Research on bystander intervention has produced a great number of studies showing that the presence of other people in a critical situation reduces the likelihood that an individual will help. As the last systematic review of bystander research was published in 1981 and was not a quantitative meta-analysis in the modern sense, the present meta-analysis updates the knowledge about the bystander effect and its potential moderators. The present work (a) integrates the bystander literature from the 1960s to 2010, (b) provides statistical tests of potential moderators, and (c) presents new theoretical and empirical perspectives on the novel finding of non-negative bystander effects in certain dangerous emergencies as well as situations where bystanders are a source of physical support for the potentially intervening individual. In a fixed effects model, data from over 7,700 participants and 105 independent effect sizes revealed an overall effect size of g = -0.35. The bystander effect was attenuated when situations were perceived as dangerous (compared with non-dangerous), perpetrators were present (compared with non-present), and the costs of intervention were physical (compared with non-physical). This pattern of findings is consistent with the arousal-cost-reward model, which proposes that dangerous emergencies are recognized faster and more clearly as real emergencies, thereby inducing higher levels of arousal and hence more helping. We also identified situations where bystanders provide welcome physical support for the potentially intervening individual and thus reduce the bystander effect, such as when the bystanders were exclusively male, when they were naive rather than passive confederates or only virtually present persons, and when the bystanders were not strangers.

In recent years, there has been a surge in the quantity of media content that glorifies risk-taking behavior, such as risky driving, extreme sports, or binge drinking. The authors conducted a meta-analysis involving more than 80,000 participants and 105 independent effect sizes to examine whether exposure to such media depictions increased their recipients' risk-taking inclinations. A positive connection was found for overall, combined risk taking (g ϭ .41); as well as its underlying dimensions: risk-taking behaviors (g ϭ .41), risk-positive cognitions and attitudes (g ϭ .35), and risk-positive emotions (g ϭ .56). This effect was observed across varying research methods (experimental, correlational, longitudinal); types of media (video games, movies, advertising, TV, music); and differing risk-related outcome measures (e.g., smoking, drinking, risky driving, sexual behavior). Multiple moderator analyses revealed 2 theoretically new boundary conditions for sociocognitive models. First, the effect was stronger for active (i.e., video games) than for passive (e.g., film, music) exposure to risk-glorifying media content. Second, the effect was stronger when there was a high degree of contextual fit between the media content and type of risk-taking measure. The theoretical, practical, and societal implications of the present research synthesis are discussed.

In recent years, media formats with risk-glorifying content, such as video games that simulate illegal street racing ("bang and crash" games), films about extreme sports, and risky stunts have emerged as top sellers of the media industry. A variety of recent studies conducted by several researchers revealed that exposure to risk-glorifying media content (e.g., video games that simulate reckless driving, smoking and drinking in movies, or depictions that glorify extreme sports) increases the likelihood that recipients will show increased levels of risk-taking inclinations and behaviors. The present article (1) reviews the latest research on the detrimental impact of risk-glorifying media on risk-taking inclinations (cognitions, emotions, behaviors), (2) puts these findings in the theoretical context of recent sociocognitive models on media effects, and (3) makes suggestions to science and policymakers on how to deal with these effects in the future.

The present research hypothesizes that thinking about one's genetic origin (i.e. ancestors) provides people with a positive psychological resource that increases their intellectual performance. To test this line of reasoning, we manipulated whether participants thought about their ancestors or not (manipulation of ancestor salience), and measured their expected as well as actual intellectual performance in a variety of intelligence tasks. Four studies supported our assumptions: participants show higher expected (Study 1) and actual intellectual performance (Studies 2-4) when they are reminded about their ancestors. We also have initial evidence that this effect may be fuelled by increased levels of perceived control and promotion orientation. Theoretical and practical implications are discussed.It is certainly desirable to be well descended, but the glory belongs to our ancestors. (Plutarch 46-120 AD).

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