Human beings have sensory systems that help us process sensory information (such as sounds, touch, or tastes) and navigate the world around us. Some people, such as those who are autistic, have differences in the way their brains process sensory information, which can affect the way they interact with the world.
Some people may be more sensitive (hypersensitive) to certain input than others (e.g. they may find sounds overwhelming) or less sensitive (hyposensitive) to certain input than others (e.g., they may not notice someone touch their arm). Other people may seek out sensory input more than others (e.g., they may continually touch soft fabrics). These differences can vary for each individual across senses and to different levels. Experiences can also vary depending on the situation and the context. Read more below about how sensory processing differences relate to the eight senses.
Someone who knows first-hand what daily life is like with sensory processing differences is our project team member, Emily. She has Sensory Processing Disorder and is autistic.
‘Sensory processing issues are a constant thing for me – my senses are ridiculously heightened at all times and totally out of my control. My mood can change so quickly if I become overwhelmed by something (e.g. loud noises, bright lights, strong scents, unexpected touch) as I cannot filter the information coming into my brain, and I cannot regulate my emotions or understand and label my own feelings. This means day-to-day it can be quite tiring being out in the world, and as a result, I’ve become very good at masking (hiding my true thoughts/feelings), and I can only really drop that mask when I am in a safe environment like my home. Both personally, and as a team, I think we feel that it’s very important to create awareness of sensory processing difficulties as they are a key part of what makes the world quite a disabling and uninviting place for autistic people.’Emily, @21andsensory
The eight senses
There are eight different ways in which people process sensory information around them. Everyone process this information in different ways, but some autistic people may be more sensitive (hypersensitive) or less sensitive (hyposensitive) than others, or they may seek out sensory inputs.
Hearing (Auditory Information)
Auditory information is the sounds that we hear through our ears. These vibrations are processed by our cochlea and transmitted to our brain as electrical impulses.
Someone hyposensitive to auditory information may not acknowledge certain sounds, even if they seem loud or distinct to other people. Someone who is auditory seeking may like making sounds with objects or their voice.
People who are hypersensitive to sound may find it hard to cope with background noise as these sounds can be magnified and may be distorted. This can make it harder to focus on conversations in crowded places. Some people may choose to wear headphones or ear defenders to make it easier to manage in loud places such as shopping centres.
Taste (Gustatory Information)
Our sense of taste (also known as gustatory information) comes from receptors in our tongue, which can detect different tastes such as sweet, salty and sour. When we are eating, our sense of taste works closely with our senses of smell and touch (to process the texture of food) to experience different foods.
Someone who is hyposensitive to taste may compensate for this by eating food with stronger flavours or lots of spice. Some people may seek out certain flavours over-and-over again or may eat non-edible items such as grass or stones (also known as pica).
People who are hypersensitive to taste can find certain food flavours or textures too overwhelming. This means that they may have a restricted diet, only eating foods with certain textures (e.g. crunchy or smooth foods) or tastes.
Smell (Olfactory Information)
The olfactory system processes information received through our nose and is processed in the same part of the brain as our emotions.
People hyposensitive to smell can have a reduced/no sense of smell and may lick items to better understand them (incorporating their sense of taste). Other people may find smells intense and overpowering which can induce nausea or headaches. Scented products, such as perfumes or cleaning sprays, or food smells may be especially challenging.
Touch (Tactile Information)
The tactile system processes information gained through your skin. It processes and connects information about touch, pressure, temperature and pain.
Someone hyposensitive to touch may have a high pain threshold or not notice if someone has touched their arm to get their attention. Some people may seek out certain textures or firm pressure. Others who are hypersensitive to touch may find wearing certain clothing more difficult (due to scratchy textures or clothing labels) or find grooming challenging, such as washing and brushing their hair. Difficulties with touch is also related to a person’s enjoyment of certain foods due to their texture.
Sight (Visual Information)
We process visual information through our eyes, which includes colours, patterns, shapes, depth and contrasts.
People with differences processing visual information may have poor depth perception making it harder to throw or catch items such as a ball. Objects may appear dark or fragmented, with images appearing clearer in their peripheral vision. People who are visually hyporesponsive may not notice objects or people in their periphery or notice changes in a room. People who are hypersensitivity may struggle with bright or flashing light and need to turn away or wear sunglasses. Whereas some people may seek out looking at ambient lighting or spinning objects.
Proprioception is the feedback we receive from muscles/joints in the body. It helps us understand where our body is in space as well as our movements and actions. This sense is important for coordinating movements of the body.
People with proprioception differences can find it hard to judge personal space and distance from other people. This means they may bump into people/objects in rooms. Fine motor skills can be difficult e.g. tying shoe laces or using buttons. Some individuals may seek out proprioceptive input by jumping and bumping into walls or soft furnishings.
Our vestibular system controls our sense of balance and coordinating movement. This system in our inner ears tells our brain about the position of our head, how fast or slow we are moving as well as where we are in relation to other objects/people.
Some people vestibular processing differences may commonly rock, swing, jump, bounce or spin. People who are hypersensitive can find movement and balance challenging, and may lose balance when turning or get car sick more easily.
Interoception is all about processing sensations that happen inside your body, such as feeling hungry, thirsty, hot/cold, nauseous or even that you need to use the toilet. Interoception can also be recognised through emotions linked to physical sensations in the body, such as having a faster heart rate when you feel scared.
Sometimes information from our other senses can disguise these or prevent people from recognising interoceptive clues at times. Someone who is hypersensitive may feel inputs such as pain or hunger more intensely or for longer periods than other people while others may not notice these signals until they are very intense or someone else points them out.
Differences reading these signals can make it harder for individuals to meet their body’s needs or understand how they are feeling.