Our brains have limited storage capacity. We can’t remember everything. So we needed to evolve a mechanism for deciding what to remember: emotion. Imagine you’re in Palaeolithic times, and a tiger sneaks into your camp at night. You’re awaken by screams. Your brain floods with chemical called Norepinephrine (adrenaline). It increases arousal and alertness, promotes vigilance, enhances formation and retrieval of memory, and focuses attention: ‘fight or flight’ mode is activated.
This scenario played out millions of times before, over hundreds of thousands of years. Unsuccessful responses got their hosts eaten. Those that survived prioritized space in memory due to heightened emotion. We evolved through natural selection to over-react to potential dangers, flood the brain with chemicals, and respond by running away or making a stand. Those that didn’t get the balance right, disappeared from the gene pool. You’re alive because your ancestors learned to react emotionally, rather than spending the time to think rationally.
However this time you’re feeling creative. You think: “if I chop down a tree, cut it into poles, and stick them in the ground around camp – next time the tigers couldn’t get in!”. One of your fellow tribe members manages to chase the Tiger off with a spear. After the danger subsides your brain released Endorphins for pain relief, so positively buzzed, you don’t immediately dismiss the idea. The chemical cocktail in your brain heightens your attention on solving this problem over all else. You start chopping wood, and it’s hard work. You think “this is stupid, maybe I should stop”, but just in time your brain keeps you motivated by rewarding you with a dose of Dopamine. It’s several hours later now, and you have a rudimentary fence set up around your tent.
As you look upon your work, you get a hit of Serotonin, which makes you feel satisfied, and reminds you to eat, sleep, and have fun to relax. As you settle down for the night, with your family safe, Oxytocin – the “love drug” – is released. This is what binds you to your kin, but also to those who share your culture. You resolve to show other members of your tribe how to build fences in the morning. They all start to build fences, and tiger attacks drop to historic lows. There’s now more time for other life-saving activities, as well as more social bonding. Increased life expectancy means more opportunity for wisdom to be passed on.
What’s more, other tribes observe your fence-building activities from a distance, and start to build fences of their own. In this fashion the meme for fence building is passed on, making the survival of the human race all the more assured. Tribes that thought more rationally were easy to predict and defeat. Those that were overly aggressive in building defences came to win. When one tribe defeats another, they kill all the men, and bring the women and children into their tribe. This Adrenaline-Endorphins-Dopamine-Oxytocin chemical cycle repeats itself in endless loops, helping us identify and solve problems. Done enough times, tribes expand and envelop each other, and something resembling civilization appears. Serious threats become less common, and humans inherit the earth. Rational thought plays an important role to play, but remember that without emotion we’d all be tiger food.
Emotion and memory
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