MRC Cognitive Development Unit,
4 Taviton Street,
London, WC1H 0BT
Abstract Timing effects in categorisation were investigated in 4 experiments with infants and adults. Experiments 1 and 2 utilised the familiarisation /novelty preference procedure with 4-month old infants and showed that when processing time is limited, infants attend more to highly salient perceptual similarity relations when categorically distinguishing between animal species. With longer looking time, however, categorisation is determined by the more abstract properties of the stimuli. Experiments 3 and 4 showed that the processes that adults use in rapid categorisation tasks correspond to those of infants. That is, in rapid categorisation adults also also rely more on those properties which are the most perceptually salient, whereas abstract properties are only processed when categorisation is slower.