Age and individual differences in letter fluency

Letter fluency tests are widely used to assess executive function, yet the cognitive processes underlying fluency performance are poorly understood. In this article, age differences in fluency were investigated in relation to "low-level speed" and "frontal-executive" theories of aging and intelligence. Age differences in fluency related to motor speed; intelligence predicted the use of retrieval strategies in fluency tasks. In contrast to literature on patients with frontal lobe lesions, individuals with lower intelligence test scores could not efficiently utilize a cued fluency strategy. Both age and intelligence predicted strategy use in a more novel fluency task requiring the generation of figural responses. Comparison with neuropsychological literature suggests different causes for poor fluency in older adults, those with low intelligence test scores, and patients with frontal lobe lesions.