Page 74 - Emotions through the eyes of our closest living relatives- Exploring attentional and behavioral mechanisms

Chapter 3
negative scenes more negative ratings than the neutral ones. Children, in contrast, did often not differentiate the emotional scenes from the neutral ones in terms of valence. However, they did rate human yawn (p = .002) and distress scenes (p < .001) more negatively, and play (p < .001) more positively than neutral scenes. Regarding the bonobo scenes, they rated scenes depicting yawning bonobos more negatively than neutral (p < .001) and distress scenes more positively than neutral scenes (p < .001). See Figure 4.
In a second analysis we focused on human adults, adding the category Sex. Within the adult sample, the main effect of Emotion Category remained significant (F(1, 10.54) = 357.92, p < .001) with the ordering of the categories being similar as before, except that the category Sex received the most positive rating. Within human adults and with the category Sex included, an effect of Gender emerged, with male participants giving more positive ratings than females (F(1, 10.54) = 13.58, p < .001). The earlier observed effect of Species disappeared (p = .239), showing that adults perceive human and bonobo scenes to be equal in valence overall. The interaction between Emotion Category and Species was maintained (F(6, 10.54) = 64.88, p < .001), and the interpretation was not altered. Interestingly, an interaction between Emotion Category and Gender (F(7, 10.54) = 6.73, p < .001) showed a significant gender difference in several emotion categories, most prominently in the category Sex (t(10.54) = 4.39, p < .001), which men rated with almost half a point more positively than women. Further, distress and yawn images were perceived more negatively by women compared to men (distress: t(10.54) = 3.32, p < .001; yawn: t(10.54) = 2.75, p = .006).
In a third analysis within human adults, we zoomed in on the human scenes specifically, and added the category Aggression. The results showed a main effect of Emotion Category (F(1, 2.62) = 462.22, p < .001) and an interaction between Emotion Category and Sex (F(1, 2.62) = 3.587, p = .001). Of all categories, Aggression was perceived most negatively and Sex most positively. Further, the only gender difference that remained significant after having excluded the bonobo scenes from the analysis was the category Sex, which males rated as more positively than females (t(2.62) = 2.85, p = .004).
Perceived arousal of human and bonobo scenes
In a first analysis where the emotion categories Sex and Aggression were excluded, participants (adults and children), showed a main effect of Emotion Category (F(1,
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