AUTISTIC SPECTRUM DISORDERS – SUMMARY
CHARACTERISTICS OF AUTISM –
Autism is medically termed as Autistic Spectrum Disorder, with it being a spectrum disorder,
meaning that whilst all Autistic individuals experience the same difficulties, the extent to which the
share them differs by individual. It is estimated by the National Autistic Society that 1.1% of the UK
population experiences ASD, and that males are 5x more likely to receive a diagnosis. According to
the DMS-5, there are 2 categories of symptoms to use when assessing an individual for ASD:
communicative issues and repetitive behaviours.
COMMUNICATIVE ISSUES –
1. Non-verbal communication: inappropriate gestures, inappropriate body language, lack
of/exaggerated facial expressions, inappropriate tone of voice.
2. Social-emotional reciprocacy: not picking up on social cues or conversational
norms/indicators.
3. Developing/maintaining relationships: a lack of Theory of Mind makes it difficult to
have close relationships by understanding others’ emotions.
REPETITIVE BEHAVIOURS –
1. Fixated interests: having specific areas of heightened knowledge and interest – savant
behaviour, also using formal, technical language for areas of interest.
2. Echolalia/repeated movements/actions: repeating the behaviour/words of others, or
repeating your own actions, like lining toys up in a particular order.
3. Routine/resistance to change: a dependence on routine/predictability in every day,
often playing with the same toys, wearing the same clothes, eating the same food. Often
overreactions to change are exhibited.
4. Literalism: being unable to detect sarcasm/humour from genuine conversation.
5. Unusual reactions to novel sensory input: responding poorly to novel
tastes/smells/touch/sounds.
However there are other characteristics of autism which aren’t listed by the DSM-5. These include
blurred/partially-obscured vision, an inability to verbally communicate, or sensitivity to lights. The
DSM-5 is only used in the US, however, whilst the UK uses the ICD-10.
ICD-10 – there is no one bracket of characteristics given to identify ASD, as this instead
acknowledges different types of Autism:
Childhood autism: defined by the previously-listed characteristics.
Atypical autism: display of aforementioned symptoms following the age of 3, or
displaying several intellectual disabilities without other symptoms such as fixations.
Asperger’s syndrome: introduced in 1992, there are similarities with autistic
children, but Asperger’s refers to a high IQ, normal intelligence, no cognitive deficits
and no delayed language development. Often referred to as high-functioning autism.
DSM-5 – one overarching bracket of ASD is given as a diagnosis for all patients showing the
above symptoms. However, it is measured instead in levels of severity:
Level 1 severity: requires some support in social-functioning, but shows little to no
impaired functioning with this support.
Level 2 severity: requires substantial support, showing impaired functioning even
with this support.
Level 3 severity: requires very substantial support, showing severely impaired
functioning.
,BIOLOGICAL EXPLANATION 1 – GENETIC PREDISPOSITION
Findings from family studies – SZATMARI found, via family studies, a 0.11% likelihood of being
diagnosed with autism when no relatives have received a diagnosis, with this likelihood doubling when
a sibling has received a diagnosis.
Findings from twin studies – BAILEY et al. found monozygotic twins to have a 60% concordance
rate for Autism, but dizygotic twins had 0% concordance. This suggests that there is likely to be a
genetic component to Autism, as MZ twins are so much more likely to share a diagnosis than DZ
twins.
Genetic mutations: CDH8 – during reproduction, DNA undergoes a division process, in which
mutations can occur to prevent DNA identically replicating its parent genes. BERNIER et al.
suggested that one such mutation on the CDH8 gene could cause autism, as it has been linked to
childhood conditions of gastrointestinal problems, wide-set eyes and a larger head. In their study
of over 6000 autistic children, 15 all shared this mutation and also exhibited similar conditions, such
as sleep disturbances, gastrointestinal problems and physical appearances.
Genetic mutations: FXS – ASD can either be a non-syndromic diagnosis (the only diagnosed
disorder) or syndromic (diagnosed with another disorder). A common syndromic diagnosis is
alongside Fragile X Syndrome, the characteristics of which include protruding ears, a long face
and intellectual disabilities. FXS is the product of a genetic mutation on the FMR1 gene on the x
chromosome, and the syndromic diagnosis suggests that Autism could also be a genetic mutation.
De novo genes – genetic inheritance typically refers to parent genes being passed onto offspring, but
modern studies have identified de novo genes (translating from Latin to mean “new genes”) which
may explain Autism. These genes are not present in either parent, but instead development in either
the egg or the sperm during fertilisation, thus allowing them to be inherited. Such mutations have
been linked to more severe characteristics of autism, namely learning difficulties, possibly
suggesting that these genes may predict more severe instances of autism, whereas mutations such
as FXS or CDH8 may predict milder cases.
BIOLOGICAL EVALUATION 1 – GENETIC PREDISPOSITION
(-) There are many methodological issues with twin studies, with the primary problem arising from
the role played by environmental factors. Twins are often treated identically, sharing hobbies, clothes
and experiencing identical treatment. Thus, any concordance observed in twin studies may be the
product of their environment, lowering the internal validity of this theory.
(+) There are positive applications to this study, namely the implication that it may be possible to
eventually predict ASD in young children or foetuses. Today, strides are being made to make
earlier diagnoses more reliable, such as diagnoses before the age of 18 months. This means that
many families in future may be able to avoid the long, stressful process of waiting for an ASD
diagnosis that is often experienced.
(-) Other explanations suggest a diathesis-stress model, proposing that that pregnancy conditions
may cause ASD. This suggests that, for example, exposure to harmful chemicals during pregnancy
may cause birth defects such as ASD, demonstrating environmental factors acting as pre-natal
triggers of brain damage which later leads to having disorders.
(-) Much debate surrounds the theories for biological causes of ASD, with many theorists questioning
if there is one sole biological cause. For example, RONALD argues that different ASD characteristics
may have distinct, individual causes, whilst CONSTANTINO states that different characteristics may
be behavioural manifestations of one underlying biological problem, caused by the same genetic
factors.
(-) However, we can ultimately conclude that there is no one cause for ASD that is solely biological, as
twin studies would have found consistent 100% concordance rates if this were the case. This lowers
the internal validity of the study.
(-) BERNIER’S study into the relationship between CDH8 mutations and ASD also only found 15 of
over 6000 participants had this mutation, showing a very weak correlation between ASD and a
genetic cause.
,BIOLOGICAL EXPLANATION 2 – AMYGDALA DYSFUNCTION
Research has found that the amygdala growth of children with ASD is often 6-9% faster
than those of neurotypical children, who still experience amygdala growth from the age of 2
until later childhood development, but at a slower rate. The amygdala is located in the
temporal lobe of the brain, present in both left and right hemispheres. It is associated
with emotional responses and social behaviour, with Leslie Brothers referring to it as part of
the “social brain”, alongside the STG and the OFC. This understanding was applied to
ASD by Simon Baron-Cohen as he noted the amygdala’s connections to the frontal lobe,
which is associated with problem-solving and social interactions. Thus, damage to the
amygdala or abnormal development in childhood could impair social and emotional
functioning, resulting in ASD characteristics such as difficulty forming relationships and
social communicative issues like inappropriate gestures or an inability to make eye
contact.
Baron-Cohen sought to evidence his theory that amygdala dysfunction causes issues of
social processing by using the eyes test, in which an fMRI scan was used to record brain
activity of a group of adults with ASD and a control group (matched on age, IQ and
educational level) of adults without ASD when being shown pictures of strangers exhibiting
different emotions. The findings revealed that the group with ASD performed significantly
worse than the control group, as well as their completely inactivated amygdala activity
versus the strongly activated amygdala usage in the control group.
BIOLOGICAL EVALUATION 2 – AMYGDALA DYSFUNCTION
(+) KENNEDY et al. carried out a case study into a woman (nicknamed SM) who had
inactivity in the amygdala due to a rare genetic condition found that her fear responses
were abnormal. When assessed for reactions to proximity of strangers, SM reported feeling
comfortable in close distances that control participants reported to be very uncomfortable.
This demonstrates external validity of the study.
(-) AGGLETON et al. found that, whilst amygdala dysfunction in primates produces “no
affective behaviour and a catastrophic breakdown in social interactions”, such results
are almost never found in humans.
(-) Many findings often create inconsistencies within the theory. PIERCE et al. found
decreased size in the amygdala of ASD individuals, whilst HOWARD et al. found increased
size, and HERBERT et al. found smaller amygdala in ASD patients compared to controls.
Not only do these results contradict the theory itself but demonstrate that there are too
many conflicted findings surrounding the relationship between amygdala and ASD
overall.
(-) LYNN-PAUL studied 2 women with amygdala-damage, and found that whilst both
exhibited impaired social functioning, it was significantly less impaired than the functioning of
those with ASD, lowering the internal validity of this theory.
(-) An alternative explanation is the role of an indirect link which is not the amygdala directly
causing ASD. For example, the amygdala is associated with fear responses, which often
manifests as fearlessness which then leads to social characteristics of ASD such as
inappropriate gestures, as they do not have typical fear regulation which would prevent
this behaviour. This lowers the internal validity of this theory.
(-) It is theorised that it may be too simplistic to focus on the amygdala alone, when other
areas of the brain also have impacts on ASD characteristics. DZIOBEK conducted a study
which found no significant role from the amygdala in the emotional/social functioning of
individuals with Asperger’s syndrome. The study concluded that more research needs to
be done on the whole brain before a conclusive cause is reached.
,INDIVIDUAL DIFFERENCES EXPLANATION 1 – THEORY OF MIND
Theory of Mind (ToM) as an explanation for ASD was developed by Simon Baron-Cohen.
ToM refers to the ability to “mind-read” or empathise with others, being able to recognise
that other people may perceive or feel other things to yourself. Baron-Cohen argues that a
deficit in ToM could lead to ASD characteristics, namely communicative issues, such as
difficulty developing relationships, an inability to detect sarcasm, or reciprocity in
conversation. Research found that most individuals will begin to develop ToM from the age
of 14 months, and this is done through activities such as joint attention, which involves an
adult using gestures or line-of-sight to direct a child’s direction. Successfully doing this
encourages the child to recognise that other people have their own wants/needs, as they
can recognise another person’s perspective. However, this development is often delayed or
impaired in individuals with ASD, leading to later issues in empathising with others.
Baron-Cohen identified 2 key deficits of ToM:
1. DISTINGUISHING MENTAL VS 2. DISTINGUISHING APPEARANCE
PHYSICAL OBJECTS – FROM REALITY –
Baron-Cohen performed a study in which he Children with a ToM deficit are likely to struggle
described characters to young participants, to understand that objects may differ in nature
which the one character holding a drink and the to how they appear. For example, when shown
other thinking about one. When posed with a candle which looks and smells like an apple, a
questions such as, “Which character can have a neurotypical child can usually recognise that it is
drink?” most neurotypical participants aged 3-4 not actually an apple despite its appearance. A
years-old could answer correctly, whereas ASD child with ASD is more likely to say that it is an
individuals struggled to recognise the difference apple or is a candle whilst struggling to
in imagining and having. understand that its true nature and looks differ.
INDIVIDUAL DIFFERENCES EVALUATION 1 – THEORY OF MIND
(+) BARON-COHEN performed the Sally-Anne test on neurotypical children, children with ASD and
children with Down’s Syndrome. The study found that 86% of those with DS answered correctly,
alongside 85% of neurotypical children and 20% of those with ASD. This suggests that there is a link
in ToM deficits and ASD.
(-) However, the Sally-Anne test involves a great deal of story-telling, which any child may
struggle to follow, but a child with a communicative disorder such as ASD is likely to especially
struggle, lowering the internal validity of this study. Also, 20% of those with ASD still answered
correctly, suggesting that ToM may be one explanation, but it is not the only one as it does not apply
to all cases.
(+) GOLAN et al. performed a study using spoken phrases with different emotive voices (e.g. happy,
angry) and found that adult participants with ASD were poorer at recognising the emotions in another
person’s voice than those without ASD.
(+) This theory has had several positive applications in the real world, such as joint activity training.
This is a brief but intensive therapy, with individuals spending 6 weeks developing ToM through
activities such as following another person’s line of sight as they look in a certain direction, to
encourage recognition of other people’s perspectives.
(-) However, other research into the effectiveness of this therapy has suggested that,
whilst there are short-term improvements, rarely do these last or generalise beyond
the therapy-setting.
(+) BARON-COHEN went on to perform the eyes test on 15 ASD participants, with a control group of
over 500 people, and found that none of the ASD participants performed strongly, suggesting that
there is a ToM deficiency in ASD individuals as they struggle to identify other people’s emotions.
(-) However, this research has a very small sample size, especially in comparison to
the control group, lowering the external validity. Internal validity is also lowered due to
the risk of researcher bias.
(-) BARON-COHEN has been criticised for this theory due to its inability to explain more than just the
social characteristics of ASD, specifically the repetitive behaviours characteristics.
, INDIVIDUAL DIFFERENCES EXPLANATION 2 – WEAK CENTRAL COHERENCE THEORY
Weak central coherence (WCC) theory as an explanation for ASD was developed by Uta
Frith. Central coherence refers to an individual’s ability to see the bigger picture rather than
only seeing respective details, and it can either be strong or weak, with the former meaning
someone can easily obtain the gist of information, and the latter meaning this is a difficult
task. For example, in conversation, someone with strong CC will be able to summarise the
information they received, but someone with weak CC will focus on specific details. Frith
argued that individuals with ASD have weak central coherence, which manifests as ASD
characteristics such as fixated interests.
Frith focused on CC being explained by a preference or bias in processing, either global
(focusing on the bigger picture) or local (focusing on the finer details). Thus, CC exists on a
continuum of extremes and averages, determined by these processing preferences.
Extremely weak CC individuals will experience high local and weak global processing,
whereas extremely strong CC individuals will experience weak local and high global
processing. The former are likely to exhibit ASD characteristics, as they show fixated
interests and savant behaviour, whilst the latter are likely to experience difficulty
remembering details.
Frith’s theory sought to present ASD characteristics as an enhancement in some areas,
rather than viewing it solely as a disability as most theories before had done. This is
promoted by the theory in recognising that some ASD individuals have strengths that
neurotypicals do not, such as detailed memories, savant behaviour and attention to
detail. For example, an ASD individual may be more successful than a neurotypical
individual when identifying rail lines on a map, due to the intricate and detailed nature of the
task.
INDIVIDUAL DIFFERENCES EVALUATION 2 – WEAK CENTRAL COHERENCE THEORY
(+) FRITH provided strong evidence for this theory, using participants consisting of 20 ASD
individuals, 17 neurotypical individuals and 13 individuals with learning difficulties. Participants
were shown a two-dimensional pattern on a card, and had to use smaller blocks/tiles to make up this
same pattern. The use of local processing required for this task means that neurotypicals are likely
to find this a very difficult task, as it demands attention to individual details by mentally “breaking up”
the image. The findings reflected this, as ASD participants performed much better than the other
groups, suggesting that there exists in ASD individuals a bias for local processing, and that this
preference can be an advantage rather than a deficit. In the second part of the task, the individuals
were given the image already divided into 4 parts, leaving no need for local processing. In this half,
those with ASD performed no better than the other 2 groups, demonstrating the different processing
biases and a relationship between local processing and ASD.
(-) However, internal validity is lowered due to researcher bias.
(+) This theory is able to explain both social and non-social characteristics of ASD, as it suggests
that fixated interests come from high local processing creating an inability to look at the bigger
picture with global processing. It also suggests that there may be issues with emotional reciprocity,
as individuals with weak CC may be unable to register the gist of a conversation, instead focusing on
one specific part, limiting the ability to have a conversation fitting social norms.
(+) This theory has strong real-world implications, as identifying the strengths that ASD individuals
possess helps to destigmatise the disorder as a disability. This encourages more people to feel
confident in seeking a diagnosis, partaking in therapy, and reduces stereotypes that otherwise
suggest that those with ASD are lesser than neurotypicals.
(-) This theory does not actually identify where WCC comes from, identifying no brain regions or
environmental influences in where the cognitive deficit comes from. Whilst the theory does
successfully explain the root of specific characteristics, it cannot be considered a complete theory as it
does not explain where theses causes themselves come from. Whilst this doesn’t dismiss the theory
entirely, it suggests more research is needed before we consider it.
