Age-related changes in processing faces from detection to identification: ERP evidence.

We examined the ability of people 70 to 90 years old to apply global, configural, and featural face-processing strategies. In addition we investigated age-related changes in the ability to categorize faces at basic, subordinate, and individual levels. Using the N170 potential as index of early face processing and the P300 component as index of categorical decision making and effort, we found significant age-related perceptual changes which slowed and somewhat impaired face processing. Specifically, older participants had problems integrating face features into global structures, demonstrating enhanced dependence on distal global information. They did not apply configural computations by default while processing faces which suggests that, unless identification is required, they process faces only at a basic level. These perceptual changes could be the cause for slower and less accurate subordinate categorization, particularly when it is based on details. At the neural levels face processing was not right-lateralized, reflecting excessive involvement of the left hemisphere in perception leading to a more general reduction of interhemispheric asymmetry. In addition we found excessive but nonselective activation of frontal regions adding support to the view that executive control and particularly inhibition of irrelevant input are reduced in the elderly.