Question: why isn't everyone the same? Why do people think differently?

Lilian Hunt answered on 11 Mar 2014:

That really is the big question of genetics! Why are we different and why do we think differently if more than 99% of our DNA is actually the same as the person sat next to us. Well funnily enough, all the tiny variations in that 1 % are enough to make up all the differences between humans! Our DNA is the basis of us, it codes for different proteins to be made which affect the way we look, the way our brains are built and how sensitive we are to the things around us. Because of this, a lot of why we think and behave differently can be because genetically, in our DNA, we have lots of differences. We all have different mutations in our DNA as many mutations can be harmless and just slightly change things about us, like our hair colour. My harmless mutations will vary from yours and that can explain some of why we are different and why we think differently.

In genetics and psychology (the study of our minds) there is a constant debate about how much of who we are is because of our genes and how much is because of everything we experience in life – the environment. Some people call this debate ‘nature v nurture’. Because of this, we can say that some people think differently because they’ve experienced different things in life. Genetics doesn’t completely explain why some people vote for different politicians or have a favourite colour. However through studying identical twins (who have exactly the same DNA!) we can try and judge how much of these differences are because of genetics and how much is because of the environment. I might love cats because my family had one when I was a child but you could have been scratched by one as a child so don’t like them. That would be ‘nurture’ or the environment causing that opinion. Whereas if you don’t like cats because you’re allergic to them (and that can be caused by genetics) then that would be ‘nature’ or your DNA differences causing that opinion.