Several recent experiments suggest that mental imagery is relevant to an explanation of memory impairment resulting from neurological damage. This study compared a group of patients with recent closed head injuries with a control group of orthopaedic patients in their recall of concrete and abstract words. The head-injured subjects demonstrated a specific deficit in the recall of concrete material, which was interpreted as an impairment in the use of mental imagery as a form of elaborative encoding in long-term memory. It is suggested that the understanding of clinical conditions would be assisted by the application of the procedures and theoretical interests of experimental psychology.