Attending to the possibilities of action
Humphreys GW., Kumar S., Yoon EY., Wulff M., Roberts KL., Jane Riddoch M.
Actions taking place in the environment are critical for our survival. We reviewevidence on attention to action, drawing on sets of converging evidence from neuropsychological patients through to studies of the time course and neural locus of action-based cueing of attention in normal observers. We show that the presence of action relations between stimuli helps reduce visual extinction in patients with limited attention to the contralesional side of space, while the first saccades made by normal observers and early perceptual and attentional responses measured using electroencephalography/ event-related potentials are modulated by preparation of action and by seeing objects being grasped correctly or incorrectly for action. With both normal observers and patients, there is evidence for two components to these effects based on both visual perceptual and motor-based responses. While the perceptual responses reflect factors such as the visual familiarity of the action-related information, the motor response component is determined by factors such as the alignment of the objects with the observer's effectors and not by the visual familiarity of the stimuli. In addition to this, we suggest that action relations between stimuli can be coded preattentively, in the absence of attention to the stimulus, and action relations cue perceptual and motor responses rapidly and automatically. At present, formal theories of visual attention are not set up to account for these actionrelated effects; we suggest ways that theories could be expected to enable action effects to be incorporated. © 2013 The Author(s) Published by the Royal Society. All rights reserved.