Imagine looking into the mirror and not recognising the face that greets you. What might it be like to sit in a room full of visitors each claiming to know you well, yet you have no knowledge of who they are. Consider the experience of asking to go home, only to be told repeatedly that this unfamiliar building is your home and has been for many years…

How much of who we are is shaped by memory? Scientists, philosophers, artists, poets, and musicians alike have all grappled with the notion of the self – that seemingly immutable and enduring sense of who we are, steadfast in the face of life’s many vicissitudes. Within the field of cognitive neuroscience, we have yet to find a universal definition of what the self does and does not encapsulate, or how we might go about operationalising and measuring this nebulous construct. It is clear that there is no single entity that we can label “the self” and certainly no neat neural substrate that we can pinpoint in the brain as supporting this construct. What is becoming increasingly clear, however, is that the self is intimately connected to memory.

Humans possess an innate proclivity to derive meaning, stability, and continuity from our personal or autobiographical experiences. As we navigate different periods of growth and change, we distil meaning from these life-changing events and incorporate them into our view of who we are as an individual. This contributes to our sense of morality, our preferences, our ambitions, and our conception of who we might become in the future. The central role of memory in shaping our view of ourselves has led many to suggest that the converse relationship must also hold, whereby memory loss necessarily erodes the self.