Page 82 - Emotions through the eyes of our closest living relatives- Exploring attentional and behavioral mechanisms
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Chapter 3
The analysis of the arousal ratings also yielded some interesting results when comparing adults and children. Intriguingly, while adults perceived the human scenes as more intense than the bonobo scenes, an opposite effect was observed in children. To what extent the zoo setting influenced these results is a factor that may be taken into consideration in a future study. However, the effects were not general, which speaks against such an explanation. More specifically, children gave higher intensity ratings to bonobo play scenes. Moreover, compared to children, adults gave higher intensity ratings for scenes depicting human distress, but lower ratings for bonobos in distress. As we will see in the following section, none of these effects were linked to specific age-related attentional biases.
The results of the dot-probe task show that in line with our earlier study, humans show a robust attentional bias toward emotions (Kret et al., 2018). The attentional bias was stronger when humans observed emotions that were expressed by other humans compared to expressions by bonobos. Interestingly, while humans’ attention was immediately captured by images of yawns, this was not driven by the visibility of the larger canines of bonobos which could potentially pose a high threat. Instead, attention capture was most pronounced when seeing other humans yawn. Yawns are extremely contagious and yawn contagion seems to work particularly well between close others, possibly due to heightened attention (Massen & Gallup, 2017). At first sight, this increased attentional bias toward human emotions seems to be in contrast to the findings of our earlier study (Kret et al., 2018). However, the current study deviates from our previous work in several important ways. Most crucially, the included stimulus materials consist of naturalistic scenes instead of isolated and greyscale neutral or threatening body expressions of male apes and humans in our earlier study. More importantly, within the adult sample of our study, the interaction between species and congruency disappeared. This suggests that the perception of other species emotional expressions is not fully developed yet in children, which is also in line with their dampened valence effects. As a following, attentional biases toward emotions or other stimuli may be partly learned (Guo et al., 2019). Other research has indeed shown that learning effects might modulate the outcomes of a dot-probe task. For instance, previous research has shown that people suffering from alcohol dependency have greater biases toward photographs of alcoholic beverages than control subjects (Townshend & Duka, 2001). Even more strikingly, in non-dependent social drinkers an attentional bias toward alcohol- related stimuli increased after priming with a small (but not large) dose of alcohol
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