Take a moment to remember an event that you experienced as a child. Pick something that’s important to you – an event that really shaped for the better the person you are today. Now ask yourself: are you sure this event truly happened?

Suppose, for example, that some well-intentioned person could have deliberately planted a vivid false memory of this fictional event in your consciousness, believing that the memory would change you in ways that would benefit your life. How would you feel to discover that this was the case? Perhaps you’d be touched that someone cared so much about your wellbeing that they would give you such a personal and life-changing ‘gift’? Or maybe outraged, that this person had brainwashed you without your consent?

The scenario sounds like a plot from a science fiction novel, but it’s not necessarily as implausible – at least in principle – as it might seem. For a start, memory researchers have known for decades that our recollections of the past are often inaccurate, and that sometimes we remember entire events that never happened at all. These false memories can occur spontaneously, but they are especially likely to occur when someone plants the seed of a false suggestion in our mind, a seed that grows into a more and more detailed recollection each time we think about it.