Open dataset of theory of mind reasoning in early to middle childhood.

Theory of mind (ToM) reasoning refers to the process by which we reason about the mental states (beliefs, desires, emotions) of others. Here, we describe an open dataset of responses from children who completed a story booklet task for assessing ToM reasoning ( n  = 321 3-12-year-old children, including 64 (neurotypical) children assessed longitudinally and 68 autistic children). Children completed one of two versions of the story booklet task (Booklet 1 or 2). Both versions include two-alternative forced choice and free response questions that tap ToM concepts ranging in difficulty from reasoning about desires and beliefs to reasoning about moral blameworthiness and mistaken referents. Booklet 2 additionally includes items that assess understanding of sarcasm, lies, and second-order belief-desire reasoning. Compared to other ToM tasks, the booklet task provides relatively dense sampling of ToM reasoning within each child (Booklet 1: 41 items; Booklet 2: 65 items). Experimental sessions were video recorded and data were coded offline; the open dataset consists of children's accuracy (binary) on each item and, for many children ( n  = 171), transcriptions of free responses. The dataset also includes children's scores on standardized tests of receptive language and non-verbal IQ, as well as other demographic information. As such, this dataset is a valuable resource for investigating the development of ToM reasoning in early and middle childhood.