This research examined the question of whether the psychology of social identity can motivate cooperation in the context of a global collective. Our data came from a multinational study of choice behavior in a multilevel public-goods dilemma conducted among samples drawn from the general populations of the United States, Italy, Russia, Argentina, South Africa, and Iran. Results demonstrate that an inclusive social identification with the world community is a meaningful psychological construct that plays a role in motivating cooperation that transcends parochial interests. Self-reported identification with the world as a whole predicts behavioral contributions to a global public good beyond what is predicted from expectations about what other people are likely to contribute. Furthermore, global social identification is conceptually distinct from general attitudes about global issues, and has unique effects on cooperative behavior.

Traditional signs and symptoms commonly attributed to hypogonadism do not correlate with testosterone levels: the Cooper Center Longitudinal Study Experience.

Evidence suggests that substantial testosterone therapy is occurring without checking levels of testosterone, presumably based on the presence of symptoms alone. We sought to explore the relationship between total testosterone level and non-specific symptoms, metabolic abnormalities, and sexual dysfunction associated with hypogonadism. This cross-sectional study included 2994 generally healthy men aged 50-79 years examined at a preventive medicine clinic in Dallas, TX from January 2012 to March 2016. Symptoms of hypogonadism were assessed. Screening morning total testosterone levels were measured and categorized into low (<250 ng/dL), low normal (250-399 ng/dL), and normal (≥400 ng/dL). Multiple logistic regression models were used to test the associations between total testosterone and signs and symptoms of hypogonadism. When considering symptoms and signs of hypogonadism, only decreased libido (OR 1.31, 95% CI 1.00 to 1.70), fasting glucose ≥100 mg/dL (OR 1.47, CI 1.15 to 1.88), and hemoglobin A1c over 6% (OR 1.47, 95% CI 1.06 to 2.03) were associated with increased odds of low testosterone after adjustment for age, body mass index, and cardiorespiratory fitness. Testosterone levels were not associated with fatigue, depression, or erectile dysfunction in our study (p>0.6). In this preventive medicine cohort, symptoms commonly attributed to testosterone deficiency were not associated with low total testosterone levels.

Physical and mental health status of Hurricane Katrina evacuees in Houston in 2005 and 2006.

OBJECTIVES: Hurricane Katrina necessitated the evacuation of over 200,000 individuals into Houston. This study compared characteristics of three samples of evacuees with those of the U.S. population and examined how evacuees' experiences have changed over time. METHODS: Sub-populations of evacuees in Houston were surveyed immediately following the hurricane, two months afterwards, and one year later. Demographic characteristics, socioeconomic status, physical and mental health status, and access to care of the most disadvantaged evacuees in Houston were analyzed. RESULTS: Predominantly, evacuees surveyed were Black, low-income, unemployed, and facing challenges accessing health care. Twenty-eight percent felt their health was worse than it was before Katrina. Almost 60% of evacuees reported nervousness, restlessness, worthlessness, hopelessness, and spells of terror or panic at least a few times a week. CONCLUSIONS: The evacuees displaced by the storm experienced loss of full-time employment, income, and deteriorating health, as well as struggles accessing necessary physical and mental health care.

The association of cardiorespiratory fitness, body mass index, and age with testosterone levels at screening of healthy men undergoing preventive medical examinations: The Cooper Center Longitudinal Study.

BACKGROUND: Currently, exogenous hormone replacement is used in many men with hypogonadism without clear organic cause. This study examines the contribution of modifiable health behaviors, i.e., physical activity and weight control, to the maintenance of testosterone levels with aging. METHODS: In a cross-sectional study of 2994 healthy men aged 50-79 years examined at a preventive medicine clinic from January 2012 to March 2016, screening morning total testosterone levels were measured and categorized as low (<250 ng/dL), low normal (250-399 ng/dL), and normal (>400 ng/dL). Cardiorespiratory fitness (fitness) was estimated from a maximal exercise treadmill test. Multiple logistic regression models were used to test the associations between low testosterone levels and age, body mass index (BMI), and fitness. FINDINGS: Mean testosterone levels were in the normal range for each age group (50-59, 60-69, and 70-79). There was a similar prevalence of low testosterone in each age group (11·3%, 10%, and 10·5%, respectively). The prevalence of low testosterone was positively associated with BMI and negatively associated with fitness but was not associated with age. INTERPRETATION: This study found no evidence that low testosterone is an inevitable consequence of aging. Maintenance of healthy weight and fitness may help maintain normal testosterone levels.

Group-Level Selection Increases Cooperation in the Public Goods Game.

When groups compete for resources, some groups will be more successful than others, forcing out less successful groups. Group-level selection is the most extreme form of group competition, where the weaker group ceases to exist, becoming extinct. We implement group-level selection in a controlled laboratory experiment in order to study its impact on human cooperation. The experiment uses variations on the standard linear public goods game. Group-level selection operates through competition for survival: the least successful, lowest-earning groups become extinct, in the sense that they no longer are able to play the game. Additional control treatments include group comparison without extinction, and extinction of the least successful individuals across groups. We find that group-level extinction produces very high contributions to the provision of the public good, while group comparison alone or individual extinction fail to cause higher contributions. Our results provide stark evidence that group-level selection enhances within-group cooperation.