SOME ADDITIONAL QUANTITATIVE OBSERVATIONS OF IMMEDIATE MEMORY IN A PATIENT WITH BILATERAL HIPPOCAMPAL LESIONS

Additional behavioral data are reported on a well-documented patient who had undergone bilateral medial temporal-lobe resection. After a brief interruption from a visual discrimination task, he was unable to describe accurately what he had been doing; yet his subsequent performance was quantitatively similar to his earlier one. With verbal material, his delayed matching-to-sample performance was unimpaired up to 40 sec, the longest delay tested. With nonverbal material that required the patient to devise his own verbal coding, the sample stimuli lost control over his behavior after delays of 24-32 sec. Although other factors undoubtedly contribute to the patient's forgetfulness, the suggestion was offered that his failure to use verbal coding plays an important role in preventing him from extending his immediate memory span. © 1968.