Page 50 - Emotions through the eyes of our closest living relatives- Exploring attentional and behavioral mechanisms
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Chapter 2
participants were also selected based on their relationship with their companions (kin and friends or colleagues. See Table S9 for an overview on relationships). The experiment was approved by the ethics committee of Leiden University (adults: CEP17-0213/74, children: CEP17-0604/222).
Equipment
Participants performed the experiment on an Iiyama T1931SR-B1 touchscreen (19”, 1280x1024 pixels, ISO 5ms) using E-Prime 2.0. The tests were conducted in an indoor compound in which visitors could see the bonobos. The touchscreen was placed on a table and participants were seated with their back against a wall to prevent others from distracting them (Figure 6).
Figure 6. Abstract representation of the human setup near the bonobo enclosure.
Stimuli and validation
For our human participants, rather than emotional scenes, we used isolated facial expressions as stimuli. This was done for practical reasons, as we could not ask zoo visitors to enact specific social scenes like the bonobo scenes. For humans, there is evidence for an attentional bias towards emotions using only facial expressions (Van Rooijen et al., 2017), but also for emotional scenes (Kret & Van Berlo, 2021). Similarly,
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