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The influences of optimism and pessimism on ambiguity aversion were investigated in two tasks that manipulated the presence or absence of a potentially competitive experimenter. A total of 112 participants chose which option--ambiguous or known-risk--they preferred in the two slightly differing Ellsberg urns tasks. Optimism was measured using the Extended(More)
In a market entry game, the number of entrants usually approaches game-theoretic equilibrium quickly, but in real-world markets business start-ups typically exceed market capacity, resulting in chronically high failure rates and suboptimal industry profits. Excessive entry has been attributed to overconfidence arising when expected payoffs depend partly on(More)
There is a long-standing debate in philosophy about whether it is morally permissible to harm one person in order to prevent a greater harm to others and, if not, what is the moral principle underlying the prohibition. Hypothetical moral dilemmas are used in order to probe moral intuitions. Philosophers use them to achieve a reflective equilibrium between(More)
Hypothetical trolley problems are widely used to elicit moral intuitions, which are employed in the development of moral theory and the psychological study of moral judgments. The scenarios used are outlandish, and some philosophers and psychologists have questioned whether the judgments made in such unrealistic and unfamiliar scenarios are a reliable basis(More)
Decision theory and game theory rest on a fundamental assumption that players seek to maximize their individual utilities, but in some interactive decisions it seems intuitively reasonable to aim to maximize the utility of the group of players as a whole. Such team reasoning requires collective preferences and a distinctive mode of reasoning from(More)
Overconfidence is said to occur when a person's confidence in a series of predictions exceeds the level of accuracy achieved. In this experiment, questionnaire items requiring predictions of personal life-events were selected according to their objective base rates of occurrence and their outcome positivity /negativity for participants in a pilot study. The(More)
In individual choices between alternatives x and y, the availability of a third alternative z, judged inferior to x but not to y, tends to increase preferences for x. Two experiments investigated corresponding strategic asymmetric dominance effects in games. In Experiment 1, 72 players chose strategies in six symmetric 3 · 3 games, each having one strategy(More)
The similarity discrimination effect occurs when a single gene or gene cluster causes its carriers to display both a variable phenotypic trait and a behavioural predisposition to cooperate preferentially with recognisably similar carriers. We distinguish this from the greenbeard effect, in which cooperation evolves through fixed phenotypic tags and(More)
This study investigated the personality differences of 21 amateurs and 20 instructors who participated in the high risk sports of skydiving, hang-gliding, paragliding, scuba diving, microlighting, and rock climbing, versus those who did not. 38 men and 28 women (M age=32.6 yr., SD= 10.0) were assessed using the Eysenck Personality Questionnaire-Revised, the(More)
Trolley problems have been used in the development of moral theory and the psychological study of moral judgments and behavior. Most of this research has focused on people from the West, with implicit assumptions that moral intuitions should generalize and that moral psychology is universal. However, cultural differences may be associated with differences(More)