This study set out to demonstrate that around six months of age the infant's ability visually to categorize stimuli in terms of their familiarity-unfamiliarity is not yet associated with manipulative approach-avoidance responses and that such responses come under visual control only some time in the course of the second half-year of life. A short-term familiarization period was administered to infants aged 5–7 months, 8–10 months and 11–13 months, followed by a simultaneous discrimination test involving the familiar and a novel stimulus. Results indicate that the ability visually to discriminate between the stimuli occurred at all three age levels, but that manipulative discrimination took place only in the two older groups. In addition, the effects on discrimination of some parameters defining the experimental procedure, namely the colour of the familiarized stimulus and the nature of the familiarization condition (visual-tactual or visual-only), were also investigated.