Abstract
Humans perform task-dependent eye movements when engaged in well-learned actions. Especially in sequential sensorimotor tasks, systematic scan paths can be observed with fixations guiding the hands to upcoming target locations. A recent study of our lab [Foerster et al., 2012] provided first evidence that this eye-hand guidance can even be observed when no visual information is available. This result argues for a long-term memory (LTM) contribution to the control of covert attention and eye movements in naturalistic tasks. To test this idea with a higher degree of experimental control, we investigated eye movements while participants performed a computerized version of the number connection test. In this sequential sensorimotor task, participants have to click as fast as possible on numbered circles in ascending order (1 – 9). During an acquisition phase, participants performed the task for 50 trials with the same spatial arrangement of 9 circles. With practice, participants became faster and performed fewer fixations. Eye-hand time spans were mainly positive throughout the experiment. In the consecutive retrieval phase, a blank screen appeared and participants were asked to click on an empty screen in the same order as during acquisition phase. Participants were able to perform this complex sequential sub-task and looked often in the right order at upcoming circle locations before clicking on them. We conclude that practice of a sequential sensorimotor task such as the number connection test does not only imply LTM-based control of sequential hand movements but is also accompanied by learning of systematic sequences of attention shifts and eye movements. These sequential selection patterns can also be reproduced from LTM when visual information is no longer available.
Meeting abstract presented at VSS 2013