Architect
Professional INTP
- Local time
- Today 9:11 AM
- Joined
- Dec 25, 2010
- Messages
- 6,691
In this post I hope to consider the ways genetics determine type. Note that I am not an expert in genetics or biology, these comments are speculation based on my observations and research.
What can we deduce about the genetic determines of type? First look at the brain, which starts with about 30 to 100 megabytes of specification in the compressed genome but ends up with a billion times more complexity*. Clearly the neural nets of the brain aren't encoded in the genome, but the structure of how they form must be encoded. If they were not there would be no reason for them to form.
Observationally, I've seen in the children in my life (mine and nephews and nieces) which I've known from gestation to adulthood, there are some traits which clearly show up very early. For example; I have a nephew who is an obvious ESFP. This behavior was obvious in the womb, where I would see him restlessly moving around, thrusting his arms about himself in his mothers abdomen. My INTP kid by contrast, well we never felt a kick. Late in the game we discovered that he was active at night while we slept, but he still wasn't all that active (my nephew would wake them up by kicking so hard that the husband would feel it!)
So in the womb let's posit that some gross aspects of temperament exert themselves; what I see here is the difference between ES and IN. Namely orientation to information (external or internal) and direction of information (intuition or physical sensation). This is interesting, we know that brain areas having to do with learning undergo more change, whereas structures having to do with sensory processing experience less change after birth*. We also know that ES is far more common than IN types. Could there then be some genetic coding that unusually makes some zygotes less attuned to Sensory processing? Certainly when they were toddlers you could see my kid was more contained and off on his own (in some toddler sense), while my nephew was ranging around, poking things, discovering the world around him. Could it be that being an IN is a defect in sensory processing wiring? Or is it something else?
Some researchers have suggested a hormonal component to type differences. This makes some sense. For example, let's go back to Darwins finches, where he discovered that finches from different Galapagos islands had different types of beaks (mainly length) depending on the type of seed available in their island. How does the genome (which Darwin didn't know about) encode this? Mostly it doesn't. What the genome encodes is the length of time a particular growth hormone is supplied during gestation, which determines beak length. There are two parts to the genome, the static encoding (of a beak which is identical for them all), and gene expression which is how characteristics are expressed in the zygote (which differ for the various finches). So, could hormones determine orientation (E/I, N/S) in the fetus? Certainly my Sensor nephews appear to have much higher hormones than my IN does. While we don't know the answer to this, I suspect it is likely.
To wrap this up, what about the functional stack Ti, Ne, Si and Fe? Surely that isn't encoded in the genome? No I think it isn't. Jung and follow ons hypothesized that the functions were a learned response to the dominant. The inferior (Fe) is a balance to the Dominant, likewise the Tertiary to the Secondary. This I think is likely, certainly we know that the functional stack develops over a childs growth in response to cultural influences, among the psychic pressure of needing to balance the strength of the Dominant**.
So there you have it. I hypothesize that our basic type (E/I and N/S primarily) is probably determined by genetic expression - possibly due to hormone levels. The functional stack is a learned response growth in childhood. So to answer the question "Do you have any free will with regards to type" my answer is "Yes, you don't have any choice"***.
*The Singularity is Near
**Myers-Briggs Theory
*** This is a tongue-in-cheek answer obviously, but I think it is mostly accurate. However, obviously as finch beaks can develop with small differences due to precise levels of growth hormones, personality type can develop somewhat differently during childhood. This is why you can take a roomful of INTP's, and while they all will likely demonstrate Ti characteristics, the exact form of that Ti will differ. Thus, when we get in arguments about how people of a type differ, I say it's a moot point. Yes they do, and yes they don't.
What can we deduce about the genetic determines of type? First look at the brain, which starts with about 30 to 100 megabytes of specification in the compressed genome but ends up with a billion times more complexity*. Clearly the neural nets of the brain aren't encoded in the genome, but the structure of how they form must be encoded. If they were not there would be no reason for them to form.
Observationally, I've seen in the children in my life (mine and nephews and nieces) which I've known from gestation to adulthood, there are some traits which clearly show up very early. For example; I have a nephew who is an obvious ESFP. This behavior was obvious in the womb, where I would see him restlessly moving around, thrusting his arms about himself in his mothers abdomen. My INTP kid by contrast, well we never felt a kick. Late in the game we discovered that he was active at night while we slept, but he still wasn't all that active (my nephew would wake them up by kicking so hard that the husband would feel it!)
So in the womb let's posit that some gross aspects of temperament exert themselves; what I see here is the difference between ES and IN. Namely orientation to information (external or internal) and direction of information (intuition or physical sensation). This is interesting, we know that brain areas having to do with learning undergo more change, whereas structures having to do with sensory processing experience less change after birth*. We also know that ES is far more common than IN types. Could there then be some genetic coding that unusually makes some zygotes less attuned to Sensory processing? Certainly when they were toddlers you could see my kid was more contained and off on his own (in some toddler sense), while my nephew was ranging around, poking things, discovering the world around him. Could it be that being an IN is a defect in sensory processing wiring? Or is it something else?
Some researchers have suggested a hormonal component to type differences. This makes some sense. For example, let's go back to Darwins finches, where he discovered that finches from different Galapagos islands had different types of beaks (mainly length) depending on the type of seed available in their island. How does the genome (which Darwin didn't know about) encode this? Mostly it doesn't. What the genome encodes is the length of time a particular growth hormone is supplied during gestation, which determines beak length. There are two parts to the genome, the static encoding (of a beak which is identical for them all), and gene expression which is how characteristics are expressed in the zygote (which differ for the various finches). So, could hormones determine orientation (E/I, N/S) in the fetus? Certainly my Sensor nephews appear to have much higher hormones than my IN does. While we don't know the answer to this, I suspect it is likely.
To wrap this up, what about the functional stack Ti, Ne, Si and Fe? Surely that isn't encoded in the genome? No I think it isn't. Jung and follow ons hypothesized that the functions were a learned response to the dominant. The inferior (Fe) is a balance to the Dominant, likewise the Tertiary to the Secondary. This I think is likely, certainly we know that the functional stack develops over a childs growth in response to cultural influences, among the psychic pressure of needing to balance the strength of the Dominant**.
So there you have it. I hypothesize that our basic type (E/I and N/S primarily) is probably determined by genetic expression - possibly due to hormone levels. The functional stack is a learned response growth in childhood. So to answer the question "Do you have any free will with regards to type" my answer is "Yes, you don't have any choice"***.
*The Singularity is Near
**Myers-Briggs Theory
*** This is a tongue-in-cheek answer obviously, but I think it is mostly accurate. However, obviously as finch beaks can develop with small differences due to precise levels of growth hormones, personality type can develop somewhat differently during childhood. This is why you can take a roomful of INTP's, and while they all will likely demonstrate Ti characteristics, the exact form of that Ti will differ. Thus, when we get in arguments about how people of a type differ, I say it's a moot point. Yes they do, and yes they don't.
