Taylor Stephens of Green Island School asks :-

Why does our brain make us think?

Mike Paulin, a neuroscientist the University of Otago's Department of Zoology, responded.

Our brains make us think for the same reason that oysters' shells make them hard to chew. The earliest animals, the ancestors of oysters and us, were little soft blobs that lived in the ocean. They fed by filtering micro-organisms from the water until, about 545 million years ago when some of them started eating other animals. The fossil record changes abruptly at this time. The soft blobby animals, called Ediacarans, were mostly wiped out and were replaced by animals called Cambrians. Cambrian animals evolved to be good at eating and/or not being eaten by other animals. Oysters' ancestors evolved hard shells, while our ancestors evolved agility.

Agile animals can anticipate what will happen, and decide how to react to it, before it happens. How will the predator strike? How will the prey dodge? Humans have evolved this ability to a level beyond all other animals. We can not only anticipate what will happen here and now, but we can think about what we might do in even in situations that are unlikely or impossible!

This self-awareness and imagination is what it is like to be human. We enjoy playing sports and games that test and develop our ability to outmaneuver and outwit our opponents; we enjoy solving problems, and exploring and discovering how nature works; we enjoy imagining situations and worlds very different from where where really are, and what we would do. We enjoy these things because fun motivates us to do things, and evolution favours animals that do things that are important for survival and reproduction. For an oyster this means growing a heavy shell, sticking to a rock, and from time to time opening a little gap to suck in food and blow out poo. It is better to be human, don't you think?