Symbolic, non-directional predictive cues affect action execution.

Predictive cues may help us to plan an action in anticipation of what will come next. Some cues such as arrows contain directional information to orient the actor. Other cues, however, may contain no spatial information that directly orients the actor to the upcoming action. Non-directional predictive cues have been shown to increase performance in visual search tasks but have not been explored in the planning and execution of actions. The first aim of this study is to determine whether participants can implicitly learn to associate symbolic cues with an upcoming action target location. The second aim is whether this association leads to transient or sustained activation of the action associated with the predicted target location. High and low predictive cues preceded target appearance at long cue-target-onset asynchronies (1,100-2,000 ms). The trajectories of participants' reaching movements were analyzed depending on whether they aimed at the predicted or the non-predicted side within each of the cue type conditions. For the highly predictive cue, participants' trajectories veered further toward the opposite target location when participants aimed for the predicted target location compared to when they aimed for the non-predicted target location. These results indicate that participants can associate an upcoming action with non-directional predictive cues but the predicted response was inhibited in the long intervening time between the cue and target. This finding is similar to the response to peripheral-onset cues in inhibition of return type paradigms.