The influence of cloze probability and item constraint on cloze task response time

In research on the role of lexical predictability in language comprehension, predictability is generally defined as the probability that a word is provided as a sentence continuation in the cloze task (Taylor, 1953), in which subjects are asked to guess the next word of a sentence. The present experiments investigate the process by which subjects generate a cloze response, by measuring the latency to initiate a response in a version of the task in which subjects produce a spoken continuation to a visually presented sentence fragment. Higher probability responses were produced faster than lower probability responses. The latency to produce a response was also influenced by item constraint: A response at a given level of probability was issued faster when the context was more constraining, i.e., a single response was elicited with high probability. We show that these patterns are naturally produced by an activation-based race model in which potential responses independently race towards a response threshold. Implications for the interpretation of cloze probability as a measure of lexical predictability are discussed.