Steering around bends is a common task performed daily by millions of people, yet the underlying neural mechanisms remain largely uncharted. It has been proposed that steering can be performed without recourse to conscious a??cognitivea?? control (Gibson, 1958), however, much simpler locomotor-related tasks, such as judging one's heading, have been shown to be affected by concurrent attentional tasks (Wann et al, 2000). Here we examine whether an attentional task placed at the point of fixation influences steering. Twelve participants were asked to steer around bending roadways (3 m wide, radius = 60 m to 35 m) at a constant speed (13.8 m/s). Participants fixated a sign positioned at 1 of 4 different eccentricities relative to screen and body midline (?±30 deg, ?±20 deg). The sign either showed a cross (no attentional load), or numbers/arrows (attentional load). The attentional loads were similar to Wann et al. (2000): i) the a??Numbera?? condition presented a sequence of two numbers, after the trial participants judged whether they were ascending or descending; ii) the a??Arrowa?? condition presented a sequence of two arrows that pointed in different directions, after the trial participants judged whether the second arrow was oriented clockwise or anticlockwise compared to the first. In all conditions participants' steering drifted in the direction of the fixation points (consistent with Robertshaw & Wilkie, 2008), but no significant effect was found in steering bias for the three different attentional load conditions. However, in the a??Numbera?? and a??Arrowa?? conditions steering was significantly less variable than the no-load condition. We suggest that this reduced variability reflects visuomotor a??lockinga?? due to reduced responsiveness to visual-feedback. As such we conclude that steering can be influenced by cognitive processing, with one potential cost being reduced flexibility in steering when there is a concurrent attentional load.
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