Somatotype and Measuring the Big Components of Personality


So the problem comes down to identifying the big functions of an organism and somehow measuring them.  That’s what this site is all about.  Sheldon’s somatotype theory both identifies and measures the big systems of the human body.  He spent a lifetime looking directly at what is hiding in plain sight.  He classifies the very thing we overlook and take for granted – the human body.  Look at the connection endomorphy, mesomorphy and ectomorphy have with the big functions of a living organism.

Endomorphy = Visceral System. An animal needs to eat.  There is no life at all without the “big” tube (intestines).  Living things must have a metabolism or there is nothing.

Mesomorphy = Muscular System. An animal needs to move.  It needs to move toward food and away from danger.

Ectomorphy = Nervous System. An animal needs coordinated and rapid movement to capture food and escape danger.  The nervous system is an emergency system. It records routines and strategies that can be quickly initiated when needed.  It deals with things that suddenly come into view.

It shouldn’t be too hard to imagine that if a person is structured with an emphasis on the gut, this will have the effect of conditioning a person to be interested in food, and the comfort of feeling full and a desire to arrange a comfortable and relaxing environment conducive to carrying out the work of digestion.  If a person is structured with a strong muscular body, wouldn’t you expect that those muscles would want to move and facilitate activity and gain proficiency at dominating their world?  A stretched out, lean ectomorph, with a high surface to volume ratio could be expected to be vigilant about protecting that boundary/surface area.

If you’ve been keeping track you should have noticed that Sheldon’s theory only involves three structures.  Are we missing something?  Aren’t there at least four temperaments?  Is there a missing “fourth” system/structure?  And if there is a fourth, could there be a fifth?  How can we know?

Let’s turn again to the ancient Greeks.  Aristotle, in his treatise on the soul refers to four capacities.

For the present let it suffice to say that soul

is the principle of the capacities we have named

the nutritive, the sensitive, the ratiocinative, and


Let’s match these up with Sheldon’s dimensions:

  • Nutritive = Endomorphy
  • Movement = Mesomorphy
  • Ratiocination (thinking) =Ectomorphy
  • Sensitive =  (blank)

It appears Sheldon’s schema is missing the Sensory system.  We will fill in that blank shortly.  In the meantime we must agree that an animal needs information from its environment.  The nervous system keeps an organism on course, but if a situation changes, it needs to know when to change directions. That is the function of the Sensory system.  It tells the organism when something is different.

Now back to the question about whether there is a fifth essential function. Can you think of one? There is a way of figuring out why there are four, and only four necessary systems/structures.  To do that we have to gain some objectivity. We have to step way out of our “selves” to accomplish this.

Consider an inanimate object – a chunk of matter.  What can we say about a “chunk” without using words that involve size, shape, texture, color, taste or any other qualitative word ?  Well, get ready because I’m going to claim that there are four and ONLY FOUR things that you can say about “chunks”.

  1. First of all, you can claim that there is some cause of the “chunk”.  If you follow the “chunk” back in time you will probably find that a couple of larger “chunks” collided and broke into pieces, one of which is the very same “chunk” we are considering.
  2. Next you can claim that the chunk is in motion.  Even a “chunk” sitting on the ground is moving – it’s moving toward the center of the Earth because of gravity.
  3. You can say that it is moving in one certain direction.  If a “chunk” were to start moving in several directions at once it would cease to be one “chunk”.  It would lose its integrity.  The movement of a “chunk” in one direction preserves the “chunk’s” integrity.
  4. Finally,the “chunk” is not everywhere, but it is moving in a certain space relative to other “chunks”.

Now let’s see what we can use from this description of a “chunk” that will help us understand what is essential for a living organism.  You can make the same claims about living organisms by simply adding the word “self”.

Organisms are:

  1. Self-causing/forming/metabolizing.  This refers to the fact that biological entities are constantly forming themselves by means of metabolic processes.
  2. Self-moving.  Their movement is not the simple result of an external force and inertia. They have muscles or in the case of microscopic organisms, flagella.
  3. Self-directing.  To maintain integrity organisms react for self-preservation.  Their trajectory is mediated by choice rather than external forces.
  4. Self-orienting.  They determine where they are in relation to other objects.

This list makes up the minimum essential systems in a living organism. The systems may vary in complexity with the type of organism we are observing, but the functions are essential and not arbitrary.


It may seem strange to start out with a strong emphasis on patterns of four and then focus on a method of classification that is clearly based on three dimensions.  But there is a hidden fourth factor in Sheldon’s schema. If you look closely at an equilateral triangle, you’ll notice that it consists not only of three points equidistant from each other, but it also has a middle, which is equi-distant from all three points.  It may sound contradictory, but what about the “extreme” middle?  Perhaps there is something about the middle that we should explore?

If the middle, in fact constitutes a fourth system, it shouldn’t be hard to figure out which one it would be.  The only system remaining unaccounted for is the sensory system.  If this is the case, we need to find out what is so special about the middle that it could be considered sensory dominance. What is there about the middle that would allow the organism to go into the sensory, exploratory or searching mode?

The middle suggests balance.  What situation results from balance?  In a tug-o-war type of struggle for dominance, an equality of forces will cancel each other out.  If the strength of the participants is close to equal, the situation becomes extremely sensitive to factors in the environment, such as wind direction and speed, or the condition of the playing field. Could it be that the sensory system is allowed to dominate only when the other systems are out of the way?  A scale that is balanced can be affected by the slightest input of information.  A mere pin is often enough to push the whole system into motion even though the total mass of the system is thousands of time greater.  Clearly,  influences outside of a balanced system become very important.

How does this idea fit into the dynamics of an organism?  Experiments on the exploratory behavior of animals seem to indicate that food and water deprivation decreases explorative behavior of rats, suggesting that satisfaction of the primary drives is a prerequisite for strong exploratory behavior.  This concept holds even with smarter animals.  H.F. Harlow noticed this tendency in his experiments with primates.  “Mice, Monkeys, Men and Motives”  Psychological Review Vol. 60,23-32,1953

The famous developmental psychologist Jean Piaget describes something similar:

“Hunger for stimuli, then is essentially an expression

of the fact that at a time when no other particular schema

is exerting any controlling action (or, in other words, when

none is making itself felt by means of any actual and

compelling need), the animal is not passive but remains

in a constantly seeking state for functional stimuli such as

may put one or other of these schemata into action.”

Biology and Knowledge Jean Piaget: University of Chicago

Press 1971

Zoologist, Hans Hass (1970) joins this chorus about the exploratory drive:

“It is characteristic of the inquisitive urge that it makes

itself felt with particular force when no other instictive

pressure exists, in other words, when other impulses have

waned.  As Schiller put it:  ‘The animal works when a

deficiency is the mainspring of its activity and plays when

the mainspring is an abundance of strength.’  As long as

his actions are governed, say by fear, hunger, or sexual

desire, man is not inquisitive either.

Only when he is without appetencies does he become

venturesome and willful.  It is then that he feels an urge

to abandon the normal pattern of existence, whatever the

alternative.  It is then that the Dionysiac, the daring and

truly human element in man, come to the fore.”  The Human

Animal  Hans Hass New York: Putnam 1970

Although Sheldon had no name for the middle “extreme” and simply referred to it as a 4,4,4 he certainly had some interesting things to say about it. Consider his description of the middle.

“4,4,4 is probably about as close as human flesh gets to God.

In this pattern all three primary components of temperament

are as strongly represented as they can usually be tolerated,

one by another.  To call a man a 4,4,4 may be tantamount

to crediting him with humor.  Whatever else humor may be,

it certainly is characterized by two qualities: (1) An inclination

toward detachment – the quality of regarding life and self

lightly: (2) An inclination to tolerate and to enjoy

incompatibilities at a high level of awareness.”  The Varieties

Of Delinquent Youths. New York:  Harper, 1949

What Sheldon has essentially said is that a 4,4,4 is a creative person. Consider Solomon Diamond’s explanation of humor and you will start to see the tie-in with creativity.

‘The humorous attitude does not merely tolerate instability,

but actively seeks it and delights in mastering it.  It

constitutes an intellectual adventurism, which gains

satisfaction from simultaneously experiencing the same field

as structured in two, even three or more, different ways.”

Personality and Temperament New York: Harper, 1957

Abraham Maslow, in his description of the self-actualizing person and their “creative” nature, gives us further insight to the significance of the 4,4,4’s

“Inclination to regard life and self lightly.”

“I think that our understanding of perception and therefore

of the perceived world will be much changed and enlarged

if we study carefully the distinction between need-interested

and need-disinterested or desire-less perception.  Because

the latter is much more concrete and less abstracted and

selective, it is possible for such a person to see more easily

the intrinsic nature of the percept.  Also, he can perceive

simultaneously the opposites, the dichotomies, the

polarities, the contradictions and the incompatibles.” Toward

A Psychology of Being New York: Van Nostrand Reinhold Co.


Many articles on creativity have discussed the so-called “blocks” to creative development. These blocks are nothing more than the attitudes that would be characteristic of a person as he moved away from the center toward one of the extremes. The ectomorph’s overly critical, sensitive and judgemental attitude would hinder his approach to a problem.  The mesomorph’s desire to get the show on the road, along with his desire to control and dominate, would make him too impatient for the ideal solution.  Too much concern with pleasing people would make the aloneness of exploration and innovation unbearable for the endomorph.  Only the middle provides a haven free from these blocks to creativity.

If you study the descriptions of the Sanguine temperament you will find a strong connection with the middle region of Sheldon’s system.  These quotes are not to be considered “hard” proof of the middle type, but they should illustrate an insight that has been shared by many skilled observers with differing perspectives over a long period of time.


 Next: Significance of Centered Somatotypes




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