The enticing introduction to Diving for Seahorses poses the question, if our cells constantly turn over, what are we? Our physical matter being temporary, maybe ‘we are our memories’. Diving into memory can be a risky business, at once opening a treasure trove and Pandora’s box. The seahorses the Ostby sisters want to take you diving for are indeed memories, and if you are going to take the plunge, having this pair for guides is about as good as it gets. With one a neuropsychologist and leading expert in memory function, the other a writer with a Masters in the History of Shared Ideas, and then the fact that they are siblings, with shared history and memories, offering active data and diverging examples to interrogate? You couldn’t write it.

Except that’s exactly what they have done, and it is beautiful to read. From a man who couldn’t form new memories to one who could not forget, notable figures in memory research become rich characters in Hilde Ostby’s prose. Lush, descriptive detail of scenes, people and even the neural processes of both contemporary and historical memory research activate the reader’s imagination – and with it their memory too.

Episodic and context-specific memories rely on a level of sensory and emotional stimuli to be prioritised in our personal archives. This book itself becomes a memory experiment: the Ostby sisters’ imaginative writing delivers information in a way that makes you more likely to be able to draw on their book’s material about how and why your brain is responding, shaping, retaining and forgetting information.

What a gift. The next time a memory attacks or protects you, a friend, or even broader society (through the shared memory that is history), you’ll have a profoundly enhanced grasp of why. But memory is not just about the past, it is about the future. Understanding and activating memory function with intentionality can also help shape more desirable future responses and realities. If we are our memories, there are huge rewards to be gained by individuals and societies from paying attention to what our memories are doing and why.

Leanne Hermosilla works as a bookseller at Readings Carlton.