Examination of stimulus persistence as the basis for superior visual identification performance among older adults

Visual identification performance of sequentially presented corresponding word-halves was studied in 12 young (mean 18.9 years, range 18-21) and 12 old (mean 68.0 years, range 59-78) male and female subjects. Corresponding word-halves were composed of straight horizontal and vertical line segments and when superimposed tachistoscopically formed clear, fully closed 3-letter words. Stimulus duration and interstimulus interval (ISI) were systematically varied. Correct word recognition was found to be an inverse function of ISI and stimulus duration for both young and old subjects. An interaction was found between age, sex, and stimulus duration. Recognition scores were significantly higher among older subjects, an effect which was particularly prominent at greater ISIs. The data offer strong support for the stimulus-persistence model as applied to age differences in the sequential integration of form.