Table 2. Overview of the experimental tasks classified by the level of complexity and description of the actions required to complete each task.

Complexity level	Task	Actions required
Simple	Open Box	(1) Pull/push the front door of the box
		Moveable Tube	(1) Pull/rotate a vertical moveable tube
		Windows Task	(1) Slide a horizontal wooden bar inserted in a tube
	Tube Cube	(1) Slide/rotate a horizontal tube inserted in the box
Intermediate	Artificial Fruit	(1) Push/pull a wooden bar
			(2) Slide a lid on the top
		Food Box	(1) Slide the frontal door
			(2) Insert a tool
		Push Box	(1) Slide a horizontal wooden bar
			(2) Push/pull the frontal door and insert a tool
		Tower Task	(1) Slide a horizontal wooden bar
	(2) Rotate/pull a vertical tube.
Complex	Complex Food Box	(1) Slide 2 horizontal wooden bars (right side)
				(2) Slide 1 vertical wooden bar
				(3) Slide 2 horizontal wooden bars (left side)
			(4) Open a door on the top
		Complex Moveable Tube	(1) Slide 3 small wooden bars
				(2) Slide a large horizontal bar
				(3) Rotate/pull a tube
			(4) Slide the front door
		Complex Artificial Fruit	(1) Push/pull a wooden bar (right side)
				(2) Pull/push a wooden bar (central position)
				(3) Pull/push a wooden bar (left side)
				(4) Slide a lid on the top
	(5) Rotate a plastic tube