Our brains are hardwired to sort, categorize and draw lines. It's how we navigate the infinite kaleidoscope of everyday information. But imagine failing an exam by a mere 1 per cent. Or being caught speeding at just 1 mph over the speed limit. It doesn't seem fair. And yet we have to draw the line somewhere, we say, even though lines can be unhelpful or even dangerous when drawn where they aren't wanted, or in too thick a hand. By thinking in terms of ' 'them' or 'us' and 'this' or 'that' we isolate ourselves from ideas we don't agree with and people who are not the same as us. We fail to listen to the other side of the argument and beliefs become increasingly polarized. Intolerance and extremism flourish. While the human race has survived by thinking in black and white and making binary decisions, such thinking might also destroy us. We may not be programmed to think in shades of grey, but it's the colour of our cognitive future. In this ground-breaking exploration of how our brains work, psychologist Professor Kevin Dutton explains that by understanding the nature of our black and white thinking we are better equipped to negotiate life's grey zones. And that, by doing so, we will make subtler and far smarter decisions.