Michiru Makuuchi, PhD
Chief, Section of Neuropsychology, Research Institutes,
National Rehabilitation Center for Persons with Disabilities, Japan
講題：Brain mechanisms for hierarchical structure building in Language
In this talk, I will explain the hierarchical structure of language, which is considered to be one of the most important properties of language, and the brain mechanism of its processing. First, I will consider language as a sequence of symbols, discuss the properties of symbols in general, and give definitions of syntax, semantics, and pragmatics in symbol systems. Next, I will explain hierarchical structures in language, using specific examples of sentences in English and Japanese. The Chomsky hierarchy, which is a theory for formulating hierarchy, will be discussed in detail. Based on fMRI experiments using the Chomsky hierarchy, it will be concluded that the Broca's area is the mechanism for constructing the hierarchical structure of sentences in the human brain. The hierarchical structure of symbolic sequences is also found in other cognitive domains besides language, as I will introduce research on the construction of hierarchical structures in arithmetic computation and drawing. Homo sapiens left wall paintings from 40,000 years ago, but there is no evidence that the Neanderthals, who lived at the same time, were able to draw. Given that drawing involves the cognitive ability to build hierarchical structures, we infer that the Neanderthals did not have the ability to produce hierarchically structured symbols in general, therefore lacked language. Finally, I will argue that language, music, art, dance, etc., which are found in any ethnic group on the earth, are all hierarchical symbol sequence producing behaviors, and that the core brain mechanism is the Broca's area.