Brain types

# Overview
Brain typing, which combines elements from neuroscience, physiology, and psychology, is a system developed by Jonathan P. Niednagel.  It is based on ideas of the psychological typology of Carl Jung, and the later work by Katharine Cooks Briggs and Isabel Briggs Myers known as the Myers-Briggs Type Indicator (MBTI).
What separates brain types from Jungian typology, and its offshoots such as the MBTI and Socionics, is its emphasis on mental and motor skills.  Each of the sixteen brain types is said to specialize in certain regions of the brain responsible for varying degrees of mental and motor skills.  Niednagel believes types are inherited, possessing a genetic basis.
Niednagel started to develop brain typing in the 1970s while coaching little league baseball.  He observed that children with similar personalities also had similar motor skills.  Having spent several decades on research, Niednagel's work began to receive more attention in the 1990s, particularly in the arena of professional sports.  Perhaps the most well-known event related to brain typing was Niednagel's prediction in 1998 that Peyton Manning would become a star quarterback in the National Football League (NFL), and that the similarly hyped Ryan Leaf would perform poorly in the league.  His prediction came true as Peyton Manning has become one of football's best quarterbacks while Ryan Leaf is remembered as one of the worst busts in football draft history.
With all the effort and research that Niednagel has put into brain types, it has not yet been validated through science. It is also uncertain how much application brain types has beyond the realm of sports, since the primary difference between brain typing and related typologies is the motor skill emphasis.

# Brain Types and Motor Skills
Niednagel divides the types into four basic motor skill groupings: SF, ST, NF, and NT.  SF, or 'Sensing-Feeling' types (ESFJ, ESFP, ISFJ, ISFP), are said to excel in the region of the brain responsible for gross motor skills.  ST, or 'Sensing-Thinking' types (ESTJ, ESTP, ISTJ, ISTP), are thought to possess the best fine motor skills of the four groups.  NF, or 'Intuitive-Feeling' types (ENFJ, ENFP, INFJ, INFP), excel in the auditory cortex, which is responsible for various hearing and language skills.  NT, or 'Intuitive-Thinking' types (ENTJ, ENTP, INTJ, INTP), are believed to excel in the cerebral cortex, where abstract levels of reasoning occur.

# Brain Types and Mental Skills
The types can also be broken down by letter, which denote certain mental skills:
Extroverted (E):
-Located in frontal (anterior) lobes of brain
-More energy-expending as opposed to energy-conserving
Introverted (I):
-Located in rear (posterior) lobes of brain
-More energy-conserving as opposed to energy-expending
Sensing (S):
-Brain more focused on physical-concrete functions than abstractions
Intuition (N):
-Brain more focused on abstract-mental functions than the physical and concrete world
Thinking (T):
-Brain more objectively focused, preferring the inanimate world (objects, things, systems, etc.)
Feeling (F):
-Brain more subjectively focused, preferring the animate world (life, people, relationships, etc.)
Judging (J):
-Left-brain dominant; inclined toward linear mental functioning; more analytic mental process
-Motor skill patterns are more rigid than fluid (tend to be less physically coordinated)
Perceiving (P):
-Right-brain dominant; inclined toward spatial mental functioning; more synthetic mental process
-Motor skill patterns are more fluid than rigid (tend to be more physically coordinated)

# Commercialization and criticism
Educational society and members of American Psychological Association criticize brain types as not valid and built for commercial purposes only. Mr. Niednagel, who has no scientific degree in psychological or medical fields, only a Bachelors degree in Business Finance from California State University, Long Beach., claims his methods as being the only valid ones.  Another post boasts of a 100% accuracy rate in assessing and localizing brain functioning on the basis of "eyeballing" and then analyzing body language, posture, motor activity, and speech. California Neuroscience Researchers and Professors requested that Niednagel remove their "endorsements" once they inspected the Brain Type website and discovered that they were being used to bolster Niednagel's stature.
Dr. Sandbek, in his publication Brain Typing: The Pseudoscience of Cold Reading criticized validity of brain types and claimed "how closely the Brain Typing of Jonathan P. Niednagel fits as a pseudoscience".