Table 2.

Description of the four scales from the Interactive Drawing Test (IDT; van Ommeren et al. 2012, 2015) used to generate total social reciprocity score

Scale	Description
Reciprocal turn-taking	Children are awarded one point if they push the paper back, and two points if they push and rotate the paper back after they have finished their turn. In order to model reciprocal turn-taking behaviour, the researcher always pushes and rotates the paper back to the child after they have finished their turn
Reciprocal interaction	Children are awarded one point each time they contribute a meaningful element to a mutual object with the researcher. For example, both the researcher and child are contributing different elements to a house, such as windows and curtains
Reciprocal interaction in the other’s initiative	Children are awarded one point each time they contribute a meaningful element to an object initiated by the researcher. For example, the researcher first draws a tree, and the child then adds an apple to the tree
Reciprocal flexibility	Children are awarded points for accepting an (1) interfering, (2) absurd, and (3) destructive input, with a maximum of one point being awarded for accepting all three. For example, the absurd input involves the researcher adding two arms and a hand to the child or adolescent’s drawing. Child acceptance is defined as contributing to the researcher’s object, such as drawing the missing hand or colouring in the arms