Autism: The Empathizing-Systemizing (E-S) Theory

THE YEAR IN COGNITIVE NEUROSCIENCE 2009
Autism: The Empathizing–Systemizing
(E-S) Theory
Simon Baron-Cohen
Autism Research Centre, Department of Psychiatry, Cambridge University,
Cambridge, UK
The mind-blindness theory of autism spectrum conditions has been successful in
explaining the social and communication difficulties that characterize these conditions
but cannot explain the nonsocial features (the narrow interests, need for sameness,
and attention to detail). A new theory, the empathizing–systemizing (E-S) theory, is
summarized, which argues two factors are needed to explain the social and nonsocial
features of the condition. This is related to other cognitive theories such as the weak
central coherence theory and the executive dysfunction theory. The E-S theory is also
extended to the extreme male brain theory as a way of understanding the biased sex
ratio in autism. Etiological predictions are discussed, as are the clinical applications
arising from the E-S theory.
Key words: autism; Asperger syndrome; empathy; systemizing
Introduction
theory is then considered, arguing it is better
subsumed by a more recent, two-factor theory,
Classic autism and Asperger syndrome share
the “empathizing–systemizing” (E-S) theory.
three core diagnostic features: (1) difficulties in
By way of background, it is worth remind-
social development and (2) in the development
ing ourselves why we need a cognitive theory of
of communication, alongside (3) unusually
autism at all. The features of autism spectrum
strong, narrow interests and repetitive behavior
conditions (ASC), of which classic autism and
(A. P. A. 1994). Since communication is always
AS are the clearest subgroups, are behavioral
social, it might be more fruitful to think of
and are diverse. Depending on how these are
autism and Asperger syndrome (AS) as shar-
counted, one can identify dozens or even hun-
ing features in two broad areas: social and
dreds of behavioral features. A cognitive theory
communication difficulties and narrow inter-
attempts to reduce these down to one or two
ests/repetitive actions. The diagnosis of AS re-
underlying mental processes. This is not instead
quires that the child began speaking on time
of a neurobiological theory, since both kinds of
and has average or above IQ. These features are
theory are needed if we are to understand how
manifested differently at different points in de-
atypical neural functioning or neural structure
velopment. This article begins by summarizing
can give rise to atypical behavior. Effectively,
the “mind-blindness” theory developed in the
the cognitive level mediates the neurobiological
1980s and 1990s, which has been a remarkably
and behavioral levels of description.
successful account of the social and communi-
cation difficulties in autism. A critique of this
The Mind-blindness Theory
This theory proposed that children with
Address for correspondence: Simon Baron-Cohen, Autism Research
autism spectrum conditions are delayed in de-
Centre, Department of Psychiatry, Cambridge University, Douglas House,
veloping a theory of mind (ToM): the ability
18B Trumpington Rd, Cambridge, CB2 8AH, UK. Tel: 44-1223746057.
sb205@cam.ac.uk
to put oneself into someone else’s shoes, to
The Year in Cognitive Neuroscience 2009: Ann. N.Y. Acad. Sci. 1156: 68–80 (2009).
doi: 10.1111/j.1749-6632.2009.04467.x C 2009 New York Academy of Sciences.
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Baron-Cohen: The Empathizing-Systemizing Theory of Autism
69
imagine their thoughts and feelings (Baron-
Cohen 1995; Baron-Cohen, Leslie, & Frith
1985). When we mind-read or mentalize,
we not only make sense of another person’s
behavior (Why did their head swivel on their
neck? Why did their eyes move left?), but we also
imagine a whole set of mental states (they have
seen something of interest, they know some-
thing or want something), and we can predict
what they might do next.
The mind-blindness theory proposes that
Figure 1. The seeing leads to knowing test. The
children with autism or Asperger syndrome are
child is told that Sally looks in the box, while Anne
delayed in the development of their ToM, leav-
touches the box. Test Question: “Which one knows
ing them with degrees of mind-blindness. As a
what’s in the box?”
consequence, they find other people’s behavior
confusing and unpredictable, even frightening.
Evidence for this comes from difficulties they
show at each point in the development of the
capacity to mind read:
A typical 14-month-old shows joint attention
(such as pointing or following another person’s
gaze), during which he or she not only looks
at another person’s face and eyes, but pays
attention to what the other person is interested
in (Scaife & Bruner 1975). Children with autism
or Asperger syndrome show reduced frequency
of joint attention, in toddlerhood (Swettenham
Figure 2. The child version of the reading the
et al. 1998). The typical 24-month-old engages
mind in the eyes test.
in pretend play, using their mind-reading skills to
be able to understand that in the other person’s
Deception is easily understood by the typ-
mind, they are just pretending (Leslie 1987).
ical 4-year-old child (Sodian & Frith 1992).
Children with autism or Asperger syndrome
Children with autism or Asperger syndrome
show less pretend play, or their pretence is
tend to assume everyone is telling the truth and
limited to more rule-based formats (Baron-
may be shocked by the idea that other peo-
Cohen 1987). The typical 3-year-old child can
ple may not say what they mean (Baron-Cohen
pass the seeing leads to knowing test: under-
1992, 2007a). The typical 9-year-old can figure
standing that merely touching a box is not
out what might hurt another’s feelings and what
enough to know what is inside (Pratt & Bryant
might therefore be better left unspoken. Chil-
1990). Children with autism or Asperger
dren with Asperger syndrome are delayed by
syndrome are delayed in this (Baron-Cohen &
around 3 years in this skill, despite their normal
Goodhart 1994). See Figure 1.
IQ (Baron-Cohen, O’Riordan, Jones, et al.
The typical 4-year-old child passes the false
1999). The typical 9-year-old can interpret
belief test, recognizing when someone else has
another person’s expressions from their eyes,
a mistaken belief about the world (Wimmer
to figure out what they might be thinking or
& Perner 1983). Most children with autism or
feeling (see Fig. 2). Children with Asperger
Asperger syndrome are delayed in passing this
syndrome tend to find such tests far more diffi-
test (Baron-Cohen et al. 1985).
cult (Baron-Cohen, Wheelwright, Scahill, et al.

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70
Annals of the New York Academy of Sciences
Happe et al. 1996). Such neuroimaging studies
provide a biological confirmation of the psy-
chological differences that have been reported.
Fourth, delays in the development of the pre-
cursors to mind reading (such as joint attention
and pretend play) have proven to be strong
predictors in infancy of a later diagnosis of
autism (Baron-Cohen et al. 1996). Finally, the
identification of mind-blindness in autism has
led to the development of novel interventions
to facilitate mind reading, with some success
(Baron-Cohen 2007b; Baron-Cohen, Golan,
Wheelwright, et al. 2004; Golan et al. in press;
Figure 3. The adult version of the reading the
Golan, Baron-Cohen, Hill, et al. 2006; Had-
mind in the eyes test.
win, Baron-Cohen, Howlin, et al. 1997).
It is also important to identify shortcomings
2001), and the same is true when the adult test
of the mind-blindness theory. First, it cannot
of reading the mind in the eyes is used (Fig. 3).
account for the nonsocial features of the condi-
Adults with autism or Asperger syndrome score
tion (such as the narrow interests and excellent
below average on this test of advanced mind
attention to detail). Secondly, while mind read-
reading (Baron-Cohen, Wheelwright, Hill,
ing is obviously one component of empathy,
et al. 2001).
true empathy also requires an emotional re-
sponse to another person’s state of mind (Davis
1994). Many people on the autistic spectrum
Evaluation of the Mind-blindness
also report that they are puzzled by how to
Theory
respond to another person’s emotions (Grandin
1996). For example, they may be able to see
There are several strengths of the mind-
that someone is crying, deduce that they are
blindness theory. First, it can make sense of
sad or upset, but not know why, or how to com-
the social and communication difficulties in
fort them. Thirdly, a range of clinical condi-
autism and Asperger syndrome, including the
tions show forms of mind-blindness, such as
pragmatic difficulties in language (since, on a
schizophrenia (Corcoran & Frith 1997), nar-
Gricean view, communication requires mind
cissistic and borderline personality disorders
reading). Second, degrees of mind-blindness
(Fonagy 1989), and, in some studies, conduct
are universal in applying to all individuals
disorder in children (Dodge 1993), so this may
on the autistic spectrum, in that when age-
not be specific to autism and Asperger syn-
and mental-age-appropriate tests are used,
drome. Fourth, some studies have failed to find
deficits are found across the life span and
any evidence of a ToM deficit in ASC, though
independent of IQ. Third, functional neu-
this may be because among high-functioning,
roimaging studies have identified key areas
older individuals the tasks need to be suffi-
of the “social brain” (medial prefrontal cor-
ciently subtle and age-appropriate to avoid
tex, temporal parietal junction, anterior cingu-
“floor effects.” Finally, as a theory, the mind-
late, insula, and amygdala) that are specifically
blindess account focuses on what people with
activated during mind reading tasks in the typ-
autism spectrum conditions find difficult, and
ical brain and are underactive in the autis-
ignores their areas of strength.
tic brain (Baron-Cohen et al. 1999; Castelli,
To address these five shortcomings, this
Frith, Happe, et al. 2002; Frith & Frith 2003;
theory has been revised in several ways: First, a

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Baron-Cohen: The Empathizing-Systemizing Theory of Autism
71
second factor has been proposed to account for
sometimes also referred to as requiring an attri-
the nonsocial areas of strength. Secondly, the
bution (since these are ultimately a postulate—
concept of ToM has been broadened to include
mental states are not visible per se) or requiring
an emotional reactivity dimension. Third, the
recognition (if the mental state leaves cues in fa-
two-factor theory is proposed to distinguish
cial or vocal or postural expressions of emotion,
ASC from other conditions. Finally, the two
for example). However, missing from ToM is
key traits have been dimensionalized in order
the second component of empathy, the response
to recognize how autism not only comes in de-
element: having an appropriate emotional
grees, but how it blends seamlessly into the gen-
reaction to another person’s thoughts and feel-
eral population.
ings. This is referred to affective empathy (Davis
This latter revision was introduced because
1994). On the Empathy Quotient (EQ), a ques-
today the notion of an autistic spectrum is
tionnaire filled out either by an adult about
no longer defined by any sharp separation
themselves or by a parent about their child,
from “normality” (Wing 1997). The clearest
both cognitive and affective empathy are as-
way of seeing this “normal” distribution of
sessed. On this scale, people with autism spec-
autistic traits is by looking at the results from
trum conditions score lower than comparison
the Autism Spectrum Quotient (AQ) (Baron-
groups.
Cohen, Hoekstra, Knickmeyer, et al. 2006;
According to the empathizing–systemizing
Baron-Cohen, Wheelwright, Skinner, et al.
(E-S) theory, autism and Asperger syndrome
2001). This is a screening instrument in the
are best explained not just with reference to
form of a questionnaire, either completed by
empathy (below average) but also with refer-
a parent about his or her child, or by self-
ence to a second psychological factor (system-
report (if the adult is high functioning). There
izing), which is either average or even above
are 50 items in total, and when administered
average. So it is the discrepancy between E and
to a large population the results resemble a
S that determines if you are likely to develop
normal distribution. The AQ neatly separates
an autism spectrum condition.
autism from control groups, 93% of the gen-
To understand this theory we need to
eral population falling in the average range
consider this second factor, the concept of
of the AQ , and 99% of the autistic popula-
systemizing. Systemizing is the drive to analyze or
tion falling in the extreme (high-end) of the
construct systems. These might be any kind
scale (Baron-Cohen et al. 2006; Baron-Cohen,
of system. What defines a system is that it
Wheelwright, Skinner, et al. 2001).
follows rules, and when we systemize we are
trying to identify the rules that govern the
system, in order to predict how that sys-
The Empathizing–Systemizing
tem will behave (Baron-Cohen 2006). These
Theory
are some of the major kinds of systems: col-
lectible systems (e.g., distinguishing between
This new theory explains the social and
types of stones), mechanical systems (e.g., a
communication difficulties in autism and As-
video-recorder), numerical systems (e.g., a train
perger syndrome by reference to delays and
timetable), abstract systems (e.g., the syntax of
deficits in empathy, while explaining the areas
a language), natural systems (e.g., tidal wave
of strength by reference to intact or even supe-
patterns), social systems (e.g., a management
rior skill in systemizing (Baron-Cohen 2002).
hierarchy), and motoric systems (e.g., bouncing
Most people regard ToM as just the cogni-
on a trampoline).
tive component of empathy in that it simply in-
In all these cases, you systemize by noting
volves identifying someone else’s (or your own)
regularities (or structure) and rules. The rules
mental states. Identification of mental states is
tend to be derived by noting if p and q are

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72
Annals of the New York Academy of Sciences
associated in a systematic way (e.g., if p, then
the world predictable. Secondly, this theory can
q). The evidence for intact or even unusu-
help characterize the unique profile of autism
ally strong systemizing in autism and Asperger
spectrum conditions. Many groups show em-
syndrome is that, in one study, such children
pathy difficulties, but arguably only people on
performed above the level that one would ex-
the autistic spectrum show the dissociation be-
pect for their age on a physics test (Baron-
tween this and their intact or even superior
Cohen, Wheelwright, Scahill, et al. 2001).
systemizing drive.
Children with Asperger syndrome as young as
Thirdly, this theory is giving rise to novel
8 to 11 years old scored higher than a compar-
interventions, in particular using the strong
ison group who were older (typical teenagers).
systemizing to teach empathy, for example,
A second piece of evidence comes from
presenting emotions in an autism-friendly
studies using the Systemizing Quotient (SQ).
format (Baron-Cohen 2007b; Golan et al.
The higher your score, the stronger your drive
2006). The DVD Mind Reading (www.jkp.com/
to systemize. People with high-functioning
mindreading) presents actors posing facial
autism or Asperger syndrome score higher on
expressions such that people with autism
the SQ than people in the general population
can teach themselves emotion recognition via
(Baron-Cohen, Richler, Bisarya, et al. 2003).
a computer. This involves taking the quite
The above tests of systemizing are designed
artificial approach of presenting mental states
for children or adults with Asperger syndrome,
(such as emotional expressions) as if they are
not classic autism. However, children with
lawful and systemizable, even if they are not
classic autism perform better than controls on
(Golan et al. 2006). The children’s anima-
the picture sequencing test, where the sto-
tion The Transporters (www.thetransporters.com)
ries can be sequenced using physical-causal
grafts human actors’ facial expressions of
concepts (Baron-Cohen, Leslie, & Frith 1986).
emotion onto mechanical systems such as trains
They also score above average on a test of how
and trams that move in a highly predictable
to figure out how a Polaroid camera works,
fashion, along tracks, so that even young chil-
even though they have difficulties figuring out
dren with autism are attracted to look at faces
people’s thoughts and feelings (Baron-Cohen
while they are drawn to watch the kinds of ma-
et al. 1985; Perner, Frith, Leslie, et al. 1989).
terial that is intrinsically rewarding for them
Both of these are signs of their intact or even
(Golan et al. in press). Such approaches, which
strong systemizing.
have been evaluated and shown to lead to im-
provements in emotion recognition, tailor the
Evaluation of the E-S Theory
information to the learning style of the learner
so that they can begin to process it.
The E-S theory has several strengths. First,
Fourth, the E-S theory can explain what is
it is a two-factor theory that can explain the
sometimes seen as an inability to “generalize”
cluster of both the social and nonsocial features
in autism spectrum conditions (Plaisted,
in autism spectrum conditions. Below average
O’Riordan, & Baron-Cohen 1998; Rimland
empathy is a simple way to explain the social
1964; Wing 1997). According to the E-S
and communication difficulties, while average
theory, this is exactly what you would expect if
or even above average systemizing is a way
the person is trying to understand each system
of explaining the narrow interests, repetitive
as a unique system. A good systemizer is a
behavior, and resistance to change/need for
splitter, not a lumper, since lumping things to-
sameness. This is because when you systemize,
gether can lead to missing key differences that
it is easiest to keep everything constant, and
enable you to predict how these two things
only vary one thing at a time. That way, you
behave differently. The typical clinical exam-
can see what might be causing what, rendering
ple is a teacher who teaches a child with autism

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Baron-Cohen: The Empathizing-Systemizing Theory of Autism
73
to perform a task in one setting (e.g., taking
glance it is not obvious that this applies
a shower at home) but has to reteach it in a
to the low-functioning individuals. This crit-
new setting (e.g., taking a shower at school).
icism may however reflect how much more
Consider though that if the child is treating the
challenging it is to test empathy and system-
situation as system, the unique features of each
izing in low-functioning people with autism. In
(e.g., how the shower at home differs to the
fact, the original ToM studies of autism did
shower at school in the detail of their tempera-
test medium-functioning people with autism,
ture control functions or the angle and height
since their IQs were low average, in the mild
of the shower-head) may be more salient than
range of learning difficulties. But empathy
their shared features (e.g., that both require get-
should be testable even in someone with low
ting in, turning the shower on, turning it off,
IQ , for example by using gaze-tracking dur-
and getting out).
ing an emotional face perception task, and
Finally, the E-S theory destigmatizes autism
systemizing should be testable in someone with
and AS, relating these to individual differences
low IQ by observing if they can detect repet-
we see in the population (between and within
itive patterns (structure) in input. Preferential
the sexes), rather than as categorically distinct
looking paradigms that have been used with
or mysterious. For many decades, the diagnosis
typical infants might be a suitable nonverbal
of autism was one that many parents dreaded,
paradigm for establishing if low IQ , nonverbal
as it suggested their child was biologically set
children with autism can discriminate (more
apart from the rest of humanity in lacking the
quickly than IQ-matched controls) two types of
basic machinery for social engagement and in
information (with high versus low structure).
suggesting autism is a disease of the brain. The
Leaving aside experimental methods, when
E-S theory focuses not just on the areas of diffi-
we think of a child with autism, many of the
culty (empathy) but also on the areas of strength
classic behaviors they show as part of their
(systemizing) in ASC, and views ASC as a dif-
natural history can be seen as a reflection of
ference in cognitive style that is part of a con-
their strong systemizing. Some examples are
tinuum of such differences found in everyone,
listed in Table 1.
rather than as a disease.
One criticism of the E-S theory is that
the evidence base for it is still quite limited.
Relating the E-S Theory
This reflects how new it is, but it does make
to Other Accounts
predictions. For example, it predicts we should
expect people with autism to show a preference
Like the weak central coherence (WCC)
for predictable over unpredictable motion, or
theory (Frith 1989), the E-S theory is about
show a preference for patterned over unpat-
a different cognitive style (Happe 1996). Like
terned information. We should expect deficits
that theory, it also posits excellent attention
not just in ToM, but also in responding to oth-
to detail (in perception and memory), since
ers’ emotions—an aspect of empathy that is
when you systemize you have to pay atten-
difficult to test. fMRI may enable the latter
tion to the tiny details. This is because each
prediction to be tested.
tiny detail in a system might have a functional
A second criticism is that perhaps the
role. Excellent attention to detail in autism
E-S theory only applies to the high-functioning
has been repeatedly demonstrated (Jolliffe &
individuals with autism or Asperger syn-
Baron-Cohen 2001; Mottron, Burack, Iarocci,
drome. While their obsessions (with comput-
et al. 2003; O’Riordan, Plaisted, Driver, et al.
ers or math for example) could be seen in
2001; Shah & Frith 1983, 1993). The difference
terms of strong systemizing (Baron-Cohen,
between these two theories is that whereas the
Wheelwright, Stone, et al. 1999), at first
WCC theory sees people with autism spectrum

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74
Annals of the New York Academy of Sciences
TABLE 1. Systemizing in Classic Autism (and/or
it exists in order to understand a system. Atten-
Asperger Syndrome, in Italics)
tion to detail is occurring for positive reasons:
• Sensory systemizing
in the service of achieving an ultimate under-
◦ Tapping surfaces, or letting sand run through one’s
standing of a system (however small and specific
fingers
that system might be).
◦ Insisting on the same foods each day
The WCC theory predicts that people with
• Motoric systemizing
◦
autism or Asperger syndrome will be forever
Spinning round and round, or rocking back and forth
◦ Learning knitting patterns or a tennis technique
lost in the detail and never achieve an un-
• Collectible systemizing
derstanding of the system as a whole (since
◦ Collecting leaves or football stickers
this would require a global overview), whereas
◦ Making lists and catalogues
the E-S theory predicts that, over time, the
• Numerical systemizing
◦
person may achieve an excellent understand-
Obsessions with calendars or train timetables
◦
ing of a whole system, given the opportunity to
Solving math problems
• Motion systemizing
observe and control all the variables in that sys-
◦ Watching washing machines spin round and round
tem. The existence of talented mathematicians
◦ Analyzing exactly when a specific event occurs in a repeating cycle
with AS, like Richard Borcherds, is proof that
• Spatial systemizing
such individuals can integrate the details into
◦ Obsessions with routes
◦
a true understanding of the system (Baron-
Developing drawing techniques
• Environmental systemizing
Cohen 2003). Pitting the WCC and the E-S
◦ Insisting on toy bricks being lined up in an invariant
theories against each other is in fact very
order
straightforward: any experiment that involves
◦ Insisting that nothing is moved from its usual position in the room
learning to understand a system should be pre-
• Social systemizing
◦
dicted to give rise to deficits according to WCC,
Saying the first half of a phrase or sentence and
or to intact or even superior performance ac-
waiting for the other person to complete it
◦ Insisting on playing the same game whenever a child comes to play
cording to E-S.
• Natural systemizing
It is worth noting that the executive
◦ Asking over and over again what the weather will be
dysfunction (ED) theory (Ozonoff, Penning-
today
ton, & Rogers 1991; Rumsey & Hamberger
◦ Learning the Latin names of every plant and their optimal
1988; Russell 1997) has even more difficulty
growing conditions
• Mechanical systemizing
explaining instances of good understanding of
◦ Learning to operate the VCR
a whole system, such as calendrical calculation,
◦ Fixing bicycles or taking apart gadgets and reassembling them
or indeed why the so-called obsessions in autism
• Vocal/auditory/verbal systemizing
and AS should center on systems at all. Thus,
◦ Echoing sounds
◦
when the low-functioning person with classic
Collecting words and word meanings
•
autism shakes a piece of string thousands of
Systemizing action sequences
◦ Watching the same video over and over again
times close to his eyes, while the ED theory sees
◦ Analyzing dance techniques
this as perseveration arising from some neural
• Musical systemizing
dysfunction that would normally enable the in-
◦ Playing a tune on an instrument over and over again
dividual to shift attention, the E-S theory sees
◦ Analyzing the musical structure of a song
the same behavior as a sign that the individual
“understands” the physics of that string move-
ment. He may for example make it move in
conditions as drawn to detailed information
exactly the same way every time. Or when
(sometimes called local processing) for nega-
he makes a long, rapid sequence of sounds,
tive reasons (an alleged inability to integrate),
he may know exactly that acoustic pattern
the E-S theory sees this same quality (excellent
and get some pleasure from the confirmation
attention to detail) as being highly purposeful:
that the sequence is the same every time. Much

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Baron-Cohen: The Empathizing-Systemizing Theory of Autism
75
as a mathematician might feel an ultimate sense
sarily entails: focusing on a specific system (the
of pleasure that the “golden ratio” ((a + b)/a =
computer game), and attempting to understand
a/b) always comes out as 1.61803399. . ., so
that system in its entirety, all the while ignoring
the child—even with low-functioning autism—
extraneous information (the messy bedroom).
who produces the same outcome every time
The clinical accounts usually report that if a
with his repetitive behavior, appears to derive
parent comes in to tidy up their child’s messy
some emotional pleasure at the predictability
bedroom this typically triggers a tantrum,
of the world. This may be what is clinically de-
because what appeared to be random mess to
scribed as “stimming” (Wing 1997). Autism was
an outsider observer was in fact a complex and
originally described as involving “resistance to
predictable pattern (or system) to the person
change” and “need for sameness” (Kanner
with AS themselves. Amid the mess, every sin-
1943), and here we see that important clini-
gle item had its own (proper) place, and the per-
cal observation may be the hallmark of strong
son with AS can typically recall the location of
systemizing.
every item within the apparent mess, such that
To return to the ED theory, one question is
the mess is itself a predictable system. A parent
whether there is executive dysfunction in ASC
can be an unwelcome intrusion who disturbs
at all. That is, does the E-S theory make the ED
this perfect system.
theory redundant? Expressed differently, can
In addition, the clinical reports of children
the E-S theory explain the findings from ED
with AS who cannot complete an essay or
theory of perseveration on the Wisconsin Card
homework assignment on time are describing
Sorting test or poor planning on the Tower
real problems, but these need not reflect ED.
of London test (Ozonoff et al. 1991; Rumsey &
These difficulties would also be predicted by
Hamberger 1988; Russell 1997)? One rejoinder
WCC (not being able to see the whole essay
to this is that deficits on tasks like the Wisconsin
because of a stronger focus on local detail) or
or the Tower of London may not reflect ED.
E-S (not wanting to leave out any information
For example, both the WCC and E-S theories
in case it is relevant to understanding the whole
could explain the Tower of London deficit in
system). Strong systemizing entails treating
terms of an overfocus on local detail, and the
all information as potentially relevant, in the
E-S theory could explain the Wisconsin deficit
search for repeating patterns (if p, then q).
in terms of a desire to persist with a systematic
A homework assignment or an exam essay
strategy. On this argument, performance on an
that appears to contain far too much detail
ED task depends on the strategy being used,
(a commonly reported problem in the work
and a strategy driven by either WCC or strong
of people with AS) may be a sign of treating
systemizing may produce performance that is
all detail as relevant (not being able to ignore
indistinguishable from ED.
information), and could also arise from a ToM
It is however clear from clinical and parental
deficit (not knowing how to judge what the
accounts of ASC that there are everyday
reader needs to know, already knows, or does
planning and organizational difficulties. In
not need to know). The point is that deficits
some people with AS, for example, their bed-
purported to reflect pure ED may reflect
rooms are totally messy and they cannot orga-
multiple possible sources.
nize their school-work to be finished in time.
Surely these are simple, everyday examples of
Extending the E-S Theory: The
ED? However, the person with AS whose bed-
Extreme Male Brain Theory
room is a total mess but who is at the same
time (systematically) working his or her way up
The E-S theory has been extended into the
through the levels of a computer game may be
extreme male brain (EMB) theory of autism
doing precisely what strong systemizing neces-
(Baron-Cohen 2002). This is because there are

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76
Annals of the New York Academy of Sciences
clear sex differences in empathizing (females
a strong predictor of brain type in the gen-
performing better on many such tests) and in
eral population, within the ASC population it
systemizing (males performing better on tests of
is not. Both males and females with ASC are
this), such that autism and AS can be seen as an
statistically more likely to have a brain of Ex-
extreme of the typical male profile, a view first
treme Type S. Instruments that can measure
put forward by the pediatrician Hans Asperger
both dimensions in individuals who are lower
(Asperger 1944). To see how this theory is effec-
functioning may help us to determine the min-
tively just an extension of the E-S theory, one
imum size of the discrepancy between E and S
needs to understand that that theory posits two
that causes an individual to develop an ASC.
independent dimensions (E for empathy and S
Apart from the evidence from the SQ and
for systemizing) in which individual differences
EQ , there is other evidence that supports the
are observed in the population. When you plot
EMB theory. Regarding tests of empathy, on the
these, five different “brain types” are seen:
faux pas test, in which a child has to recognize
when someone has said something that could
• Type E (E > S): individuals whose empathy
be hurtful, typically girls develop faster than
is stronger than their systemizing
boys, and children with autism spectrum con-
• Type S (S > E): individuals whose system-
ditions develop even slower than typical boys
izing is stronger than their empathy
(Baron-Cohen, O’Riordan, Jones, et al. 1999).
• Type B (S = E): individuals whose empathy On the reading the mind in the eyes test, on
is as good (or as bad) as their systemizing
average women score higher than men, and
(B stands for balanced”)
people with autism spectrum conditions score
• Extreme Type E (E
S): individuals whose
even lower than typical males (Baron-Cohen,
empathy is above average, but who are
Jolliffe, Mortimore, et al. 1997). Regarding tests
challenged when it comes to systemizing
of attention to detail, on the embedded figures
• Extreme Type S (S
E): individuals whose
test, which requires one to find a target shape
systemizing is above average, but who are
as quickly as possible, on average males are
challenged when it comes to empathy
faster than females, and people with autism are
These “brain types” are defined at the
even faster than typical males (Jolliffe & Baron-
cognitive or psychometric level, but they
Cohen 1997).
should correlate with structural and functional
Recently, the EMB theory has been extended
differences at the neural level, something that
to the level of neurology, with some interesting
should be tested in the future. The E-S model
findings emerging (Baron-Cohen, Knickmeyer,
predicts that more females have a brain of
et al. 2005).Regions of the brain that on aver-
Type E, and more males have a brain of Type
age are smaller in males than in females (such
S. People with autism spectrum conditions, if
as the anterior cingulate, superior temporal
they are an extreme of the male brain, are
gyrus, prefrontal cortex, and thalamus) are even
predicted to be more likely to have a brain
smaller in people with autism than in typical
of Extreme Type S. If one gives people in
males. In contrast, in regions of the brain that
the general population measures of empathy
on average are bigger in males than in females
and systemizing (the EQ and SQ), the re-
(including the amygdala, cerebellum, overall
sults fit this model reasonably well. More
brain size/weight, and head circumference),
males (54%) have a brain of Type S, more
these regions or measurements are even big-
females (44%) have a brain of Type E, and
ger in people with autism than in typical males.
more people with autism or Asperger syn-
Also, the male brain is, on average, larger than
drome (65%) have an extreme of the male brain
the female, and people with autism have been
(Goldenfeld, Baron-Cohen, & Wheelwright
found to have even larger brains than typical
2005). It is of interest that while one’s sex is
males. Not all studies support this pattern but

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Baron-Cohen: The Empathizing-Systemizing Theory of Autism
77
some do, and it will be important to study such
as strongly driven to discover the truth. Here
patterns further. It will also be important to ad-
we are using the term truth as precise, reliable,
dress the neurobiological mechanisms that may
consistent, or lawful patterns or structure
be causing this hypermasculinization, one can-
in data. If a wheel is spinning round and
didate being fetal testosterone (Auyeung et al.
round, there are consistent, lawful patterns
2009).
to be detected. Sometimes the pattern will
In summary, the EMB theory is relatively
occur with 100% predictability (this particular
new and may be important for understand-
person’s birthday always falls on April 4th),
ing why more males develop autism or As-
sometimes with relatively high predictability
perger syndrome than do females. As with any
(daffodils typically bloom in the second week of
scientific program, this theory must be tested
March in England). Systemizing is the means
by a systematic search for evidence that does
by which we identify lawful patterns in data.
not fit the theory. The EMB theory extends the
When we systemize, we make the implicit
E-S theory, which has the power to explain not
assumption that the pattern of data coming into
just the social and communication deficits in
our senses reveals the truth. The contention is
autism spectrum conditions, but also the un-
that the autistic brain, being highly tuned to
even cognitive profile, repetitive behavior, islets
systemize, is the ultimate pattern-detector and
of ability, savant skills, and unusual narrow
truth-detector (Baron-Cohen 2006). In a high-
interests that are part of the atypical neurol-
functioning individual on the autistic spectrum,
ogy of this subgroup in the population. Future
such pattern seeking can reveal scientific truths
research should also test if—while deficits in
about the nature of reality, since their system-
empathy are seen in many clinical groups—the
izing can help the individual understand how
particular pattern of low E in combination with
things work. What was previously dismissed as
intact or even high S is indeed unique to ASC.
an “obsession” can be viewed more positively as
Candidate clinical control groups to test this
a “strong, narrow interest” in a topic that, when
hypothesis would be obsessive-compulsive dis-
harnessed, can lead the person with autism or
order (OCD) and schizophrenia. In OCD one
AS to excel in a highly specific field.
sees rigid behavior, but this may be more related
Although systemizing can deliver truths
to anxiety than to a love of systems per se. In
in the form of laws, it can only do so in
schizophrenia one sees empathy difficulties, but
domains that are ultimately lawful. One rea-
it is unlikely that the logical thought required
son why people with ASC (postulated to be
for strong systemizing is seen in this condition.
hypersystemizers) may struggle with empathy
and be less interested in topics such as pure fic-
Implications of the E-S Theory: The
tion, pretence, or deception is that these are not,
Autistic Mind in Search of “Truth”
and never will be, truth oriented. Regarding the
domain of emotions, human behavior is not
The function of systemizing is to predict
100% lawful. Different people can expression
lawful events, including lawful change, or
the same emotion differently, or an emotion
patterns in data. The E-S theory can explain
may even have no external expression. Re-
the preference of people with ASC for systems
garding the domain of mental states, as Leslie
that change in highly lawful or predictable
pointed out, the domain of mental states plays
ways; why they become disabled when faced
havoc with “truth relations.” This is because
with systems characterized by less lawful
of the opacity of mental states like belief or
change, and their “need for sameness” or
pretence (Leslie 1987). The sentence “Mary
“resistance to change.” If truth is defined as
believes that John is having an affair with his
lawful patterns in data then, according to the
colleague” is true if Mary believes it, irrespec-
E-S theory, one could view people with ASC
tive of whether John really is having an affair.

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