Looking at the four personality types depicted in the graphic above, which most accurately describes you? By 'you', we mean the natural you, the you you don't have to work at, the you which feels most comfortable to you when there are no pressures to be anyone else.

We're talking about the you you were born with: your natural temperamental type. Of course, very, very few people remain totally true to that type in all circumstances - especially when their vMEMES motivate them to do things beyond their temperamental type. (For example, as someone slightly on the Melancholic side, when leading a workshop event, I find my ORANGE's achievement orientation will lead me to perform in an outgoing, even charismatic way that contains little hint of my natural mild Introversion.)

How much you are any one type will depend on where you tend to locate naturally on each of the 2 Dimensions of Neuroticism (Instability) and Extraversion. A number of studies have supported Hans J Eysenck’s (1967) contention that our default position on these Dimensions is birthed in us. One of the most notable of these is that of John C Loehlin (1992) who found, in monozygotic (MZ) twins reared together correlations for Extraversion of 0.51 and Neuroticism of 0.46; in MZ twins reared apart Loehlin found correlations of 0.38 for both Extraversion and Neuroticism, suggesting differing environments made only small differences  compared to the effects of being genetically identical.

However, most people can and do move along these axes, according to circumstances and especially if those circumstances require a vMEME shift. Though it will take considerable regular reinforcement, people can be conditioned by either positive reward or positive punishment to behave substantially different to natural type. However, as William Moulton Marston (1928) pointed out when considering how and why behavioural traits shift, there is always a natural tendency to revert to type when under severe pressure.

The concept of Phlegmatic, Choleric, Melancholic and Sanguine temperamental types has its roots in the ancient Greek medical philosophy of the 4 Humours, popularised in the writings of the 2nd Century Roman physician Claudius Galen. Such is the accuracy of this typing system that it has stood the test of time and has been given a scientific basis - initially by Wilhelm Wundt (1879), one of the founding fathers of modern Psychology, and then more especially by Ivan Pavlov (1927) in his famous work on conditioning dogs. The Pavlovian version has been refined by Eysenck and it is Eysenck's version* represented in the graphic above.

Neuroticism & Extraversion

It was in 1947 that Eysenck factor-analysed 39 items of personal data for each of 700 neurotic soldiers, including brain damage, physical illness and personality ratings. 2 uncorrelated factors emerged: Introversion-Extraversion (E) and Neuroticism-Stability (N). (Introverts and extraverts had already been identified as distinctive characteristic types by Carl Gustav Jung back in 1923.) These 2 Dimensions are assumed to be distributed normally amongst a general population so that most people will score somewhere in the middle and very few at either extreme.

Eysenck attributed position along the Extraversion axis to the level of electrical stimulation in the cerebral cortex from the ascending reticular activating system (ARAS). The main function of the ARAS is to maintain an optimum level of alertness or ‘arousal’. It does this by enhancing the incoming sensory data to the cortex through the excitation of neural impulses or it can damp them down. In extraverts the ARAS causes inhibition which reduces the intensity of sensory stimulation reaching the cortex. For introverts the ARAS builds up excitation which increases the intensity of sensory information reaching the cortex. The result of this is that introverts have a lot of internal activity and, therefore, seek a 'quiet life' to avoid further, external stimulation whereas extraverts are proverbial 'emptyheads' who seek external stimulation to fill the void inside.

In 1965 Eysenck wrote: “The typical introvert is a quiet, retiring sort of person, introspective, fond of books rather than people; he is reserved and distant except to intimate friends....He does not like excitement, takes matters of everyday life with proper seriousness and likes a well-ordered mode of life. He keeps his feelings under close control, seldom behaves in an aggressive manner and does not lose his temper easily. He is reliable, somewhat pessimistic....

The typical extravert is sociable, likes parties, has many friends, needs to have people to talk to and does not like reading or studying by himself. He craves excitement...is carefree, easy-going, optimistic and likes to ‘laugh and be merry’.  He prefers to keep moving and doing things, tends to be aggressive and lose his

temper easily; altogether his feelings are not kept under tight control and he is not always a reliable person.”

Neuroticism - not to be confused with neurosis (though there may be a relationship) - depends on how easily excited the limbic system's amygdala is. (Take this test: if someone shouts "Fire!", do you go "Oh, yeah.... Where?" (Stable) or have you already jumped through the nearest window to escape before the shout has faded (Unstable)?

Eysenck attributed the sympathetic branch of the autonomic nervous system (ANS) as reacting to a highly-reactive amygdala to produce the stress symptoms associated with displays of Neuroticism - eg: increases in heart rate, breathing rate, blood pressure, sweating, adrenaline production, etc.

Eysenck (1965) describes the typical high N scorer as “...an anxious, worrying individual, moody and frequently depressed; he is likely to sleep badly and to suffer from various somatic disorders. He is overly emotional, reacting too strongly to all kinds of stimuli and finds it difficult to get back on an even keel after each emotionally-arousing experience.”

The low N scorer “...tends to respond emotionally only slowly and generally weakly and to return to baseline quickly after emotional arousal; he is usually calm, even-tempered, controlled and unworried.” [1965 excerpts from ‘Fact & Fiction in Psychology’ (Penguin, Hammondworth)]

Hans J Eysenck

Graphic copyright © 1999-2003 Heffner Media Group Inc.

Types & Traits

Eysenck’s Dimensions - producing types or supertraits - are the highest level of a hierarchy. Next level down are a number of personality (or temperamental) traits that are correlated in certain patterns that suggest the more complex concepts types or supertraits. For example, Extroversion is a type or supertrait based on the observed correlations of sociability, liveliness, activity, etc.

Below the traits are the habitual responses - typical ways of behaving linked to a trait - and below that the specific responses - responses specific to one particular occasion.

The structure of Eysenck’s hierarchy is shown left and applied to Introversion and Extraversion below.

Since the original 1947 study, E and N have been found in a number of studies replicating Eysenck’s findings.

There have also been findings with implications for those who deal with people who are strongly introverted and extroverted.

Steve Harkins & Russell Green (1975) found that introverts were significantly better at vigilance tasks which require prolonged periods of intense concentration. However, extraverts were more likely to try to change an unsatisfactory situation. Eysenck (1970) discovered that introverts had lower pain thresholds while extroverts were more susceptible to the adverse effects of sensory deprivation. Working with his son, Michael, Eysenck (1985) found that extraverts were more likely to change jobs and sexual partners more frequently, more likely to divorce, show less brand loyalty in shopping behaviour and move house more often.

Interestingly, in an unpublished study by N N Trauel (1961), reported in Hans Eysenck (1967), extraverts were shown to have more difficulty conforming to instructions because they felt the need to express themselves. This may be evidence that strong extraverts may favour the self-expressive warm side of the Spiral while strong introverts are comfortable with the self-sacrifice/conformity cool side of the Spiral.