Page 24 - Emotions through the eyes of our closest living relatives- Exploring attentional and behavioral mechanisms

Chapter 1
how children and adults perceive the emotions of other humans and bonobos is examined to assess differences and similarities in the perception of emotional expressions across closely related species.
Chapter 4 builds on the works in Chapters 2 and 3 by examining attention for emotions in bonobos and humans in more detail using an eye-tracking paradigm. Here, the goal was to examine the similarities and differences between the two species in focusing attention on emotional versus neutral scenes (Figure 1a, c).
In Chapter 5, the dissertation moves on to study spontaneous mimicry (Figure 1ii). Through behavioral observations, the existence of contagious self-scratching is examined in orangutans. Moreover, the link between contagious self-scratching, context, and social closeness is studied (Figure 1a-c).
Chapter 6 follows up on this work with an experimental investigation of yawn contagion in orangutans to move towards a better understanding of the function of contagious yawning, as well as its relation with familiarity (Figure 1a, b).
Next, Chapter 7 focuses on the validation of a touchscreen-based, pictorial adaptation to the classic Implicit Association Test to examine implicit associations (Figure 1iii, a, b). Though a validation in great apes is outside the scope of this dissertation, the chapter makes a first step towards finding ways to probe implicit associations in animals other than humans.
Finally, in Chapter 8, the main findings are summarized and discussed to highlight the most crucial similarities and differences in the cognitive and behavioral mechanisms that underlie emotion processing in hominids.
I would like to emphasize that all the work disseminated in this dissertation is the result of intense collaborations with colleagues. I am the first author of the works described in Chapters 2, 4, 6, and 7, and I am the second author of the works described in Chapters 3 and 5. Chapter 3 is written by Daan W. Laméris, MSc., and Chapter 5 by principal investigator Dr. Mariska E. Kret. Both of these works are important to the dissertation’s overarching theme, and although most of the work can be ascribed to Drs. Daan Laméris and Dr. Mariska Kret (as evidenced by their first-authorship), I have made substantial contributions to both studies. With the permission of Daan Laméris, MSc., and Dr. Mariska Kret, Chapters 3 and 5 have therefore become a part of this dissertation.
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