In an experiment, psychologists used an illusion to convince young children they built a copying machine that could replicate anything, such as their favourite toy. Most of the children favoured their original toy and many were horrified with the idea of taking home a copy.

This thinking about objects stays with us into adulthood. Many of us are reluctant to part with family heirlooms which help us feel connected to loved ones.

The endowment effect is when we value items more highly from the moment we own them.

In a demonstration, students were given a choice between a coffee mug or a Swiss chocolate bar for participating in research. Half chose the coffee mug and the other half the chocolate. The...