Fig 1.
Examples of stimulus images, areas of interest and the gaze patterns of dogs.
The gaze data were collected from five areas of interest (AOIs) of three facial expressions (Threatening, Pleasant and Neutral) of dogs and humans. The AOIs are drawn in the left panel: eyes, midface, mouth, inner face (eyes, midface and mouth combined) and the whole face. In the right panel, the averaged gaze fixation distributions of 12 dogs during 1500 ms presentations are given with color coding: the minimum fixation duration (≤ 5 ms) is indicated by light blue and maximum (≥ 100 ms) by bright red. See also S2 Movie for examples of scanning patterns. The original photos by S. Somppi and 123rf®. The images were purchased with a license to publish these images in electronic and printed documents and reports.
Table 1.
Facial actions of Dog and Human images with three emotional expressions.
Fig 2.
Expression dependent gazing behavior toward the inner face area.
A) Fixation score B) 1st fixation probability for inner face area (eyes, midface and mouth combined) during viewing different facial expressions (Threatening, Pleasant and Neutral) of dogs and humans. The brackets with asterisks indicate statistically significant differences among the expressions within the depicted species (** p ≤ 0.01, * p < 0.05).
Fig 3.
Expression dependent looking duration distribution among eyes, midface and mouth areas.
The fixation scores for target facial features (eyes, midface and mouth) of the three facial expressions (Threatening, Pleasant and Neutral) of dogs and humans. The brackets above the bars indicate statistically significant differences among the target facial features within the species and the brackets below the bars differences among the expressions within the species (*** p ≤ 0.001, ** p ≤ 0.01, * p < 0.05, # p < 0.08).
Fig 4.
Examples of the first fixation targets and scanning paths.
Fixations (circles) and scanning paths (lines between the circles) of two dogs during the 1500 ms presentations of three facial expressions (Threatening, Pleasant and Neutral) of dogs and humans faces. Different dogs are marked with different colors. White circles represent the targets of the first fixations. The original photos by S. Somppi and 123rf®. The images were purchased with a license to publish these images in electronic and printed documents and reports.