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EASP – European Association of Social Psychology

EASP Seedcorn Grant Report by Anouk van der Weiden

04.11.2015, by Kai Sassenberg in grant report

Brain Center Rudolf Magnus, University Medical Center Utrecht, The Netherlands; Project: When Two Become One (in cooperation with Roman Liepelt and Thomas Mussweiler)

How do people distinguish their own actions from those of others in social interaction? How does this affect their perception of self and other? These are the questions I investigated with the EASP postdoctoral research seedcorn grant.

In social interactions, people are able to distinguish self and other by representing (i.e., coding) their own actions in reference to their interaction partner. For example, people tend to spatially code their actions as being 'left' when sitting to the left of their interaction partner, and vice versa1. This spatial coding is commonly measured using the well-documented social Simon task, in which participants are instructed to respond to stimuli that are spatially congruent (e.g., left) or incongruent (e.g., right) with their seating arrangement, resulting in slowed reaction times (i.e., action interference) when incongruent2.

Yet, people do not always use spatial references to code and distinguish own and others’ actions. That is, action interference as a function of spatial coding is reduced when interacting with an unfriendly co-actor compared with a friendly co-actor3; an out-group member (e.g., of other ethnicity) compared with an in-group member (e.g., of same ethnicity)4, and in independent (e.g., division of labor) compared with interdependent (e.g., cooperative) action contexts5. This social modulation of spatial coding has been suggested to occur because people pay more attention to similar (e.g., friendly or in-group) rather than dissimilar (e.g., unfriendly or out-group) others6. However, as dissimilar others are actually more likely to attract attention7, this model cannot fully explain the findings. More recently it has been proposed that actions of similar others may cause more response conflict because their actions are represented in a more similar way as one’s own actions1. However, this account does not easily explain why, for example, the mere presence of a metronome or a Chinese waving cat do induce action interference6, whereas unfriendly or independent interaction partners do not3,5.

The main aim of my EASP proposal was to test whether, depending on their interpersonal goals, people code their actions in reference to either personal (e.g., friendliness) or impersonal (e.g., spatial) characteristics. That is, when in an interdependent (e.g., cooperative) or satisfactory relationship (e.g., with an in-group member or friendly other), people are biased to perceive similarities rather than differences between self and other at a personal level8. In these cases, people more easily code and distinguish their actions in reference to impersonal (e.g., spatial) characteristics. As such, they avoid a dissociation of self and other on a personal level. Yet, in the presence of others with whom one has no relationship, or an unsatisfactory relationship (e.g., with an out-group member or unfriendly other), people are less likely to perceive similarities between self and other, or are even motivated to dissociate themselves from the other9. In these cases, people are more likely to code and distinguish their actions in reference to personal (e.g., identity) characteristics. For this purpose, I visited and collaborated with Roman Liepelt (an expert on the cognitive mechanisms underlying joint action performance) and Thomas Mussweiler (an expert on social comparison and perceived similarity). Following intensive and inspiring discussions with these experts, I ran three studies that each tapped into the social nature and consequences of joint action coding.

Study 1: Predictability

In a first study, I investigated whether people are less able to distinguish own and other’s actions through spatial action coding when their interaction partner behaves in a dissimilar and unpredictable way. For this purpose, I employed an auditory social Simon task in which the participant on the left had to respond to low tones, and the participant on the right to high tones (or vice versa). The tones were presented to the left ear or the right ear, rendering the tones congruent (i.e., low tone presented in left ear) or incongruent (i.e., low tone presented to right ear) to the participants’ seating arrangement. In the predictable baseline condition, both participants received identical stimuli (i.e., same tone in same ear), and could thus predict whether their interaction partner was going to respond, or not. Crucially, in the unpredictable condition, both participants received different stimuli, such that they only heard the same tone on 50 % of the trials (25 % in same ear, 25 % in other ear), and were thus unable to predict their interaction partner’s responses. Analyses revealed that spatial action coding is indeed decreased when the interaction partner behaves unpredictably. In further analyses I will explore the role of participants’ attachment style in coding the actions of unpredictable others.

Study 2: Spatial versus Social Action Coding

In a second study, I tested the hypothesis that people are more inclined to code their actions in reference to spatial characteristics when they are similar to their interaction partner, while they are more inclined to code their actions in reference to identity characteristics when they are dissimilar to their interaction partner. To test this hypothesis, I developed a multi-dimensional social Simon task, in which participants responded to blue or orange words. These words were either their own name, their co-actor’s name, or a no name control condition (identity dimension), and were presented either on the left, middle, or right of a computer screen (spatial dimension). Perceived similarity between co-actors was manipulated through a minimal group paradigm, creating in-group and out-group participant pairs. Preliminary results show strong spatial and identity interference effects. In contrast to previous research, spatial interference was unaffected by perceived group membership. However, identity interference was enhanced when interacting with dissimilar compared with similar others, indicating that depending on the social context humans use various reference frames to code their actions.

Study 3: Experienced control

Finally, I studied whether people experience more control over joint task performance when they distinguish own and others’ actions by representing their own actions in spatial reference to their interaction partner. Based on the notion that people generally experience more control over behaviors that are consistent with how the behavior is represented10, joint action coding should especially enhance experienced control over responses to spatially congruent stimuli. In a first pilot study I measured experienced control after each trial as a function of spatial congruency. Although I was able to replicate the spatial congruency effect in this set-up, I could not detect differences in experienced control over congruent versus incongruent trials. Perhaps variations in experienced control as a function of spatial congruency are too subtle to pick up on a trial level. Hence, in a second study, I manipulated the percentage of congruent trials (20 %, 50 %, or 80 %) between participants, and measured experienced control afterwards. Results revealed that the spatial congruency effect was strongest in the 80 % condition, followed by the 20% condition (although reversed), and the 50 % condition. In line with the hypotheses, the results further suggest that people experience more control when trials are 80% congruent (compared with 50 % or 20 %). Surprisingly, however, experienced control correlated negatively with the spatial congruency effect in the 80% condition. It thus seems that different processes are at play that need to be further disentangled in follow-up studies.

Together, these studies have yielded promising results that will stimulate further research and collaboration with Roman Liepelt, Thomas Müssweiller, and their lab members. As such, the EASP postdoctoral seedcorn grant allowed me to extend my network and gather first evidence for my ideas. The data already served as input for a conference presentation at the European Society for Cognitive Psychology (ESCOP) in September, as part of a symposium on the "social antecedents and consequences of action control". Furthermore, the studies produced valuable pilot data for future grant applications.


  1. Dolk, T., Hommel, B., Colzato, L. S., Schütz-Bosbach, S., Prinz, W., & Liepelt, R. (2014). The joint Simon effect: a review and theoretical integration. Frontiers in Psychology, 5, 974.
  2. Sebanz, N., Knoblich, G., & Prinz, W. (2003). Representing others’ actions: just like one's own? Cognition, 88, B11–B21.
  3. Hommel, B., Colzato, L. S., & van den Wildenberg, W. P. M. (2009). How social are task representations? Psychological Science, 20, 794–8.
  4. McClung, J. S., Jentzsch, I., & Reicher, S. D. (2013). Group membership affects spontaneous mental representation: failure to represent the out-group in a joint action task. PloS One, 8, e79178.
  5. Ruys, K. I., & Aarts, H. (2010). When competition merges people’s behavior: Interdependency activates shared action representations. Journal of Experimental Social Psychology, 46, 1130–1133.
  6. Dolk, T., Hommel, B., Prinz, W., & Liepelt, R. (2013). The (not so) social Simon effect: A referential coding account. Journal of Experimental Psychology. Human Perception and Performance, 39, 1248–1260.
  7. Olson, J. M., & Janes, L. M. (2002). Vigilance for Differences: Heightened Impact of Differences on Surprise. Personality and Social Psychology Bulletin, 28, 1084–1093.
  8. Slotter, E. B., & Gardner, W. L. (2009). Where do you end and I begin? Evidence for anticipatory, motivated self–other integration between relationship partners. Journal of Personality and Social Psychology, 96, 1137–1151.
  9. Brewer, M. B. (1991). The Social Self: On Being the Same and Different at the Same Time. Personality and Social Psychology Bulletin, 17, 475–482.
  10. van der Weiden, A., Aarts, H., & Ruys, K. I. (2010). Reflecting on the action or its outcome: Behavior representation level modulates high level outcome priming effects on self-agency experiences. Consciousness and Cognition, 19, 21–32.