THE FACTOR ANALYTIC STUDY OF THE DEVELOPMENT IN SEVERELY OR PROFOUNDLY RETARDED INDIVIDUALS

Abstract

The present study attempted to describe the factorial structure of the development in severely or profoundly retarded individuals. Subjects were 50 severely or profoundly retarded individuals. They were divided into two groups: the younger group (CA= 10:6-17:10) and the older group (CA= 18:0-26:11). Data on two developmental tests (Tsumori's Developmental Test and Enjoji's Developmental Test) of 50 subjects were analyzed. A total of 11 variables which were analyzed in this study consisted of 5 subdomains in Tsumori's Developmental Test and 6 subdomains in Enjoji's Developmental Test. We calculated developmental ages of each subdomain. And then the productmoment correlation coefficients among 11 subdomains were calculated. On this correlation matrix, factor analysis was performed by use of the principal factor method. The first three factors were then rotated orthogonally to a varimax solution. These three factors accounted for over 80 percent of the total variance. Three psychologically significant factors were extracted after varimax rotation. Factor I related to "the self-care activities". Subdomains with the highest loadings on this factor were motor function, locomotion, habit of living skills and fundamental habit. Factor II was defined by the cluster of subdomains that were "the verbal behaviors". These included verbal reception and verbal expression. Factor III was defined by subdomains reflective of "the contact with person and object." Subdomains having the highest loadings on this factor included social behavior, search for objects and human relations. Furthermore, factor scores were estimated for each individual in order to determine whether there were developmental changes or not. As a result, it was cleared that the older group was higher than, the younger group in the developmental level of "the self-care activities". On the other hand, it was suggested that the younger group was a little higher than the older group in the developmental level of "the verbal behaviors" and "the contact with person and object". The above-mentioned results indicated that the applicaton of factor analysis to data on the development of severely or profoundly retarded individuals was useful.