Eye-movements support chronometric imagery performance even when the task is occluded

ABSTRACT

Mental chronometry has often been used to provide a temporal comparison between executed and imagined movements, with smaller discrepancies indicating more accurate image production and better imagery performance. In this study, we examined the importance of retinal and extra-retinal information in the performance of simple, sequential movements. After physical practice of four activities of daily living (Southampton Hand Assessment Procedure), nineteen participants imagined completing the same tasks with: 1) free eye-movements and visible objects, 2) free eye-movements and no visibility of the objects, and 3) constrained eye-movements and visible objects. Results suggested imagery performance was slower/less accurate compared to physical execution when the eyes were constrained. Conversely, chronometric imagery performance was unaffected with free eye movements, even when task-specific visual information was occluded. This study highlights the crucial role that eye-movements play in the regulation of the temporal aspects of imagery even when retinal information is absent, suggesting that temporal sequencing of imagined actions is largely dependent on extra-retinal information sources.