Periodic Reporting for period 1 - JORIGINS (Building blocks of human sociality: A comparative assessment of joint action in humans and their closest ape relatives)
Reporting period: 2023-11-01 to 2025-10-31
Many social animals collaborate, but only humans supposedly engage in joint action – cooperative interactions that involve normative, mutually obligating joint commitments (JCs). JC presumably facilitated the evolution of hyper-cooperation observed in human societies, including complex collaborations like governments, and has likely played a pivotal role in human evolution. Given the significance, there has been a long-standing interest in the developmental (i.e. ontogenetic) and evolutionary origins of human joint action capacities like JC.
One classical approach to assess the evolutionary and developmental building blocks of JC involves experiments with human children and nonhuman great apes (mostly chimpanzees), where individuals of each group interact with a human experimenter by playing a social game. In this paradigm, the experimenter then typically stops to interact, causing a sudden interruption to the task. Former results of this research showed that humans, yet never or rarely apes, reengage passive experimenters. This has been taken as evidence that humans engage in joint actions via JC, yet that apes’ interactions rely on egoistic motives.
Although these findings are important for our understanding of how human joint action evolved, it is important to note that such tasks are anthropocentric, as they involve engagement with human confederates and human-centric tasks. Drawing on a more ecologically valid approach, newer research related to this project demonstrated that when apes interact with conspecifics naturally, they appear to exhibit specific joint action capacities like JC. Yet firm conclusions cannot be drawn unless the following empirical issues are solved: i) behaviours do not permit insights into internal states, ii) comparative joint action research is still in its infancy, lacking a holistic picture of affective and behavioural processes supporting coordination, and iii) previous ape studies are deficient of critical experimental controls.
Building on and expanding unique expertise in this domain, this projects goal was to overcome the former challenges by pioneering a comparative investigation of spontaneous joint action coordination in human children and bonobos. Developing cutting-edge automated posture tracking and thermal imaging techniques, as well as timely experimental controls, this project explored pivotal joint action features like the fixing of communicative trouble, bodily synchrony, and JC-related emotions. The outputs will provide important insights into whether humans and apes share basic joint action capacities, notably related to JC, and hence reassess the question of the evolutionary building blocks of human sociality.
One classical approach to assess the evolutionary and developmental building blocks of JC involves experiments with human children and nonhuman great apes (mostly chimpanzees), where individuals of each group interact with a human experimenter by playing a social game. In this paradigm, the experimenter then typically stops to interact, causing a sudden interruption to the task. Former results of this research showed that humans, yet never or rarely apes, reengage passive experimenters. This has been taken as evidence that humans engage in joint actions via JC, yet that apes’ interactions rely on egoistic motives.
Although these findings are important for our understanding of how human joint action evolved, it is important to note that such tasks are anthropocentric, as they involve engagement with human confederates and human-centric tasks. Drawing on a more ecologically valid approach, newer research related to this project demonstrated that when apes interact with conspecifics naturally, they appear to exhibit specific joint action capacities like JC. Yet firm conclusions cannot be drawn unless the following empirical issues are solved: i) behaviours do not permit insights into internal states, ii) comparative joint action research is still in its infancy, lacking a holistic picture of affective and behavioural processes supporting coordination, and iii) previous ape studies are deficient of critical experimental controls.
Building on and expanding unique expertise in this domain, this projects goal was to overcome the former challenges by pioneering a comparative investigation of spontaneous joint action coordination in human children and bonobos. Developing cutting-edge automated posture tracking and thermal imaging techniques, as well as timely experimental controls, this project explored pivotal joint action features like the fixing of communicative trouble, bodily synchrony, and JC-related emotions. The outputs will provide important insights into whether humans and apes share basic joint action capacities, notably related to JC, and hence reassess the question of the evolutionary building blocks of human sociality.
The reporting of the work progress is structured into four parts: posture tracking algorithm (A), and observations of communicative trouble (B), bodily synchrony (C), and JC-related emotions (D). Please note that the project duration was shortened to 15 months instead of 24 months, which impacted the publication of results.
A. Developing a posture tracking algorithm to study gaze and keypoints in bonobos
• Progress: Satisfactory progress
• Brief summary of the work performed: We made substantial progress in developing a tracking algorithm to measure body key points and gaze in bonobos. To meet this goal, we trained an algorithm on over 700 bonobo images (quantifying movements of body joints and gaze) collected during the project. Specifically, we collected high-quality walking and gaze videos of 20 bonobos at La Vallée des Singes (LVdS), to validate and test the performance of the algorithm. This validation test is in progress and will be performed in the next few months. We plan on submitting this method paper (or possibly two, separating the walking and gaze data) in computer vision journals (e.g. IEEE) and/or a biology journal (e.g. PLoS Biology).
• Outcome and results: No published results yet, but work progress – especially the body and gaze tracking - has been disseminated at a conference as well as during further invited seminars/workshops.
• Achievement of scientific deliverables and milestones (partly achieved):
Deliverables: algorithms for gaze and key points mostly developed, requires further refinement before publication of method paper.
Milestones: method scientific paper to be submitted end of 2025.
B. Fixing communicative trouble in bonobos and human children (age 4)
• Progress: Satisfactory progress
• Brief summary of the work performed: We collected all the relevant observational data in bonobos (dataset with over 800 communication events from 15 bonobos, and about 80 communicative exchanges) yet not in human children. Due to the early termination of this project, the children data will have to be collected in future studies. The field work with bonobos took us much longer than expected (total of 10 months) as the behaviors in question did not appear as much as expected, and because the bonobos took longer to learn the respective tasks, see point C and D below. There were also tensions in the group, which caused delays in our research. The second paper within this work package/objective will be written & submitted to an interdisciplinary Open Access journal once we have collected the children data (planned in the years 2025/2026/2027).
• Outcome and results: No published results yet.
• Achievement of scientific deliverables and milestones (partly achieved):
Deliverables: data from bonobos available; data from children not yet present; manuscript reporting findings from bonobos/children still needs to be written.
Milestones: completed data collection bonobos in December 2024; data collection children starting in March 2025; scientific paper to be submitted end of 2025/early 2026.
C. Studying bodily synchrony and its link to JC in bonobos and human children (age 4)
• Progress: Satisfactory progress
• Brief summary of the work performed: We finished data collection with bonobos by conducting an experiment at the field site LVsD as defined in the objectives. The dataset included 14 bonobos and behavioral results from over 100 experimental trials, as required. We are now launching data collection in human children (University of Konstanz, UKON) in March 2025, though through the early termination of the grant the data collection phase in children has not yet been completed. The paper of this work package/objective will be written & submitted to an interdisciplinary Open Access journal once we have finished collecting the children data (presumably end of the year 2025).
• Outcome and results: No published results yet, but work progress/goals have been communicated at a conference as well as during further invited seminars/workshops.
• Achievement of scientific deliverables and milestones (partly achieved):
Deliverables: data from bonobos available; data from children not yet gathered; manuscript reporting findings from bonobos/children still to be submitted.
Milestones: completed data collection bonobos in December 2024 ; data collection children not yet started; submission of paper presumably end of 2025/early 2026.
D. JC-related emotions (aka "affective signatures") in bonobos and human children (age 4)
• Progress: Satisfactory progress
• Brief summary of the work performed: We finished data collection with bonobos by conducting a complex coordination experiment at the field site LVsD as defined in the objectives. The dataset includes 5 bonobos and over 150 trials; the number of trials was adapted based on a power analysis, to ensure statistical power at the low sample size of bonobo subjects. We are now launching data collection in human children (University of Konstanz, UKON) in March 2025, though through the early termination of the grant this phase has not yet been completed. The paper within this work package/objective will be written & submitted to an interdisciplinary Open Access journal once we have finished collecting the children data (presumably early 2026).
• Outcome and results: No published results yet, but work progress/goals have been communicated at a conference as well as during further invited seminars/workshops.
• Achievement of scientific deliverables and milestones (partly achieved):
Deliverables: data from bonobos; data from children not yet present; manuscript reporting findings from bonobos/children to be submitted in 2026.
Milestones: completed data collection bonobos in December 2024 ; data collection children not yet started; submission of paper in 2026.
A. Developing a posture tracking algorithm to study gaze and keypoints in bonobos
• Progress: Satisfactory progress
• Brief summary of the work performed: We made substantial progress in developing a tracking algorithm to measure body key points and gaze in bonobos. To meet this goal, we trained an algorithm on over 700 bonobo images (quantifying movements of body joints and gaze) collected during the project. Specifically, we collected high-quality walking and gaze videos of 20 bonobos at La Vallée des Singes (LVdS), to validate and test the performance of the algorithm. This validation test is in progress and will be performed in the next few months. We plan on submitting this method paper (or possibly two, separating the walking and gaze data) in computer vision journals (e.g. IEEE) and/or a biology journal (e.g. PLoS Biology).
• Outcome and results: No published results yet, but work progress – especially the body and gaze tracking - has been disseminated at a conference as well as during further invited seminars/workshops.
• Achievement of scientific deliverables and milestones (partly achieved):
Deliverables: algorithms for gaze and key points mostly developed, requires further refinement before publication of method paper.
Milestones: method scientific paper to be submitted end of 2025.
B. Fixing communicative trouble in bonobos and human children (age 4)
• Progress: Satisfactory progress
• Brief summary of the work performed: We collected all the relevant observational data in bonobos (dataset with over 800 communication events from 15 bonobos, and about 80 communicative exchanges) yet not in human children. Due to the early termination of this project, the children data will have to be collected in future studies. The field work with bonobos took us much longer than expected (total of 10 months) as the behaviors in question did not appear as much as expected, and because the bonobos took longer to learn the respective tasks, see point C and D below. There were also tensions in the group, which caused delays in our research. The second paper within this work package/objective will be written & submitted to an interdisciplinary Open Access journal once we have collected the children data (planned in the years 2025/2026/2027).
• Outcome and results: No published results yet.
• Achievement of scientific deliverables and milestones (partly achieved):
Deliverables: data from bonobos available; data from children not yet present; manuscript reporting findings from bonobos/children still needs to be written.
Milestones: completed data collection bonobos in December 2024; data collection children starting in March 2025; scientific paper to be submitted end of 2025/early 2026.
C. Studying bodily synchrony and its link to JC in bonobos and human children (age 4)
• Progress: Satisfactory progress
• Brief summary of the work performed: We finished data collection with bonobos by conducting an experiment at the field site LVsD as defined in the objectives. The dataset included 14 bonobos and behavioral results from over 100 experimental trials, as required. We are now launching data collection in human children (University of Konstanz, UKON) in March 2025, though through the early termination of the grant the data collection phase in children has not yet been completed. The paper of this work package/objective will be written & submitted to an interdisciplinary Open Access journal once we have finished collecting the children data (presumably end of the year 2025).
• Outcome and results: No published results yet, but work progress/goals have been communicated at a conference as well as during further invited seminars/workshops.
• Achievement of scientific deliverables and milestones (partly achieved):
Deliverables: data from bonobos available; data from children not yet gathered; manuscript reporting findings from bonobos/children still to be submitted.
Milestones: completed data collection bonobos in December 2024 ; data collection children not yet started; submission of paper presumably end of 2025/early 2026.
D. JC-related emotions (aka "affective signatures") in bonobos and human children (age 4)
• Progress: Satisfactory progress
• Brief summary of the work performed: We finished data collection with bonobos by conducting a complex coordination experiment at the field site LVsD as defined in the objectives. The dataset includes 5 bonobos and over 150 trials; the number of trials was adapted based on a power analysis, to ensure statistical power at the low sample size of bonobo subjects. We are now launching data collection in human children (University of Konstanz, UKON) in March 2025, though through the early termination of the grant this phase has not yet been completed. The paper within this work package/objective will be written & submitted to an interdisciplinary Open Access journal once we have finished collecting the children data (presumably early 2026).
• Outcome and results: No published results yet, but work progress/goals have been communicated at a conference as well as during further invited seminars/workshops.
• Achievement of scientific deliverables and milestones (partly achieved):
Deliverables: data from bonobos; data from children not yet present; manuscript reporting findings from bonobos/children to be submitted in 2026.
Milestones: completed data collection bonobos in December 2024 ; data collection children not yet started; submission of paper in 2026.
The results are not yet available and will be communicated in the consecutive scientific publications, submitted end of 2025 or 2026.
What could be said, however, is that the results will provide important insights into the role of emotions, communicative skills, bodily synchrony in the context of cooperation and joint commitment, highlighting parallels and differences between humans and bonobos.
The algorithms being developed will facilitate the automated quantification of fast-paced behavioral processes linked to bodily synchrony and gaze in naturalistic social interactions of nonhuman primates - a promising area currently emerging in the field of comparative cognition.
What could be said, however, is that the results will provide important insights into the role of emotions, communicative skills, bodily synchrony in the context of cooperation and joint commitment, highlighting parallels and differences between humans and bonobos.
The algorithms being developed will facilitate the automated quantification of fast-paced behavioral processes linked to bodily synchrony and gaze in naturalistic social interactions of nonhuman primates - a promising area currently emerging in the field of comparative cognition.