A Market Model of Human Personality 1: Summary

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Baron-Cohen pages on this site:
The Essential Difference (2003):

The Essential DifferenceSummaryCommentsClassismFive Brain Types

This page summarises Simon Baron-Cohen's recent book, The Essential Difference (2003), which is a particular statement of the market model of human personality.

The numbers in square brackets link to corresponding points on the Comments pages.

Female and male brain types

Baron-Cohen is a Cambridge psychology professor and leading autism specialist. At the start of The Essential Difference, he immediately states his theory that the female and male brain types are predominantly hard-wired differently: the female for empathising and the male for systemising. Empathising is an emotion triggered by another person's emotion; systemising is a drive to understand and build systems of whatever kind. [2.1]

This distinction gives 5 possible brain types, ranging from extreme E (empathising) to extreme S (systemising). with most people between the two extremes as E, B (balanced) or S. Statistically, more females will have E dominant type brains, more males S dominant type. [4.1]


At the personal level, empathy is about constant awareness of other people's emotional state, about genuinely caring, genuinely communicating. At the social level, it is what holds relationships together. At the societal level, moral codes arise from it. [2.11]

Empathy has 2 components: the cognitive, which enables a person to see things from another's point of view, and the affective, which enables a person to respond appropriately to another's emotional state.

Evidence for Empathy

Baron-Cohen offers various sorts of evidence for his association of the female brain type with empathy. For one thing, there are the play styles of small children. Girls tend to achieve their self-interested goals by manipulation, whereas boys tend to go for brute force. Girls regard cooperation and intimacy as more important than establishing dominance, whereas with boys competition and social status are more important. [2.2]

This is in line with what the author claims about women:

Women tend to value the development of altruistic, reciprocal relationships. [p 34]

Male crime

Another sort of evidence is male crime. Date rape [2.3], conning old ladies and the like argue for lower levels of empathy in men than in women. Again, there is evidence to suggest that in pre-industrial societies, 1 in 3 men die in fights; indeed killing will enhance a man's status if it happens in a fair fight. Data going back over 700 years in a range of societies shows that two thirds of killings of men by men have been about social status. [2.4]

A further line of evidence is that boys from an early age are quick to establish a dominance hierarchy, which suggests less empathy and more systemising. To support this argument, the author offers a lengthy account of a study of a teenage summer camp, presumably in the USA.

Boys and girls have different agendas as far as friendship is concerned. Girls focus on one to one relationships, boys on some shared activity involving a group. For a boy, being good at the particular activity will secure promotion within the group.


Another significant area is the difference between the sexes in their communication. Thus women's and men's conversation tends to differ in both content and style. The conclusion is that female speech is more other-centred, male speech more self-centred.

Looking at the superior language skills of females in relation to their greater empathy skills, Baron-Cohen recognises that a Darwinian view might be that the latter derive from the former, but prefers to see the two sorts of skills as independent of each other and the relationship between them as complex.


Turning to the male type brain, the author defines systemising as

the drive to understand a system and build one. [p 63]

He distinguishes 6 main sorts of system: technical, natural, abstract, social, organisable (where the components can be organised in various ways, as in a collection of objects), motoric (involving the use of human motor skills).

Evidence for systemising

As evidence of male systemising, Baron-Cohen returns to the topic of play, suggesting that little boys prefer mechanical and constructional toys, while little girls prefer dolls. Moving on to teenagers, he argues that, if girls outperform boys at school level maths, it is because they are more accurate than boys at this stage, rather than fundamentally more able.

Evidence supports the idea that men perform better at tasks requiring systemising in relation to shapes, orientation and topography. The same kind of thing applies to motor systems. It is not that men have superior motor skills, but they are better at judging the movement of objects in space, such as the trajectory of a ball.

As far as organisable systems are concerned,.it has been found that in tribal peoples, men produce more complex systems for classifying animals than do women. Men's leisure activities show their love of classificatory systems. Thus sports fans get involved in several such systems, such as lists of teams and players.

Cultural factors

Baron-Cohen now raises the nature ~ nurture issue, asking whether the sex differences he has described can be accounted for in terms of culture alone. Are differences in the parenting of girls and boys what make the differences between them. There is good evidence that parents talk differently to children according to their sex, but this could be in response to the child's behaviour rather than the cause of it.

Over all, the sex differences are so marked so early in children's development that cultural factors alone are unlikely to explain them.

Biological factors

More space is devoted to the biological factors, starting with looking at animals, where it is possible to discern some hints of difference between the sexes, i.e. from the point of view of empathising and systemising.

It is possible to distinguish 5 levels of human sex differentiation: genetic, gonadal, genital, brain type, sex-typical behaviour. To illustrate the highest level, we get typically male interest in e.g.

gadgets, CD collections and football results

contrasted with typically female interest in

caring for friends, worrying about their feelings and striving for intimacy [p 99].

Pre-natal testosterone

Baron-Cohen describes research that he was personally involved which indicated that the higher their levels of pre-natal testosterone have been, the lower the signs of empathising skills in young children, female and male. Normally, these levels are higher in males. Other research points to higher levels of pre-natal testosterone being linked to systemising skills.

It has been proposed that pre-natal testosterone affects the development of the brain, tending to make the right hemisphere of male brains develop earlier and faster than the left. Baron-Cohen looks at research relating to this and to sex differences in brain structure. He supposes that the genes controlling empathising and systemising will one day be identified.


The author explores what might have been the evolutionary advantages of the systemising and empathising brains. [2.5]

Advantages of the male, systemising brain would have been making and using tools, hunting and tracking, trading, power (improving rank), social dominance (competition), expertise (in the particular skills needed for success in a given culture), tolerating solitude (for working alone, as in tracking), aggression (for reproductive advantage - getting and keeping sexual partners etc), leadership.

Advantages of the female, empathising brain would have been making friends, mothering, gossip (for acquiring information and the human equivalent of primate grooming), social mobility (getting on well with your partner's family), reading your partner (for successful sexual partnership). [4.2]

[We are now well over 2/3 through the text of The Essential Difference, but only 1/2 through this account of it. From the point of view of this site, the later chapters call for more detailed reporting.]


Baron-Cohen now turns to his extreme brain types. He associates autism with the extreme male brain. Until the 1990s, autism was a rare condition, apparently affecting only 1 in 2,500 children. Its basic characteristics were

poor social skills, limited imagination and obsessive interests in unusual topics. [p 134]

Notably, some of the children showed islets of ability, amazing levels of ability in isolated fields. Thus, they might acquire foreign language grammar and vocabulary extremely quickly, though they were unable to converse.

The author sees this as a different kind of intelligence. [p 135]

The autism spectrum

In the 1990s, Asperger Syndrome (AS) started to be recognised: a variant of autism in which talking begins at the usual stage in a child's development. Previously, late development of the ability to talk had been a key feature of autism diagnosis. AS has meant that 1 in 200 children is now seen as having some form of autism, known collectively as the autism spectrum. [4.3]

Some facts about autism spectrum conditions are that they are strongly genetic, that they affect brain development and functioning and that 10 times as many males as females are involved. People with autism have major problems with empathy as defined earlier.

Baron-Cohen sees people on the autism spectrum as driven to control their environment. They find unpredictability difficult, e.g. in social interactions, and are drawn to predictability, e.g. to computers.

Defenders against injustice

Very significantly from the point of view of this site, the author notes that people on the autism spectrum

Are often the most loyal defenders of someone they perceive to be suffering an injustice. [p 137]

Also, they notice details that other people have missed.

Baron-Cohen runs a clinic for adult AS, mostly dealing with people whose AS related difficulties in life cause them to suffer from depression, even suicidal depression. This is caused by an inability to socialise naturally. Thus, people with AS do not appreciate that speaking one's mind can give offence and be hurtful to others. [2.6]

The author notes that

Most have no time for political correctness or spin. [p 147]

In fact, many such people hold very strong political or other views and fail to appreciate that:

one's beliefs can be a matter of subjectivity or just one point of view. [p 147]

The extreme male brain theory of autism

Baron-Cohen now introduces the extreme male brain (EMB) theory of autism, first suggested by Hans Asperger in 1944, in German [p 150] [2.7], but taking nearly 50 years to reach the English speaking world. He points to 3 sorts of evidence for this idea that autistics have an extreme type of male intelligence. Firstly, they show low scores in empathy tests. Secondly, they show high scores in tests indicative of systemising ability.

Thirdly, there are biological and inherited indicators. One biological indicator is ring finger length: this is longer than the index finger in average males as compared to females and longer still in people on the autistic spectrum. The author points out that there is a high rate of autism in families that also show ability in professions requiring advanced systemising abilities, e.g. mathematics.

AS cases

In fact, Baron-Cohen details his real life diagnosis of fellow Cambridge professor, the brilliant mathematician, Richard Borcherds, as having AS. He emphasises that because the professor has found an ideal niche in life, his AS is not causing him any distress.

The author also looks briefly at some putative AS cases: a Silicon Valley high flyer, Michael Ventris, who deciphered Linear B, plus 3 physicists, Paul Dirac, Isaac Newton and Albert Einstein.


Baron-Cohen ends his introductory remarks on physicists thus:

an arrogant assumption that you are right and everyone else is wrong suggests low empathizing skills in failing to recognize not only that others might have a valid point of view (there might be several ways of seeing a problem) but also that a dismissal of another's point of view might be hurtful to their feelings. [pp 165-166]

The Extreme Female Brain

Turning to the extreme female brain, Baron-Cohen conjectures that 2.5% of the population have one, though it has not yet been detected. People with this brain type would be systemblind. But this should not be a problem in our society, where it doesn't really matter if you don't understand cars or computers: you can always go to an expert.

At present, it is possible to see what the extreme female brain is not, but not what it actually is. [4.4]

At one point, Baron-Cohen refers to empathising and systemising as processes and asks what they are like:

Are they really independent dimensions? [p 174]

An overview of the EMB theory of autism

The author concludes the main text by contextualising the EMB theory of autism. To start with, two competing theories of autism, the executive dysfunction theory and the central coherence deficit theory are acknowledged and rapidly dismissed.

Similarly, a criticism of the theory is countered. The bias towards males in AS is far higher than in other developmental conditions that occur more frequently in males. That means it is wrong to claim that it is no more significant than these other conditions.

Finally, the EMB theory has various attractions. First, it explains the cluster of symptoms seen in the condition. Second, it makes sense of previously unexplained symptoms, such as the islets of ability and also repetitive behaviour, which the author sees as a type of systemising. Third, it explains the attention to detail found in autism: this is essential in systemising. Fourth, it offers a more positive view of the people with the condition: it's not that they are lacking something most people have, it's that they have something different.

The brain resculptured

Last of all, Baron-Cohen considers some issues about attitudes to the autism spectrum. For one thing, there is the question of intervention. Pre-natally, this could mean screening for autism. Later, it could be some form of educational effort: for

there is plenty of evidence that the brain can be resculptured by experience. [p 181]

For another thing, people on the autism spectrum should be valued. Thus, somebody with autism has pointed out to the author that

Without autism, we might not have fire and the wheel. [p 181-182]

Again, in some cases, parents

admire independence of mind, their lack of conformity, their unusual intellect. [p 182]

Finally, in a section entitled Respect, the author emphasises society's need for people with both main brain types, linking each type with particular professions.

Academic apparatus

It would be misleading to account for The Essential Difference in terms only of its content. For format is very important, in the shape of some extremely prominent academic apparatus.

Before the main text, a particularly extensive acknowledgements section mentions over 80 individuals, some more than once, and over 20 organisations. A list of figures has a dozen entries. [2.8]

After the main text of 185 pages, there are 4 appendices reproducing tests used in research, that readers can try out for self-assessment as to their own empathising and systemising. [2.9]


Then comes the references section. There are getting on for 600 mentions of sources, including over 80 that Baron-Cohen himself is involved in, mainly as co-author. There are up to 17 sources for a single reference number. The bibliography lists over 450 sources involving maybe 600 or more named scholars. [2.10]

(c) John C Durham, 2003

Baron-Cohen pages on this site:
The Essential Difference (2003):

The Essential DifferenceSummaryCommentsClassismFive Brain Types