Deciding to look: revisiting the linking hypothesis for spoken word recognition in the visual world

The visual world paradigm (VWP) studies of spoken word recognition rely on a linking hypothesis that connects lexical activation to the probability of looking at the referent of a word. The standard hypothesis is that fixation probabilities track activation levels transformed via the Luce Choice Rule. Under this assumption, given enough power, any difference between positive activations should be detectable using VWP. We argue that looking at a referent of a word is a decision, made when the word’s activation exceeds a context-specific threshold. Subthreshold activations do not drive saccades, and differences among such activations are undetectable in VWP. Evidence is provided by VWP experiments on Japanese. Bayesian analyses indicate a relatively high threshold: saccades to cohort competitors do not exceed those to unrelated distractors unless the cohort competitor shares the initial CVC with the target. We argue that threshold setting constitutes an understudied source of variability in VWP data.