The present study represents an attempt to explain intellectual decline in old age in terms of experiential and environmental deficit notions. It was hypothesized that test-related response speed in the elderly (n = 32 females; mean age = 70) was modifiable through either practice or reinforced practice. The two-session training program not only increased response speed on the training materials, but also produced slight positive transfer to performance on 11 ability tests. It was suggested thata major proportion of intellectual decline in old age reflects performance rather than competence deficits, and that further research investigating the range of modifiableness of performance indices is necessary for specifying the determinants of intellectual ontogeny during old age.