The basic purpose of this study was to measure cognitive similarity, and to test the hypothesis that the cognitive organization of a child (normal or schizophrenic) is more like that of his own parents than it is like that of randomly chosen, unrelated adults. Thirty-six matched family triads, half with sons hospitalized for a schizophrenic reaction and half with sons hospitalized for medical reasons, comprised the sample. All families were administered the S-D and the Shipley-Hartford Vocabulary Test. Data analyses were conducted. Results support the assumption that, for schizogenic families, members of the same family are similar where cognitive organization is concerned. Their cognitive structure is idiosyncratic and not shared by others. It is suggested that children raised in normal families learn generalized, socially shared ways of construing other people and the world around them. As a result, they are cognitively more like members of constructed, unrelated "families" who share these more general world-views. (TL)