Abstract This study provides a partial replication of Stankov's (1988a; Psychology and Aging, 3, 1–16) finding that attentional variables can account for at least some of the age-related changes in intelligence test performance. Particularly important are processes involved in Search (Perceptual/Clerical speed) tasks and tasks that require mental concentration. Another aim was to study the role of the speed of test-taking scores. Estimates of this variable are shown to give additional information to that of number-correct measures and to correlate highly amongst themselves providing support for a separate broad speediness (Gs) factor. The implication of this finding to models of cognitive ability is discussed.