Myth or Real, The four functions develop over time.

[TheCheeseBurgerKing]

Maybe you have or maybe you haven't heard that each of the four cognitive functions develop within an individual at different points in time. What I have heard is that the first one starts around 6 years, the second around 14, the third around 20, and the fourth around 28 or so. Do you all buy this? In your experience, is there any degree of truth to this?

 

[skylights]

I think it's pretty solid that cognition grows and changes and its weaker aspects tend to strengthen over time. It seems reasonable to assume that the functions would tend to strengthen throughout life in the order that they are most exercised, but specific age and development? I don't know how anyone could have reliable evidence for that. Though maybe it is something Nardi has gotten into. Someone with a stronger neuroscience background would be helpful here.

 

[Seymour]

I think it's pretty solid that cognition grows and changes and its weaker aspects tend to strengthen over time. It seems reasonable to assume that the functions would tend to strengthen throughout life in the order that they are most exercised, but specific age and development? I don't know how anyone could have reliable evidence for that. Though maybe it is something Nardi has gotten into. Someone with a stronger neuroscience background would be helpful here.

In Big Five terms, it looks like folks tend to become more agreeable (Feeling) and conscientious (Judging) as they age.


As far as the brain at middle age, this article is interesting (if not directly about typology):

Researchers now have an unprecedented wealth of data on the aging brain from the Seattle Longitudinal Study, which has tracked the cognitive abilities of thousands of adults over the past 50 years. These results show that middle-aged adults perform better on four out of six cognitive tests than those same individuals did as young adults, says study leader Sherry Willis, PhD, of the University of Washington in Seattle.

While memorization skills and perceptual speed both start to decline in young adulthood, verbal abilities, spatial reasoning, simple math abilities and abstract reasoning skills all improve in middle age.

[...]

For example, psychologist Cheryl Grady, PhD, of the University of Toronto, and her colleagues have found that older adults use more of their brains than young adults to accomplish certain tasks. In a study published in the Journal of Neuroscience (Vol. 3, No. 2) in 1994, Grady reported that performing a face-matching task activates mainly the occipital visual areas in younger adults, but older adults use these areas as well as the prefrontal cortex. (Both groups of adults are equally skilled at the task.)

Several groups, including Grady’s, have also found that older adults tend to use both brain hemispheres for tasks that only activate one hemisphere in younger adults. Younger adults show similar bilateralization of brain activity if the task is difficult enough, Reuter-Lorenz says, but older adults use both hemispheres at lower levels of difficulty.

The strategy seems to work. According to work published in Neuroimage (Vol. 17, No. 3) in 2002, the best-performing older adults are the most likely to show this bilateralization. Older adults who continue to use only one hemisphere don’t perform as well.

I believe Nardi claimed to have seen signs of tertiary and inferior function development in older people, but also claims that ongoing experiences (like one's career or long term hobbies) appear to have a big effect over time in the areas of the neocortex are habitually used.

 

[INTP]

It depends on the person in what age the functions develop. Some might start to develop fourth before 30's and some might had not developed it much at all even when they are old. Usually second starts to develop more in teens, tert in mid 20's to mid 30's and fourth in 40-50's, but any of them can develop during the life at any point and all of them are present one way or another during all the life. It kinda depends on what happens in life whether or not the function are developed, but the theory says that people have this sort of drive to develop the functions, and really i think that its what this whole growing up thing is all about.

 

[Kullervo]

I have overdeveloped Fi for my age, and that is almost certainly due to circumstances throughout my childhood, though my natural personality (more present as a small child than now probably) was quite fiery and sensitive. I don't have fond memories of my earlier life. At all.

By contrast, I have hardly if any Se. I am highly unobservant - I don't notice things in the environment that people might point out to me, even two or three times. A flock of birds might be flying past in the distance and I will have no idea, because that isn't where my focus is.