Autism is a neurodevelopmental disorder that can adversely affect one’s ability to interact and communicate with others in a social setting (American Psychiatric Association, 2000). As a result, autistic individuals can find it difficult to interpret the thoughts and feelings of those around them, and to understand that the contents of another person’s mind may be different from their own.
Furthermore, sufferers of autism tend to have very narrow interests in a specific field, and so they typically prefer to engage in the same types of routine behaviours which are often accompanied by a resistance to change (Baron-Cohen, 2009).
Collectively, these impairments are referred to as a “triad of impairments” (Wing, 1981) and can also be seen in other developmental disorders such as Asperger’s syndrome. For this reason, autism is classified as a “spectrum disorder”. Unlike Asperger’s syndrome however, autism is characterised by delays in language and cognitive development which therefore allow it to be distinguished from other conditions within the autistic spectrum (Bishop, 1989).
Several theories have been proposed to explain the effects of autism. One such theory is the empathising-systemising (E-S) theory, which states that autistics may suffer from the triad of impairments previously discussed due to deficits in empathising and an intact or above average ability in systemising (Baron-Cohen, 2009).
This essay will expand upon this theory by critically evaluating the extreme male brain (EMB) theory of autism, which is itself an expansion of the E-S theory, and then conclude with a discussion as to how effectively the EMB theory explains autism.
The Extreme Male Brain Theory of Autism
As with the E-S theory, the EMB theory (Baron-Cohen, 2002) states that autism can be better understood using the two psychological dimensions of empathising and systemising.
Empathising can be defined as the ability to interpret an emotional state and then respond appropriately to it (Baron-Cohen, 2004), and the EMB theory states that females tend to be better than males in their ability to do this. Support for this proposal comes from several sources.
Hoffman (1977) for example, found that females are more likely to express concern and offer comfort to others than males, a finding that was later supported by Eisenberg and Randy (1983) who, using self-report questionnaires, also found women to be more empathetic than men.
In addition, females have been shown to make more eye-contact (Lutchmaya, Baron-Cohen & Raggett, 2002) and pass false belief tests earlier than males (Happé, 1995), thereby suggesting that they may be better at seeing things from another person’s perspective.
Sex differences also exist with the ability to systemise, which can be defined as a drive to understand a system (i.e., something that transforms inputs into outputs) by analysing the rules upon which it is governed in order to predict a given outcome (Baron-Cohen, 2004).
In contrast to empathising however, males typically possess the greater ability for this dimension. Benbow (1988) for example, found that females tended to score much lower than males on mathematical tests, something that has also been observed with physics and mental rotation tests (Kimura, 1999).
As a result of the sex differences between empathising and systemising, the EMB theory proposes that different “brain types” can exist as a result of differing levels of ability between these two dimensions (Baron-Cohen, 2002).
Individuals with a “Type E” brain for example, are better at empathising than they are at systemising. Whereas, individuals with a “Type S” brain, are better at systemising than they are at empathising.
Accordingly, one would therefore expect for there to be more males than females with a type S brain, and more females than males with a type E brain, given the apparent empathising/systemising sex differences previously discussed. Research carried out by Goldenfeld, Baron-Cohen and Wheelwright (2005) suggests that this may indeed be the case.
In their study, an Empathy Quotient (EQ) and Systemising Quotient (SQ) were used to categorise subjects based on their ability to empathise or systemise. As judged from responses to a self-report questionnaire, it was discovered that more females than males were type E (44%), and that more males than females were type S (54%).
This could be viewed as providing support for the EMB theory, as it backs up the previous assumption that there would be a difference in brain types between the two sexes.
The EMB theory however, also proposes that those with autism will have a hyper-developed ability to systemise and a hypo-developed ability to emphasise, thereby resulting in an “Extreme Type S” brain-an extreme male brain.
This proposal was also supported by the study carried out by Goldenfeld et al. (2005) that was previously described, as it was discovered that 65% of those within the autistic spectrum were classified as having the extreme type S brain.
How Well Does the EMB Theory Explain Autism?
The EMB theory attempts to explain the social and cognitive aspects of autism. If an individual has an under-developed ability to empathise for example, then the EMB theory predicts that they will also suffer impairments in their ability to interact socially with others as a result of being less able to recognise and interpret another person’s mental states (e.g., beliefs, desires, intentions) (Baron-Cohen, Knickmeyer & Belmonte, 2005). In this regard, the EMB theory is able to explain the social aspects of autism, as autistics tend to suffer from an impaired theory of mind ability.
Baron-Cohen, Leslie and Frith (1985) for example, tested the ability of children with either autism or Down’s syndrome to predict the beliefs and behaviour of others using a variation of Wimmer and Perner’s (1983) unexpected transfer test.
When presented with the belief question “Where will Sally look for her marble?”, 80% of autistics failed to provide the correct answer, whereas 86% of the children with Down’s syndrome were able to respond correctly.
Thus, despite having a mental retardation, individuals with Down’s syndrome do not appear to suffer from the same theory of mind impairments as those with autism do, thereby suggesting that these impairments are relatively specific to the autistic mind.
The EMB theory also explains why autistic individuals tend to display a weak central coherence (i.e., narrow fields of interest) and are often very attentive to detail (Firth & Firth, 2003).
Jolliffe and Baron-Cohen (2001) for example, found that when presented with an Embedded Figures Task (EFT), a task that requires the participant to locate a specific shape amongst a series of different shapes, adults with autism were found to perform significantly better, as judged by reaction time to shape discovery, than adults without autism, thereby suggesting that autistics may show a preference for local rather than global information processing (Happé, 1999).
Such results may be explained by the EMB theory, as if autistics have an over-developed ability to systemise, then this is likely to result in a heightened attention to detail (Ashwin, Ashwin, Rhydderch, Howells & Baron-Cohen, 2009).
Taken together, the under-developed ability to empathise, and the over-developed ability to systemise, suggests that an autistic brain may differ anatomically from a non-autistic brain.
Support for this proposal comes from Piven, Bailey, Ranson and Arndt (1997), who found that autistic individuals tend to have a smaller sized corpus callosum than non-autistic individuals.
These findings may therefore help to account for the different brain types proposed by the EMB theory, and perhaps also the executive dysfunction typically observed in autistics (Kleinhans, Akshoomoff & Delis, 2005), as the corpus callosum is responsible for connecting the two hemispheres of the brain and allowing them to communicate with each other.
As a result, it may be possible that having a smaller corpus callosum results in an over-lateralisation of brain function, whereby one ability (e.g., systemising) becomes dominant at the expense of another ability (e.g., empathising) (Just, Cherkassky, Keller, Kana & Minshew, 2007).
Overall, the EMB theory helps to explain many aspects of autism, particularly those relating to the social and cognitive effects. In contrast, other theories, such as the executive dysfunction (ED) theory, have struggled to account for why autistics can often display talent in certain fields such as mathematics (Ozonoff, Pennington & Rogers, 1991). However, the EMB theory is not without its flaws as the rest of this essay shall now discuss.
Criticisms and Flaws of the EMB Theory
It has been suggested that the reason why females tend to be better at empathising is because they have a larger corpus callosum than males, which, in turn, then allows for a more “adaptive” brain due to bilateralisation of brain function (Allen, Richey, Chai & Gorski, 1991).
However, in a meta-analysis of 49 studies which each investigated the size of the corpus callosum in males and females, Bishop and Wahlsten (1997) discovered that males do not typically have a smaller corpus callosum than females.
Furthermore, it was also found that the size differences previously observed, such as with Allen et al. (1991), between the two sexes, were caused by measuring the relative size of the corpus callosum in relation to brain volume, rather than measuring the overall size.
As a result of these findings, one cannot argue that the presence of a smaller corpus callosum in those with autism is why autistics typically demonstrate an extreme male brain profile, as the meta-analysis conducted by Bishop et al. (1997) shows that, for overall size, there are no sex differences in corpora callosa size.
Innate sex differences
As the EMB theory proposes that males tend to be better at systemising, and females better at empathising, one could justifiably expect that, at birth, males would show a preference for non-social stimuli and females would show a preference for social stimuli.
Research carried out by Connellan, Baron-Cohen, Wheelwright, Batki and Ahluwalia (2000) did indeed find this to be the case, as it was discovered, with a sample size of 102 one-day-old neonates, that males spent the most time looking at a mobile (i.e., a mechanical stimulus) and that females spent the most time looking at a human face (i.e., a social stimulus).
The validity of these findings have, however, been criticised by Nash and Grossi (2007) who argue that a preference for mechanical or social stimuli at an age of one-day, does not necessarily mean that those preferences will be reflected in that child’s ability to process (i.e., empathise or systemise) such stimuli later in life.
Furthermore, as neonates in the Connellan et al. (2000) study were shown a real human face, it is not clear whether other factors such as facial expressions, head movements or the odour emitted by the experimenter were what caused the apparent preference for faces by the female neonates.
In addition to these criticisms, other researchers have argued that there is no innate predisposition towards mechanical or social stimuli in either sex. Wynn (1992) for example, found that both males and females of five months of age possessed an equal subitizing ability (i.e., quantify a number of items without consciously counting them) and Newcombe (2002) reported no sex differences in spatial reasoning ability either.
This suggests that the differences in male and female empathising and systemising abilities, as proposed by the EMB theory, could be due to a process of social conditioning, such as due to how a male or female child is typically treated by their parents (i.e., being given a doll or toy car to play with) (Vigil, 2008).
Interestingly, autism has been found to occur more often in children whose parents are in a highly systemising profession, such as engineering or mathematics, thereby lending support to the idea that parental influence can indeed affect one’s empathising or systemising ability (Baron-Cohen, Bolton, Wheelwright, Scahill, Short, Mead & Smith, 1998).
These findings may in turn help to explain why not all individuals who fall within the autistic spectrum have an Extreme Type S brain. As differences in upbringing and environmental exposures may, quite possibly, affect the “brain type” that one develops as a result of the epigenetic effects those influences have on the maturational unfolding of a child’s cognitive and emotional development (Schanen, 2006).
Prenatal testosterone
Another argument that has been put forward to explain a highly developed systemising ability in males, is that high levels of prenatal testosterone (Baron-Cohen, 2003) result in an enhanced development (i.e., of size and function) of the right brain hemisphere at the expense of left hemisphere development (Bryden, McManus & Bulman-Fleming, 1994).
Witelson, Beresh and Kigar (2005) however, reported that, upon a post-mortem examination of cerebral volume in 100 individuals, there were no differences, after correcting for total brain volume, in the size of the left or right brain hemisphere from individuals of the same sex or between sexes.
Furthermore, other studies have found that high levels of prenatal testosterone exposure resulted in poorer systemising abilities in females, as judged by their ability to mentally rotate an object (Chapman, Baron-Cohen, Auyeung, Knickmeyer, Taylor & Hackett, 2006), but did not appear to correlate with the performance of males (Jacklin, Wilcox & Maccoby, 1988).
If however, one were to accept the view of Baron-Cohen (2003) that prenatal testosterone affects empathising and systemising abilities, then one may also expect there to be other aspects of development affected.
For example, if high levels of testosterone are responsible for the over-developed systemising autistic mind, then surely autistics would display characteristics associated with high levels of testosterone, such as above-average muscular development and increased aggressiveness. Currently however, further research is needed to examine these issues in greater depth (Edge, 2005, Armand Leroi).
An additional point of criticism of the EMB theory relates to the uncertain link between one’s ability to empathise and systemise. Valla, Ganzel, Yoder, Chen, Lyman, Sidari and Belmonte (2010) for example, found that when females were given the “Reading the Mind in the Eyes” test and the “Embedded Figures” test, they appeared to possess a strong ability to both emphasise and systemise.
In males however, a high level of systemising often came at the expense of a low level of empathising. Therefore, the EMB theory does not appear to be able to account for why women develop autism, as, according to Valla et al. (2010), it is only males who appear to sacrifice empathising for systemising.
To add to this point of contention is the assumption made by the EMB theory that males without autism will have an under-developed ability to empathise in relation to normal females. But this may not always be the case.
Russell, Tchanturia, Rahman and Schmidt (2007) for example, found that when males and females were given “Happé’s “cartoon” task”, a task that involves attributing mental or physical states to a cartoon scenario, males were able to correctly attribute states more often than females.
It could be argued however, that the males in the study did have an under-developed ability to empathise, but that this deficit was somehow compensated for via the use of a systemising strategy (Golan & Baron-Cohen, 2006).
Conclusion
The EMB theory was proposed as an all-encompassing theory, one that would be able to explain all the symptoms of autism. However, even though it is able to identify the sex differences that exist between males and females in empathising and systemising, and the extreme male brain profile typically found in autistics, it ultimately fails to explain why these differences exist or what may have caused such differences to occur in the first place.
As a result, other theories, such as those which propose examining the relationship between empathising and Machiavellianism, as opposed to empathising and systemising, have been put forward as a suggestion for future research (Andrew, Cooke & Muncer, 2008).
Currently however, the EMB theory, despite its flaws, provides the best explanation of autism and one that will hopefully spur future research into this field.
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Reviewed – 26th March 2016