How decisions evolve: the temporal dynamics of action selection

To study the process of decision-making under conflict, researchers typically analyze response latency and accuracy. However, these tools provide little evidence regarding how the resolution of conflict unfolds over time. Here, we analyzed the trajectories of mouse movements while participants performed a continuous version of a spatial conflict task (the Simon task). We applied a novel combination of multiple regression analysis and distribution analysis to determine how conflict on the present trial and carry-over from the previous trial affect responding. Response on the previous trial and the degree of conflict on the previous and the current trial all influenced performance, but they did so differently: The previous response influenced the early part of the mouse trajectory, but the degree of previous and current conflict influenced later parts. This suggests that in this task experiencing conflict may not proactively ready the system to handle conflict on the next trial; rather, when conflict is experienced on the subsequent trial the previous compensatory processing may be re-activated more efficiently.