Aivar MP, Brenner E, Smeets JBJ. Hitting a target is fundamentally different from avoiding obstacles.
Vision Res 2014;
110:166-78. [PMID:
25454701 DOI:
10.1016/j.visres.2014.10.009]
[Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 09/18/2014] [Accepted: 10/12/2014] [Indexed: 10/24/2022]
Abstract
To successfully move our hand to a target, it is important not only to consider the target of our movements but also to consider other objects in the environment that may act as obstacles. We previously found that the time needed to respond to a change in position was considerably longer for a displacement of an obstacle than for a displacement of the target (Aivar, Brenner, & Smeets, 2008. Experimental Brain Research 190, 251-264). In that study, the movement constraints imposed by the obstacles differed from those imposed by the target. To examine whether the latency is really different for targets and obstacles, irrespective of any constraints they impose, we modified the design of the previous experiment to make sure that the constraints were matched. In each trial, two aligned 'objects' of the same size were presented at different distances to the left of the initial position of the hand. Each of these objects could either be a target or a gap (opening between two obstacles). Participants were instructed to pass through both objects. All possible combinations of these two objects were tested: gap-target, target-gap, gap-gap, target-target. On some trials one of the objects changed position after movement onset. Participants systematically responded faster to the displacement of a target than to the displacement of a gap at the same location. We conclude that targets are prioritized over obstacles in movement control.
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