Drifts of the remembered location of visual, auditory and bimodal targets.
Poster Presentation

Philip Jaekl
Psychology, York University

Laurence Harris
Psychology, York University

     Abstract ID Number: 188
     Full text: Not available
     Last modified: March 19, 2006
     Presentation date: 06/19/2006 10:00 AM in Hamilton Building, Foyer
     (View Schedule)

Abstract
Auditory and visual stimuli are subject to systematic drift in spatial memory. We determined if drift occurs for bimodal auditory-visual stimuli and if change in the remembered locations across time could be estimated from the combination of unimodal auditory and visual data. We recorded the remembered location of 15° and 30° auditory, visual and bimodal targets after delays of 0, 4, 8 and 12s using a staircase technique. There was drift over time towards a centrally located fixation point for 30° targets and drift away from the fixation point for 15° targets, regardless of modality. Multiple regression analysis revealed the remembered location of a bimodal target could be reliably estimated from unimodal data. Visual estimates accounted for more variability in the 15° bimodal estimates while unimodal auditory data accounted for more variablity in the the 30° bimodal estimates. For both target eccentricities the variance averaged across delay periods was lower for vision compared to audition and lowest for bimodal estimates. suggesting sensory integration was governed by a statistically optimal process. These data confirm systematic drift of sensory stimuli in memory and indicate that in more peripheral regions auditory estimates of remembered target location account for more variance compared to vision.