Our love affair with our possessions seems to be all-consuming, even as our planet reaches breaking point. Despite the constant warnings about our future, we are reluctant to change our ways when it comes to accumulating more and more things. Why is this? The answer is our need for ownership. Ownership is a uniquely human pre-occupation that has its origins deeply rooted in our biology. It can be seen in everything from children fighting over toys to the rise of political extremism. Award-winning psychologist Bruce Hood draws on research from his own lab and others around the world to explain why psychological ownership is an emotional state of mind that governs our behaviour from the cradle to the grave, even when it is often irrational and destructive.