Task-Specific, Age Related Effects in the Cross-Modal Identification and Localisation of Objects.

We investigated age-related effects in cross-modal interactions using tasks assessing spatial perception and object perception. Specifically, an audio-visual object identification task and an audio-visual object localisation task were used to assess putatively distinct perceptual functions in four age groups: children (8-11 years), adolescents (12-14 years), young and older adults. Participants were required to either identify or locate target objects. Targets were specified as unisensory (visual/auditory) or multisensory (audio-visual congruent/audio-visual incongruent) stimuli. We found age-related effects in performance across both tasks. Both children and older adults were less accurate at locating objects than adolescents or young adults. Children were also less accurate at identifying objects relative to young adults, but the performance between young adults, adolescents and older adults did not differ. A greater cost in accuracy for audio-visual incongruent relative to audio-visual congruent targets was found for older adults, children and adolescents relative to young adults. However, we failed to find a benefit in performance for any age group in either the identification or localisation task for audio-visual congruent targets relative to visual-only targets. Our findings suggest that visual information dominated when identifying or localising audio-visual stimuli. Furthermore, on the basis of our results, object identification and object localisation abilities seem to mature late in development and that spatial abilities may be more prone to decline as we age relative to object identification abilities. In addition, the results suggest that multisensory facilitation may require more sensitive measures to reveal differences in cross-modal interactions across higher-level perceptual tasks.