Despite this, Sharrock has learned to try and use positive memories to override the negative ones: “At the start of every month, I’d pick out all of the best memories that I had of previous years for that month.” Reliving positive events makes it easier to deal with the “invasive memories” that bring her down.

Sharrock says what she remembers from a particular date are things “that I came across myself that day because I don’t research when current events happened, I just remember them as I personally saw them or came across them”. While people with HSAM can remember basic news events from a certain day, often those things are also part of a personal experience or interest which may help them encode the memory.

HSAM might also give us an unprecedented insight into how babies and children view the world. Sharrock describes what caught her eye as a baby, as well as learning how to walk: “I’d be in my crib and I’d just turn my head around and look at things around me, such as the stand-up fan next to my cot. I was fascinated by that. It wasn’t until I was about one-and-a-half that it dawned on me, ‘Why don’t I get up and explore what it could be?’”