Abstract
Visual and manipulative responses to the novel objects were studied in 40, 3-, 6-, 9-, 12-, and 18-month old infants. The stimuli were two novel objects (A, B), and were matched in terms of ease of holding, stimulus complexity, audio-visual feedback potentiality, and similarity to everyday tools. The Ss were assigned to either one of the two stimulus presentation orders: AAABBBAB and BBBAAABA. Termination of each trial was contingent on the S's response, and therefore not determined by a fixed time lapse.
With the exception of the 3-month old infants, initial decrement in visual responsiveness was followed by a significant recovery at the fourth trial when the other novel stimulus was introduced, but not at the seventh or eighth trial when the familiar stimulus was introduced again. The amount of decrement in the short-term familiarization process was not directly related to that of the response for the following novel stimulus. Especially in 9-month-old infants, the former was small and the latter was large.
In the infants aged 6 months and older, visual and manipulative responsiveness to novelty was concordant, not supporting Schaffer's findings. And there was the discrepancy in findings by the measures of manipulation: Total manipulation time and Latency to manipulation.
The 3-month old infants had longer visual regard per response, larger percentage of looking within one trial and smaller percentage of manual activity within one trial. The 6-month old infants had shorter visual regard, smaller percentage of looking and larger percentage of manipulation. Beginning at 9 months, infants had longer visual regard, larger percentage of looking and manipulation. These findings suggest the transition of relative dominance of vision and manipulation during infancy.
