Research interests

When humans interact, they spend a lot of their interaction sharing mental processes. They share attention to things that cross their path, intentions and commitments in collaboration and cooperation, information while teaching and gossiping, and emotions about the things that happen to them. If individuals interact multiple times, they will, as a consequence, over time create a distinct set of shared memories, accomplishments, knowledge, discourse, attitudes and preferences. As such, it is clear that being able to engage in shared psychology is fundamental for participating in the human social world. But how exactly does shared psychology work? And what role does it play in the formation of social relationships?

  • Sharing psychological processes
  • Social interaction & social closeness
  • Theory of mind & communication
  • Developmental & Comparative social cognition

To answer this question, my research aims to increase our understanding of how sharing psychological processes works and how it influences social relationships in human adults, how it develops in young children, and how our capacity to share mental processes compares to other animals. To do so, we conduct primarily behavioral experiments with human infants and adults, and great apes. Additionally, we conduct longitudinal correlational studies to track the relationship between sharing mental states and social closeness over time.

Research Projects

  • Connecting through joint attention

    The effect of attending a stimulus together on subsequent social closeness

    Humans connect through a variety of social activities. In contrast to other animals, many human social activities revolve around aligning and sharing mental states about the world around us, like for example when we go to see a movie together. So is this sharing of mental states about the world a psychological mechanism that allows us to build a social connection with others? If so, then this process would be fundamental in what it means to live in a human social world.

    In order to answer this question we first conducted an experiment where college students engaged in two sessions of a cognitive task, one in which they attended to the same stimulus with one partner, and one in which they attended to a different stimulus with another partner. After each session we asked them a variety of questions, eight of which were part of a social closeness scale. We then compared how close participant felt towards the partner with whom they had attended to the same stimuli versus the partner with whom they had attended to different stimuli. We found that participants reported to feel closer towards the partner with whom they had attended to the stimulus together. We therefore concluded that even something minimal as sharing attention towards an external stimulus already causes individuals to feel more connected towards each other.

    Next, we wanted to know if the effect of joint attention on social closeness emerges early in child development. We therefore conducted an experiment with 2.5 year olds in which they were watching a video together with an adult experimenter, or the experimenter sat in the same place, but was not able to see the video and was reading their own book instead. We found that children are more willing to interact with the experimenter (i.e. approach faster) after having watched the video together than when the experimenter had been reading their own book.

    Finally, we wanted to know if such an effect was truly unique to the human species. We therefore modified the procedure to conduct a similar experiment with great apes. In Study 1 chimpanzees and bonobos engaged in one trial in which they were watching a video together with a human experimenter and one trial in which the human experimenter sat in the same place, but could not see the screen and was reading her own clipboard. Surprisingly, we found that the apes approached the experimenter faster after having watched the video together than after having watched it alone. To make sure that this effect was not limited to interactions with humans in a zoo environment, Study 2 had pairs of chimpanzees in a sanctuary engage in one trial where they watched a video on the same screen, and one trial where they watched a video on different screens. Here, we found that the pairs of chimpanzees spent more time in the same part of the room when they had been watching the video together then when each of them had been watching their own video.

    Together, these studies show that sharing attention creates social closeness between individuals, that this effects emerges early in childhood, and that we share at least the fundamentals of this mechanism with our closest living evolutionary relatives, the great apes.


    Wolf, W., Launay, J., & Dunbar, R. I. M. (2015). Joint attention, shared goals, and social bonding. British Journal of Psychology, 107(2), 322–337.

    Wolf, W., & Tomasello, M. (2019). Visually attending to a video together facilitates great ape social closeness. Proceedings of the Royal Society B286(1907), 20190488.

    Wolf, W., & Tomasello, M. (2020). Watching a video together creates social closeness between children and adults. Journal of experimental child psychology189, 104712.

  • Ostracism Online

    Studying social sharing online: A new paradigm for studying online ostracism

    New technology allows for new ways of sharing internal states. We publish information about our lives on Facebook profiles, share pictures through instagram, or send short videoclips containing snippets of our lives through Snapchat. When we use these novel ways of sharing our lives, we need different ways of inferring that we have actually shared our internal states with others. That is, where we used to simply rely on physical cues such as a look or a smile, this new technology requires cues that can get a signal across in the absence of others’ physical presence. Many social media platforms have therefore introduced digital cues aimed at letting others know that you have shared attention to a part of another individual’s life, such as a Facebook ‘Like’. Signals such as these allow individuals to infer and experience a sense of sharedness and connection to others, even if those others respond from the others side of the world, perhaps minutes, hours or months after the original signal was send.

    However, with new means of sharing, connecting and inclusion come new means of exclusion and ostracism. Being excluded by others is a highly unpleasant and stressful experience. This is not surprising, as for the majority our evolutionary history not being included in a group usually meant certain death. So do the digitally communicated signals that allow us to share our lives with others have the same impact as real life ostracism?

    To answer this question we created Ostracism Online, a paradigm in which participants make a social media-like profile after which they are put in a group with other (pre-programmed) participants who can ‘Like’ their profile. Crucially, the software allows researchers to manipulate the amount of ‘Likes’ a participant get. We hypothesized that if individuals indeed use digital cues such as ‘Likes’ to infer whether or not others are sharing their internal states about their lives with them, then an absence of ‘Likes’ should elicit negative psychological consequences in individuals that are similar to the consequences of ostracism in previously developed paradigms.

    We thus examined the effects of exclusion in the Ostracism online paradigm and the classic Cyberball manipulation (a commonly used digital paradigm based on the original studies in which participants were excluded from tossing a ball around) on participants’ self reported need-threat and mood, and found similar effects. We thus conclude that the absence of digital social cues of inclusion in social media has the same negative psychological effects as has been found in previous real life and digital (non-social media based) ostracism paradigms. Furthermore, our results show that Ostracism Online is a cost-effective, easy to use, and ecologically valid tool for studying the psychological and behavioral effects of ostracism.


    For a more detailed overview of the procedure and results Click here.


    You can download the software here


    Published papers

    Wolf, W., Levordashka, A., Ruff, J. R., Kraaijeveld, S., Lueckmann, J. M., & Williams, K. D. (2015). Ostracism Online: A social media ostracism paradigm. Behavior Research Methods, 47(2), 361–373.