Page 135 - Emotions through the eyes of our closest living relatives- Exploring attentional and behavioral mechanisms
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                                Evidence for yawn contagion in orangutans
highly social species, and because orangutans do not show high affiliative tendencies, we therefore expected that orangutans do not show CY.
Method
Participants
Eight orangutans (ages: 15 months-36 years, 4 males) housed at Apenheul (The Netherlands), were tested (see Table S1 for more information about the participants). Individuals were divided over four neighboring enclosures and group composition varied weekly (Figure 1). The two adult females that had dependent offspring were always housed with their offspring and sometimes with one adult male. Experiments took place in the visitor area but while the park was closed to visitors. We tested individuals using a movable 47′′ TV (LG 47LH5000, 1920 * 1080 pixels) placed in front of the enclosures to which the orangutans were habituated before commencing
6
  Figure 1. Abstract representation of the testing area and group composition. Experiments took place in the visitor area but while the park was closed to visitors. Only the experimenters and, occasionally, a caretaker, were present during testing. The TV screen was always directed at one of the four enclosures, which prevented orangutans in the other enclosures from seeing the videos.
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