STABILITY OF VISUAL EXPECTATIONS AT 3.0 MONTHS OF AGE

Three-month-old infants were observed on 2 days to examine stability in forming visual expectations. Babies saw pictures that appeared in left-right alternation, 700-ms on with a 1,000-ms ISI. Anticipatory fixations and speeded RTs were the indexes of expectation. Split-half correlations were stable for each session (r = > .42, for RTs, and r = > .51, for % anticipations). The Session-1-Session-2 correlation was stable for median RTs (r > .48) and marginal for % anticipations (r = .34). The Session-1-Session-2 correlation for optimal RT (fastest median RT in a block of 10 trials) was r = .67. This correlation remained stable (r = .61) when the median RT for the first 10 pictures was partialed out. Thus, the optimal RT correlation reflected the effect of expectations on RT, apart from natural quickness. Eye-movement RT is a reliable performance measure in 3-month-olds, and individual differences exist in infants' tendency to form visual expectations.