Motor imagery in typing: effects of typing style and action familiarity.

The influences of typing style and action familiarity on executed and imagined typing were investigated. A group of touch typists and a group of hunt-and-peck typists were asked to imagine and execute typing texts of different lengths in two different styles: with ten fingers (familiar for touch typists, unfamiliar for hunt-and-peck typists) and with two fingers (unfamiliar for touch typists, familiar for hunt-and-peck typists). The imagination (but not the execution) of familiar and unfamiliar typing was correlated in both groups, indicating that participants used skill knowledge from the familiar action to imagine the unfamiliar action. Only when touch typists imagined familiar typing accurate motor imagery was observed (similar durations of and positive correlations between imagination and execution). When touch typists imagined unfamiliar typing, the average imagination durations resembled the execution durations, but correlations indicated individual differences in the processes of imagination and execution. Hunt-and-peck typists showed shorter imagination than execution durations with both familiar and unfamiliar typing, indicating that in both styles they did not imagine all details of typing. Also, they did not imagine some details specifically related to unfamiliar typing (reflected in particularly high percentages of absolute error). However, correlations indicated that individual difficulties in executing the unfamiliar action were reflected in the imagination durations. In conclusion, skill knowledge from familiar actions is used to imagine unfamiliar actions. Familiarity with actions promotes accurate motor imagery, but only if stable internal action representations have been acquired, and not if action control relies on online, step-by-step control. However, stable internal action representations of familiar actions may be detrimental for imagery of unfamiliar actions.