Infant habituation: assessments of individual differences and short-term reliability at five months.

This study is concerned with individual differences and short-term reliability of infant-control habituation of visual attention. Habituation to single female faces and to single geometric patterns was observed separately in 2 groups of comparable 5-month-olds. Each group participated in habituation twice, and habituation sessions for each were separated from one another by 10 days. Across the 2 conditions, habituation was found to be distributed into 3 patterns: Most infants decreased looking and achieved criterion in a negatively exponential fashion, some infants first increased looking and then rapidly habituated, and some infants showed fluctuating and idiosyncratic looking-time functions prior to habituating. Both qualitative patterns and quantitative indexes of habituation showed moderate but significant reliability between assessment sessions. Quantitative and psychometric characteristics of habituation and the meaningfulness of habituation of attention as an index of infant cognition are discussed.