Abstract：Abstract: Scalar reasoning is a basic human cognitive ability. Fillmore et al. (1988), in their study of the Negative Polarity Item, let alone construction, proposed a scalar reasoning model which has become the basis for the following studies on the scalar reasoning. However, their study was still lack of conceptual and cognitive analyses. Based on the definition of the polarity nature of the let alone construction, the present study further explores its scalar reasoning mechanism and constructs a scalar reasoning model which is closer to its cognitive nature. It is found that the negated proposition is processed first in the conceptual processing of this construction. When the negative operator is integrated, the inverted and canonical scales are sequentially activated. The scalar reasoning occurring on both scales is related to event roles of both propositions involved in the let alone construction. Each role’s contribution to the truth of the proposition is determined by a fundamental human rational behavior principle: the comparison and judgment of costs and rewards. The study provides further proof for the basic position of cognitive linguistics: the exploration of the cognitive nature of languages cannot be done without considering the experiential foundation of human beings.
Key words: Negative Polarity Items; let alone construction; scalar reasoning
