Abstract
Many everyday tasks involve moving one’s fingers to a target. Previous research has shown that such movements can rely on both egocentric (object-to-self) and allocentric (object-to-object) visual information. However, the use of allocentric information to guide ongoing movements towards continuously visible targets is yet to be demonstrated. We previously found no evidence for the use of allocentric information in a task where participants intercepted a visible target using a cursor that represented their finger position, even though the finger was moving in a different plane than the cursor. On each trial there was either an independent perturbation of the target, cursor or background, or the simultaneous perturbation of all three task components. In the latter condition the relative positions of the task components remained constant such that relying on allocentric information would be advantageous in avoiding unnecessary adjustments to the ongoing movement. Participants responded to the simultaneous perturbation in accordance with how we would expect them to respond if they dealt with each individual perturbation egocentrically. In the present study, we modified the task such that participants’ finger position determined the velocity rather than the position of the cursor. Doing so further dissociates finger movements from cursor movements. For example, when the finger stops moving, the cursor does not stop moving but continues to move at the prevailing velocity. Participants still responded to the simultaneous perturbation of target, cursor and background. Again they did so in accordance with how they responded to each perturbation individually. This supports the idea that allocentric spatial information is not used to control ongoing actions when the target is visible.