Psychology

Testing Whether Humans Have an Accurate Model of Their Own Motor Uncertainty in a Speeded Reaching Task

Published on 2013-05-23 in PLoS Computational Biology, vol 9. DOI: 10.1371/journal.pcbi.1003080
In many motor tasks, optimal performance presupposes that human movement planning is based on an accurate internal model of the subject's own motor error. We developed a motor choice task that allowed us to test whether the internal model implicit in a subject's choices differed from the actual in isotropy (elongation) and variance. Subjects were first trained to hit a circular target on a touch screen within a time limit. After training, subjects were repeatedly shown pairs of targets… Read more

Using Pattern Classification to Measure Adaptation to the Orientation of High Order Aberrations

Published on 2013-08-14 in PLoS ONE, vol 8. DOI: 10.1371/journal.pone.0070856
BackgroundThe image formed by the eye's optics is blurred by the ocular aberrations, specific to each eye. Recent studies demonstrated that the eye is adapted to the level of blur produced by the high order aberrations (HOA). We examined whether visual coding is also adapted to the orientation of the natural HOA of the eye.Methods and FindingsJudgments of perceived blur were measured in 5 subjects in a psychophysical procedure inspired by the “Classification Images” technique. Subjects… Read more

Time-Integrated Position Error Accounts for Sensorimotor Behavior in Time-Constrained Tasks

Published on 2012-03-21 in PLoS ONE, vol 7. DOI: 10.1371/journal.pone.0033724
Several studies have shown that human motor behavior can be successfully described using optimal control theory, which describes behavior by optimizing the trade-off between the subject's effort and performance. This approach predicts that subjects reach the goal exactly at the final time. However, another strategy might be that subjects try to reach the target position well before the final time to avoid the risk of missing the target. To test this, we have investigated whether… Read more