TOPLINE WELLNESS
OUR FACT-FILLED, FLUFF-FREE PAGE OF TRAVEL, FITNESS OR WELLNESS Memory
Outline A recent survey found that
80 per cent of us worry about memory loss. There are the little annoyances: forgetting the gym locker code or where we left the car keys. Then there are the bigger concerns such as dementia, which affects one in 14 over-65s.
But should we worry about the things we forget?
Frontline Enter neuroscientist Charan Ranganath, 53, who is spearheading a deep dive into how memory works with his new book, Why We Remember: The Science of Memory and How it Shapes Us (Faber, €16.99). The good news? You shouldn’t worry so much. Dr Ranganath says ‘our typical [memory] complaints’ – forgetting someone’s birthday, for example – are benign. ‘The problem isn’t our memory,’ he explains, ‘it’s that we have the wrong expectations of what memory is.’
Story line
Our memory is like a huge filing cabinet in our neocortex – the grey tissue on the outside of the brain – powered by more than 80 billion neurons. This cabinet stores two types of files: semantic memory is knowledge and facts; episodic memory is our ability to reimagine scenes from our past.
Keyline It’s this distinction that makes humans special. AI has semantic memory, so it learns facts. But it doesn’t have episodic memory, which allows us to remember exceptions and contradictions. ‘Most birds have wings and can fly’ is a fact (semantic). Tell a human a penguin can’t fly but is a bird, and we store that anomaly (episodic). That anomaly will make AI glitch.
Blurred line Episodic memory requires imagination. When we recall a past episode, we imagine it anew. This explains distorted memories. If we’ve forgotten certain details, ‘a healthy dose of imagination’ fills in the gaps, explains Dr Ranganath. It’s easier to imagine how something made you feel than concrete details. That means childhood memories often focus on emotion (how a teacher’s words made you feel) rather than physical realities (the colour of the shirt they wore).
Online The key to memory is focusing on important details and discarding surrounding noise. Nowadays, that’s near impossible. We’re exposed to around 11.8 hours’ worth of information a day thanks to our phones,
radios and TVs. This sensory assault means it’s not surprising we don’t remember some things. ‘On the contrary,’ says Dr Ranganath, ‘it’s amazing that we remember anything.’
Help line The harder you focus, the more you remember. Sounds simple, but how often do you check your texts while scheduling plans? Another example is recording a special event. Because you’re focusing on filming (getting the right angle etc), you’ll remember less about the event than if you just concentrated on proceedings.
Dotted line
Our brains love using connections as a memorising tool. For example, says Dr Ranganath, if you met someone called Charan (as in, Dr Charan Ranganath), you might link his name with the ferryman of the underworld in Greek mythology (called Charon). If you can find part of Charan’s appearance that reminds you of Greece or mythology, you’ll recall his name more easily.
Lifeline
Then there’s the straightforward stuff that keeps our brain cells healthy: sleep, exercise and a balanced diet. Running is good for your memory, because it causes your brain to create a chemical that makes your neurons work better. It also reduces risk of hypertension and diabetes, which both damage your cortex.
Timeline
Dr Ranganath concedes that ‘we’re designed to forget’. But this isn’t all bad news. As we age, semantic memory persists more robustly than episodic. That means we might forget our keys, but we retain a wealth of facts. That’s why elders have always played an important societal role: they can pass this bank of knowledge (language, recipes, medicine) to the younger generation. As we get older and wiser, says Dr Ranganath, we prioritise memories that can help our offspring. ‘Memory, then, is doing exactly what it has evolved to do, and in the process it connects us with one another.’