Page 104 - Emotions through the eyes of our closest living relatives- Exploring attentional and behavioral mechanisms

Chapter 4
= 100%, as well as those depicting bonobos (Mdn = 0.52, 89%CI [0.51 – 0.52], pd+ = 100%, Table 2). Additionally, we found robust evidence for a difference between PLDemotion to stimuli depicting bonobos or humans (OR = 0.88, 89% HDI [0.84 – 0.91]). Thus, the looking duration to emotional stimuli was higher for human emotions than for bonobo emotions.
When examining the specific emotion categories per species in model 3, we found robust evidence that humans looked longer at other humans in distress (Mdn = 0.56, 89% CI [0.54 – 0.58], pd+ = 100%), having sex (Mdn = 0.56, 89% CI [0.54 – 0.57], pd+ = 100%, or humans playing (Mdn = 0.55, 89% CI [0.54 – 0.57], pd+ = 100%), grooming/ embracing (Mdn = 0.56, 89% CI [0.54 – 0.57], pd+ = 100%, Table 2 and Figure 3b). For the yawning category, the effect was in the expected direction (pd+ = 90%), but it was weak (Mdn = 0.51, 89% CI [0.50 – 0.53]). For the bonobo category, we found robust evidence for PLDemotion of stimuli of grooming (Mdn = 0.54, 89%CI [0.52 – 0.56], pd+ = 100%) and playing bonobos (Mdn = 0.52, 89% CI [0.52 – 0.56], pd+ = 100%). We also find a weak effect of humans looking towards neutral scenes that were matched with distressed bonobos (Mdn = 0.48, 89% CI [0.46 – 0.50], pd- = 96%, Table 2, Table S5, and Figure 3d).
Table 2. Overview of results per factor level of interest for the three models. Robust effects are in bold.
Model
1 (Intercept)
2 (Species)
3 (Species*Emotion Category)
Species on stimulus
Bonobo and human Bonobo
Human Bonobo
Human
Emotion Median CI 89% pd Category
All 0.53 [0.52 – 0.54] 1.00 All 0.52 [0.51 – 0.52] 1.00
All 0.55 [0.54 – 0.56] 1.00
Distress 0.48 [0.46 – 0.50] 0.96 Yawn 0.51 [0.49 – 0.52] 0.78 Groom 0.54 [0.52 – 0.56] 1.00 Sex 0.51 [0.49 – 0.53] 0.87 Play 0.54 [0.52 – 0.56] 1.00 Distress 0.56 [0.54 – 0.58] 1.00 Yawn 0.51 [0.50 – 0.53] 0.90 Groom 0.56 [0.54 – 0.57] 1.00
Sex 0.56 Play 0.55
[0.54 – 0.57] 1.00 [0.54 – 0.57] 1.00
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