Abstract
In the causal inference model of multi-sensory cue integration (Körding et al., 2007) the integration of sensory signals from multiple modalities is determined by the discrepancy between sensory signals. Crossmodal integration is the strongest when signal discrepancies are small. When signal discrepancies are large, the perceptual system assumes that the signals are caused by different sources. Consequently, the influence of one modality on another is flexibly adjusted in a manner contingent on the degree of crossmodal signal discrepancy. Little, however, is known about how aging affects this adaptive crossmodal integration. Methods: 10 older adults (age>60) and 10 young adults participated in a motion direction judgment task. In the vision condition, subjects reported the motion direction of random dot motion. In the haptic condition, subjects reported the motion direction of visually occluded right hand motion that was controlled by a robot arm. In the multimodal condition, haptic motion and visual motion were presented synchronously. In 40% of multimodal trials, both hand and dot direction were identical, whereas in the remaining trials their motion differed by 7, 15, 30, or 50 deg. Participants were always asked to report the direction of visual motion. Results: For young adults the weight of hand motion on their visual estimates significantly decreased from 0.45 to 0.16 (F(3,27)=10.28, p=.0001) as the discrepancy between visual motion and hand motion direction increased from 7 deg to 50 deg. This result is consistent with the prediction of the causal inference model. For older adults,, there was no significant change in the weight of hand motion (F(3,27)=0.93, p=.43). The interaction between group and discrepancy was significant (F(3,54)=3.54, p=.021). Conclusion: These results show that older adults do not adaptively adjust their cue combination strategy in a manner that depends on the discrepanc
Meeting abstract presented at VSS 2016