Abstract
When performing sequential manual actions on objects of the environment (e.g., making a cup of tea), visual information is prioritized according to the task determining where and when to attend, look, and act. In well-practiced sequential actions, long-term memory (LTM)-based expectations specify which action targets might be found where and when. We have previously demonstrated (Foerster & Schneider, 2015) that violations of such expectations that are task-relevant (e.g., target location change) cause a regression from a memory-based to a search-based attentional selection mode. In this study we asked how task-irrelevant expectation violations might modify attentional selection in such well-practiced sequential manual actions. This question was investigated by a computerized version of the number-connection test. Participants clicked on nine spatially-distributed numbered circles (action targets) in ascending sequence. Visual features and locations of action targets stayed constant for 65 prechange-trials, allowing to practice this simple sequential manual action. In 20 consecutive change-trials, we implemented an expectation violation in a task-irrelevant dimension, that is, action target number 4 appeared in a different font. In 15 reversion-trials, number 4 returned to the original font. During the first trial of a task-irrelevant change (font), manual clicking was slower and eye scanpaths were larger and contained more fixations. The additional fixations were mainly checking fixations on the changed target while acting on later targets. Whereas gaze was captured by the task-irrelevant change of the action target, cursor-paths remained completely unaffected. Effects lasted for 2-3 change trials and did not reappear during reversion. We conclude that a task-irrelevant expectation violation in a well-practiced sequential manual action leads to eye-hand decoupling and a "check-after-surprise" mode of attentional selection.
Meeting abstract presented at VSS 2016