Joanisse Marc F, Seidenberg Mark S
Department of Psychology, University of Western Ontario, London, ON, N6A 5C2 Canada.
Cogn Affect Behav Neurosci. 2005 Sep;5(3):282-96. doi: 10.3758/cabn.5.3.282.
This article presents fMRI evidence bearing on dual-mechanism versus connectionist theories of inflectional morphology. Ten participants were scanned at 4 Tesla as they covertly generated the past tenses of real and nonce (nonword) verbs presented auditorily. Regular past tenses (e.g., walked, wugged) and irregular past tenses (e.g., took, slept) produced similar patterns of activation in the posterior temporal lobe in both hemispheres. In contrast, there was greater activation in left and right inferior frontal gyrus for regular past tenses than for irregular past tenses. Similar previous results have been taken as evidence for the dual-mechanism theory of the past tense (Pinker & Ullman, 2002). However, additional analyses indicated that irregulars that were phonologically similar to regulars (e.g., slept, fled, sold) produced the same level of activation as did regulars, and significantly more activation than did irregulars that were not phonologically similar to regulars (e.g., took, gave). Thus, activation patterns were predicted by phonological characteristics of the past tense rather than by the rule-governed versus exception distinction that is central to the dual-mechanism framework. The results are consistent with a constraint satisfaction model in which phonological, semantic, and other probabilistic constraints jointly determine the past tense, with different degrees of involvement for different verbs.
本文展示了功能磁共振成像（fMRI）的证据，这些证据与屈折形态学的双机制理论和联结主义理论相关。十名参与者在4特斯拉的磁场强度下接受扫描，他们在听到真实动词和假词（非词）动词时暗中生成其过去式。规则过去式（如walked、wugged）和不规则过去式（如took、slept）在两个半球的颞叶后部产生了相似的激活模式。相比之下，规则过去式在左右额下回的激活程度比不规则过去式更高。之前类似的结果被视为过去式双机制理论的证据（平克和乌尔曼，2002年）。然而，进一步的分析表明，在语音上与规则动词相似的不规则动词（如slept、fled、sold）产生的激活水平与规则动词相同，且比在语音上与规则动词不相似的不规则动词（如took、gave）产生的激活要显著更多。因此，激活模式是由过去式的语音特征预测的，而不是由双机制框架核心的规则支配与例外的区分所预测的。这些结果与一个约束满足模型一致，在该模型中，语音、语义和其他概率性约束共同决定过去式，不同动词的参与程度不同。
