Local-global auditory processing:

Perception involves many processes, one of which is the organization of complex stimulus input. One approach to understanding perceptual organization is testing integration across differing levels of structure. With my colleague, Timothy Justus, we have carried a series of studies using two auditory stimulus sets designed to mimic visual local-global (Navon, hierarchical) stimuli. These stimuli vary either over the dimension of frequency or time. We have shown that certain visual effects in local-global processing can be reproduced in auditory processing ( e.g., level-priming). More recently, we have tested the lateralization of such processes using monaural stimulus presentation and ERPs. Currently, I am further testing the laterality hypothesis (a local left hemisphere bias and a complimentary global right hemisphere bias) using patient-based and TMS approaches. This line of investigation will hopefully reveal whether the visual and auditory systems similarly organize complex information, whether the critical neural loci for these processes are overlapping and whether, if any analogy is to hold between modalities, visual-spatial frequency processing is similar to auditory frequency and/or temporal processing.