What interests them in the pictures? — Differences in eyetracking between rhesus monkeys and humans

Abstract

Studies estimating eye movements have demonstrated that non-human primates have fixation patterns similar to humans at the first sight of a picture. In the current study, three sets of pictures containing monkeys, humans or both were presented to rhesus monkeys and humans. The eye movements on these pictures by the two species were recorded using a Tobii eye-tracking system. We found that monkeys paid more attention to the head and body in pictures containing monkeys, whereas both monkeys and humans paid more attention to the head in pictures containing humans. The humans always concentrated on the eyes and head in all the pictures, indicating the social role of facial cues in society. Although humans paid more attention to the hands than monkeys, both monkeys and humans were interested in the hands and what was being done with them in the pictures. This may suggest the importance and necessity of hands for survival. Finally, monkeys scored lower in eye-tracking when fixating on the pictures, as if they were less interested in looking at the screen than humans. The locations of fixation in monkeys may provide insight into the role of eye movements in an evolutionary context.

A novel system for bi‐ocular eye‐tracking in vertebrates with laterally placed eyes

“…Simple moving and static dots were not sufficient for eliciting fixations, even though dots do elicit fixations in humans (Duchowski 2007). Similarly, a recent eye-tracking study found that humans and rhesus monkeys (Macaca mulatta) have different fixation patterns (Hu et al 2013). Taken together, these results suggest that the visual system of non-human vertebrates may be responsive to different types of visual stimuli.…”

“…Similarly, a recent eye‐tracking study found that humans and rhesus monkeys ( Macaca mulatta ) have different fixation patterns (Hu et al . ). Taken together, these results suggest that the visual system of non‐human vertebrates may be responsive to different types of visual stimuli.…”

“…Eye-tracking studies are now relatively common in vertebrates with frontally placed eyes (e.g. Machado & Nelson 2011;Hu et al 2013;Dixson et al 2014). Yet, tracking gaze is more difficult in vertebrates with laterally placed eyes because of hardware and software constraints.…”

Differences in Looking at Own- and Other-Race Faces Are Subtle and Analysis-Dependent: An Account of Discrepant Reports

“…In stark contrast to these reports, another eye-tracking study of the ORE [ 26 ] has reported that regardless of the race of the observer (East Asian or Caucasian), own-race faces elicited a relatively greater proportion of fixations to the eyes and hair, while other-race faces elicited a relatively greater proportion of fixations to the nose and mouth. Further, several other studies involving East Asian (Chinese or Japanese) participants viewing faces robustly show the “classical” T-shaped fixation pattern of fixations that, notably, almost exclusively demonstrate peak density over the eyes when spatial density or scatter plot analyses were utilized [ 28 , 29 , 32 , 56 – 59 ] or show greater fixation over the eyes relative to the nose when area-normalized AOI analyses were utilized [ 60 , 61 ]. Other studies without area normalized AOIs are also at least suggestive of the same tendency for East Asian observers to principally fixate the eyes [ 25 , 62 – 64 ].…”

The application of noninvasive, restraint-free eye-tracking methods for use with nonhuman primates

“…A primary concern in obtaining accurate measurements of eye position is ensuring that the primate's head remains motionless such that subjects can only track stimuli via discrete eye movements. A subject's movement restriction is typically accomplished through the use of primate chairs (e.g., Hall-Haro, Johnson, Price, Vance, & Kiorpes, 2008;Hu et al, 2013;Sugita, 2008), with additional means to restrain the head (e.g., Emery, Lorincz, Perrett, Oram, & Baker, 1997;Machado, Bliss-Moreau, Platt, & Amaral, 2011;Machado, Whitaker, Smith, Patterson, & Bauman, 2015). To achieve precise visual measurement, some studies have relied on implantation of head posts or fixation devices (e.g., Adams, Economides, Jocson, & Horton, 2007;Blonde et al, 2018;Dal Monte, Noble, Costa, & Averbeck, 2014) in addition to scleral search coils, which are implanted directly into the eye (e.g., Deaner, Khera, & Platt, 2005;Gothard, Erickson, & Amaral, 2004;Shepherd, Deaner, & Platt, 2006).…”