In Study 1, 24 participants generated sentences expressing ways of dealing with positively and negatively valued noun stimuli (objects and humans). They were instructed to begin each sentence with One auxiliary verb. The auxiliary was to be selected from a set including auxiliaries expressing high (must) and low (can) necessity. As predicted on the basis of a minimal nonsocial model of behavioral adaptation, higher necessity was associated with negative stimuli than with positive stimuli. In Study 2, this effect was replicated using trait adjectives as stimuli. Consistent with the model, the effect was produced by stimulus valences belonging to an approach-avoidance related evaluative dimensioǹ other-pro®tability'. However, additional effects, involving an alternative evaluative dimension`selfpro®tability', were not fully accounted for by the model. They suggested that genuine social factors were involved that, however, were only required to explain some marginal effects. Copyright # 2002 John Wiley & Sons, Ltd.Various authors have described asymmetries in the ways in which subjects deal with positively valued stimuli, such as liked people and objects, on the one hand, and negatively valued stimuli, such as disliked people and objects, on the other (Cacioppo, Gardner, & Berntson, 1997;Kanouse & Hanson, 1972;Higgins, 1998;Lewicka, 1988;Peeters, 1971;Peeters & Czapinski, 1990;Reeder & Brewer, 1979;Skowronski & Carlston, 1989;Taylor, 1991). At least many of those positive±negative asymmetries can be reduced to a basic structural asymmetry between approach and avoidance dispositions which has survival value and which has been described on referring to a metaphorical fungus eater who survives only if he or she succeeds in (a) approaching (consuming) mushrooms and (b) avoiding (consumption of) lethal toadstools (Peeters, 1971;Peeters & Czapinski, 1990).Taking the perspective of evolutionary psychology, one can readily assume that the adaptive strategy of the fungus eater may have evolved in species with relatively low reproduction rates such as humans. Hence the validity of the model of the mushroom eater is not questioned. What can be questioned is the extent to which the model can account for the processing of positive and negative
