Neural Systems Mediating American Sign Language: Effects of Sensory Experience and Age of Acquisition

ERPs were recorded from deaf and hearing native signers and from hearing subjects who acquired ASL late or not at all as they viewed ASL signs that formed sentences. The results were compared across these groups and with those from hearing subjects reading English sentences. The results suggest that there are constraints on the organization of the neural systems that mediate formal languages and that these are independent of the modality through which language is acquired. These include different specializations of anterior and posterior cortical regions in aspects of grammatical and semantic processing and a bias for the left hemisphere to mediate aspects of mnemonic functions in language. Additionally, the results suggest that the nature and timing of sensory and language experience significantly impact the development of the language systems of the brain. Effects of the early acquisition of ASL include an increased role for the right hemisphere and for parietal cortex and this occurs in both hearing and deaf native signers. An increased role of posterior temporal and occipital areas occurs in deaf native signers only and thus may be attributable to auditory deprivation.     

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.