Page 69 - Emotions through the eyes of our closest living relatives- Exploring attentional and behavioral mechanisms

Attention towards humans’ and bonobos’ emotion
category depicted crying individuals. The category aggression differed for adults and
children; adults viewed violent scenes (e.g., fist-fights) and children saw images of
bullying scenes. Adults and children further viewed the same stimulus set, excluding
the category sex for children. In the bonobo version, all scenes showing distress
showed the bared teeth display, a facial expression that is frequently used to signal
submission and shows commonalities with the human fearful facial expression and
to the expression of the smile (Kret & Straffon, 2018). The distressing images had a
negative valence, but did not include overt aggression. Omission of overt aggression 3 was due to the fact that bonobos are a relatively non-aggressive species, therefore
there was no sufficient amount of aggressive images available. All stimuli were sized 400 * 330 pixels.
Procedure
The task was displayed on a Dell S2240 Tb touchscreen monitor (21.5 inch, 1920 * 1080 resolution, 60 Hz refresh rate) and ran on a Dell OPTIPLEX 990 desktop computer using E-prime 2.0. The experimental set-up was placed in a quiet, public corner of the indoor bonobo enclosure and facing the wall to minimize distractions (Figure 2).
Figure 2. Picture of a child performing one of the dot-probe tasks in the zoo.
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