Abstract
Prolonged exposure to fixed temporal lag between observer’s keypress and visual feedback recalibrates motor-visual temporal relationship, and consequently shifts the point of subjective simultaneity (PSS) in subsequent temporal order judgments between keypress and visual flash (Stetson et al., 2006, Neuron, 51, 651-659). We conducted two experiments in order to examine how manipulation of observer’s attention during adaptation affected the adaptive shift. Experimental sessions were composed of adaptation and test phases. In the adaptation phase, observers constantly pressed a key. Each keypress was accompanied by presenting a white square (1.5 x 1.5 arc deg) for 12 ms as a visual feedback. We injected 0ms or 200ms fixed temporal lag between the keypress and visual feedback. During the adaptation phase, we presented target stimuli with random timing for attentional task in which observers counted the frequency of their presentations. In the test phase, observers conducted temporal order judgment between the keypress and presentation of a square. In Experiment 1, we presented either of a extended fixation cross (from 1.0 x 1.0 arc deg to 3.5 x 3.5 arc deg) or auditory beep (160Hz) as a target for the attentional task. If observers attended to the visual targets during the adaptation phase, the PSS shifted significantly although, if they attended to the auditory targets, we found no significant shift. In Experiment 2, we presented visual targets for the attentional task in the same or opposite visual field in which the visual feedbacks were presented. In this experiment, the PSS shifted significantly regardless of the visual field to which observer attended during the adaptation phase. These results suggest that the motor-sensory temporal recalibration requires attention to the perceptual modality which is engaged in the adaptation.
Meeting abstract presented at VSS 2013