| The purpose of this age related, cross-sectional study was to investigate the conservation abilities of twenty noninstitutionalized, Caucasian, moderately retarded males attending either a special school or a sheltered workshop in a major southwestern city. There was an equal number of adolescent and adult subjects (CA range: 11 to 30 years; IQ range: 35 to 55). All subjects were administered a battery of Piagetian experiments assessing the conservation of number, substance, and weight. All subjects were questioned according to a structured interview format. Explanations after countersuggestion were used as criteria for the determination of conservation stages.;Qualitative analysis of the data indicated that one adult subject was a conserver of number and an intermediate conserver of substance. No subject conserved substance or weight. No adolescent subject demonstrated an ability to conserve. Quantitative analysis of the data indicated neither statistical significant difference in the conservation explanations between experiments as measured by t tests of correlated means nor statistical significant difference in the conservation explanations between chronological age groups as measured by t tests of independent means. There was no indication of a "horizontal decalage" for the conservation of number, substance, and weight or of a relationship between chronological age and conservation ability.;It was qualitatively significant that one subject demonstrated an ability to conserve, therefore the theoretical premise regarding the inability of moderately retarded persons to conserve was unsubstantiated. It was qualitatively significant that identity justifications of conservation were offered by one subject, therefore the theoretical premise regarding the incapability of moderately retarded persons to offer conservation justifications of invariant quantity was unsubstantiated. There was evidence substantiating the slight possibility of continued cognitive development beyond adolescence by moderately retarded persons. These findings should be taken cautiously due to the limitations inherent in this study. Yet, they encourage the exploration of a new frontier of research in the field of mental retardation, the investigation of the reasoning of mentally retarded adults. |
