Wendell E. Jeffrey

Habituation in the human infant.

Publisher Summary Habituation is not readily obtained in the neonate. A possible exception to that statement is the case of olfactory stimulation, but perhaps habituation is common to any situation involving observations of arousal from sleep rather than the more specific components of orienting behavior. By 2 or 3 months of age, however, habituation of orienting behavior is clearly observable in a variety of modalities. Several factors might underlie the general failure to obtain clear evidence for habituation in very young infants. Investigations of habituation to auditory stimulation have typically measured heart rate. Developmental changes in the nature of the heart rate response may account, in part at least, for the discrepancies in findings of response habituation at different ages. Before approximately 2 months of age, the usual heart rate response to a novel auditory stimulus is acceleration, while beyond 2 months it is deceleration.

Response tendencies of children in a two-choice situation

Abstract Two groups of children, ranging in age from 3 years to 3 years and 9 months and from 4 years and 3 months to 5 years, were run in a simple 2-choice situation with undiscriminable stimuli and 100%, 50%, and 33% reinforcement regardless of their response. Under 100% reinforcement all but one of the 4 1 2 - year-old group showed very strong alternation behavior whereas the largest alternation score for the 3-year-old group was 4 alternations in 60 trials. An additional group of Ss, ranging in age from 3 years and 10 months to 4 years and 3 months, who were given 100% reinforcement, did not respond randomly but could be clearly classified as showing either alternation or perseveration tendencies. Under 50 and 33% reinforcement the 4-year-old Ss did not consistently alternate or perseverate with a single response. Although the effect of lowered reinforcement on the 3-year-old group was toward less consistent perseveration, the mean number of alternations remained below chance under both 50 and 33% reinforcement conditions.

The child's concept of proportionality: A re-examination

Abstract A partial replication and extension of Bruner and Kenneys (1966) study of the concept of proportionality was run with 5- and 7-year-old children. Experimental Ss were given preliminary training to facilitate their understanding of the task and their attention to the relevant cues. Training effectively altered the performance of both the 7- and 5-year-old E groups although only the older group was shown to possess the proportionality concept as measured by the criterion task. The results demonstrated the importance of avoiding verbal ambiguity in the investigation of nonverbal cognitive competence.