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MOTM Aug 2010
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Discussion Starter · #1 ·
When Carl Jung wrote about the cognitive functions, he did not have the technological resources we have today to study parts of the brain, so he relied largely on anecdotal evidence from interactions with people. Now, neuroscience has evolved to the point where we can pinpoint certain aspects of the brain that are responsible for personality and behavior. This has allowed people like Jonathan Niednagel and Lenore Thomson to expand upon Jung's original theories and give an added dimension to personality typing. However, science hasn't proven everything, and a lot of the theories surrounding MBTI are still not evidence-based as of yet.

I will point out that neither myself, Niednagel, nor Thomson are neuroscientists; it is the work of others that has led them to develop their theories. I also do not currently have access to the original research articles that formed the basis of these theories, but I do have a copy of Niednagel's book, Your Key To Sports Success, which has a chapter on the neuroscience behind typing. Most of my information will come from that chapter, as well as the page on Niednagel's web site, "Brain Types & The Brain".

Front and Back: Extraversion and Introversion

Niednagel associates Extraversion with the front of the brain (anterior to the central sulcus) and Introversion with the back of the brain (posterior to the central sulcus). Most of the areas in the brain that initiate action and speech are located in the front of the brain, while the back of the brain gathers and processes data.

Here are some lines from Niednagel's site regarding Extraversion:

--personality—the prefrontal cortex is the most significant area for creating one’s outward “personality”.

--Expressing language through conversation/speech (activated by Brocas [left anterior forebrain]). In general, Extraverts speak more and louder than Introverts. (Nurturing, environment, and genetic variances also affect speech patterns; thus explaining most speech differences among Extraverts [and Introverts].)

A University of California medical school used PET scans to examine brain regions of people while speaking. They looked at the brain while they (1) made nonsense syllables, (2) recited the months of the year, and (3) recited a briefly memorized prose passage. While both the "mindless" recitation of the months and the prose passage used Wernicke's area (the top back part of the temporal lobe), ONLY the prose showed activity in Broca's area. The conclusion: rote memorized verbal tasks require little thought or sophisticated cortical activity. Bookheimer, S., et al. 2000. Neurology, Vol 55(8), 1151-1157.

--voluntary motor movements (activated by primary motor cortexanterior to central sulcus). Moving the body is an Extraverted (energy-expending) function, activated by the motor cortex.

--high degree of “attention” to outside world (principally a function of the anterior forebrain—especially right superior frontal gyrus)

--expressing emotion (left anterior forebrain)

--dopamine (a neurotransmitter that says “do it” is primarily in anterior forebrain.

--cingulate gyrus—regarded as the volition and will center (located in anterior forebrain); it causes humans to act. In addition, Extraverts are innately designed to expend energy whereas Introverts conserve it.

--planning—an integral part of taking action and expending energy.

Planning involves maintaining one main goal while working on sub-goals for that main goal. This is apparently one of the unique human brain functions. The National Institutes of Health in Bethesda, Maryland has published findings that show that that particular task is performed in the most anterior part of the frontal lobes called the fronto- polar prefrontal cortex. Koechlin et. al, Nature 1999, vol 399(6732) 148-151.
And here are the points regarding Introversion:

--understanding and comprehension of language (processed in left temporal lobe—Wernickes)

--5 senses (taking in world around self)

--touch and pressure (parietal lobe—which controls the primary sensory cortex.

Behind the primary sensory cortex is a large association area that controls fine sensation—weight, size, shape, etc.)

--smell and sound (temporal lobe)

--sight (occipital lobe)

--long-term memory—stored primarily posterior to central sulcus

--neuroscientists now suspect there are 4 separate memory systems in the brain (rather than one as long believed). Conscious memory of facts and events—hippocampus; associative learning (like Pavlovian conditioning)—cerebellum; emotional memories—amygdala; memories of learned skills—basal ganglia. These are posterior brain regions.

--In Alzheimer’s disease, long-term memory fades as the posterior brain cells die

--self awareness (parietal lobe)

--Introverts conserve energy whereas Extraverts expend it.

--reading (posterior region)

Dr. Kenneth Pugh, Psychiatrist and Medical Researcher at Yale, has been studying the neural pathways which are generated in good readers. When the brain is asked to go from the listening and speaking modes to the visual spatial, yet abstract production of reading, new relationships between regions in the cortex are formed. This is true for all written languages. Skilled readers have engineered neural networks, which take the visual sensory input from "eye to meaning" in about 150 milliseconds. This is done through the dominant path of the eye to three posterior gyrus (areas in the back half of the cortex). The lingual, fusiform and angular gyrus collaborate to convert letters into meaning.
Left and Right: Judging and Perceiving

It had been thought that the left side of the brain was associated with Thinking and Sensing, while the right side of the brain was associated with Feeling and Intuition. More recent studies, though, have shown that aspects of all four are located in both hemispheres. For example, while verbal logic comes from the left hemisphere (and especially Broca's area in the left anterior), the right hemisphere is superior in spatial and synthetic reasoning. The left frontal region expresses emotion, while the amygdala (located in the posterior) is responsible for emotional memory. The understanding of abstract words comes from Wernicke's, in the left posterior region of the brain, while the right anterior part is responsible for intonation, mental imagery, and the understanding of metaphor.

Here's what Niednagel has to say about the left side of the brain:

Judging (J): Structure, organization, seeking closure, local/detailed, methodical, and analytic (step-by-step).

--the left brain is essentially the Judging hemisphere (unknown to Jung and Myers)

--left brain performs sequential analysis, approaching matters methodically

--left brain performs sequential body functions—which are mechanical, inflexible, rigid

--left brain is orchestrated to a state of “local” bias

--the “J” left brain is the conscious hemisphere, more in touch with the moment. It is time driven, clock driven—especially the SJs.
And here's what he has to say about the right side of the brain:

--right brain is principally the Perceiving hemisphere

--it’s involved in parallel/pattern processing

--right brain processing is tilted towards the “global”

--performs holistic body functions—which are smooth, graceful

--the “P” right brain is the subconscious hemisphere; it is has greater difficulty paying attention. This explains why the vast majority of persons diagnosed with ADD are right-brained dominant Ps. The right-brained “P” is process-oriented rather than time/clock driven.

--as reported above, many who suffer right-brain strokes can understand the literal meaning of sentences--their left brain can still decode the words--but they can no longer get jokes or allusions. An intact right brain is needed to make the more playful connections.

-- the current assumptions about the relationship between handedness and lateralization are oversimplified. This is especially evident in left handed people who demonstrate use of their "non-dominate hand" in many more activities than right handed people.
In addition, it is worth noting that, even though J's may be left-brain dominant and P's may be right-brain dominant, we all are capable of using both hemispheres. We will, if possible, prefer one over the other, however.

A study out of Duke University shows that, if at all possible, our brain will solve tasks by processing information in only one hemisphere. We see this on simple problem solving tasks. However, as the tasks get more complex, the brain will always choose to process by coordinating information between the two hemispheres. Weissman and Banich (2000). Neuropsychology, vol 14(1), 41-59.
So What Hasn't Been Proven?

As I've mentioned above, Thinking, Feeling, Sensing, and Intuition are all located in both the left and right hemispheres of the brain, with specific aspects in each. Thomson organizes the functions as follows (note that Thomson is making an approximation here; science hasn't specifically pinpointed the functions to these specific regions):

Front-Left: Te, Fe
Front-Right: Se, Ne
Back-Left: Si, Ni
Back Right: Ti, Fi

Interestingly, each region of the brain is associated with two functions. According to this, Ti and Fi are in the same part of the brain, so how can we neurologically tell the difference between the two?

Niednagel primarily uses motor movements to distinguish between SFs, STs, NFs, and NTs. Motor movements are initiated from the primary motor cortex, with specific regions of the cortex correlating to specific regions of the body:

Niednagel's theory is that SFs specialize in the gross motor region (from the toes to the elbow), STs specialize in the fine motor region (from the wrist to the eye), NFs specialize in the "language" region (face to swallowing), and NTs specialize in the cerebral cortex (separate from the fine motor cortex).

And from this, comes this:

While science has pinpointed specific areas of the primary motor cortex to specific muscles in the body, the association between the middle two letters of one's type and their motor skills comes largely from anecdotal evidence (basically Niednagel observed that certain people of the same personality type had the same motor skill arrangement).

Effectively, we have only really proven the existence of two of the four letters of the type code: E vs. I and J vs. P.

5 Posts
This is almost always a benign tumor on the pituitary gland, and it's very treatable. Usually with medication and/or surgery. It doesn't require chemo, and almost never spreads to other parts of the body.

8,229 Posts
These were confirmed by PET scans. It is not pseudo-science.
Its interesting though that the emotion center is right in the center of the brain, and that the only distinction in brain hemispheres has to do with E and I, and J and P. Not S N or T F, since they share spaces.

That being said, this might only be the surface of the iceberg.

Also, was brain activity evenly distributed in each hemisphere?

757 Posts
Neuroscience hasn't got as far enough as to cure autism, so it can't possibly justify enough about personality other than identifying the lobes for traits.

MOTM August 2012
3,467 Posts
When I read Thomson's book I thought it was strange that she wrote about such a potentially important finding based on just one source. Until I looked up Mr Niednagel on Wikipedia: Brain types - Wikipedia, the free encyclopedia
Yea I have a tendency to trust Nardi's work a little bit more since it is much more grounded in actual neurology.

I do find it funny that this thread is linked as a source on the wiki page though.
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