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How many New Year's resolutions have you already consigned to the dust bin? If the answer is none, I'm guessing that's probably because you learned long ago that it's futile making them to start with.

Change is hard, isn't it? From changing the way we eat and exercise to the amount of time we spend on social media, we tend to be stuck in our ways. You have probably found the same with your investment habits. Do you keep making the same mistakes? Do you swear you'll capitalise on the next market crash only to find yourself still holding excess cash when markets have fully recovered?

You're not alone. There are good reasons why it's so hard to change.

Our brain plasticity changes dramatically from the time we're 25 years old. We start life with an extremely plastic brain - ready and eager to be adapted to the world in which our body needs to live. 

It is full of a messy web of billions of connections that offer up many billions more possible future brains. 

As we experience the world and learn, some connections strengthen and many others are removed until our brains are wired for adulthood (the first six episodes of the Huberman Lab Podcast explain this process in fascinating detail).

Roughly 25 years after we're born, that process stops. It is possible to change the wiring (some people who become blind as adults learn to use the "seeing" part of their brains for other purposes, for example). But it is many magnitudes harder than it was in our youth. (In our podcast, Stocks Neat, my colleague Gareth likened the adult brain to driving a Kia Sportage after previously driving a Ferrari - not nearly as fast, or as fun.)

This has two important implications.

Firstly, what you experience in the first 25 years of life shapes you forever. For the first 16 or so years, your parents most likely control what sort of environment that is. From 16 to 25, though, you have a lot of control over how the world shapes your brain. That is going to be the easiest period of life to form habits, good and bad. Healthy diets, exercise and drug habits can all become a permanent part of life.

Unfortunately, most of us perusing the Livewire website are well past the age of 25. For us, it is important to recognise that changing who we are is nigh on impossible. 

If you, like me, are stuck with the less-plastic brain, we're best off spending our time understanding our strengths and weaknesses rather than trying to change them. What experiences influenced the first 25 years of your life? How do you think that might impact your optimal investing style?

If you grew up on a farm like me, you would rapidly grow accustomed to cycles and stress. At least once every summer, I would watch the storm clouds roll down the Wellington Valley and destroy the drying lucerne hay that was our family's livelihood (the smell of rotting hay bales has stuck with me for life). It wasn't uncommon to watch a whole crop float down the river in a flood.

It's probably not surprising that my tolerance for risk and capacity to deal with stress is higher than average. Moreover, hard work, patience, and knowing how to live with inevitable periods of hardship have been essential to the growth of Forager Funds.

When it comes to investing, at least, very few traits are unequivocally good or bad. My flaws are a result of that exact same environment. A tolerance for risk can be healthy; it can also be dangerous. A strong work ethic can get things done; it can also stunt the growth and development of junior staff.

There are many different paths to investment success. The trick is to choose the path that's right for the way your brain is wired.

For me, my risk tolerance and understanding of cycles mean I can run a concentrated portfolio of stocks. I can keep cash for market downturns because I know I will be "greedy when others are fearful", as Warren Buffett put it, and often well before the market bottoms. 

But I need checks and balances around me to ensure I don't take on too much risk, including individual stock limits and thesis roadmaps to stop me becoming overconfident.

Someone who grew up with two school teachers as parents might be far less risk-tolerant (my parents were actually both teachers, too, but that was simply a source of funding for the farm losses). 

A better investment portfolio for them might be a diverse collection of index funds. Knowing they are unlikely to be comfortable investing in times of distress, they should commit to being close to fully invested all the time and, preferably, looking at the market as infrequently as possible.

I have some investors as clients who couldn't guess their investment balance with Forager to the nearest 20%. Those who check CommSec five times every day probably view that as lazy and reckless, but these people have been highly successful. 

They simply worked out long ago that looking at their balance every day only causes them to do stupid things. As long as I am investing my own money alongside theirs, letting me worry about it has been their recipe for success.

Introspection can be uncomfortable. And the idea that we are almost impossible to change can be downright scary for some. But, soon to celebrate my 44th birthday, I've found it all quite liberating. Those New Year's resolutions were nothing but a bore to start with.

Everyone is different, of course, but that's what makes humans - and investing - so interesting. 

Written By Steve Johnson