Most studies of perceptual decision making use reaction times and accuracy as dependent measures. In this study, we instead decomposed arm movements made by subjects towards targets while the decision making process was ongoing, and used these to track the evolving decision making process. In this task, subjects were required to classify faces as male or female, with varying noise levels. They indicated their response by reaching out and pointing to a target on a touchscreen in front of them. The arm movements during the response were recorded with a motion capture system. We tested four groups of subjects with different instructions / demands. The first group was required to begin moving within 350 ms of stimulus onset. The second group had a long movement onset deadline (1 s), and instructions only to be as fast and accurate as possible. The third group had no liftoff deadline but rather a deadline for touching the screen (1.1 s), while the fourth group had no time constraints but accuracy was emphasised. We observed systematic changes in the initial direction of movement, the speed of the decision process and the accuracy as a result of the different time / accuracy requirements.
|Number of pages||1|
|Journal||Clinical EEG and neuroscience|
|Publication status||Published - 2012|
|Event||Australasian Cognitive Neurosciences Conference (21st : 2011) - Sydney|
Duration: 9 Dec 2011 → 12 Dec 2011