Hands, not eyes, hold clue to illusion
By Ruth Bennett
Seeing is believing, but acting is more accurate. That’s what two Canadian psychologists conclude after investigating the size-weight illusion, an error that arises when people try to estimate the weights of two objects of different sizes but the same mass.
J. Randall Flanagan and Michael A. Beltzner of Queen’s University in Kingston, Ontario, presented 40 people with two square boxes topped by handles, each unit weighing 0.39 kilograms. One box measured 5.2 centimeters on each edge; the other, 10.9 cm.