Long-term recognition memory for faces assessed by visual paired comparison in 3- and 6-month-old infants.

Abstract

It has been argued that operant conditioning is the only type of long-term memory present in infants prior to 6 months of age. In this study, memory for faces was investigated in 3- and 6-month-old infants with a visual paired-comparison task. In Experiment 1, infants were habituated to a face presented in different poses; recognition was assessed after a 2-min or a 24-hr retention interval. The 6-month-old infants and the male but not (he female 3-month-old infants exhibited novelty preferences. A 2nd experiment showed that 3-month-old female infants were delayed relative to male infants in their face-processing ability rather than in their memory capacity. The results of Experiment 3 demonstrated in 3-month-olds an electrophysiological correlate of delayed recognition memory. These findings are discussed in the context of the neural systems thought to be involved in visual recognition memory (but not in procedural memory), namely the limbic system. One crucial issue in developmental psychology is to understand when and how episodes taking place in infants' environments modify their cortical representations of the world and their expertise in various cognitive abilities. For several years, researchers have essentially attempted to describe the cognitive abilities that may guide learning and memory at the very beginning of life. Investigations of memory itself in this same early period of life were scarce. For instance, there are numerous studies of the development of face processing in infancy (for a review, see de BoyssonBardies, de Schonen, Jusczyk, MacNeilage, & Morton, 1993). In contrast, there are almost no data available on memory for faces. Thus, it remains unclear when infants become able to memorize exemplars of several different faces, for how long they can retain these memories, how far memory for exemplars is involved in the early development of face-processing competencies, and whether the develomental path for face memory is the same as for object memory. To model the development of cortical functions and cogni