Action recognition in the visual periphery

Abstract

Recognizing whether the gestures of somebody mean a greeting or a threat is crucial for social interactions. In real life, action recognition occurs over the entire visual field. In contrast, much of the previous research on action recognition has primarily focused on central vision. Here our goal is to examine what can be perceived about an action outside of foveal vision. Specifically, we probed the valence as well as first level and second level recognition of social actions (handshake, hugging, waving, punching, slapping, and kicking) at 0° (fovea/fixation), 15°, 30°, 45°, and 60° of eccentricity with dynamic (Experiment 1) and dynamic and static (Experiment 2) actions. To assess peripheral vision under conditions of good ecological validity, these actions were carried out by a life-size human stick figure on a large screen. In both experiments, recognition performance was surprisingly high (more than 66% correct) up to 30° of eccentricity for all recognition tasks and followed a nonlinear decline with increasing eccentricities.

Action Recognition in a Crowded Environment

“…Similar adaptation aftereffects in central vision and at 40° eccentricity indicate that action recognition mechanisms that are susceptible to adaptation can discriminate actions even in the far periphery. These results are in line with other research that suggests that participants have little difficulty in recognizing moving actions in the visual periphery up to 45° eccentricity ( Fademrecht et al., 2016 ).…”

“…These results corroborate what we have observed in Experiment 2 with an adaptation paradigm. Moreover, these findings also agree with a previous study that had showed that action recognition is possible in far periphery up to 60° but tends to decrease for eccentricities larger than 45° ( Fademrecht et al., 2016 ). Hence, these results suggest that the presence of a crowd reduces the accuracy of action recognition in the periphery if the crowd is executing similar actions to that of the target actor, but this effect is not observed in central vision.…”

“…Due to a technical error, however, the eye-tracking data could not be used. However, previous research using the same testing environment had shown that participants could reliably fixate (proportion of invalid trials was less than 0.8%) even during stimulation of the visual periphery ( Fademrecht et al., 2016 ).…”

“…Moreover, action recognition performance in the visual periphery as probed by life-size human stick figures (see example in Figure 3 ) is different from action recognition performance probed by small point-light humans. For example, we have previously shown that action recognition of life-size stick figures (∼32° visual angle [VA]) is excellent up to 75° eccentricity ( Fademrecht, Bülthoff, & de la Rosa, 2016 , 2017 ). In contrast, the detection and discrimination of small point-light walkers (11° VA) was significantly decreased already at 12° eccentricities ( Ikeda, Blake, & Watanabe, 2005 ; Ikeda, Watanabe, & Cavanagh, 2013 ; Thompson, Hansen, Hess, & Troje, 2007 ).…”

Pupil size in the evaluation of static and dynamic stimuli in peripheral vision

“…Work by Ludvigh and Miller [16] has already described the ability of the eyes to resolve stimuli that move relative to an observer as "dynamic visual acuity". It is interesting to note that most methods that have been used to investigate specific perceptual and attentional capabilities or processes of the cognitive system, have focused on interactions with static stimuli; and that the various studies that have compared static and dynamic stimuli suggest that dynamic events show an overall higher sensitivity over the visual field than static events (see e.g., [17]). However, it has also been claimed that attending to dynamic stimuli comes at a higher cost than static stimuli [18].…”