Dual-route model of the effect of head orientation on perceived gaze direction.

Abstract

Previous studies on gaze perception have identified 2 opposing effects of head orientation on perceived gaze direction—1 repulsive and the other attractive. However, the relationship between these 2 effects has remained unclear. By using a gaze categorization task, the current study examined the effect of head orientation on the perceived direction of gaze in a whole-head condition and an eye-region condition. We found that the perceived direction of gaze was generally biased in the opposite direction to head orientation (a repulsive effect). Importantly, the magnitude of the repulsive effect was more pronounced in the eye-region condition than in the whole-head condition. Based on these findings, we developed a dual-route model, which proposes that the 2 opposing effects of head orientation occur through 2 distinct routes. In the framework of this dual-route model, we explain and reconcile the findings from previous studies, and provide a functional account of attractive and repulsive effects and their interaction.

A generalized tendency toward direct gaze with uncertainty

“…These scaling values are further from the identity matrix than for direct heads, suggesting that there is a greater influence of the prior in the rotated heads than in the direct heads, affecting both the cardinal and noncardinal directions. The finding of a greater influence of the prior in rotated heads is consistent with Otsuka et al (2014) who have reported greater uncertainty in gaze judgments with rotated heads than direct heads. …”

“…Since then, some authors have reported repulsive effects of the head rotation (eyes appeared shifted away from the head direction, e.g., Anstis, Mayhew, & Morely, 1969;Gamer, Hecht, Seipp, & Hiller, 2011;Gibson & Pick, 1963;Mareschal et al, 2013a) while others have reported attractive effects (gaze deviation appears shifted toward the head rotation; e.g., Cline, 1967;Langton, Honeyman, & Tessler, 2004;Todorovic, 2006). We recently showed how observers combine eye deviation and head rotation cues when making judgments of eye gaze, with the repulsive effect prevailing in conditions where a whole head is viewed (Otsuka, Mareschal, Calder, & Clifford, 2014). Importantly, we also reported an associated increase in observers' uncertainty with head rotation, suggesting that the prior may have a greater influence for rotated heads.…”

The center of attention: Metamers, sensitivity, and bias in the emergent perception of gaze

“…And yet these facts seem contradictory, at least if gaze were determined by one visual feature alone. Here, we demonstrated that the visual system leverages the process of emergent gaze representation—combining information from the pupils with the face and head (Cline, 1967; Kluttz et al, 2009; Langton et al, 2004; Murayama & Endo, 1984; Otsuka et al, 2014; Wollaston, 1824)—to balance these competing demands of sensitivity and bias. We found that when eye gaze is relatively direct, the visual system is especially likely to utilize information from head rotation to inform judgments of where a person is looking.…”

“…Unlike a head rotation in the same direction, this change in local information from the eyes actually repels the perceived direction of gaze. These attractive and repulsive effects from the head and eyes are likely to be related and potentially complementary (Otsuka et al, 2014, 2016), and the extent to which one dominates the other likely depends on the relative visibility of information from the head or eyes (Gamer & Hecht, 2007). For simplicity we focus here on the attractive effect from the rotation of the head.…”

“…This interaction produces a striking percept—the Wollaston effect—where a person’s perceived gaze direction is pulled by the rotation of the head (Cline, 1967; Kluttz, Mayes, West, & Kerby, 2009; Langton, Honeyman, & Tessler, 2004; Murayama & Endo, 1984; Otsuka, Mareschal, Calder, & Clifford, 2014; Wollaston, 1824). The perceived gaze that results form this integration is carried neither by the pupils nor by the head alone, and thus has a unique quality.…”