The role of social presence on moral decision-making : realistic settings for the understanding of utilitarian and deontological preferences

Project Information

YOURMORALS

Grant agreement ID: 101108680

DOI

10.3030/101108680

Project closed

EC signature date 2 May 2023

Start date 1 February 2024

End date 31 January 2026

Funded under

• Marie Skłodowska-Curie Actions (MSCA)

Total cost

No data

EU contribution

€ 175 920,00

Coordinated by

UNIVERSITEIT GENT
Belgium

Periodic Reporting for period 1 - YOURMORALS (The role of social presence on moral decision-making : realistic settings for the understanding of utilitarian and deontological preferences)

Reporting period: 2024-02-01 to 2026-01-31

Summary of the context and overall objectives of the project

Imagine a doctor making a triage decision while being observed by colleagues, a judge deliberating in a politically charged courtroom, or a professional facing an ethical dilemma within a hierarchical organisation. In each case, a moral decision must be made, but not alone or in isolation. The presence of others, the expectations of a group, and the dynamics of authority are all key factors. For decades, the scientific study of moral decision-making has largely overlooked this question. The dominant approach has been to present individuals with hypothetical moral dilemmas in isolated laboratory settings, where a single participant reads a scenario alone and selects a response. This approach has generated foundational theoretical insights. However, it has also produced a science of morality based on the rarely justified assumption that moral decisions are made independently of social context. Yet moral decisions are made in the presence of peers, authority figures, and institutional structures whose expectations, judgements, and behaviours inevitably influence individual choices. The YourMorals project was designed to answer the central question of how these social factors shape the moral choices we make.
Through a programme of empirical research combining behavioural science, cognitive neuroscience, and computational methods, the main goal was to characterise how social context — from the mere presence of an observer to real-time social interaction — shapes moral decision-making at both the behavioural and neurophysiological levels. Three interconnected objectives structured the project. The first was to examine, using electroencephalography (EEG), whether social observation modifies moral preferences and the neural processes underlying moral conflict. The second was to develop the Ecological Moral Dilemmas Stimulus Bank (EMDS), a new open-access scientific resource providing researchers with ecologically valid moral scenarios grounded in real-world content, rather than the hypothetical sacrificial dilemmas that currently dominate the field. The third was to investigate dyadic social interaction during moral decision-making using EEG hyperscanning — a technique enabling the simultaneous recording of brain activity from multiple individuals — in order to examine the neural and behavioural dynamics of collective moral deliberation.
Together, these objectives reflect a commitment to advancing the scientific understanding of moral cognition under conditions that more realistically approximate the social complexity of real human life.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

Studies 1 and 2 — Social Presence and Moral Decision-Making (EEG)
The first two studies examined whether being observed by another person changes how individuals make moral decisions. Participants completed a series of moral dilemmas — scenarios requiring a choice between two morally distinct courses of action — while their brain activity was recorded using EEG. In Study 1 (N = 83), the experimenter was positioned behind the participant, creating a passive monitoring condition. In Study 2 (N = 32), the experimenter was positioned beside the participant, increasing the salience and proximity of social observation. Both studies used identical stimuli and acquisition protocols, enabling direct comparison across conditions.
Across both studies, participants showed stable moral preferences regardless of whether they were being observed: the distribution of responses and the time taken to make decisions were not significantly altered by social presence. However, a more fine-grained analysis revealed something subtle and theoretically important: participants spent more time reading the moral scenarios when observed, but not more time actually deliberating. This suggests that social observation heightens attentional vigilance at an early stage of information processing — people read more carefully when watched — without penetrating the core of moral evaluation itself.
At the neural level, EEG analyses revealed that frontal midline theta oscillations — a well-established marker of cognitive conflict and executive control — were significantly elevated when participants made utilitarian choices compared to deontological ones. This finding confirms that utilitarian decisions, which require overriding an immediate emotional response, involve greater cognitive effort. Critically, this neural conflict signal was not modulated by social presence, providing converging evidence that the neurophysiological architecture of moral deliberation is robust to social observation. These results were further corroborated by drift-diffusion modelling, a computational approach to decision-making, which showed that neither the efficiency of evidence accumulation nor the decision threshold was affected by the presence of an observer. Together, the behavioural, computational, and neural findings from Studies 1 and 2 offer a comprehensive and methodologically rigorous account of how social monitoring relates to moral cognition.
A joint empirical manuscript reporting these findings is in preparation for submission to a specialised peer-reviewed journal in social and affective neuroscience.

Study 3 — Joint Moral Decision-Making and EEG Hyperscanning
The third study moved beyond passive social observation to examine genuine social interaction during moral decision-making. An original experimental paradigm was developed specifically for this project: pairs of participants simultaneously viewed identical moral dilemmas on separate screens and were required to reach a joint decision — without any verbal communication, interacting exclusively via keyboard and mouse. This non-verbal, digitally-mediated interaction design allows the study of social influence and consensus-building under precise experimental control, while preserving a meaningful and naturalistic form of joint deliberation.
The paradigm was programmed in Unity and validated across two pilot sessions prior to full data collection. A total of 23 pairs (N = 46 participants) were tested — exceeding the originally projected target of 22 pairs — with simultaneous EEG recorded from both participants throughout each session. At the end of each session, participants completed a semi-structured interview assessing their subjective experience of the interaction, perceived social influence, stress, and perceptions of leadership dynamics during the joint decision process. This mixed-methods design enriches the dataset beyond purely neurophysiological measures. A complete inter-brain coherence analysis pipeline was developed to quantify brain-to-brain synchrony between interacting partners. EEG analyses are currently ongoing.

Ecological Moral Dilemmas Stimulus Bank (EMDS)
In parallel with the experimental studies, a new scientific resource was developed to support more ecologically valid research on moral cognition. A large corpus of real-world moral content was assembled through systematic collection of publicly available text data targeting ethical topics across multiple thematic domains. This corpus was processed through a complete Natural Language Processing pipeline, including text preprocessing, lemmatisation, bigram and trigram modelling, and Latent Dirichlet Allocation topic modelling — an unsupervised machine learning approach that identifies recurring latent themes within large text collections. The pipeline assigns each document a dominant and secondary moral topic with associated probability scores, and is designed to support continuous data ingestion as new content is collected. The full pipeline is publicly available on GitHub, constituting a standalone open-science contribution that any researcher can use and build upon independently of the completed stimulus bank. Scenario construction and psychometric validation with human participants are currently underway.

Theoretical Contribution
Cutting across all three studies, a major theoretical and methodological manuscript was produced during the fellowship: Rethinking Human Morality in Real-Life Social Contexts (Vives & Caspar), currently under review (preprint available at https://doi.org/10.31234/osf.io/umwvd_v1). This paper argues that dominant models in moral psychology and neuroscience insufficiently account for social context, group dynamics, and ecological validity, and proposes actionable solutions for integrating naturalistic validity into experimental research — including a self-reflection tool for researchers across disciplines. This manuscript provides the theoretical framework underpinning the full research programme and positions its contributions within a broader call for methodological reform in the moral cognition field.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

In a series of studies conducted among Dutch-speaking samples (N = 115 participants), I manipulated both experimenter and peer presence, to induce social observation effects while participants were processing conflictual moral dilemmas. At the neural level, results showed that the midfrontal theta activity (θ, 4-8 Hz), a marker of cognitive conflict (Caspar & Pech, 2024; Cavanagh & Shackman, 2015) was higher for utilitarian responses specifically in higher-conflict, instrumental dilemmas, but was not affected by the presence of the audience. By separately recording the time participants spent reading the moral scenario and the time they spent making their decision, we observed slowness that originated in the reading phase: participants read moral scenarios more carefully when they were observed. These findings, hence demonstrated for the first time in the field of moral psychology and neuroscience, the association between theta oscillations and moral judgements. While moral preferences were not sensitive to our social presence manipulation, we made a step forward by testing our hypotheses during real-life social interactions. In a third study (N = 23 dyads), I developed an original paradigm, adapted to inter-brain coupling recording (hyperscanning EEG), in which pairs of participants must make collective moral decisions without any verbal communication. This social context was induced by pairing participants into face-to-face dyads. During the task, participants were presented a series of moral dilemmas and had to first report their decision privately on an external device (alone trials) then achieve a collective decision after reaching a consensus (social trials). Simultaneous EEG recordings of the participants’ brain activity were made during the whole task. While the data analysis of this last study is ongoing, we hypothesised that participants will i) adjust their decisions to match those of their interaction partners, reflecting moral normativity, ii) increase their proportion of utilitarian choices, and iii) that moral conflict (quantified by the midfrontal theta activity) will increase when participants’ social decisions are incongruent with their personal moral preferences.

In this setup, the experimenter stands next to the participant taking a moral dilemmas task

In this hyperscanning setup, participants make collective moral decisions without verbal interaction