The effects of age of acquisition on an object classification task

The age at which an item is acquired (age of acquisition; AoA) affects naming latencies for words, objects, and faces. Ellis and Lambon Ralph (2000) proposed an account of AoA that predicts its effect in any task requiring access to stored information. AoA effects have been found in non-naming tasks for faces (e. g., Lewis, 1999) and words (e. g., Brysbaert, van Wijnendaele, & de Deyne, 2000) but not for pictures (e. g., Morrison, Ellis,& Quinlan, 1992). The current study explored the effect of AoA on a manmade/natural picture classification task, but extended previous work by implementing a matched groups design. Early acquired objects were classified significantly more quickly than later acquired objects. Experiment 2 collected naming latencies for the same picture stimuli to allow a comparison of the magnitude of the AoA effect for semantic classification and naming. The AoA effect was significantly greater for the naming task. The implications of these findings in relation to accounts of AoA and its locus of effect are discussed.