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Open Imaging Index
MRI Brain

Social Exchange Rules of Engagement fMRI (ds004553)

Learning rules of engagement for social exchange within and between groups

Task fMRI and T1-weighted brain MRI from adults making repeated ultimatum-game offers to responders from unfamiliar groups or to a computer, collected to study how people learn what others will accept in social exchange.

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Overview

This OpenNeuro dataset holds the neuroimaging part of a Leiden University study on how people learn the bargaining norms of groups they do not know. Participants acted as proposers in repeated ultimatum games. In the social condition each offer went to a responder from one of three groups, each marked only by a neutral symbol and each with its own hidden acceptance threshold; in the non-social condition the same choices were framed without a human partner. The study, published in PNAS in 2023, models proposers as Bayesian learners who dislike unequal splits. Snapshot 1.0.1 (April 2023) is the current version and is released under a CC0 waiver. Behavioral data and analysis code are kept separately on the Open Science Framework (osf.io/rkbev).

Composition

The repository has 50 subject folders (sub-003 to sub-052). Every subject has one T1-weighted scan and BOLD runs of the task: 49 have four runs (two social, two non-social) and one has three. The paper reports 49 fMRI participants, 35 of them female. No participants.tsv is shared, so age and sex per subject are not available, and the paper does not report the age of the fMRI sample in the main text.

Acquisition

All scans come from a 3 T Philips Achieva with a standard head coil at Leiden University Medical Center. Each functional run has 400 echo-planar volumes with a TR of 2.2 s, TE of 30 ms, 38 slices and 2.75 mm voxels. A B0 field map was recorded after each run and is included. The anatomical scan is a 3D T1-weighted image with roughly 1.2 mm voxels.

Annotations

There are no image labels. Events files give the trial timing of the offer task. The code folder holds the fMRIPrep scripts used for preprocessing.

Known limitations

  • The release has one more subject folder (50) than the paper's fMRI sample (49), and the paper does not say which subject was excluded.
  • No demographic file is included.
  • Single site, single scanner and a modest sample size.

Cohort

Aggregate numbers from the sources below. Bars are relative to the 50 subjects.

Sex

  • Female 35 100%

Covers 35 of 50 subjects.

Materials and Methods in Rojek-Giffin et al. 2023, Learning rules of engagement for social exchange within and between groups, PNAS

Contrast / sequence

Groups can overlap

  • T1-weighted 50 100%
  • BOLD fMRI 50 100%

anat/*_T1w.nii.gz, func/*_bold.nii.gz in File listing and JSON sidecars of the ds004553 BIDS repository (CC0), NIfTI files counted per subject folder

Country

  • Netherlands 49 98%

Materials and Methods, Neuroimaging in Rojek-Giffin et al. 2023, Learning rules of engagement for social exchange within and between groups, PNAS

Modality

  • MRI 50 100%

sub-* folders in File listing and JSON sidecars of the ds004553 BIDS repository (CC0), NIfTI files counted per subject folder

Scanner vendor

  • Philips 49 98%

Materials and Methods, Neuroimaging in Rojek-Giffin et al. 2023, Learning rules of engagement for social exchange within and between groups, PNAS

Field strength

  • 3 T 49 98%

Materials and Methods, Neuroimaging in Rojek-Giffin et al. 2023, Learning rules of engagement for social exchange within and between groups, PNAS

Contrast combinations

How many subjects have exactly each set of contrasts.

T1wboldSubjects with exactly this set
50

anat/func NIfTI files in File listing and JSON sidecars of the ds004553 BIDS repository (CC0), NIfTI files counted per subject folder

License and access

Our reading of the license, not legal advice. Before you use the data, read the original license and confirm that your use is allowed. We take no responsibility for how you use a dataset. Full disclaimer

Access
Open download

Download without an account

Access page

Creative Commons Zero 1.0 Universal

Public domain dedication. Do anything with the data, including commercial use, without asking and without having to give credit.

dataset_description.json of snapshot 1.0.1 states "License" CC0.

Original license text Version read: 1.0 Checked 2026-10-07

What you can do

  • Yes
  • Yes
  • Yes
  • Yes
  • Yes

What you can share

  • Yes
  • Yes
  • Yes

What you must do

  • No
  • Share alike No
  • No
  • No
  • Manuscript review No
  • Release code No
  • Return results No
  • Delete after use No

Limits

  • No
  • Location limits No

Citation

Rojek-Giffin M, Lebreton M, Daunizeau J, Fariña A, Gross J, De Dreu CKW. Learning rules of engagement for social exchange within and between groups. PNAS 120(19), e2218443120 (2023). doi:10.1073/pnas.2218443120

@article{rojekgiffin2023,
  title={Learning rules of engagement for social exchange within and between groups},
  author={Rojek-Giffin, Michael and Lebreton, Ma{\"e}l and Daunizeau, Jean and Fari{\~n}a, Andrea and Gross, J{\"o}rg and De Dreu, Carsten K. W.},
  journal={Proceedings of the National Academy of Sciences},
  volume={120},
  number={19},
  pages={e2218443120},
  year={2023},
  doi={10.1073/pnas.2218443120}
}

Sources

Every number on this page comes from one of these documents. Each chart names the table or page it is taken from. The raw numbers are in stats.csv.