In the present study, we investigated age-related decline in face recognition memory and whether this decline is moderated by the age of the target faces and by the number effaces that the participant must learn (memory load). Thirty-two participants in each of three age groups (18-39 years, 60-75 years, and 76-96 years) completed a face recognition task. Signal detection analyses confirmed that face recognition accuracy declined with age. However, this finding was qualified by an interaction between participant age and target age, which revealed that the age-related decline in face recognition accuracy occurred only for young target faces. Increased memory load was associated with comparable performance decrements across all age groups. However, memory load appears not to be the cause of these decrements. Instead, they appear to be a product of recognition load (the number of stimuli presented in the recognition phase).
Humans learn to recognize thousands of faces during the course of their lives. The vast number of faces we learn, coupled with the high level of similarity of these stimuli, led Damasio (1989) to suggest that learning and recognizing faces is one of the most cognitively demanding and neurologically complex tasks in which we engage. Face recognition has been intensively investigated over the last few decades, resulting in a voluminous body of literature. A large amount of research has investigated the effects of participant age on face recognition. However, little attention has been given to variables that may interact with age in determining face recognition performance. In the present study, we examined two possible interacting variables: (1) the age of the target face and (2) memory load (the number of faces that the participants are required to learn). The main questions we investigated were: Do people of different ages have differential recognition success with target faces of different ages? Does increasing memory load have a greater impact on the elderly than on younger individuals, or does it have approximately the same impact across the life span? In addition, we were interested in determining whether the effects of memory load can be distinguished from those of recognition load (the total number of target and distractor faces seen in the recognition phase).
Adults can successfully encode large numbers of new faces from briefly inspected photographs and subsequently identify these from distractors at hit rates of over 90% (Carey, 1992; Goldstein, 1977). However, with increasing age come declines in various cognitive abilities, including face-recognition accuracy (Salthouse, 2004; Shapiro & Penrod, 1986). Researchers have shed light on various aspects of this cognitive decline, including its time course. Crook and Larrabee (1992), for instance, found significant age-related decrements in participants as young as 50, but found that the largest decrements occurred over the age of 70. This indicates that memory decline in face recognition is not linear but accelerates after the age of 70 and is consistent with evidence suggesting that memory in general deteriorates more rapidly in those over 70 years of age than in those a decade or so younger (Parkin, 1993). Researchers have also shed light on the nature of the deficits in face recognition with age. It appears that young adults and elderly people have similar hit rates, but that elderly people have an elevated level of false alarms (Bartlett & Leslie, 1986; Crook & Larrabee, 1992; Ferris, Crook, Clark, McCarthy, & Rae, 1980; Fulton & Bartlett, 1991; Smith & Winograd, 1978; but see Bäckman, 1991).
Although there is good evidence that increasing age is associated with a decline in the ability to recognize faces, little is known about the variables that might interact with age. For instance, only a handful of studies have considered how the age of the participant might interact with the age of the target face. …