Amnesic H.M.'s performance on the language competence test: parallel deficits in memory and sentence production.

To test conflicting hypotheses regarding amnesic H.M.'s language abilities, this study examined H.M.'s sentence production on the Language Competence Test (Wiig & Secord, 1988). The task for H.M. and 8 education-, age-, and IQ-matched controls was to describe pictures using a single grammatical sentence containing prespecified target words. The results indicated selective deficits in H.M.'s picture descriptions: H.M. produced fewer single grammatical sentences, included fewer target words, and described the pictures less completely and accurately than did the controls. However, H.M.'s deficits diminished with repeated processing of unfamiliar stimuli and disappeared for familiar stimuli-effects that help explain why other researchers have concluded that H.M.'s language production is intact. Besides resolving the conflicting hypotheses, present results replicated other well-controlled sentence production results and indicated that H.M.'s language and memory exhibit parallel deficits and sparing. Present results comport in detail with binding theory but pose problems for current systems theories of H.M.'s condition.