The power of more money to increase happiness is strongest at low incomes.

Religious involvement is a predictor of health and longevity.

positive versus negative; low versus high

Researchers have been unable to pin down specific environmental factors that influence sexual orientation.

test-taker’s own previous intelligence test performance.

involves a surge in sex hormones.”

driven to engage in these behaviors.

Obesity is associated with increased depression.

the behavior of a group is assessed by different researchers.”

influenced more by their environment than by their shared genes.”