Abstract
To investigate the neural preparation and awareness of an intention to act, neuroscientists typically examine spontaneous movements: self-paced flexions of the hand or foot. However, these movements may not present a straightforward case of intended action as they are performed in absence of reasons to act and without the evaluation of action consequences. Therefore, a common criticism of these studies is that they lack ecological validity, because the results do not generalize to the more societally relevant deliberate actions that we perform in daily life. We agree that research on intended action should include reason-based deliberate actions in order to be more relevant for debates about human agency and free will. Therefore, we have developed a computer game called "Free Wally", which invites players to perform deliberate actions to achieve a goal. Free Wally provides a controlled environment for studying deliberate intended action, by presenting information for deciding whether or not to act, what action to perform and when to perform it, incorporating all basic components of an ecologically valid intended act. As a first step to validate our setup, we compare this game to a second computer game that measures spontaneous actions in a traditional way. While playing either game, the timing of the experienced intentions to act is measured using a real-time probing method. Moreover, the neural preparation for action is measured in terms of the (lateralized) readiness potential and alpha/beta event-related desynchronization across the motor cortex. No differences were found between the games in these last stages of action preparation, suggesting that the Free Wally game can be used to study intended action. However, differences in earlier stages during intention formation are to be expected. With Free Wally as a tool, we hope to encourage further research into the formation and content of ecologically valid motor intentions.
