Abstract:The current research examined the hypothesis that males derive greater benefits than females do from cooperation with same-sex peers versus parents. In Study 1, 194 children, early adolescents, older adolescents, and adults from Brussels, Belgium predicted whether parents or same-sex peers would provide more benefits to a typical individual of their same age and sex. Results showed that at all four age levels, compared with females, males predicted that same-sex peers would provide more benefits relative to parents. Study 2 was designed to examine which benefits same-sex peers relative to parents provide more for males than females. In Study 2, 50 young adults from Montreal, Canada were asked to report to what extent same-sex peers and parents satisfied physical needs, fulfilled socioemotional needs, and helped with acquiring societal skills over the past year. Males more than females reported that same-sex peers relative to parents satisfied socioemotional needs and helped with the acquisition of societal skills. Discussion revolves around the hypothesized differential relations of males and females to families versus same-sex peers.

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Two studies examined the hypothesis that accepting false premises as true in order to make the modus ponens (MP) inference requires inhibition of contradictory knowledge. Study 1 presented both MP and affirmation of the consequent (AC) inferences using either false, but plausible premises or completely unbelievable premises, with standard logical constructions using either an evaluation or a production paradigm. The rate of acceptance of the MP inferences was significantly greater with unbelievable premises than with plausible premises, in both evaluation and production, while no such effect was observed with the AC inferences. Study 2 used a computer-generated presentation allowing for measures of response times. Participants who tended to accept the MP inference with unbelievable premises took longer to do so with plausible premises than with unbelievable premises. Participants who tended to reject the MP inference showed an opposite pattern. In both studies, the observed effects were not shown for the AC inferences. The overall pattern of results was consistent with the hypothesis that inhibition is a key component of logical reasoning with false premises.

This study examined conditional reasoning with premises referring to associations between professions and traits that were either stereotypical ("Accountants like mathematics") or counter-stereotypical ("Nurses like mathematics"). In the first study, participants were asked to rate the degree of certainty of MP and AC inferences based on an individual's profession ("John is an accountant") or based on an individual trait ("John likes mathematics"), under pragmatic instructions or under strong logical instructions, using a context that required them to put themselves in the position of a fictitious actor. Results showed that both forms of inference were rated as more certain with stereotypical premises than with counter-stereotypical premises and that logical instructions increased the overall strength of inferences without reducing the difference between the two forms of premise. The second study presented both stereotypical premises and inferences with believable and unbelievable conclusions, with no additional context. Participants were given inferences under pragmatic instructions followed by logical instructions, or only under logical instructions. Results show that ratings for both MP and AC inferences were higher for stereotypical than counter-stereotypical items, with a similar difference for inferences with belief-consistent and beliefinconsistent conclusions. Logical instructions clearly reduce the influence of premise type, on both types of problems. Receiving pragmatic instructions initially reduced overall levels of normative responding for stereotypical, but not for classical belief-bias inferences. Individual differences in responding indicate that the debiasing effect of logical instructions depends on initial level of bias shown under pragmatic instructions. The results are interpreted as supporting dual-process theories of reasoning.Logical reasoning involves making deductions on the basis of some given premises that are considered to be true. Logical reasoning is, at least in theory, decontextualized, and thus involves the ability to disregard the specific content of premises when generating a conclusion. However, studies examining reasoning have consistently found that people are influenced by -----Cécile Saelen and Henry Markovits are affiliated to the Université du Québec à Montréal, Canada, Olivier Klein is affiliated to the Université Libre de Bruxelles.