Nobuhiro Hagura, Center for Information and Neural Networks (CiNet), National Institute of Information and Communications Technology
March 13 2017, 11h Salle de réunion du LPP, H432, 4ème étage, Centre Biomédical des Saints Pères 45 rue des Sts Pères, 75006 Paris
Action modulating perceptual decisions
Perceptual decisions are classically thought to depend solely on characteristics of the sensory signal. In this view, the motor response is considered to be a neutral output channel that only reflects the upstream decision. Contrary to the view, I will present two examples, which show that the processing involved in action generation can modulate our perceptual decisions. First, I will show that the duration of a visual stimulus presented during reaching preparation is felt dilated, due to the increased capacity of visual processing during this period. Second, I will show that the visual motion direction judgement can be biased by the asymmetric physical resistance applied to the two judgment options (i.e. left or right reaching movement). The asymmetric resistance on hand during the motion judgments can similarly bias the subsequent motion judgments performed vocally, suggesting that the bias is not occurring at the stage of action selection, but at the stage of judgement based on the input stimulus.
These results indicate the existence of mutual interaction between the perceptual and action system in the human brain. Actions are selected using the information from the environment, but at the same time, how we act may define how we interpret the environment.