Subject	Developmental and Educational Psychology
Specific subject area	Children's “theory of mind” reasoning: the process by which they reason about the mental states (beliefs, desires, emotions) of others.
Data format	Analyzed
Type of data	Spreadsheet
Data collection	Participants were 321 3–12-year-old children. Data were acquired via in-person administration of our theory of mind (ToM) booklet task, over the course of eight years (2009–2017). The task involves an experimenter telling a scripted story and asking two-alternative forced choice and free response questions that evoked reasoning about the characters’ mental states. Experimental sessions were video recorded; data were subsequently coded and transcribed offline by trained researchers. ToM booklet task materials, example administration videos, and guidelines for coding are publicly available alongside the dataset (https://osf.io/g5zpv/).
Data source location	Institution: Massachusetts Institute of Technology City/Town/Region: Cambridge, MA Country: USA
Data accessibility	Repository name: Open Science Framework (OSF) Data identification number: 10.17605/OSF.IO/G5ZPV Direct URL to data: https://osf.io/g5zpv/
Related research article	[1] Richardson, H., Riobueno-Naylor, A., Lisandrelli, G., Saxe, R. Development of the social brain from age three to twelve years. Nature Communications, 9(1), 1027. https://doi.org/10.1038/s41467–018–03399–2