Spatial and temporal sequencing of signs and words by severely mentally retarded children.

The effects of manual sign or spoken word labels on the spatial or temporal ordering of sequences of stimuli by severely mentally retarded children were investigated. The stimuli were presented in a spatial array so that the spatial (left-right) order never corresponded with the temporal (first-last) order. Other researchers have suggested that sign labels would be recalled in the spatial order of presentation and word labels, in the temporal order. The results did not support this, revealing instead that subjects tended to preserve spatial order and reverse temporal order, irrespective of the modality of the stimulus label.