Perceptual delay and the Fehrer-Raab effect in metacontrast J Sackur1, D R Zarebski2, M Dutat3 |
|---|
1LSCP, École Normale Supérieure, France |
| Metacontrast is a phenomenon whereby perception of a brief visual stimulus (the target) is modulated by a second brief stimulus (the mask) that surrounds and abuts it without overlap. A mask impacts perception of the target along many dimensions. Of interest to the present study is the apparent displacement in time (“perceptual delay”---Didner & Sperling, 1980) to the effect that the target is phenomenally postponed when it is masked. As opposed to this, metacontrast is also known for the Fehrer-Raab effect, such that motor responses to the target are not significantly modified by the presence of the mask. The opposition of the Fehrer-Raab effect and of the perceptual delay seems to imply two distinct routes: a motor route, time-locked to the external stimulation, and a phenomenal route that depends on a posteriori reconstruction, and integrates later events. Here, we study the interaction between these two routes, by pitting perceptual delay and the Fehrer-Raab effect one against the other within the same experimental paradigm. We show that subjective temporal estimations are improved both in terms of accuracy and precision when they are followed by a motor response to the target. |
| Up Home |
|---|