Experimental Task
Children sat on their parent’s lap at a semi-circular table, with the experimenter seated across the table and directly in front of the child. Each child completed a series of object retrieval tasks, which involved retrieving a small toy figurine from a transparent box (Task 1), opaque box (Task 2), and a transparent box nested within the opaque box (Task 3; see Figure 1 for boxes and toy figurine used in the study). For task 1 and 2, children would have to make manual contact with the box, open the lid of the box, and remove the toy from the box. For task 3, children would open the lid of opaque box, remove the transparent box from the opaque box, and then open the lid of the transparent box to retrieve the toy. Each task started with the experimenter showing an animal toy figurine to the child to gage attention, followed by placing the toy in the box in front of the child. The box was then presented to the child by saying “Can you get the toy?”. If the child seemed disinterested, the experimenter would reorient them to the task by repeating the verbal prompt or pointing to the toy in the box. The task would end upon toy retrieval or after 60 seconds of exploration with the box(es). If the child was unsuccessful to retrieve the toy after 60 seconds, the experimenter would open the lid and/or take the toy out of the box. One child in the TD group and 2 children in the DS group were missing data for task 3.