Subconscious Visual Cues during Movement Execution Allow Correct Online Choice Reactions

Part of the sensory information is processed by our central nervous system without conscious perception. Subconscious
processing has been shown to be capable of triggering motor reactions. In the present study, we asked the question
whether visual information, which is not consciously perceived, could influence decision-making in a choice reaction task.
Ten healthy subjects (2865 years) executed two different experimental protocols. In the Motor reaction protocol, a visual
target cue was shown on a computer screen. Depending on the displayed cue, subjects had to either complete a reaching
movement (go-condition) or had to abort the movement (stop-condition). The cue was presented with different display
durations (20–160 ms). In the second Verbalization protocol, subjects verbalized what they experienced on the screen.
Again, the cue was presented with different display durations. This second protocol tested for conscious perception of the
visual cue. The results of this study show that subjects achieved significantly more correct responses in the Motor reaction
protocol than in the Verbalization protocol. This difference was only observed at the very short display durations of the visual
cue. Since correct responses in the Verbalization protocol required conscious perception of the visual information, our
findings imply that the subjects performed correct motor responses to visual cues, which they were not conscious about. It
is therefore concluded that humans may reach decisions based on subconscious visual information in a choice reaction task.