Age differences and similarities in patterns of cerebral hemispheric asymmetry.

Younger (M age = 20.4 years) and older (M age = 70.7 years) adults participated in 3 visual half-field experiments. These were designed to examine specific aspects of hemispheric asymmetry: (a) hemispheric dominance for phonetic-linguistic processing (as measured by identification of non-word trigrams), (b) hemispheric differences in trigram processing strategy, (c) characteristic perceptual biases thought to reflect hemispheric arousal asymmetries, and (d) hemispheric dominance for processing emotions shown on faces. Patterns of left-right asymmetries were comparable for older and younger participants, and intercorrelations among the various measures of asymmetry were similar for both groups. In view of the present results, it seems unlikely that changes in hemispheric asymmetry contribute significantly to age-related changes in cognitive functioning.