Aging, Cognitive Abilities, and Word Frequency as Factors Affecting the Speed of Lexical Access

The present study evaluated the impact of age and several individual difference measures on lexical access. Additionally, eight different levels of frequency were evaluated for the stimulus words. These frequency levels were derived from the frequency of usage of these words in common reading materials. The response measured was latency of reading words out loud as they appeared on a screen. The results indicated no difference between older and younger adults on measures of anxiety, depression, or overall health. The older adults scored higher on a measure of vocabulary skills, while the younger adults scored higher on tasks involving abstract reasoning and perceptual motor problem solving. The main finding was that younger adults were significantly faster in their latency of response to words at all levels of frequency. Both the younger and older adult groups demonstrated a pattern of quicker responding to high-frequency words and a gradual increase in response time as the level of frequency was lower. The age x frequency interaction was significant statistically but not meaningful to interpretation. The data suggest a similar response pattern for both age groups according to word frequency variable, although the younger subjects consistently responded with shorter response latencies. However, further analysis of the data suggests that a significant slowing with age or naming time independent of age slowing in peripheral responses. The present results would be consistent with a theory of overall slowing of cognitive operations in older adults