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Has evolution made our brains lazy?

We’ve all heard the term “the law of the least effort” and interestingly this applies to our brain power as much as physical exertion. The law of the least effort means that as human beings we naturally gravitate towards the easiest course of action.

Laziness is built deep into our nature.” Daniel Kahneman, psychologist and economist known for his work on judgement and decision making

In other words, if we have an appointment on the 17th floor, we will tend to take the lift and not the stairs. Our brain does exactly the same thing.

Our lazy brain comes courtesy of our ancestors who aimed to do less to increase the likelihood they would survive. Expending unnecessary mental or physical energy would have made them more vulnerable to lions, tigers, and bears (oh my!). Conserving energy was helpful when scoping out danger, competing against rivals, fighting, hunting, and searching for food. So, we can blame our ancestors.

Think about it - we often look for the easy option, the path of least resistance, the shortcut to success. If we have a remote control, why get up and switch channels on the TV itself? If we have a car, why cycle to the supermarket? If we can make (get) an oversized lasagne that’ll feed us all week, why cook every day?

“The brain is actually a pretty lazy organ. It’s pretty underpowered relative to everything it does, so it often tries not to pay attention or forget things in order to cut corners.” Martina Ratto, Beingwell Cognitive Scientist

Is a lazy brain useful?

Our brain has developed through evolution to be lazy and it is actually laziness that allows our mind to function so well and be able to muddle through challenging situations.

In day-to-day life, it can be useful for prioritising where our mental energy is spent. If you had to divide the bill at the end of a meal out, why do the mental arithmetic if you can use a calculator? If there’s an easy route to the supermarket from our house, why spend time looking at all the other routes when we can just take that first one? It minimises the effort for us.

And it helps us make quick decisions based on our gut feelings, minimising the time we spend mulling stuff over. A renowned idea from the world-leading psychologist Gerd Gigerenzer is to ‘go fast and frugal’ (no it’s not a cheap remake of Fast and Furious).

Gigerenzer calls this our “ecological rationality”. Our brain doesn’t need to perform like a supercomputer, rather just get by in any real-world situation that we meet. You’ve heard ‘less is more’, and in trying to be simple and fast, our lazy brain actually leads us to the best decisions or the best solutions to a problem. If we tried to do more than we can humanly take, we might end up getting stuck, unable to act, because we were striving for unachievable perfection.

Is simple and fast always the best way?

Not always. The lazy brain might make day to day life a little easier but there are times when we need to dig down, roll up our sleeves and get our brains working.

For example, when something is not automatic for us. You know, like following a new recipe while making dinner. We have to put some mental effort into the task when learning something new, or even when we’re doing something we do all the time except under difficult circumstances - have you ever tried making spag bol with kids having a tantrum?

Sometimes we need to evaluate a situation, our thoughts or plans, for important life decisions. Leaving a job, finding a new job, our relationships, buying a house! Or when we’re communicating with others, in a group or even online - sometimes the first thing we think to say isn’t quite what we mean and we need to put some thought into it.

And probably unsurprisingly, the lazy brain isn’t ideal when it comes to tasks that require some self-control from impulsivity or choosing what’s right for us. The lazy brain isn’t useful when crossing the road, for example, we need to wait to make sure it’s safe, not just march out. Or when you’ve had a long day, and know that walking home is good for you (it’s the whole reason you didn’t drive today) but the bus stop is just there, and there’s actually a bus just about to pull up - the lazy brain’s going to put you on that bus, instead of stretch your legs and get some exercise in.


The lazy win: Sometimes, a lazy brain is exactly what we need to ensure our resources aren’t dwindling all the time, especially on simple tasks we do naturally. Martina says

“Let our brain be frugal and a bit lazy when we can, and things will just come easier! It will also allow us to save our effort only for red-light situations, when we can’t allow our brain to sit back and relax, leaving us with no driver.”




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