ABSTRACTRecognising a facial expression is more difficult when the expresser's body conveys incongruent affect. Existing research has documented such interference for universally recognisable bodil...

Embodiment theories have proposed a reciprocal relationship between emotional state and bodily reactions. Besides large body postures, recent studies have found emotions to affect rather subtle bodily expressions, such as slumped or upright sitting posture. This study investigated back muscle activity as an indication of an effect of positive and negative emotions on the sitting position. The electromyography activity of six back muscles was recorded in 31 healthy subjects during exposure to positive and negative affective pictures. A resting period was (...) used as a control condition. Increased muscle activity patterns in the back were found during the exposure to negative emotional stimuli, which was mainly measured in the lumbar and thorax regions. The positive emotion condition caused no elevated activity. The findings show that negative emotions lead to increased differential muscle activity in the back and thus corroborate those of previous research that emotion affects subtle bodily expressions. (shrink)

Despite the tight link between the visibility of the iris and pupil, the perceived effects of these two have been studied largely in isolation. We demonstrate, across two experimental studies, that the effects of perceived pupil size are dependent on the visibility of the iris. In a first study, our participants donated more and had more positive impressions of portraits of non-human primates when these were manipulated to appear having larger pupils. Post-hoc inspection of our data suggested that the difference (...) was greater for species with more conspicuous irises. In a second study, we concomitantly manipulated iris brightness and pupil size. Brighter irises and larger pupils elicited greater donations. Participants rated photographs with brighter irises as cuter, more attractive and friendlier, but only when they had dilated pupils. Our results have methodological implications for studies manipulating eye appearance, and help interpret results from previous studies. (shrink)

Honest signalling theory suggests that humans and chimpanzees can extract socially relevant information relating to personality from the faces of their conspecifics. Humans are also able to extract information from chimpanzees’ faces. Here, we examine whether personality characteristics of chimpanzees, including measures of psychopathy, can be discerned based purely on facial morphology in photographs. Twenty-one chimpanzees were given naïve and expert personality ratings on the Ten Item Personality Inventory (TIPI) and the Chimpanzee Triarchic Model of Psychopathy (CHMP-Tri) before and following (...) behavioural observations. Characteristics relating to openness, conscientiousness, extraversion, and disinhibition could be distinguished from the faces of chimpanzees. Individuals higher on disinhibition have lower scores on conscientiousness and emotional stability and higher scores on extraversion, while those higher on meanness have lower conscientiousness and agreeableness. Facial expressions are linked to personality traits present in the TIPI and CHMP-Tri models: the Relaxed Face and the Grooming Face were displayed more by chimpanzees higher on agreeableness, whereas the Compressed Lips Face was observed more in those individuals higher on boldness, and the Full Open Grin was displayed more by chimpanzees higher on extraversion but lower on emotional stability and conscientiousness. Facial expressions were also found to be associated with particular behavioural contexts, namely the Grooming Face in affiliative contexts and the Relaxed and Relaxed Open Mouth Faces in neutral contexts. Dominant chimpanzees display higher levels of boldness and more Compressed Lips Faces, Relaxed Open Mouth Faces, and Grooming Faces than subordinate individuals. These findings support and extend evidence for an honest signalling system and a personality structure shared between humans and chimpanzees. Future research could further explore how personality is conveyed through the face, perhaps through more than just singular aspects of character, and maybe reflecting what chimpanzees themselves are able to do. (shrink)

While new regulations obligate or recommend people to wear medical masks at public places to prevent further spread of the Covid-19 virus, there are still open questions as to what face coverage does to social emotional communication. Previous research on the effects of wearing veils or face-covering niqabs showed that covering of the mouth led to the attribution of negative emotions and to the perception of less intense positive emotions. The current study compares a sample from the Netherlands with a (...) sample from the United Arab Emirates on their perception of emotions from faces covered by a niqab, censoring black bars, or uncovered faces. The results show that covering the mouth area leads to greater anxiety in participants in both countries. Furthermore, although participants did not report greater decoding difficulties for faces that were covered as compared to fully visible, results show that face coverage did influence emotion perception. Specifically, happiness and anger were perceived as being less intense. Further, face coverage by a niqab, as compared to black bars, yielded lower emotional intensity ratings. We conclude that face coverage in particular can modulate the perception of emotions, but that affective contextual cues may play a role as well. (shrink)

Sensitivity to others’ emotional signals is an important factor for social interaction. While many studies of emotional reactivity focus on facial emotional expressions, signals such as pupil dilation which can indicate arousal, may also affect observers. For example, observers’ pupils dilate when viewing someone with dilated pupils, so-called pupillary contagion. Yet it is unclear how pupil size and emotional expression interact as signals. Further, examining individual differences in emotional reactivity to others can shed light on its mechanisms and potential outcomes. (...) In the current study, adults’ (N = 453) pupil size was assessed while they viewed images of the eye region of individuals varying in emotional expression (neutral, happy, sad, fearful, angry) and pupil size (large, medium, small). Participants showed pupillary contagion regardless of the emotional expression. Individual differences in demographics (gender, age, socioeconomic status) and psychosocial factors (anxiety, depression, sleep problems) were also examined, yet the only factor related to pupillary contagion was socioeconomic status, with higher socioeconomic status predicting less pupillary contagion for emotionally-neutral stimuli. The results suggest that while pupillary contagion is a robust phenomenon, it can vary meaningfully across individuals. (shrink)

ABSTRACTThe eyes are extremely important for communication. The muscles around the eyes express emotional states and the size of the pupil signals whether a person is aroused and alert or bored and fatigued. Pupil size is an overlooked social signal, yet is readily picked up by observers. Observers mirror their own pupil sizes in response, which can influence social impressions. In a landmark study by Hess [1975. The role of pupil size in communication. Scientific American, 233, 110–119] it was shown (...) that individuals with large pupils are perceived more positively than individuals with small pupils. In that behavioral study, participants were asked to draw pupils in line drawings of faces with empty irises and they drew large pupils in the happy face, and small ones in the angry face. The current study tested 579 participants and extended this work by showing that this association between large pupils and a positive impression develops over age and is absent in... (shrink)