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During the COVID-19 pandemic, the use of face masks has become a daily routine. Studies have shown that face masks increase the ambiguity of facial expressions which not only affects (the development of) emotion recognition, but also interferes with social interaction and judgement. To disambiguate facial expressions, we rely on perceptual (stimulus-driven) as well as preconceptual (top-down) processes. However, it is unknown which of these two mechanisms accounts for the misinterpretation of masked expressions. To investigate this, we asked participants (N = 136) to decide whether ambiguous (morphed) facial expressions, with or without a mask, were perceived as friendly or unfriendly. To test for the independent effects of perceptual and preconceptual biases we fitted a drift-diffusion model (DDM) to the behavioral data of each participant. Results show that face masks induce a clear loss of information leading to a slight perceptual bias towards friendly choices, but also a clear preconceptual bias towards unfriendly choices for masked faces. These results suggest that, although face masks can increase the perceptual friendliness of faces, people have the prior preconception to interpret masked faces as unfriendly.

Robots are increasingly implemented in safety-critical environments and function as intelligent and autonomous agents that cooperate with humans in alleged human-robot teams (HRTs). It is expected that robots need to increasingly make trade-off decisions, sometimes trading an individual militant’s safety for a mission’s objective. This can have a negative impact on human trust towards a robot team member. This study tested different moral intentions behind harmful decision-making. Participants formed a team with a virtual partner, either human or robot, to finish two missions. Halfway in the missions, a harmful decision was made whereafter two declarations of the partner revealed different intentions for this decision, both aimed at restoring trust. The declarations exposed that the harmful decision was either based on utilitarianist or deontologist considerations and revealed the partner’s lack of respectively benevolence and competence. Participant’s trust was measured prior to violation, after violation and after the reveal of the different intentions. It was found that there was no difference in trust development between partner types. Participant’s competence-based trust dropped the most after violation. Trust after a competence-based trust violation was found to be more easily restored than after a benevolence-based trust violation. This suggests that in all teams, benevolence-based trust is the least easily restored after a benevolence-based trust violation. It is recommended to be careful in being transparent about utilitarianist decision-making. Suggestions for future research are focused on the examination of the best trust repair technique, possibly through investigating the alignment of human moral expectations and their robot partner’s decision-making. An additional note that contradicts previous studies is that – although errorless design is crucial in safety-critical industries – humans can forgive their robot team member after they make a mistake.

This study investigates the magnitude of the post-auricular muscle reflex (PAMR) in response to feedback about low and high rewards in order to determine whether the reflex could be used as an implicit measure of individual reward perception. The PAMR was elicited by administering rapid click sounds and recorded with an electromyograph. Meanwhile, participants (N = 32) had to complete a reaction time task in which they could either increase, maintain or decrease their score. Obtaining a higher score would lead to a higher monetary reward. The rewards and losses were each divided into a high and a low level. We found that feedback about a loss and reward elicits a significantly stronger PAMR magnitude than neutral feedback, indicating that the reflex reacted to mutual properties of reward and loss stimuli. It was further found that gaining high rewards affects the PAMR more strongly than gaining low rewards. The study proposes that reward and loss are similar in motivation and arousal properties, which could be the underlying factors influencing the PAMR magnitude. Derived from that, higher motivation and arousal could lead to increases in PAMR magnitude.

There is growing consensus that testosterone is related to mental and physical health, but the underlying mechanisms are still poorly understood. One explanation for the conflicting results found in the study of testosterone is that this hormone is needed for the arousal that signals the expectation of a positive outcome, meaning that high testosterone can be expected to lead to impulsive behavior and thus enhance a person’s risk to develop an anxiety disorder, whereas low testosterone would lead for instance to apathy and thus enhance a person’s risk to develop a mood disorder. To investigate this hypothesis I explored the relation between emotionality, mental health and the self-reported number of digital hairs as an indicator of expressed testosterone in an online survey in which 316 Dutch (speaking) men and women participated. Using factor analysis on a pool of items probing the participant’s tendency to react emotionally I identified four types of emotionality: an internalized negative type, a positive type, a sexual type and an externalized negative type. I found that mental health was indeed higher at intermediate levels of digital hair, and that there was a positive association between general emotionality and digital hair, though only in partnered persons and women. These results should be interpreted with caution because data were collected during the COVID-19 pandemic and with the exception of partnered men all participants had relatively low scores on the used measure for mental health. Nevertheless, the fact that by using the digital hair measure a distinct pattern was found suggests that this measure may be employed as an easy to use and non-invasive marker for expressed testosterone, although the measure is probably more reliable if the assessment is done by a trained assessor, especially in men as they have more digital hair then women. To further elucidate the association between testosterone and reward related arousal I introduce the concept of rei

The bed nucleus of the stria terminalis (BNST) plays a critical modulatory role in driving fear responses. Part of the so-called extended amygdala, this region shares many functions and connections with the substantially more investigated amygdala proper. In this chapter, we review contributions of the BNST and amygdala to subjective, behavioral, and physiological aspects of fear. Despite the fact that both regions are together involved in each of these aspects of fear, they appear complimentary in their contributions. Specifically, the basolateral amygdala (BLA), through its connections to sensory and orbitofrontal regions, is ideally poised for fast learning and controlling fear reactions in a variety of situations. The central amygdala (CeA) relies on BLA input and is particularly important for adjusting physiological and behavioral responses under acute threat. In contrast, the BNST may profit from more extensive striatal and dorsomedial prefrontal connections to drive anticipatory responses under more ambiguous conditions that allow more time for planning. Thus current evidence suggests that the BNST is ideally suited to play a critical role responding to distant or ambiguous threats and could thereby facilitate goal-directed defensive action.