Rate of forgetting in H.M.: 6-month recognition.
The picture-recognition performance of H.M. and six control subjects was evaluated 6 months after initial learning, using materials from an earlier study in which H.M. received additional study time in order to equate his yes-no and delayed-match-to-sample (DMS) performance 10 min after learning to that of control subjects. In the study detailed here, 6-month recognition performance was assessed with no intervening exposure to the target items. H.M. performed at chance levels when tested using the standard yes-no recognition procedure. When the yes-no procedure was modified so that distractor stimuli required positive responses, H.M.'s performance was comparable with that of control subjects. In addition, H.M.'s DMS and delayed-nonmatch-to-sample (DNMS) performance were comparable with that of control subjects 6 months after learning. Conclusions regarding H.M.'s 6-month recognition performance are thus dependent on the procedures used to assess memory.
Freed
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DM
Clinical Research Center, Massachusetts Institute of Technology.
Corkin
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S
D000647:Amnesia / Q000523:psychology*; D001288:Attention; D001925:Brain Damage, Chronic / Q000523:psychology*; D004193:Discrimination Learning; D004833:Epilepsy, Temporal Lobe / Q000601:surgery*; D006801:Humans; D008297:Male; D008568:Memory; D011939:Mental Recall; D008875:Middle Aged; D010364:Pattern Recognition, Visual; D011183:Postoperative Complications / Q000523:psychology*; D012153:Retention, Psychology