Marslen-Wilson W D, Tyler L K
Centre for Speech and Language, Birkbeck College, University of London, UK.
Nature. 1997 Jun 5;387(6633):592-4. doi: 10.1038/42456.
A fundamental issue in the study of cognition and the brain is the nature of mental computation. How far does this depend on internally represented systems of rules, expressed as strings of symbols with a syntax, as opposed to more distributed neural systems, operating subsymbolically and without syntax? The mental representation of the regular and irregular past tense of the English verb has become a crucial test case for this debate. Single-mechanism approaches argue that current multilayer connectionist networks can account for the learning and representation both of regular and of irregular forms. Dual-mechanism approaches, although accepting connectionist accounts for the irregular forms, argue that a symbolic, rule-based system is required to explain the properties of the regular past tense and, by extension, the properties of language and cognition in general. We show here that the regular and irregular past tense are supported by different neural systems, which can become dissociated by damage to the brain. This is evidence for functional and neurological distinctions in the types of mental computation that support these different aspects of linguistic and cognitive performance.
认知与大脑研究中的一个基本问题是心理计算的本质。与更分布式的、以亚符号方式运作且没有句法的神经系统相比，心理计算在多大程度上依赖于以具有句法的符号串形式表达的内部表征规则系统？英语动词规则和不规则过去式的心理表征已成为这场辩论的关键测试案例。单机制方法认为，当前的多层联结主义网络可以解释规则形式和不规则形式的学习与表征。双机制方法虽然接受联结主义对不规则形式的解释，但认为需要一个基于符号和规则的系统来解释规则过去式的属性，进而解释一般语言和认知的属性。我们在此表明，规则和不规则过去式由不同的神经系统支持，这些系统可能因大脑损伤而分离。这证明了在支持语言和认知表现这些不同方面的心理计算类型中存在功能和神经学上的差异。
