Personality assimilation across species: enfacing an ape reduces own intelligence and increases emotion attribution to apes

Trust in virtual ingroup or outgroup members relies on perceived self-other overlap

Why do we trust each other? We carried out three experiments to test whether interpersonal trust depends on perceived self-other overlap. As previous studies suggest that enfacing (feeling ownership for, and include more into oneself of the face of) an avatar might make one trust this avatar more, we exposed participants to faces of ingroup and outgroup avatars that moved in synchrony or out of synchrony with the participant's own facial movements, and assessed the impact of synchrony on self-other overlap and trust measures. Experiment 1 used ingroup faces and successfully showed that synchrony (manipulated within-participants) increased self-other overlap and trust, which we assessed by means of the Trust Game and the Implicit Association Test (IAT). In Experiment 2, which used outgroup faces and a within-participants design, synchrony still increased scores in the Trust Game but the IAT was no longer affected. Experiment 3 replicated Experiment 2 but with synchrony varying between participants, which eliminated the synchrony effect in both trust measures. Importantly, Inclusion of Other in the Self (IOS) ratings were found to predict the IAT effect in synchronous conditions. Taken altogether, our findings suggest that interpersonal trust is mainly driven by perceived self-other overlap. Besides group identification, appearance, and voluntary movement, synchrony is just one of several sources contributing to perceived self-other overlap.

Investigating the impact of motion visual synchrony on self face recognition using real time morphing

Face recognition is a crucial aspect of self-image and social interactions. Previous studies have focused on static images to explore the boundary of self-face recognition. Our research, however, investigates the dynamics of face recognition in contexts involving motor-visual synchrony. We first validated our morphing face metrics for self-face recognition. We then conducted an experiment using state-of-the-art video processing techniques for real-time face identity morphing during facial movement. We examined self-face recognition boundaries under three conditions: synchronous, asynchronous, and static facial movements. Our findings revealed that participants recognized a narrower self-face boundary with moving facial images compared to static ones, with no significant differences between synchronous and asynchronous movements. The direction of morphing consistently biased the recognized self-face boundary. These results suggest that while motor information of the face is vital for self-face recognition, it does not rely on movement synchronization, and the sense of agency over facial movements does not affect facial identity judgment. Our methodology offers a new approach to exploring the 'self-face boundary in action', allowing for an independent examination of motion and identity.

The Open Virtual Mirror Framework for enfacement illusions : Enhancing the sense of agency with avatars that imitate facial expressions

Enfacement illusions are traditionally elicited by visuo-tactile stimulation, but more active paradigms become possible through the usage of virtual reality techniques. For instance, virtual mirrors have been recently proposed to induce enfacement by visuo-motor stimulation. In a virtual mirror experiment, participants interact with an avatar that imitates their facial movements. The active control over the avatar greatly enhances the sense of agency, which is an important ingredient for successful enfacement illusion induction. Due to technological challenges, most virtual mirrors so far were limited to the imitation of the participant's head pose, i.e., its location and rotation. However, stronger experiences of agency can be expected by an increase in the avatar's mimicking abilities. We here present a new open-source framework for virtual mirror experiments, which we call the Open Virtual Mirror Framework (OVMF). The OVMF can track and imitate a large range of facial movements, including pose and expressions. It has been designed to run on standard computer hardware and easily interfaces with existing toolboxes for psychological experimentation, while satisfying the requirement of a tightly controlled experimental setup. Further, it is designed to enable convenient extension of its core functionality such that it can be flexibly adjusted to many different experimental paradigms. We demonstrate the usage of the OVMF and experimentally validate its ability to elicit experiences of agency over an avatar, concluding that the OVMF can serve as a reference for future experiments and that it provides high potential to stimulate new directions in enfacement research and beyond.

Reduced ownership over a virtual body modulates dishonesty

Although studies suggest that even higher-order functions can be embodied, whether body awareness may bias moral decisions toward (dis)honesty remains underinvestigated. Here, we tested if the Sense of body Ownership (SoO) and the magnitude of monetary rewards influence the tendency to act immorally. Through a virtual body, participants played a card game in which they could lie to others to steal high or low amounts of money. To manipulate SoO, the virtual body was seen and controlled from a first-person perspective, with hands attached or detached, or from a third-person perspective. In third-person perspective, SoO was significantly reduced and more egoistic lies were produced in high reward conditions. Thus, SoO reduction and high monetary reward facilitate dishonest behavior, likely by separating the self from the dishonest actions performed through the disowned body. Because most future interactions will likely occur in a digital metaverse, our results may have crucial societal impact.

Reluctance against the machine: Retrieval of observational stimulus-response episodes in online settings emerges when interacting with a human, but not with a computer partner

Observing how another person responds to a stimulus creates stimulus–response (SR) episodes. These can be retrieved from memory on later occasions, which means that observed responses are utilized for regulating one’s own actions. Until now, evidence for storage and retrieval of observationally acquired SR episodes was limited to dyadic face-to-face interactions between two partners who respond in an alternating fashion. In two preregistered studies (total N = 252), we demonstrate for the first time that observational SR episodes can also be acquired in online interactions: Robust retrieval effects emerged when observers believe to be interacting with another person. In turn, retrieval effects were absent when observers believe to be interacting with a computer. Our findings show that feature-based binding and retrieval principles are pervasive and also apply to social interactions, even under purely virtual conditions. We discuss implications of our findings for different explanatory accounts of social modulations of automatic imitation.

An event-coding account of attitudes

Attitudes (or opinions, preferences, biases, stereotypes) can be considered bindings of the perceptual features of the attitudes' object to affective codes with positive or negative connotations, which effectively renders them "event files" in terms of the Theory of Event Coding. We tested a particularly interesting implication of this theoretical account: that affective codes might "migrate" from one event file to another (i.e., effectively function as a component of one while actually being part of another), if the two files overlap in terms of other features. We tested this feature-migration hypothesis by having participants categorize pictures of fictitious outer space characters as members of two fictitious races by pressing a left or right key, and to categorize positive and negative pictures of the International Affective Picture System (IAPS) as positive and negative by using the same two keys. When the outer space characters were later rated for likability, members of the race that was categorized by means of the same key as positive IAPS pictures were liked significantly more than members of the race that was categorized with the same key as negative IAPS pictures - suggesting that affective feature codes from the event files for the IAPS pictures effectively acted as an ingredient of event files for the outer space characters that shared the same key. These findings were fully replicated in a second experiment in which the two races were replaced by two unfamiliar fonts. These outcomes are consistent with the claim that attitudes, opinions, and preferences are represented in terms of event files and created by feature binding.

Enfacing a female reduces the gender-science stereotype in males

The enfacement illusion refers to the illusory perception that features of another face that moves in synchrony with one's own facial movements become part of one's own body. Here, we tested whether males whose facial movements are synchronized with a virtual female face exhibit a less pronounced implicit gender-science stereotype than males whose movements are not synchronized. Results show that illusory ownership and agency of the face with opposite gender was successfully induced, and that synchrony significantly reduced the implicit gender-science stereotype as compared with nonsynchrony. Our findings are in line with previous demonstrations about being synchronized with other individuals facilitates feature migration-that is, the integration of their features into one's self-representation.

Representing Oneself and Others

Human beings are assumed to own a concept of their self, but it remains a mystery how they represent themselves and others. I shall develop a theoretical framework, inspired by the Theory of Event Coding, of how people represent themselves and others, how and under which circumstances these two kinds of representations interact and what consequences this has. In a nutshell, I shall argue that self- and other-representations can overlap to the degree that they share features, that the shared features are particularly relevant or salient, and that the individual is under a particular metacontrol state. Then I shall argue that self-concepts emerge through active exploration of one's physical and social environment during infancy and childhood, as well as through cultural learning, and that their main purpose is related to social communication but not online action control.