3.1 Explain theories about autism related to: • brain function • genetics • psychology

This guide will help you answer 3.1 Explain theories about autism related to: • brain function • genetics • psychology

Autism Spectrum Condition (ASC), often called autism, is a developmental condition that affects the way a person communicates, relates to others, and interprets the world. There is no single known cause, and researchers continue to explore many different ideas, called theories, that try to explain why autism happens. These theories cover how the brain works, the role of genetics, and insights from psychology.

In this guide, we will cover these three main groups of theories.

Theories Related to Brain Function

Theories about brain function look at how the structure, chemistry, and development of the brain relate to autism. Scientists have found several clues by studying the brains of people with autism.

Differences in Brain Structure

Studies using brain scans, like MRI or CT, show that some parts of the brain tend to look or work differently in people with autism, including:

• Amygdala: This area helps control emotions. Some researchers found that the amygdala can be larger than usual in young children with autism, affecting how they respond to emotions and faces.
• Cerebellum: This part is involved in movement and balance but there is evidence it may also affect attention and language. Certain structures in the cerebellum, called Purkinje cells, appear reduced in some people with autism.
• Corpus Callosum: This thick band of fibres connects the two halves of the brain and helps them communicate. In some studies, this area is smaller in people with autism.
• Frontal Lobe: This controls planning, judgement, and social behaviour. It may develop differently or function at a different activity level in those with autism.

Theories About Brain Connectivity

Connectivity means the way brain regions talk to each other. There are two main ideas:

• Under-connectivity: Some think that brain areas do not connect efficiently in autism, making it harder to process complex information or link different types of thinking.
• Over-connectivity within regions: At the same time, some brain regions might be too connected internally, which can lead to focused or repetitive interests.

This might explain why people with autism may find certain tasks, like reading facial expressions or switching attention, more challenging while excelling at detail-focused tasks.

Theory of Abnormal Growth

Some researchers found that the brains of children with autism may grow too quickly in early childhood but slow later on. This could lead to the building of more connections than usual, but not all are useful or efficient. This abnormal early growth may disrupt the balance of connections the brain needs for social and communication skills to flourish.

Chemical Signals in the Brain

The brain communicates using chemicals called neurotransmitters. Researchers have looked at different neurotransmitters in people with autism, including:

• Serotonin: People with autism often have higher serotonin levels in their blood. Serotonin affects mood, sleep and social behaviour.
• Dopamine and glutamate: These change how messages are sent around the brain, influencing movement, motivation, and learning. Differences in these chemicals could contribute to some autism traits.

These differences may help explain some common difficulties, like sensory sensitivity or changes in behaviour.

Mirror Neuron Theory

Mirror neurons fire both when we do an action and when we see someone else do that action. Some theorists suggest that differences in mirror neurons might make it harder for people with autism to “read” social signals, mimic facial expressions, or develop empathy. Evidence for this theory is mixed, but it still shapes how some people understand autism.

Theories Related to Genetics

Genetics is the study of inherited traits and how genes influence who we are. Many researchers believe that autism has strong genetic links.

Twin and Family Studies

• Twin studies: Identical twins have the same DNA. If one twin has autism, the chance the other twin will also have autism is higher than in non-identical twins. This suggests a strong genetic influence.
• Family studies: Brothers and sisters of people with autism have a higher risk than the general public of having autism themselves.

Specific Genes

No single gene causes autism. Instead, several hundred genes may each play a small part. Sometimes changes in genes called mutations can cause differences in how the brain develops. These might occur by chance or be inherited.

Researchers have found that certain rare genetic differences, called copy number variations (CNVs), are more common in people with autism. These involve “extra” or “missing” sections of DNA.

Syndromic and Non-Syndromic Autism

• Syndromic autism occurs alongside other known genetic conditions, such as Fragile X syndrome or Rett syndrome.
• Non-syndromic autism is not linked to a known genetic syndrome but is thought to involve a complex combination of many genes.

Interaction Between Genes and Environment

Genes do not work alone. Environmental factors, like age of parents or some complications during pregnancy or birth, may interact with genes to affect risk. This is called the “gene-environment interaction”. For example, a child might inherit a “higher risk” but not develop autism unless certain triggers occur.

Heritability

Heritability measures how much of a condition can be explained by genes. Current estimates suggest that genetic factors explain about 60-90 per cent of the likelihood of developing autism. This leaves some room for other factors.

Genetic Theories Summary

• Many genes act together to raise the risk.
• Some single-gene syndromes have high autism risk.
• Most cases are caused by complex genetic patterns, not one faulty gene.
• Environmental factors may make a difference, especially when combined with genetic risk.

Psychological Theories

Psychological theories are models that try to explain how people with autism think, feel and react differently, often without focusing directly on physical or genetic causes. These are important for understanding how autism affects behaviour and experiences.

Theory of Mind

Theory of Mind means being able to understand that other people have thoughts, feelings, and beliefs which may be different from your own.

• Simon Baron-Cohen and colleagues found that some people with autism find certain tasks “mindreading” tasks harder. This includes recognising what someone else might be thinking or feeling based on their behaviour.
• This theory helps explain why social interaction and communication may be affected in autism. A person might not pick up on the unspoken thoughts or feelings of others.
• Not every autistic person has difficulty with theory of mind, and many learn these skills with practice or support.

Executive Functioning Theory

Executive function is the ability to plan, organise, remember instructions, shift between tasks, and control impulses.

• Some people with autism find multitasking, adapting to change, or planning ahead more difficult.
• Problems with executive function may explain why routines and sameness feel so important, and why changes in plan or unexpected events can lead to distress.
• Difficulties with starting or stopping tasks, or switching attention, are often described in this group of theories.

Weak Central Coherence Theory

This theory suggests that people with autism notice details but may find it harder to see the “big picture”.

• For example, someone might be very good at spotting patterns or small differences but find it hard to understand the overall meaning of a story or situation.
• Thinking might be more focused on the parts than on joining them together as a whole.
• This can lead to strengths, such as good memory for facts or patterns, but also to challenges in situations that need combining information.

Sensory Processing Theories

People with autism often experience the world in a very intense or unusual way through their senses.

• Sensory processing means how the brain handles input like sounds, smells, touch, taste, and vision.
• Some people with autism are very sensitive to sounds or lights, while others may not notice pain or cold in the usual way.
• This can affect behaviour (covering ears, seeking certain textures, avoiding crowds).
• Psychological theories look at how these sensory differences affect responses and everyday life.

Social Motivation Theory

This newer idea suggests that autism may be linked to finding social signals, like faces or voices, less rewarding or interesting from an early age.

• Children with autism may pay less attention to social cues, leading to differences in learning language or building social skills.
• This theory is connected to research on reward centres in the brain and motivation.

Putting Theories Together

Each theory gives a possible piece of the puzzle, but none explain autism on their own. Most experts think that a mix of brain differences, genetics and thinking styles combine to produce the traits seen in autism.

Research continues and these theories change over time as new evidence emerges. It is also important to remember that autism affects everyone differently.

Final Thoughts

Understanding autism means looking at several theories, not just one. Brain function theories help us see how differences in structure or chemistry may shape behaviour. Genetic theories show that inherited genes play a major part but are not the only factor. Psychological theories give insight into how people with autism may process the world, relate to others, and understand themselves.

Most researchers and support workers believe that all these areas are important. They guide how we support autistic people, talk with families, and adapt care. Each person will have a unique pattern of strengths, challenges and needs. Listening and learning from autistic people’s own experiences is just as valuable as research findings.

By knowing about different theories, workers can better explain autism to others, recognise why certain strategies are helpful, and build trust with those they care for. This knowledge leads to fairer, more respectful support for autistic people throughout their lives.