We all like to think of ourselves as individuals, making up our own minds what to do and when to do it. But this eye-opening new documentary, presented by Jimmy Doherty, reveals new evidence that suggests that in many ways we actually think and move like members of a herd of animals. We each leave behind us a vast 'data trail' every time we travel, use our phone or credit card, search or buy online, use social media or visit a supermarket. The documentary reveals how, by analysing and unlocking this mountain of data, scientists can monitor, predict and even manipulate our actions with amazing precision.