Naming and perception tasks show robust effects of age of acquisition (AoA), with faster processing of stimuli learnt earlier in life compared to stimuli acquired later. That AoA effects prove to be more elusive on semantic processing tasks is of importance in attempting to determine the mechanism and locus (or loci) of AoA effects. Three accounts of AoA effects were tested empirically using perceptual familiarity decision tasks to record response latency and accuracy to the faces and names of famous people, with the quantity of semantic knowledge being manipulated. The results do not support the semantic ‘hub’ network or arbitrary mapping explanations of AoA but are consistent with the Set-up of a Specialized Processing System hypothesis
