Memory for faces with emotional expressions in Alzheimer's disease and healthy older participants: positivity effect is not only due to familiarity.

Young individuals better memorize initially seen faces with emotional rather than neutral expressions. Healthy older participants and Alzheimer's disease (AD) patients show better memory for faces with positive expressions. The socioemotional selectivity theory postulates that this positivity effect in memory reflects a general age-related preference for positive stimuli, subserving emotion regulation.