AbstractWhen presented with two different target-penalty configurations of similar Maximum Expected Gain (MEG), participants prefer aiming to configurations with more advantageous spatial parameters rather than more advantageous gain parameters (Neyedli & Welsh, 2015) â€“ perhaps due to the motor system's inherent prioritization of spatial information during reaching movements. To test this hypothesis, participants chose between target-penalty configurations via keypress responses to reduce feedback and the importance of spatial parameters. Configurations varied in both spatial (target-penalty region overlap) and gain parameters (negative penalty values) and could be of similar or different MEG. Choices were made without prior aiming experience (Experiment 1), after aiming experience provided information of movement variability (Experiment 2), or after aiming experience provided information of movement variability and outcome feedback (Experiment 3). At the group level, configurations with the advantageous spatial or gain parameters were chosen equally (Similar condition) in all experiments. Interestingly, the larger MEG configuration was not chosen at a level above chance (Different condition) when no prior aiming experience or when variability information was given, but was chosen more often when both variability and outcome information were given prior to the keypress task. Further, participant-by-participant analyses revealed 3 subgroups: those with a value preference, a distance preference, or no preference. These individual differences cannot be explained by MEG differences between prospects or participant's movement variability. Overall, the data indicate that prioritization of spatial information did not emerge when performing keypress responses and optimal behaviour emerged only when information regarding movement variability and outcome feedback were given.
Acknowledgments: Natural Sciences and Engineering Research Council of Canada