UBC Theses and Dissertations
Age differences in infants' attention to stimuli varying in complexity Brennan, Wendy Margaret
The research presented in this thesis was designed to investigate the effects of age on infant preferences for stimuli of different complexity levels. The hypothesis was that the older the infant, the more complex the pattern he prefers. Hershenson (1964) presented three checkerboard designs containing 2x2, 4 x4, and 12 x 12 black and white squares to newborn infants. He found that the infants preferred the stimuli in decreasing order of their complexity. The purpose of the first experiment of the present research was to compare the responses of older Infants towards these stimuli with those of Hershenson's newborns. In Experiment I, 10 and 20 week old infants were presented with the three checkerboards in a single stimulus presentation procedure. The length of time during which each stimulus was fixated by an infant was recorded. It was found that the Infants of both age groups preferred the stimuli in increasing order of their complexity. These results complemented those of Hershenson (I964) I n supporting the hypothesis that older infants prefer stimuli of greater complexity than do younger infants. The fact that no difference was found in the preferences of the 10 and 20 week olds was attributed to the fact that the set of stimuli used did not encompass a wide enough range of complexity. Further support of the hypothesis was sought on Experiment II. Using the same single stimulus presentation procedure as that used in Experiment I, three, eight and 14 week old infants were presented with three black and white checkerboards containing 2x2, 8x8, and 24 x 24 squares. In terms of total fixation time for each stimulus, three week olds preferred the least complex stimulus, eight week olds preferred the stimulus of intermediate complexity, and 14 week olds preferred the most complex stimulus. These results support the hypothesis that the older the infant, the more complex the pattern her prefers. However, three week olds did not look significantly longer at the 24 x 24 checkerboard than at a plain gray square with which they were also presented. This suggests the possibility that they could not perceive the pattern of this stimulus. A control study seems warranted. One subsidiary purpose of the research was to compare various response measures, namely total fixation time, length of first fixation, and rate of habituation. The latter response measure was of no value in detecting the preferences of the infants for the stimuli. The total fixation time and length of first fixation measures gave the same patterns of preference with each age group. With both measures an increasing preference for complexity with age was found. However, it was felt that total fixation time was the more sensitive and reliable of the two measures. Another purpose of the research was to compare two experimental procedures in the study of infant attention - single stimulus and pair comparisons. In Experiment III, 8 and 14 week old infants were presented with the 2x2, 8x8, and 24x24 checkerboards in a modified pair comparisons procedure. The results obtained were consonant with those obtained in Experiment II and supportive of the hypothesis. The eight week old group preferred the stimulus of intermediate complexity over the other two, while the 14 week old group preferred the most complex, stimulus over the others. The results of the experiments presented in this thesis were congruent, and were supportive of the hypothesis that increased preference for complexity comes with age.
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