Mechanisms of semantic ambiguity resolution: Insights from speech perception

The speech signal is inherently ambiguous and all computational and behavioral research on speech perception has implicitly or explicitly investigated the mechanism of resolution of this ambiguity. It is clear that context and prior probability (i.e., frequency) play central roles in resolving ambiguities between possible speech sounds and spoken words (speech perception) as well as between meanings and senses of a word (semantic ambiguity resolution). However, the mechanisms of these effects are still under debate. Recent advances in understanding context and frequency effects in speech perception suggest promising approaches to investigating semantic ambiguity resolution. This review begins by motivating the use of insights from speech perception to understand the mechanisms of semantic ambiguity resolution. Key to this motivation is the description of the structural similarity between the two domains with a focus on two parallel sets of findings: context strength effects, and an attractor dynamics account for the contrasting patterns of inhibition and facilitation due to ambiguity. The main part of the review then discusses three recent, influential sets of findings in speech perception, which suggest that (1) top-down contextual and bottom-up perceptual information interact to mutually constrain processing of ambiguities, (2) word frequency influences on-line access, rather than response biases or resting levels, and (3) interactive integration of top-down and bottom-up information is optimal given the noisy, yet highly constrained nature of realworld communication, despite the possible consequence of illusory perceptions. These findings and the empirical methods behind them provide auspicious future directions for the study of semantic ambiguity resolution.