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Abstract

When performing a sensorimotor task, e.g. pointing to visual targets, we constantly make errors. Those errors can be random as a result of sensorimotor noise or they can be systematic indicating that the sensorimotor system is miscalibrated. It is generally assumed that in the absence of visual feedback we are unaware of the random pointing errors due to noise. Here we show the opposite.
Subjects performed a rapid pointing task to visual targets presented on a touch screen. They were encouraged to hit as accurately as possible by earning points when hitting close to the target. Pointing was conducted open-loop: visual feedback was prevented at the onset of the pointing movement. After the movement was completed subjects had to indicate whether they believed to have landed left or right of the target. Results show that subjects‘ left/right-discriminability was well above chance. It was still above chance when subjects were instructed to point slowly, enabling them to correct for any unintended movement error.
Together this indicates, that even though we cannot control the noise we are aware of the errors it results in. This finding has major implications for models of sensorimotor control in which noise is considered an unconscious error.