Traditionally, Myers-Briggs theorists have taught that people develop their primary function first, followed by their secondary function up until their 20s, then their tertiary function in their 30s and 40s, and sometimes they’ll go on to start using their inferior function later in life. It’s a neat, orderly formula. Too neat for my tastes. (If you felt lost when I started talking about functions, click here to read a post explaining that aspect of Myers-Briggs personality types.)
When you start talking about type development in more depth, though, Myers-Briggs experts will add that environment and an individual’s commitment to personal growth does influence when our functions develop and how well we learn to use them. They’ll also talk about life-long type development and offer tips for dealing with your less developed functions before the age you’re “supposed” to develop them. And I’ve also talked with people who feel like they developed their tertiary before their secondary function, or had to go back later in life and become comfortable with their dominant function because they’d been suppressing it. Clearly, there’s more going on than a neat developmental progression from one function to another.
Personality Hacker proposes a different look at how we develop functions, or “mental processes.” I’ve not seen them directly address the question of type development from childhood on, but they do see our secondary function as our growth position. We’re most comfortable using our dominant function and (baring some kind of trauma) it’s typically also the one you’ve spent the most time developing. This function is either introverted (i.e. focused on our inner world) or extroverted (i.e. focused on the outer world). Your secondary function is focused in the other direction — if you’re a dominant introvert, your secondary mental process it extroverted (and vice versa). But your tertiary function matches your primary one in terms of introvert-extrovert, so it can be more comfortable (though not as healthy) for us to spend time in that one rather than cultivate our secondary function.
What About Culture and Family?
I think our early experiences and upbringing have quite a bit to do with which mental processes we develop and when. For example, an introverted child leads with an inward-focused mental process. How their society and family treats their introversion will have a huge impact on their development. They might develop their extroverted side more quickly as a defense mechanism for fitting into an extroverted world. On the other hand, the same thing (developing their secondary introverted function early) could also happen if given support for their introverted development as well as encouragement to stretch themselves in the outer world.
Alternately, our hypothetical introvert might reject the push to be more extroverted and end up developing their tertiary process more quickly than their secondary process. That could be a reaction against the external push to be something they’re not, or in response to a particular subculture that values their introverted traits. If no one’s telling you to cultivate a less comfortable aspect of your personality, then why bother?
The same can hold true for extroverts. Many cultures, including the United States, have historically held extroverted traits up as more desirable. If you’re constantly being admired for your outgoing personality, social skills, and ability to navigate the outer world, why focus on developing your un-cool introvert side in high school? Or maybe you’re an extrovert growing up in a family of introverts who constantly ask you to give them alone time or be quiet, and you suppress your dominant function’s development until you’re older. I’ve seen both happen.
There are other factors in play as well. An ExTJ guy would typically find encouragement for his dominant function, where a woman with the same personality type could face criticism for not “acting like a girl.” An ExFJ girl would fit more easily into what society expects from young women, while a guy with the same type might be told to “man up.”
Messy, Beautiful Variations In Type
Personally, I feel I developed my dominant function first (as an INFJ, that’s Introverted Intuition/Ni), stunted my own secondary function’s growth by being incredibly shy (Extroverted Feeling/Fe), ended up using my tertiary function trying to make sense of things (Introverted Thinking/Ti), and was completely blind to my inferior function (Extroverted Sensing/Se). That described me pretty much until age 19 or 20. At that point, I’d been in college for about a year and started working to overcome my shyness. That finally gave my secondary Fe a chance to develop into a healthy version of that function. At the same time, I think I started using Ni in a healthier way, too, while still occasionally tapping into Ti. As I started learning more about my personality type, I’ve also started trying to develop my Se (though I’ll admit it’s with little success so far). But since I’m not even 30 yet, I “shouldn’t” be consciously using either my tertiary or inferior function yet.
I’m certainly not trying to argue that Myers-Briggs gets everything (or even most things) wrong about type development. The MBTI is a fantastic tool for describing how people’s mind’s work, how we typically learn information, and the ways we interact with our worlds. And the typical type development model has lots of truth in it, including the fact that our primary and secondary functions are the ones we develop most fully. It’s just that there’s more influencing the nuances of type development than how old we are.
These variations are one reason why no two people who share a personality type will be exactly the same. We all have different circumstances that shape our type development, different levels of comfort with our type’s functions, and different ways of expressing how our minds work. If you feel like you didn’t follow the standard model of type development, don’t worry — you haven’t missed out on your chance to grow and there isn’t anything wrong with you. Our personality types aren’t boxes we fit in neatly or hoops of development we jump through. They’re a way of describing how your mind works and a tool we can use to accelerate personal growth, including developing all facets of our personality type more fully.