Learning as a function of coordination bias: building upon pre-practice behaviours.

Instructions and demonstrations were manipulated to make pre-practice behaviours explicit and inform participants how to build-upon these to perform a novel bi-manual movement. In Experiment 1, participants who could perform only in- and anti-phase movements were studied, whereas in Experiment 2, individuals who could perform additional movements were tested. Zanone and Kelso (Journal of Experimental Psychology: Human Perception and Performance 23 (1997) 1454) predicted differential learning progressions as a result of initial ability. Instruction promoting gradual adaptation of an existing skill would be more likely to benefit participants in Experiment 2. Irrespective of initial ability, participants did not benefit from instruction. Instructions that built-upon the in-phase pattern were particularly detrimental to acquisition, as compared to withholding instruction and providing only feedback. Instructional effects were related to decreased within-trial variability early in practice due to avoidance of certain movements and a complement bias to another undesirable one. It was suggested that trying to implement instructions, especially for the participants in Experiment 2, caused individuals to exert control over processes better controlled by lower, less cognitive levels of the motor system.