The authors studied reasons of a domineering perceptive generalizations in the Piaget test by children with schizophrenia. In teaching the children to distinguish and measure different properties of objects, the most typical appeared to be the following actions: a complete or partial refusal to accomplish them, a substitution of measurements by a perceptive comparison, difficulties in the narration of personal activity in well developed speech. Better results were attained in those who were emotionally positive. On these grounds the authors presumed an autistical genesis of these disturbances.