ABSTRACTThis paper reports the results of a study in which elderly dysphasic subjects, and elderly subjects with senile dementia of the Alzheimer type (SDAT) were asked to name two representations of familiar objects. These were presented as coloured photographs, and as black and white line drawings. The results show that, although patients with SDAT perform better overall, there is a significant difference in their ability to name drawings compared to photographs. Analysis of the errors made by both subject groups shows significant differences, especially with regard to errors of visual misperception. The implications of these differences are discussed.