Some people describe themselves as introverted and soft-spoken, others announce they are extroverted and outgoing, but what exactly is a personality? And is it possible to change your personality type?
Neuro-scientist, psychologist and author Dr Sabina Brennan joined Laura Fox on RTÉ 2FM to share all.
"In the simplest terms, your personality is your patterns of acting, thinking and feeling," she explains.
The topic of human behaviour is especially complex because they are influenced by such a wide variety of factors, ranging from our external environments to our genetics.
"How likely you are to engage in one-night stands has a genetic component to it," she insists.
Not only that, but we are constantly growing and changing as we experience culture, society, relationships, and more.
"Your brain is constantly changing; it's your behaviours, your experiences, your life choices that shape it."
External factors aside, your sense of self also plays a huge part when it comes to your personality.
"Who you think you are influences how you behave," she explains. "The interesting thing is that most of us tend to think that our sense of self is fixed, it doesn't change. I am who I am. The I behind our eyes, that's just the way I am.
"But the thing is, our sense of self does change. If you compare yourself at 35 to 15, you are a completely different person. Hopefully, you're not throwing temper tantrums as you go to the supermarket and they don't have what ice cream you want," she laughs.
Generally, our brains develop in slow and imperceptible ways, however, a period of exceptional growth occurs at puberty up until the age of 25. This growth spurt can lead to high emotions and, sometimes, poor decision-making.
"Because your brain is going through this developmental period, you actually are not in possession of a brain that has its full faculties," she muses.
During this time, the brain is "hungry for knowledge" which may lead to more risk-taking behaviour that is often associated with our teenage years.
Once we are fully grown, our brains are better at assessing situations, predicting outcomes, and adjusting our behaviours accordingly.
With all this in mind, is it possible to change our personalities? Surprisingly, the answer is yes.
"If your natural set point is to be pessimistic - you think, 'bad things always happen to me', or whatever - there's tons of research that shows that you can cultivate optimism. You can learn to be more optimistic."
As it turns out, your perception of the world has a huge impact on how your brain works. For example, if you believe that bad things always happen to you, your brain has learned that bad things are very important to pay attention to.
"Your brain is processing billions of bits of information all the time; it can't process all that information, so it has to filter the information," Dr Brennan explains.
First, the brain will focus on things that are detrimental to your safety and health. After that, the salience network in your brain (a network that helps determine which stimuli are most important) will take its cues from you as to what's important, and then start actively looking for those things.
This can eventually lead to something called inattentional blindness, a cognitive phenomenon where individuals fail to perceive something right in front of them.
So, in the example of the pessimist who believes only bad things happen to them, that person will miss out on the good things that are happening around them.
In order to keep our personalities open to change, we must feed our brains new experiences and allow ourselves to take different actions than usual, especially if it gets us out of our comfort zone.
"Trying new things is a great way to actually understand yourself," says Dr Brennan. "Challenge some of those limited beliefs."
By seeking out new experiences, sensations and knowledge, we satisfy our curiosity, which enhances our brain's neuroplasticity.
"Life should be constantly learning, and reshaping, and growing," she insists. "That's where life becomes interesting. Setting yourself challenges is really important for your brain health and your brain development."
