Attending to the possibilities of action

Abstract

Actions taking place in the environment are critical for our survival. We review evidence 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 pre-attentively, 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 action-related effects; we suggest ways that theories could be expected to enable action effects to be incorporated.

Keywords: action; attention; visual affordance.

Figure 1.

Simuli used by Riddoch et al. [12]. (a,b) Upright objects (a) objects positioned for action, (b) objects not positioned for action). (c,d) Inverted objects (c) derived from action-related objects; (d) derived from action-unrelated objects).

Figure 2.

Stimuli used by Roberts & Humphreys [19]. Participants were cued at the start of each trial as to which pair of stimuli to attend to and they either made judgements about the pair of objects (this would be the case for display (b) following display (a)) or the scenes (this would happen for display (c) following display (a)).

Figure 3.

Examples of objects subject to a congruent grip (a) or an incongruent grip (b). The incongruent grips were selected from congruent grips to other objects (here a congruent grip to a pin).

Figure 4.

De-synchronization power in the mu frequency. Black, objects with congruent grip; red, objects with incongruent grip; green, non-objects with congruent grip; blue, non-objects with incongruent grip. Data here are recorded from electrodes above the supplementary motor area (SMA).

Figure 5.

Stimuli used by Kumar et al. [41]. Participants saw a verb and then had to verify if an object associated with the verb was present. In our example, the target was present and gripped correctly, whereas the distractor was gripped incorrectly (TC-DIC).

Figure 6.

The N2pc responses recorded by Kumar et al. [41]. Red, target object correctly gripped and distractor incorrectly gripped (TC-DIC); black, target object correctly gripped and distractor gripped correctly (TC-DC); purple, target object incorrectly gripped and distractor gripped incorrectly (TIC-DIC); blue, target object gripped incorrectly and distractor gripped correctly (TIC-DC).