Recent Submissions

  • Evaluating the relative contributions of copying and reconstruction processes in cultural transmission episodes

    Strachan, James W. A.; Curioni, Arianna; Constable, Merryn D.; Knoblich, Günther; Charbonneau, Mathieu (Public Library of Science, 2021)
    The ability to transmit information between individuals through social learning is a foundational component of cultural evolution. However, how this transmission occurs is still debated. On the one hand, the copying account draws parallels with biological mechanisms for genetic inheritance, arguing that learners copy what they observe and novel variations occur through random copying errors. On the other hand, the reconstruction account claims that, rather than directly copying behaviour, learners reconstruct the information that they believe to be most relevant on the basis of pragmatic inference, environmental and contextual cues. Distinguishing these two accounts empirically is difficult based on data from typical transmission chain studies because the predictions they generate frequently overlap. In this study we present a methodological approach that generates different predictions of these accounts by manipulating the task context between model and learner in a transmission episode. We then report an empirical proof-of-concept that applies this approach. The results show that, when a model introduces context-dependent embedded signals to their actions that are not intended to be transmitted, it is possible to empirically distinguish between competing predictions made by these two accounts. Our approach can therefore serve to understand the underlying cognitive mechanisms at play in cultural transmission and can make important contributions to the debate between preservative and reconstructive schools of thought.
  • Prioritization of arbitrary faces associated to self: An EEG study

    Woźniak, Mateusz; Kourtis, Dimitrios; Knoblich, Günther (Public Library of Science, 2018)
    Behavioral and neuroimaging studies have demonstrated that people process preferentially self-related information such as an image of their own face. Furthermore, people rapidly incorporate stimuli into their self-representation even if these stimuli do not have an intrinsic relation to self. In the present study, we investigated the time course of the processes involved in preferential processing of self-related information. In two EEG experiments three unfamiliar faces were identified with verbal labels as either the participant, a friend, or a stranger. Afterwards, participants judged whether two stimuli presented in succession (ISI = 1500ms) matched. In experiment 1, faces were followed by verbal labels and in experiment 2, labels were followed by faces. Both experiments showed the same pattern of behavioral and electrophysiological results. If the first stimulus (face or label) was associated with self, reaction times were faster and the late frontal positivity following the first stimulus was more pronounced. The self-association of the second stimulus (label or face) did not affect response times. However, the central-parietal P3 following presentation of the second stimulus was more pronounced when the second stimulus was preceded by self-related first stimulus. These results indicate that even unfamiliar faces that are associated to self can activate a self-representation. Once the self-representation has been activated the processing of ensuing stimuli is facilitated, irrespective of whether they are associated with the self.
  • Crossmodal correspondences as common ground for joint action

    Schmitz, Laura; Knoblich, Günther; Deroy, Ophelia; Vesper, Cordula (Elsevier, 2021)
    When performing joint actions, people rely on common ground – shared information that provides the required basis for mutual understanding. Common ground can be based on people's interaction history or on knowledge and expectations people share, e.g., because they belong to the same culture or social class. Here, we suggest that people rely on yet another form of common ground, one that originates in their similarities in multisensory processing. Specifically, we focus on ‘crossmodal correspondences’ – nonarbitrary associations that people make between stimulus features in different sensory modalities, e.g., between stimuli in the auditory and the visual modality such as high-pitched sounds and small objects. Going beyond previous research that focused on investigating crossmodal correspondences in individuals, we propose that people can use these correspondences for communicating and coordinating with others. Initial support for our proposal comes from a communication game played in a public space (an art gallery) by pairs of visitors. We observed that pairs created nonverbal communication systems by spontaneously relying on ‘crossmodal common ground’. Based on these results, we conclude that crossmodal correspondences not only occur within individuals but that they can also be actively used in joint action to facilitate the coordination between individuals.
  • Infants understand collaboration: Neural evidence for 9-month-olds’ attribution of shared goals to coordinated joint actions

    Begus, Katarina; Curioni, Arianna; Knoblich, Günther; Gergely, Gyorgy (Public Library of Science, 2020)
    Interpreting others’ actions as goal-directed, even when the actions are unfamiliar, is indispensable for social learning, and can be particularly important for infants, whose own action repertoire is limited. Indeed, young infants have been shown to attribute goals to unfamiliar actions as early as 3 months of age, but this ability appears restricted to actions performed by individuals. In contrast, attributing shared goals to actions performed by multiple individuals seems to emerge only in the second year of life. Considering the restrictions that this would impose on infants’ understanding and learning from interactions in their environment, we reexamine this ability by introducing 9-month-old infants to simple joint actions, in which two agents coordinate their actions toward the same goal. To establish whether infants formed an expectation about future actions of these agents, infants’ cortical activity was measured using functional near-infrared spectroscopy (fNIRS). The hemodynamic response, recorded in (p)STS, indicated that infants attributed goals to simultaneous and coordinated joint actions of two individuals. Thus, even prior to actively engaging in collaborative activities themselves, infants can attribute shared goals to observed joint actions, enabling infants to learn from, and about, the complementary roles of social interactions, a central characteristic of human culture.
  • Giving a helping hand: effects of joint attention on mental rotation of body parts

    Böckler, Anne; Knoblich, Günther; Sebanz, Natalie (Springer, 2011)
    Research on joint attention has addressed both the effects of gaze following and the ability to share representations. It is largely unknown, however, whether sharing attention also affects the perceptual processing of jointly attended objects. This study tested whether attending to stimuli with another person from opposite perspectives induces a tendency to adopt an allocentric rather than an egocentric reference frame. Pairs of participants performed a handedness task while individually or jointly attending to rotated hand stimuli from opposite sides. Results revealed a significant flattening of the performance rotation curve when participants attended jointly (experiment 1). The effect of joint attention was robust to manipulations of social interaction (cooperation versus competition, experiment 2), but was modulated by the extent to which an allocentric reference frame was primed (experiment 3). Thus, attending to objects together from opposite perspectives makes people adopt an allocentric rather than the default egocentric reference frame.
  • Do Implicit and Explicit Measures of the Sense of Agency Measure the Same Thing?

    Dewey, John A.; Knoblich, Günther (Public Library of Science, 2014)
    The sense of agency (SoA) refers to perceived causality of the self, i.e. the feeling of causing something to happen. The SoA has been probed using a variety of explicit and implicit measures. Explicit measures include rating scales and questionnaires. Implicit measures, which include sensory attenuation and temporal binding, use perceptual differences between self- and externally generated stimuli as measures of the SoA. In the present study, we investigated whether the different measures tap into the same self-attribution processes by determining whether individual differences on implicit and explicit measures of SoA are correlated. Participants performed tasks in which they triggered tones via key presses (operant condition) or passively listened to tones triggered by a computer (observational condition). We replicated previously reported effects of sensory attenuation and temporal binding. Surprisingly the two implicit measures of SoA were not significantly correlated with each other, nor did they correlate with the explicit measures of SoA. Our results suggest that some explicit and implicit measures of the SoA may tap into different processes.
  • Expecting to lift a box together makes the load look lighter

    Doerrfeld, Adam; Sebanz, Natalie; Shiffrar, Maggie (Springer, 2012)
    The action abilities of an individual observer modulate his or her perception of spatial properties of the environment and of objects. The present study investigated how joint action abilities shape perception. Four experiments examined how the intention to lift an object with another individual affects perceived weight. In Experiments 1, 2a, and 2b, participants judged the perceived weight of boxes while expecting to lift them either alone or with a co-actor. In Experiment 3, the co-actor was healthy or injured. Participants intending to lift a box with a co-actor perceived the box as lighter than participants intending to lift the same box alone, provided that the co-actor appeared healthy and therefore capable of helping. These findings suggest that anticipated effort modulates the perception of object properties in the context of joint action. We discuss implications for the role of action prediction and action simulation processes in social interaction.
  • Communication and action predictability: two complementary strategies for successful cooperation

    Woźniak, Mateusz; Knoblich, Günther (Royal Society, 2022)
    Making one's actions predictable and communicating what one intends to do are two strategies to achieve interpersonal coordination. It is less clear whether these two strategies are mutually exclusive or whether they can be used in parallel. Here, we asked how the availability of communication channels affects the use of strategy to make one's actions predictable. In three experiments, we investigated how people reach joint decisions if they are not allowed to communicate at all (Experiment 1), allowed minimal reciprocal communication (Experiment 2), or allowed to use the full range of conventional communication (Experiment 3). We found that when participants were not allowed to communicate, coordination was achieved by increasing action predictability. When conventional communication was allowed, there were no attempts to increase action predictability. In the minimal reciprocal communication condition, successful pairs both increased action predictability and established a communication system. Overall, this study demonstrates that people are able to flexibly adapt to coordination challenges during joint decision making and that communication reduces behavioural constraints on joint action coordination.
  • Understanding others’ distal goals from proximal communicative actions

    Dockendorff, Martin; Schmitz, Laura; Vesper, Cordula; Knoblich, Günther (Public Library of Science, 2023)
    Many social interactions require individuals to coordinate their actions and to inform each other about their goals. Often these goals concern an immediate (i.e., proximal) action, as when people give each other a brief handshake, but they sometimes also refer to a future (i.e. distal) action, as when football players perform a passing sequence. The present study investigates whether observers can derive information about such distal goals by relying on kinematic modulations of an actor’s instrumental actions. In Experiment 1 participants were presented with animations of a box being moved at different velocities towards an apparent endpoint. The distal goal, however, was for the object to be moved past this endpoint, to one of two occluded target locations. Participants then selected the location which they considered the likely distal goal of the action. As predicted, participants were able to detect differences in movement velocity and, based on these differences, systematically mapped the movements to the two distal goal locations. Adding a distal goal led to more variation in the way participants mapped the observed movements onto different target locations. The results of Experiments 2 and 3 indicated that this cannot be explained by difficulties in perceptual discrimination. Rather, the increased variability likely reflects differences in interpreting the underlying connection between proximal communicative actions and distal goals. The present findings extend previous research on sensorimotor communication by demonstrating that communicative action modulations are not restricted to predicting proximal goals but can also be used to infer more distal goals.
  • Inter-individual coordination in walking chimpanzees

    Schweinfurth, Manon K.; Baldridge, Dylan B.; Finnerty, Kyle; Call, Josep; Knoblich, Günther (Elsevier, 2022)
    Humans, like many other animals, live in groups and coordinate actions with others in social settings. Such interpersonal coordination may emerge unconsciously and when the goal is not the coordination of movements, as when falling into the same rhythm when walking together. Although one of our closest living relatives, the chimpanzee (Pan troglodytes), shows the ability to succeed in complex joint action tasks where coordination is the goal, little is known about simpler forms of joint action. Here, we examine whether chimpanzees spontaneously synchronize their actions with conspecifics while walking together. We collected data on individual walking behavior of two groups of chimpanzees under semi-natural conditions. In addition, we assessed social relationships to investigate potential effects on the strength of coordination. When walking with a conspecific, individuals walked faster than when alone. The relative phase was symmetrically distributed around 0° with the highest frequencies around 0, indicating a tendency to coordinate actions. Further, coordination was stronger when walking with a partner compared with two individuals walking independently. Although the inter-limb entrainment was more pronounced between individuals of similar age as a proxy for height, it was not affected by the kinship or bonding status of the walkers or the behaviors they engaged in immediately after the walk. We conclude that chimpanzees adapt their individual behavior to temporally coordinate actions with others, which might provide a basis for engaging in other more complex forms of joint action. This spontaneous form of inter-individual coordination, often called entrainment, is thus shared with humans.
  • Joint rushing alters internal timekeeping in non-musicians and musicians

    Wolf, Thomas; Knoblich, Günther (Nature Publishing Group, 2022)
    Recent studies have shown that people engaging in joint rhythmic activity unintentionally increase their tempo. The same tempo increase does not occur when the same rhythmic activity is performed alone. This phenomenon is known as joint rushing. In two experiments, we investigated whether joint rushing is caused by correction mechanisms that facilitate sensorimotor synchronization. Because such correction mechanisms require perceptual input, joint rushing should discontinue when auditory feedback in a joint rhythmic activity is interrupted. This prediction was clearly supported in two experiments, one with musicians and one with non-musicians. Surprisingly, there was no indication that the amount of joint rushing differed between musicians and non-musicians. Furthermore, neither musicians nor non-musicians were able to return to the initially instructed tempo after feedback had been interrupted. This result indicates that joint rushing has a lasting effect on an internal timekeeper. An important question for future research is whether joint rushing is only a dysfunctional side effect of the way sensorimotor synchronization works or whether it has a function in enabling precise temporal coordination between different individuals.
  • Differences in working memory coding of biological motion attributed to oneself and others

    Woźniak, Mateusz; Schmidt, Timo Torsten; Wu, Yuan-hao; Blankenburg, Felix; Hohwy, Jakob (Wiley, 2022)
    The question how the brain distinguishes between information about self and others is of fundamental interest to both philosophy and neuroscience. In this functional magnetic resonance imaging (fMRI) study, we sought to distinguish the neural substrates of representing a full-body movement as one's movement and as someone else's movement. Participants performed a delayed match-to-sample working memory task where a retained full-body movement (displayed using point-light walkers) was arbitrarily labeled as one's own movement or as performed by someone else. By using arbitrary associations we aimed to address a limitation of previous studies, namely that our own movements are more familiar to us than movements of other people. A searchlight multivariate decoding analysis was used to test where information about types of movement and about self-association was coded. Movement specific activation patterns were found in a network of regions also involved in perceptual processing of movement stimuli, however not in early sensory regions. Information about whether a memorized movement was associated with the self or with another person was found to be coded by activity in the left middle frontal gyrus (MFG), left inferior frontal gyrus (IFG), bilateral supplementary motor area, and (at reduced threshold) in the left temporoparietal junction (TPJ). These areas are frequently reported as involved in action understanding (IFG, MFG) and domain-general self/other distinction (TPJ). Finally, in univariate analysis we found that selecting a self-associated movement for retention was related to increased activity in the ventral medial prefrontal cortex.
  • Understanding distal goals from proximal communicative actions

    Dockendorff, Martin; Schmitz, Laura; Knoblich, Günther; Vesper, Cordula (Cognitive Science Society, 2021)
    Can people interpret communicative action modulations in terms of the actor’s distal goal? We investigated situations in which the proximal goal of an action (i.e., the movement endpoint) does not overlap with its distal goal (i.e., a final location beyond the movement endpoint). Participants were presented with animations of an object being moved at different velocities towards a designated endpoint. The distal goal, however, was for the object to be moved past this endpoint, to one of two occluded final locations. Participants were asked to select the location which they considered the likely distal goal of the action. As predicted, participants detected differences in movement velocity and, based on these differences, systematically mapped the movements to the two distal goal locations. These findings extend previous research on sensorimotor communication by demonstrating that communicative action modulations are not restricted to proximal goals but can also contain information about distal goals.
  • Strategic Task Decomposition in Joint Action

    Gordon, Jeremy; Knoblich, Günther; Pezzulo, Giovanni (Wiley, 2023)
    The core of human cooperation is people's ability to perform joint actions. Frequently, this requires effectively decomposing a joint task into individual subtasks, for example, when jointly shopping at the market to buy food. Surprisingly, little is known about how collaborators balance the costs of establishing a joint strategy for such decompositions and its expected benefits for a joint goal. We created a new online task that required pairs of randomly matched participants to jointly collect colored items. We then systematically varied the cognitive costs and benefits of applying a color-splitting strategy. The results showed that pairs adopted a color-splitting strategy more often when necessary to lower cognitive costs. However, once the strategy was jointly adopted, it continued to be used even when the cost–benefits changed. Our results provide first insights on how people decompose joint tasks into individual components and how decomposition strategies may evolve into conventions.
  • Human adults prefer to cooperate even when it is costly

    Curioni, Arianna; Voinov, Pavel; Allritz, Matthias; Wolf, Thomas; Call, Josep; Knoblich, Günther (Royal Society, 2022)
    Joint actions are cooperative activities where humans coordinate their actions to achieve individual and shared goals. While the motivation to engage in joint action is clear when a goal cannot be achieved by individuals alone, we asked whether humans are motivated to act together even when acting together is not necessary and implies incurring additional costs compared to individual goal achievement. Using a utility-based empirical approach, we investigated the extent of humans' preference for joint action over individual action, when the instrumental costs of performing joint actions outweigh the benefits. The results of five experiments showed that human adults have a stable preference for joint action, even if individual action is more effective to achieve a certain goal. We propose that such preferences can be understood as ascribing additional reward value to performing actions together.
  • Videos posted on the internet provide evidence for joint rushing in naturalistic social interactions

    Wolf, Thomas; Novák, Tamás; Knoblich, Günther (Nature Publishing Group, 2023)
    When people engage in rhythmic joint actions, they unintentionally increase their tempo. However, this phenomenon of joint rushing has so far been investigated only under very specific and somewhat artificial conditions. Therefore, it remains unclear whether joint rushing generalizes to other instances of rhythmic joint action. In this study our aim was to investigate whether joint rushing can also be observed in a wider range of naturalistic rhythmic social interactions. To achieve this, we retrieved videos of a wide range of rhythmic interactions from an online video-sharing platform. The data suggest that joint rushing indeed can also be observed in more naturalistic social interactions. Furthermore, we provide evidence that group size matters for how tempo unfolds in social interactions with larger groups showing a stronger tempo increase than smaller groups. Comparing the data from naturalistic interactions with data collected in a lab study further showed that unintended tempo changes in social interactions are reduced in naturalistic interactions compared to interactions in a lab context. It is an open question which factors led to this reduction. One possibility is that humans might have come up with strategies to reduce the effects of joint rushing.
  • The Sense of Commitment: A Minimal Approach

    Michael, John; Sebanz, Natalie; Knoblich, Günther; Department of Cognitive Science (Frontiers Media, 2016)
    This paper provides a starting point for psychological research on the sense of commitment within the context of joint action. We begin by formulating three desiderata: to illuminate the motivational factors that lead agents to feel and act committed, to pick out the cognitive processes and situational factors that lead agents to sense that implicit commitments are in place, and to illuminate the development of an understanding of commitment in ontogeny. In order to satisfy these three desiderata, we propose a minimal framework, the core of which is an analysis of the minimal structure of situations which can elicit a sense of commitment. We then propose a way of conceptualizing and operationalizing the sense of commitment, and discuss cognitive and motivational processes which may underpin the sense of commitment.
  • When Height Carries Weight: Communicating Hidden Object Properties for Joint Action

    Schmitz, Laura; Vesper, Cordula; Sebanz, Natalie; Knoblich, Günther; Department of Cognitive Science (Wiley, 2018)
    In the absence of pre-established communicative conventions, people create novel communication systems to successfully coordinate their actions toward a joint goal. In this study, we address two types of such novel communication systems: sensorimotor communication, where the kinematics of instrumental actions are systematically modulated, versus symbolic communication. We ask which of the two systems co-actors preferentially create when aiming to communicate about hidden object properties such as weight. The results of three experiments consistently show that actors who knew the weight of an object transmitted this weight information to their uninformed co-actors by systematically modulating their instrumental actions, grasping objects of particular weights at particular heights. This preference for sensorimotor communication was reduced in a fourth experiment where co-actors could communicate with weight-related symbols. Our findings demonstrate that the use of sensorimotor communication extends beyond the communication of spatial locations to non-spatial, hidden object properties.
  • Perceptual judgments made better by indirect interactions: Evidence from a joint localization task

    Voinov, Pavel Valeryevich; Sebanz, Natalie; Knoblich, Günther; Department of Cognitive Science (Public Library of Science, 2017)
    Others’ perceptual judgments tend to have strong effects on our own, and can improve perceptual judgments when task partners engage in communication. The present study investigated whether individuals benefit from others’ perceptual judgments in indirect interactions, where outcomes of individual decisions can be observed in a shared environment. Participants located a target in a 2D projection of a 3D container either from two complementary viewpoints (Experiment 1), or from a single viewpoint (Experiment 2). Uncertainty about the target location was high on the front-back dimension and low on the left-right dimension. The results showed that pairs of participants benefitted from taking turns in providing judgments. When each member of the pair had access to one complementary perspective, the pair achieved the same level of accuracy as when the two individuals had access to both complimentary perspectives and better performance than when the two individuals had access to only one perspective. These findings demonstrate the important role of a shared environment for successful integration of perceptual information while highlighting limitations in assigning appropriate weights to others’ judgments.
  • Joint action coordination in expert-novice pairs: Can experts predict novices’ suboptimal timing?

    Wolf, Thomas; Sebanz, Natalie; Knoblich, Günther; Department of Cognitive Science (Elsevier, 2018)
    Previous research has established that skilled joint action partners use predictive models to achieve temporal coordination, for instance, when playing a music duet. But how do joint action partners with different skill levels achieve coordination? Can experts predict the suboptimal timing of novices? What kind of information allows them to predict novices’ timing? To address these questions, we asked skilled pianists to perform duets with piano novices. We varied whether, prior to performing duets, experts were familiar with novices’ performances of their individual parts of the duets and whether experts had access to the musical scores including the novices’ part of the duet. Familiarity with the score led to better coordination when the score implied a difficult passage. Familiarity with novices’ performances led to better joint action coordination for the remaining parts of the duet. Together, the results indicate that experts are surprisingly flexible in predicting novices’ suboptimal timing.

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