Effects of stimulus dimensionality and other stimulus characteristics on classification performance in children of ages 3 to 7 years
Creators: name: Scribner, Donna Marilyn
Publisher: name: University of British Columbia
Year: 2010

description: The problem studied in this investigation was the effects of stimulus dimensionality, other stimulus characteristics and the age of subjects on free classification performance. The theoretical basis was earlier research (Inhelder &amp; Piaget, 1964) and the experimental procedures were adapted from a test developed to assess conceptual functioning in brain damaged children (Graham-Ernhart Block Sort Test, 1963) GEBST. Ninety children, 18 from each of the following age groups; preschool three year olds, preschool four year olds, kindergarten, grade one and grade two were subjects in this investigation. There were three sets of stimulus objects; three dimensional styrofoam objects, two dimensional flat styrofoam objects and photographs of the three dimensional objects. Each stimulus set required subjects to match or group stimuli which differed in respect to three characteristics; color (yellow, red and blue), form (circle, square and triangle), and size (large, medium and small). The GEBST procedures were followed with minor changes in the order of task presentation and in the scoring. Two difficulty levels in the GEBST were used and each level contained three trials. Level III stimuli differed on one characteristic and were constant in respect to the remaining characteristics. Level IV stimuli differed on two characteristics simultaneously while the third characteristic was held constant. Dimensionality of the test material was randomly assigned with six subjects in each age group receiving the GEBST in each dimension, A subject received only one dimension but all three characteristics. Two separate analysis of variance procedures were performed, one for each level on the GEBST. Dimensionality, characteristics, age as a categorical variable and their interactions were assessed with analysis of variance. Age as a continuous variable, sex and their interactions were assessed with two least square regression analyses, one for each difficulty level of the GEBST. Unequal numbers of each sex for some age groups necessitated analysis of the sex variable by least squares regression analysis. Age was the most significant factor affecting performance on a free classification task. The age range of this investigation seemed adequate to test the performance of preconceptual classification behavior as described by Inhelder &amp; Piaget (1964). The sex of subjects did not significantly affect classification performance, a finding supported by most research in this area. The characteristic of the stimulus object was a significant factor affecting classification performance. Size appeared to be a much more difficult characteristic to base classification on than color or form particularly with the youngest subjects. Stimulus dimensionality was not found to be a significant factor affecting classification performance. This was contrary to research in this area and also the hypotheses made in this investigation. Two explanations seemed plausible for the results occurring in this study: the scoring system of the GEBST did not sufficiently reflect the performance of the tested subjects, and the choice paradigm of Level IV, implicit in the design of the GEBST, obscured some of the variability of stimulus dimensionality. Further research in the area of stimulus dimensionality in a free classification task seems necessary as the results of this investigation did not support other investigations in this area. It is also an area which has not been fully studied and stimulus dimensionality has great practical applicability to the study of young children's performance on conceptual tasks.