A Feel for Weight

Lift the boxes individually and together. The exhibit shows that our brains do not perceive weight objectively; our expectations influence what we feel.

The Science Behind It

Here you experience what is known as the size-weight illusion. Our brains expect large objects to be heavier than small ones. When you lift both boxes at once, you unconsciously prepare for a greater weight and apply more force. As a result, the boxes feel lighter than expected. If you lift only the smaller box, you expect less weight, so it suddenly feels heavier. Your sense of weight is shaped not only by actual mass, but also by your expectations and experiences.