Sensory Processing

Autistic brains process the world around them differently. All autistic people have some differences in sensory processing – they may be hypersensitive to some sensory input (meaning they feel it more intensely); hyposensitive to some sensory input (meaning they feel it less intensely); a mixture of both depending on the particular sensory input involved; and/or a mixture of both depending on their situation, environment, and exhaustion levels.

There is a huge variety of ways to process sensory input differently, and it would be impossible to list all of them. This resource will list some of the common sensory experiences autistic people have.

Visual

• Some autistic people are hypersensitive to bright light. This could mean they find it uncomfortable or painful to be in a brightly lit room, and find it easier to relax in dim lighting or darkness.
• Everyone finds it difficult to see when the sun is extremely bright and there’s a lot of glare – some autistic people have that same experience whenever the sun is a bit brighter than usual, or whenever the sun is out at all. (If you are around autistic adults, you may notice that some of them wear sunglasses even when it’s cloudy – if they’re hypersensitive to bright light, the sunglasses are helping them see.)
• Visual clutter can be overwhelming to some autistic people. This includes spaces where there’s a lot to process visually, like supermarkets and shopping malls, as well as having a lot of patterns or colours present.
• Aphantasia is more common in the autistic population. Aphantasia is the inability to form images in your mind; many autistic people experience this to some degree. For those who can form mental images, it’s common for those images to be very simple or undefined; or to be unable to mentally rotate or manipulate objects. (This can make spatial tasks like reading maps or planning where to put furniture very difficult.)
• Prosopagnosia, or face blindness, is also much more common in autistic people. Many autistic people have some degree of difficulty recognising faces, ranging from being unable to recognise someone’s face at all and relying on other cues, like voices and hairstyles, to being able to recognise faces in context (such as recognising co-workers at work), but struggling when presented with a familiar face in an unfamiliar context (like running into your boss at the supermarket).

Auditory

• Some autistic people experience most or all sounds as louder than non-autistic people. You might notice them covering their ears or using headphones or earplugs, even in an environmnent that doesn’t seem that loud.
• It’s common for autistic people to find high-pitched noises more irritating or even painful than non-autistic people. Sometimes this is because the noise is louder to the autistic person; sometimes it’s just more intense.
• Many autistic people find it difficult or impossible to tune out background noise or distracting sounds. For most non-autistic people, important sounds like conversation automatically drown out unimportant sounds, like traffic outside; for many autistic people, it can be impossible to follow a conversation if there is background noise going on.
• Complex sounds, or sounds that need more processing energy, can also be difficult for some autistic people. A conversation, for example, takes more energy to process than familiar music or a repetitive banging sound (which can be why some autistic people, particularly young children, become upset when other people are talking around them, and may try to drown out the conversation with repetitive noises).

Tactile

• It’s common for autistic people to experience touch and texture more intensely. This can mean that textures which are mildly unpleasant or even unnoticeable to most people are irritating or intolerable for autistic people. There is a wide range of textures that autistic people may find difficult or impossible to touch, but some of the more common ones are scratchy clothing or clothing labels; squishy or slimy textures; and unexpected textures (for example, a fabric that looks smooth but feels rough).
• Experiencing texture more intensely can affect eating – trying to eat a food with an unacceptable texture can make an autistic person feel sick, or in some cases actually cause them to gag, choke, or throw up. Unexpected textures triggering this sort of response is why some autistic people prefer processed foods over fresh fruit and vegetables; the texture of crackers or chips is always the same, while two berries from the same packet might have very different textures.
• Some autistic people are much more sensitive to heat or cold. They may get too hot or too cold long before others do.

Taste

• Many autistic people taste foods more intensely. Everyone has specific flavours they tend to seek out or avoid, but for autistic people, eating a food they don’t like can be much more intense, similar to a non-autistic person trying to force themselves to eat something that tastes rotten, or that isn’t food at all.
• Some autistic people are particularly sensitive to spicy foods, and will avoid even slightly spicy foods, or foods seasoned with pepper.
• It’s common for autistic children to have strong food-related preferences and to give odd reasons for these preferences, like carrots being too spicy.
  • Some of this is due to experiencing the taste of the food differently or more intensely; some of it is due to still learning the words for different taste experiences (so a child might express that a salty food that makes them thirsty is ‘too spicy’).

Scent

• Like the other senses, it’s common for autistic people to be more sensitive to smells. In enclosed spaces, strong perfume, cleaning, or food smells can become overwhelming.
• Some autistic people are particularly sensitive to artificial scents, and may experience the smell of floral-scented cleaning produts, for example, as overwhemingly harsh and chemical. (Odourless cleaning products are often much more tolerable for these people, and floral scents tend to be the most unpleasant.)
• Some autistic people have different experiences in terms of which scents are more unpleasant than others; for example, preferring body odour over the smell of deodorant or perfume.

Proprioceptive

• Proprioception is the sense of where your body is in space. When you touch your nose with your finger, proprioception is what tells you where to put your finger. It affects your balance, the way you move through the world, and your knowledge of what your body is doing.
• Many autistic people have poor proprioception, which can lead to difficulties with clumsiness, and frequently tripping over things or bumping into furniture. It’s easy to trip over things when you’re never entirely aware of where your feet are!
• Proprioception can also affect some fine motor skills. Decreased awareness of where your finger is can make pointing to a precise object more difficult, so some autistic people can struggle with things like pointing to images to communicate if the images are too small, or with typing on a small keyboard.

Interoceptive

• Interoception is the sense of internal states in your body. This is what tells you whether you’re hungry, thirsty, in pain, or need to use the toilet.
  – Some autistic people cannot tell when they’re hungry, and may go without eating until they are reminded or they get so hungry that it becomes painful. It’s also common for autistic people to not have a sense of being full after eating, which can make knowing how much to eat difficult.
• It’s common for autistic people (especially children) to have a decreased sense of whether they need to use the toilet. Some autistic people will never develop this sense, and will always rely on timers or reminders to make sure they use the toilet regularly and avoid accidents; others will only become aware that they need to use the toilet when it’s urgent.
• Some autistic people may react unexpectedly to physical pain – for some people, external pain (like a graze directly on their skin, or a pinprick) is much more intense than internal pain (like a stomachache or a broken bone).

Vestibular

• The vestibular system controls our sense of balance and orientation in space.
• Some autistic people struggle with balance due to decreased input from their vestibular system. They might get motion-sick very easily (sometimes just from having their eyes closed). Repetitive swinging or rocking motions can help to reorient their sense of balance.
• Other autistic people may need to move around a lot to maintain their balance. They may need to climb on things, run around, or sit on a Swiss ball instead of a chair. Intensely movement-oriented hobbies like rock climbing, gymnastics, or swimming can help decrease the constant need to be moving.