Constructive and deconstructive tool modification by chimpanzees (Pan troglodytes)

Nine chimpanzees (Pan troglodytes) were tested for their ability to assemble or disassemble the appropriate tool to obtain a food reward from two different apparatus. In its deconstructed form, the tool functioned as a probe for one apparatus. In its constructed form, the tool functioned as a hook, appropriate for a second apparatus. Each subject completed four test trials with each apparatus type. Tool types were randomized and counter-balanced between the two forms. Results demonstrated that adult and juvenile chimpanzees (N = 7) were successful with both tool types, while two infant chimpanzees performed near chance. Off-line video analyses revealed that tool modifications followed by attempted solutions by the adults and juveniles were typically correct on the first attempt. Neither infant was successful in modifying tools correctly on the first attempt over all eight trials. The older chimpanzees’ ability to modify the appropriate tool consistently prior to use indicates an immediate recognition of the functional attributes necessary for the successful use of tool types on each apparatus, and represents a non-replication of a previously reported study by Povinelli.

Children's and adolescents' perception of the authenticity of smiles

Recently, Thibault and colleagues described the Duchenne marker as a cultural dialect for the perception of smile authenticity. The current study had the goal to follow up on this finding and to investigate the cues that French Canadian children use to evaluate the authenticity of smiles from members of three ethnic groups. The authenticity of six smiles differing in intensity and presence of orbicularis oculi (Duchenne marker) was rated by 1206 children from 4 to 17 years of age. No differences were found as a function of encoder group. All children perceived medium Duchenne smiles as more authentic than equally intense medium non-Duchenne smiles. Furthermore, results suggest a decrease in the reliance on intensity across the age span. Younger children use the intensity marker along the whole continuum to infer authenticity. In contrast, older children (14- to 17-year-olds) rated all smiles that did not contain the Duchenne marker as roughly equally low in authenticity.     

Causal explanations for school performance: Contrasts between mothers and children

This study investigated the causal attributions given by mothers and their fifth and sixth grade children to explain the children's success in a school subject of relatively high achievement as well as their failure in an area of low performance. Participants were asked to weight the importance of four attributions: ability, effort, personality, and training. Analyses of variance revealed significant differences between mothers' and children's weightings. Mothers cited children's ability as the main cause of success, while lack of effort was viewed as the reason for failure. Children, in contrast, gave effort as the explanation for success and lack of ability as the reason for failure. The apparent lack of concordance between mothers' and children's causal beliefs is discussed in terms of three explanatory possibilities: (a) actor/observer differences, (b) the effects of the affective bond between mother and child, and (c) the tendency toward self-presentational bias.     

Adult age differences in explanations and memory for behavioral information

Age differences in the effects of knowledge-based expectations on both the use of integrative memory processes and recall were examined. In the context of an impression-formation task, young and older adults were presented with lists containing behaviors that varied in consistency with attributed personality traits. Younger adults recalled trait-inconsistent behaviors better than consistent ones, but older adults exhibited no such consistency effect. The age difference in performance was related to the younger adults' spontaneously producing more explanations for inconsistent behaviors. Explanations are assumed to facilitate access to such information by establishing associations with other behavioral information residing in memory. When age differences in the use of explanation-based processing were controlled, the age differences in the effects of consistency on memory were eliminated.     

Specific exemplar retention and prototype abstraction in young and old adults

The effects of age differences in retention of information about specific concept members on the ability to abstract central tendency information were examined. Young and older adults were presented with a series of visual patterns that were organized around a prototype. They were then presented with these same patterns plus a set of new patterns varying in prototype similarity in a recognition test. It was found that young adults retained more information about specific acquisition set exemplars, which resulted in slightly different recognition responses for new patterns. However, the recognition behavior of both young and older adults appeared to be governed by the same rules. It is suggested that the organization of conceptual information does not change with age, but the poorer retention of specific item information in older adults may result in a less complete representation.