Aging and Predicting Inferences: A Diffusion Model Analysis

In the domain of discourse processing, it has been claimed that older adults (60-90-year-olds) are less likely to encode and remember some kinds of information from texts than young adults. The experiment described here shows that they do make a particular kind of inference to the same extent that college-age adults do. The inferences examined were "predictive" inferences such as the inference that something bad would happen to the actress for the sentence "The director and cameraman were ready to shoot close-ups when suddenly the actress fell from the 14th story" (McKoon & Ratcliff, 1986). Participants read sentences like the actress one and then later they were asked to decide whether words that expressed an inference (e.g., "dead") had or had not appeared explicitly in a sentence. To directly compare older adults' performance to college-age adults' performance, we used a sequential sampling diffusion model (Ratcliff, 1978) to map response times and accuracy onto a single dimension of the strength with which an inference was encoded. On this dimension, there were no significant differences between the older and younger adults.