Effects of Peripheral Eccentricity and Head Orientation on Gaze Discrimination

Abstract

Visual search tasks support a special role for direct gaze in human cognition, while classic gaze judgment tasks suggest the congruency between head orientation and gaze direction plays a central role in gaze perception. Moreover, whether gaze direction can be accurately discriminated in the periphery using covert attention is unknown. In the present study, individual faces in frontal and in deviated head orientations with a direct or an averted gaze were flashed for 150 ms across the visual field; participants focused on a centred fixation while judging the gaze direction. Gaze discrimination speed and accuracy varied with head orientation and eccentricity. The limit of accurate gaze discrimination was less than ±6° eccentricity. Response times suggested a processing facilitation for direct gaze in fovea, irrespective of head orientation, however, by ±3° eccentricity, head orientation started biasing gaze judgments, and this bias increased with eccentricity. Results also suggested a special processing of frontal heads with direct gaze in central vision, rather than a general congruency effect between eye and head cues. Thus, while both head and eye cues contribute to gaze discrimination, their role differs with eccentricity.

Keywords: covert attention; face perception; gaze discrimination; peripheral vision; spatial attention.

Figure 1

Schematic representation of stimulus presentation. The dotted rectangles are shown to represent all of the 9 possible locations of stimuli presentation, but were invisible during trials. Negative (−) eccentricities represent target positions to the left of fixation, while positive (+) eccentricities represent those to the right of fixation. The fixation cross was shown during the entire duration of each trial to keep participants’ fixation focused. Please also note that for averted gaze faces, both left- and right-looking faces were used, and for deviated head views, both left- and right-facing head orientations were used.

Figure 2

Results, as a function of gaze direction and eccentricity, for (A) RT responses, (B) Error rates, and (C) Response presses (all shown with standard error bars). Please note that for (B) and (C), gaze direction data were computed within each head orientation (i.e., DG vs. AG for frontal heads, and DG vs. AG for deviated heads). DG vs. AG paired comparisons: stars above lines represent deviated head comparisons; stars below lines represent frontal head comparisons; *p < .001.