The effects of minor closed head injury upon human memory: Further evidence on the role of mental imagery

Abstract

Patients with minor closed head injuries have been found to show a specific deficit in the recall of concrete material, which suggests an impairment in the use of mental imagery as a mnemonic code. The first experiment in the present investigation compared the recognition of unfamiliar faces by head-injured and control patients. The second experiment studied the free recall of pictured objects. In neither case did the head-injured patients demonstrate a significant impairment, which was taken to mean that minor closed head injury has a selective effect upon the encoding of verbal information in the form of mental images. The third experiment compared the free recall of lists of concrete and abstract nouns by head-injured and control patients under either standard learning instructions or imagery mnemonic instructions. Under the standard instructions, head-injured patients demonstrated a selective deficit in the recall of concrete material. However, under interactive imagery instructions, both head-injured and control patients showed superior performance with concrete material, and there was no sign of any difference between the two groups of subjects. The effects of minor closed head injury upon human memory are interpreted as a functional deficit attributable to the patients' failure to employ the optional mnemonic strategy of constructing interactive images. The results suggest that an appropriate approach for dealing with cases of psychological dysfunction following brain injury would be to provide training in the use of relevant cognitive strategies.