Page 213 - Emotions through the eyes of our closest living relatives- Exploring attentional and behavioral mechanisms
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                                Table S3. Overview of number of trials per individual, per trigger and per condition.
*Indah *Kawan Kevin Samboja Sandy Wattana
Total
14 14 19 18 17 14 14 16 15 19 18 12
123 113
13 16 21 19 17 15 14 15 16 18 19 18
122 118
11 11 79 18 18 113 15 16 94 17 15 91 14 13 95 16 18 101
108 116 700
17
13
13 15 83
11
6 4 10 44
Appendices
 Trigger
Individual
Amos
*Baju 9
Familiar
Unfamiliar
Avatar
Control Yawn Total
 Control
Yawn
14
6 9
Control
Yawn
   * Baju and Kawan are the offspring of Wattana. Indah is the offspring of Samboja. Note: The numbers are not equally divided across individuals, as bystanders were present in the same enclosure as the focal were also exposed to the videos (for instance in the case of mother-offspring pairs). Furthermore, within individuals, numbers are not equal between conditions because in some cases the focal individual paid no attention to the screen, leading to no data for these particular trials. Finally, one video was accidentally presented an extra time, which means that after data collection we had 289 rather than the planned 288 sessions.
Testing the link between yawn occurrence, condition, and familiar and unfamiliar trigger (excluding avatar)
As CY seemed to be present only in response to a familiar or unfamiliar trigger, but not significantly so with the avatar trigger, we performed an extra exploratory analysis without the avatar trigger. Specifically, we first tested whether yawn occurrence is moderated by condition (yawn vs. control), trigger (familiar vs. unfamiliar), and their interaction using a binomial GLMM with subject nested in trial. Next, in those cases that at least one yawn occurred, we tested whether yawning rate is moderated by condition, trigger, and their interaction using a negative binomial GLMM with subject nested in trial.
In the first analysis looking at the likelihood of yawning, we re-confirmed the
presence of CY in the reduced dataset: we found a main effect of condition (b = 6.74,
SE = 1.65, Z = 4.082, p < .001) in which individuals were more likely to yawn in the
yawn vs. control condition. We did not find evidence for an interaction between condition*trigger (b = -3.24, SE = 2.05, Z = 1.57, p = .115). Despite our reduced dataset, A we still confirm the presence of CY in orangutans, but find no evidence for a familiarity
effect using ‘real’ orangutan stimuli only.
In the second analysis in which we looked at yawning rates, we found no significant main effect of condition (b = .37, SE = .46, Z = .81, p = .420), nor an interaction effect between condition*trigger (b = .32, SE = .61, Z = .52, p = .603). Similar to the original analysis including the avatar trigger, we find no differences in strength between
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