Individual Differences In Autism

Autism affects the way a person acts. It reflects a difference in how the brain operates in other people and appears during childhood development. Autism has gained some notoriety throughout the years through no faults of its own (some of you may be familiar with the incorrect assumption that vaccines cause autism, a study that was debunked but remains prevalent today).

Autism spectrum disorder (ASD) is a category of various developmental disorders, affecting around four in 10,000 children. The typical autism spectrum disorder symptoms are:

• Difficulties with social interactions and talking to others
• Difficulties with empathy
• Easily overwhelmed by stimuli
• Engages in repetitive behaviour

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What are the causes of individual differences in Autism Spectrum Disorder?

Research investigating individual differences is used to identify if the differences found between people can explain behaviour. Or, specifically, mental illnesses.

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Personality And Individual Differences In Autistic Adults

People with autism tend to have difficulties in social situations, be anxious, and stick to strict routines. These are characteristics of some personality styles. Psychology research attempts to identify an association between specific personality styles and autism.

Schriber, Robins and Solomon (2014) compared the Big Five Personality scores of neurotypical children and children with autism.

The results found that children with autism scored significantly less in extraversion, agreeableness, conscientiousness and openness. However, children with autism had significantly higher scores indicating neuroticism than neurotypical children.

Individual Differences In Autism Based On Gender

Typically, more males than females are diagnosed with autism. This data suggests that sex differences may be a cause of autism. Many have even referred to autism as an 'extreme male brain' condition.

Why there is a higher prevalence rate of autism in males than females is still not fully understood. However, research has identified that individual differences in autism based on gender may be because:

• Males are more likely to inherit mutated genes that are linked to autism
• They have high levels of testosterone, a sex hormone found in men
• Women may inherit protective factors that make them less likely to inherit autism

It is important to note that it has been argued that gender differences in the prevalence of autism may not be a valid argument. This is because this difference may be due to bias in diagnosis. Symptoms of high-functioning women with ASD may be similar to other disorders, called co-morbidity.

Baron-Cohen et al. (2005): Exaggeration of the male brain

A study conducted by Baron-Cohen et al. (2005) suggested that females tend to be strong empathisers whilst males tend to be strong systemisers.

This means that females tend to succeed more in inferring emotional states and responding appropriately in social situations. In contrast, males tend to focus more on the rules surrounding the situation (input vs output) and predict and respond to behaviours based on this principle, relying on the rules that govern this system. They are weaker empathisers.

Baron-Cohen et al. (2005) suggested that the 'extreme male brain' is behind the gender differences in autism. An autistic brain is simply an exaggerated male brain structure, focusing on the neuroanatomical aspects of the disorder.

Bailey et al. (1994): Heavier brains

Whilst normal male brains tend to be heavier than female brains (male brains usually weigh around 1,350 grams, whilst female brains weigh approximately 1,200 grams), Bailey et al. (1994) found that the brains of male autistic patients were even heavier than this. The table below shows their results, indicating their age, brain weight, and what their brains should weigh based on the averages of a normal brain. In some cases, we can see that their actual brain weight was considerably larger than that of a normal brain.

What are the theories of individual differences causes of Autism?

Theories such as the theory of mind and the weak central coherence theory have been proposed to explain individual differences in autism. The theories explain how differences such as how differences in cognitive processing can cause autism.

Theory of Mind (ToM)

Research suggests that people with ASD have a weak theory of mind (ToM). This theory explains why people with ASD may have difficulties talking and interacting with others, as they cannot truly empathise with and understand another person's perspective.

ToM is needed for:

• Social communication skills
• Being able to predict how someone will feel based on the situation that they have just experienced
• Predict behaviour
• Understanding how one's own emotions may differ from others

The ToM may not be an innate cognitive process. In other words, we may not be born with it; it develops over time. The theory suggests ToM develops through experiences and interactions with peers.

For instance:

• Observing others actions
• Imitation

ToM in people diagnosed with ASD tend not to fully develop a ToM:

• Neuroimaging studies show that the medial prefrontal cortex and amygdala are involved in ToM processes. Brain scans of young children diagnosed with autism have shown larger amygdalas, for instance. Therefore, dysfunction in these areas may explain why people with ASD do not fully develop a ToM.
• Research showed that 80% of participants with autism failed the false-belief task. The pass rate of typically developed children were 85% (Baron-Cohen, 1985).

Baron-Cohen (1985) Study

Consider the following study by Baron-Cohen (1985).

Aim

Identify if typically developed children with autism or Down's Syndrome could pass a false-belief task.

Procedure

A research scenario was enacted using dolls and is known as the Sally-Anne Test.

Sally has a basket in this scenario, and Anne has a box. Sally places a marble in a basket and leaves. Anne then takes it out of the basket and places it in her box. The participants are then asked, "Where will Sally look for her marble?"

Children should say Sally would look in her basket to pass the task, as she still believes the marble is in her basket. She did not witness Annie move the marble. Children fail this task if they say Sally would look in Anne's box.

Findings

80% of children with autism, 14% of children with Down's Syndrome, and 15% typically developed children failed the task.

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Evaluation

Let's consider the strengths and weaknesses of this test.

• A strength of this theory is that it was proposed after conducting research. This indicates that there is valid, empirical evidence that supports the theory.
• A weakness of this theory is that poor ToM has affected other disorders. Poor ToM also characterises schizophrenia, attention-deficit hyperactivity disorder and schizophrenia. Therefore, ToM cannot solely explain ASD.

Weak Central Coherence Theory (WCC)

Frith (1989) proposed the weak central coherence theory (WCC) to autism.

As the theory's name suggests, Frith argued that people diagnosed with ASD have a weak CC (WCC).

Frith criticised other explanations of autism because they tend only to explain the deficits of ASD. However, although people with ASD have these deficits there are also things that they do well/better at.

Additionally, some people diagnosed with ASD can be detail-orientated. This means that they can easily see details that are hard to pick out from others.

Frith's WCC can explain deficits and strengths of people with ASD:

• Strengths - people with ASD would excel at tasks that involve people focusing on details
• Deficits - people with ASD may not be as good at tasks that involve looking at the big picture

Frith explained that this is a result of people with ASD having superior local processing and inferior global processing.

Evaluation

• A strength of this theory is that it does not focus on deficits that people with autism have. Instead, it also explains how people with ASD have advanced skills.
• A weakness of this theory is that it does not consider how environmental factors such as experience may affect autism. This suggests that the theory is reductionist, as it does not consider all factors that may explain ASD.