Examining independence of facial identity and age processing using the Garner Speeded Classification Paradigm

The question of whether age and facial identity are processed through a shared or parallel route has scarcely been examined, despite being of theoretical relevance for face processing models. For the first time, the Garner speeded classification paradigm was applied to assess the independence of age and facial identity processing. Across three experiments, participants made either age or facial identity judgements while both dimensions varied (Filtering) or only one dimension varied while the other remained constant (Baseline). Garner interferences, represented by slower response times for the Filtering condition compared to the Baseline condition, were recorded for both Experiments 1 (familiar, cropped, single-image stimuli) and 2 (unfamiliar, cropped, single-image stimuli). A weaker Garner interference was recorded for Experiment 3 (familiar, naturalistic, multi-image stimuli). Garner interference for the first two experiments is indicative of the shared route hypothesis for identity and age perception. However, findings from Experiment 3 suggest that these effects are weaker for naturalistic images, and the implications of this are discussed.