Individual talks: Evolution and fear processing

July 11th A2.09

Familiarity Breed Humanity: People Decode Facial Expressions of Emotion in Dogs Better than in Chimpanzees

Lasana Harris & Sarah Sullivan

Human beings are a highly familiar, over-learnt stimuli. This suggests that a person’s perception of humanity may be grounded in their experiences with other people, not in the biology (genes and physical morphology) of what makes human beings a separate species. Evidence for this comes from the flexible nature of social cognition (Harris, 2017); given that social cognition engagement is required to perceive another as a full human being, instances of reduced social cognition to people suggest that they may not be perceived as full human beings despite the requisite biology (Beyer et al., 2015; Cikara, Eberhardt, & Fiske, 2010; Gutzel & Inzlicht, 2010; Harris & Fiske, 2006; 2007; 2011; Harris, et al., 2014; Mathiak & Weber, 2006). Such dehumanised perceptions are moderated by familiarity (Harris & Fiske, 2006; 2011). Here, we test some predictions of this familiarity theory by exploring how human beings decode facial expressions of emotion in non-human animal species that demonstrate some human-like social cognition abilities and can communicate with humans. Participants infer the facial expressions of emotion in dogs, a highly familiar species with dissimilar genetics and physical morphology, and chimpanzees, an unfamiliar species but our closest genetic cousins with a more similar physical morphology. We find support for the familiarity theory, such that people are more efficient and more accurate at inferring the facial expressions of dogs compared to chimpanzees. This supports the familiarity theory, and implies that emotion perception relies on shared experiences.

Experience with enacted autonomy affects threat perception

Yulia Chentsova Dutton, Derya Gürcan-Yıldırım & Andrew Ryder

Cultural contexts differ in the frequency and types of threats in the environment, and in the extent to which children encounter threats on their own. Recent decades have witnessed rapid changes in childrearing norms in the US and Canada. Children spend more of their time under adult supervision and wait longer to be granted permission to meet autonomy milestones. Although these cultural contexts are described as valuing autonomy, studies based on measures of enacted autonomy (e.g., walking outside without supervision) characterize them as autonomy-inhibiting. A cross-cultural study showed that Turkish college students (n=166) reported meeting enacted independence milestones earlier than students in the US (n=120), who met them earlier than students in Canada (n=157). Participants evaluated safety of their college environments, described recent encounters with potential threats, and completed psychological functioning measures. In the US and Canada, but not Turkey, students who reported meeting autonomy milestones later were more likely to experience their college environments as unsafe than their peers who met these milestones earlier. In turn, perceived safety of the college environment was negatively associated with psychological distress. Moreover, the association between ratings of objective danger of potentially threatening situations and subjectively experienced distress was higher in Turkey than in the US and Canada, suggesting that fear and discomfort in the North American samples may be less calibrated to features of threatening situations. This study suggests that cultural and individual differences in opportunities to independently explore one's environment as a child helps calibrate responses to threats among young adults.

Surprise and freezing responses

Marret K. Noordewier, Daan T. Scheepers, John F. Stins & Muriel A. Hagenaars

When people are confronted with unexpected stimuli, they experience surprise. Previous research showed that initial responses to surprises are primarily driven by the unexpectedness of the outcome and reflect an interrupted and surprised state (irrespective of whether the surprising outcome is positive or negative). In the current project, we aimed to further understand the nature of this initial interruption phase. We reasoned that because unexpectedness is in conflict with people’s epistemic need to predict, prepare, and understand outcomes, surprise could result in a freezing response—i.e., a reduction in heart rate and body motion. We conducted three studies, where we surprised participants with neutral as well as positive pictures in a repetition-change paradigm. In all studies we measured heart rate and found a reduced heart rate after the surprise as compared to baseline. The heart rate remained lower during the time the surprising stimulus was shown, not just in the beginning. In Study 3, we also included a measure of body sway (i.e., participants stood on a stabilometric platform when they were surprised) and found a marginal reduction in body sway in the first second after the surprise. Taken together, these studies provide support for a connection between surprise and freezing. Implications will be discussed, including a follow-up study where we compared repeated exposure to positive versus negative surprises with additional physiological measures (blood pressure and finger temperature).

Emotional coherence of fear

Ben Meuleman & David Rudrauf

A core concept in psychological theories of emotion is “emotional coherence”. Among other aspects, this concept captures that an emotion episode consists of a pattern of mental and bodily changes that is concurrent in time, involves the whole body, is differentiated qualitatively from non-emotional or emotional states, is reliably observed, and/or is driven as a whole by underlying organising factors. Empirical research into emotional coherence has faced a number of important obstacles, however, which are (a) the absence of a clear theoretical definition of emotional coherence, (b) the weakness with which emotional states are typically induced in the lab, (c) the lack of comprehensive measurement across mental and bodily subsystems, and (d) the statistical complexities associated with the analysis of these multivariate measurements. In this talk, I will first decompose emotional coherence into 7 major sub-aspects. Second, I will present data of a recent study in which we elicited strong fear by a virtual depth exposure, and measured a large number of objective and subjective emotional responses. These data were then analyzed with a combination of model-based clustering and multilevel regressions. Results of the analyses showed that higher depth exposure was associated with more intense fear feelings and more “coherent” overall patterns of fear responses, in the sense of (a) involving changes in the entire body, (b) being differentiated from the no-emotion pattern of responses, (c) implicating specific appraisals and action tendencies, and (d) being labelled systematically with fear-related words.

Does maternal odor impact fear processing in infancy?

Sarah Jessen

Within the first year of life, human infants undergo an astonishing development in social and emotional abilities. While newborns show little evidence of emotion discrimination, infants at six to seven months of age can differentiate between various emotional states based on facial expressions but also voice and body posture. Typically, infants at this age show an attentional bias towards threatening, in particular fearful, signals that can be observed in looking behavior but also neural responses. However, it is unclear whether this enhanced fear response can be observed in any situation or might be reduced by signals of security, such as maternal presence. We therefore investigated how maternal odor as a potentially potent signal of maternal presence may impact the attentional response to fearful faces in 7-month-old infants. To that end, we recorded the electroencephalographic (EEG) signal while the infants watched happy and fearful faces. In a between-group design, infants were randomly assigned to one of three groups (each n=25); a "maternal odor" group exposed to maternal odor, a "stranger odor" group exposed to the odor of an unfamiliar mother of a same-aged infant, and a "no-odor" group. We found that while infants in both, the stranger odor and the no-odor group, showed the expected enhanced attentional response to fearful faces, this response was abolished in the maternal odor group. Our results therefore point to a clear impact of maternal signals on fear processing in infancy and underscore the important role maternal odor may have as a proxy for maternal presence.