The effects of laterality, movement, and language on children's ability to conserve multiple space relations were investigated in this study of visuo-spatial dimensionality acquisition. The sample for the experiment consisted of 160 first-graders (80 boys, 80 girls) who were matched on intelligence and socioeconomic status. These subjects were tested for their functional knowledge of language (Piaget's schedule) and lateral dominance (D-K Scale of Lateral Dominance) and then randomly assigned to a spectator or participation condition. An apparatus was devised and constructed to test spatial conservation. Those children who were clearly lateralized had less success in reproducing space relations than did children who were mixed in their laterality. Results were interpreted to be in support of an iconic mode of representation and did not offer support for an extreme emphasis on the importance of language or activity. Further analysis of the data on laterality patterns revealed that right-handed, left-eyed children produced the main laterality effect obtained. Recent neurophysiological evidence indicates that the cerebral hemispheres function asymmetrically. The results of this study are consistent with that evidence. (MH/Author)