  Use-dependent bias is a phenomenon in human sensorimotor behavior whereby
movements become biased towards previously repeated actions. Despite being
well-documented, the reason why this phenomenon occurs is not yet clearly
understood. Here, we propose that use-dependent biases can be understood as a
rational strategy for movement under limitations on the capacity to process
sensory information to guide motor output. We adopt an information-theoretic
approach to characterize sensorimotor information processing and determine how
behavior should be optimized given limitations to this capacity. We show that
this theory naturally predicts the existence of use-dependent biases. Our
framework also generates two further predictions. The first prediction relates
to handedness. The dominant hand is associated with enhanced dexterity and
reduced movement variability compared to the non-dominant hand, which we
propose relates to a greater capacity for information processing in regions
that control movement of the dominant hand. Consequently, the dominant hand
should exhibit smaller use-dependent biases compared to the non-dominant hand.
The second prediction relates to how use-dependent biases are affected by
movement speed. When moving faster, it is more challenging to correct for
initial movement errors online during the movement. This should exacerbate
costs associated with initial directional error and, according to our theory,
reduce the extent of use-dependent biases compared to slower movements, and
vice versa. We show that these two empirical predictions, the handedness effect
and the speed-dependent effect, are confirmed by experimental data.
