One can choose one’s own saccadic reaction times



Saccade latencies are conventionally viewed as reflecting the accumulation of information underlying decision-making processes. However, we have previously shown that latency distributions may be strongly affected by reinforcement contingencies (Madelain et al., 2007). Here we further probe whether one can control one’s own reaction times.

In a first series of experiments, participants had to choose between “short” and “long” saccadic latencies (80-300ms range) in a set of concurrent interval schedules. The relative proportions of latencies matched the relative proportions of reinforcers earned from each option (sensitivity up to 0.95), following the generalized matching law (Baum, 1974). 

In a second series of experiments, we assessed whether “short” and “long” latencies (80-500ms range) could be place under discriminative control in a visual search task. We used a latency-contingent display in which finding the target was made contingent upon specific saccadic latencies. In probe trials we found considerable differences in latency distributions depending on the discriminative stimuli (on average 72ms). 

Altogether, our results reveal that learned contingencies might considerably affect the allocation of saccades in time and provide strong evidence of the ability to choose when to saccade, extending saccade triggering well beyond conventional information accumulation hypothesis.

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