SENSITIZATION DURING VISUAL HABITUATION SEQUENCES - PROCEDURAL EFFECTS AND INDIVIDUAL-DIFFERENCES

Although individual differences in visual habituation have long been i nterpreted in terms of processes derived from comparator theory, resea rch over the last decade has suggested that arousal or arousability as manifest in sensitization may contribute to infants' attentional prof iles, and thus, to individual differences in those profiles. We explor ed this possibility by habituating 4-month-old infants to 4 x 4, 10 x 10, or 20 x 20 checkerboards in a fixed-trial paradigm. The first spec ific aim was to examine the attentional characteristics of infants wit h habituation patterns showing sensitization versus those that did not . The second specific aim was to determine whether patterns of attenti on suggestive of sensitization effects reported in past research might be attributable to the use of illuminated interstimulus intervals (IS Is). Trends were observed for sensitization to occur more frequently w ith more complex than with less complex checkerboards. Infants who sho wed looking patterns characteristic of sensitization looked longer and did not habituate as readily as infants who did not show sensitizatio n. Finally, different ISIs did not engender different levels of sensit ization, bur dark ISIs significantly increased infants' looking times to stimuli during trials. (C) 1997 Academic Press.