Effect of imagery ability on letter-level and word-level processing.

In a letter-identification task, subjects matched a probe letter to the initial letter of a subsequently presented probe word. We varied word frequency and predicted that the performance of vivid imagers would resemble that of typical young adults, whereas the performance of poor imagers would fall in between that of typical young adults and of older adults, or would simply resemble the performance of typical older adults (a linear decrease in reaction time [RT] with word frequency; see Allen & Madden, 1989). The in-between function for young and older adults combined predicts a dip in RT for very-high-frequency words compared to medium-high-, low-, and very-low-frequency words. As predicted, vivid imagers exhibited increased latencies for medium-high-frequency words relative to the other three word-frequency categories, whereas poor imagers exhibited a dip.