Abstract
The relationship between Temporal Order Judgment (TOJ) and Response Time (RT) has been an object of debate since Exner and even more so in the context of the ongoing dispute on the sensorimotor dissociation1,2. If anything, the most pervasive fact in the TOJ-RT literature is that the two sorts of behavior display a non-systematic relationship whether across studies, experimental conditions within the same study and even across subjects within the same study and for the same experimental conditions.
The present work presents a first time trial by trial analysis of paired RT-TOJ performances appraising the relationship between motor and sensory decisions. Observers produced speeded key presses (simple RTs) to pairs of equal and different contrast increments, orientation changes, and a combination of the two applied with a variable SOA to two spatially distinct Gabor pedestals; for the same trial, they also made a TOJ. RTs simulated as a function of SOA with a simple model assuming that they reflect the same internal response temporal distributions as those inferred from the measured TOJ psychometric functions3 fit the measured RTs for both “correct” and “incorrect” TOJ judgments. These findings bias the current sensorimotor dissociation debate in favor of a common source of information subtending motor and perceptual decisions and suggest that inconsistencies in the literature result from uncontrolled stimulus parameters and/or response strategies.
1. Gegenfurtner etal,. (2003). J. Vision. 3, 865-876.
2. Osborne etal., (2005). Nature. 437, 412-416.
3. Adams Mamassian. (2004). Proc. R. Soc. Lond. B. 271, 139-146.