Making Sense of the Senses – Part 1 – The Big Five – Sight, Sound, Smell, Touch and Taste

By Nanny Aut

Something that the majority of autistics have to manage is sensory processing differences. And it is something that is often misunderstood in the wider community. Managing the senses is often seen as providing noise-cancelling headphones to deal with sound and sunglasses to deal with sight, along with providing a range of sensory toys / activities with little to no understanding of how they actually manage the sensory profile. Sometimes touch is recognised by trying to desensitise through brushing or by giving deep pressure hugs to regulate. These can work if it meets the actual sensory needs of the child but can make things significantly worse if they don’t.

Two things affect sensory processing, one is the lack of input filter so information is coming in from ALL of our senses, ALL of the time, unless we take steps to manage this. In addition to this, most autistics also have to deal with sensory imbalance, where are senses are set too high or too low. This means that our over-worked air-traffic controller is dealing with all this input and all of these imbalances, which can easily lead to overload, overwhelm and meltdown if not managed properly.

Over time, we may become less conscious of this overload and these imbalances. We tune them out in the same way that someone with chronic pain moves the pain into the background. It is still there, it is still stressing the nervous system, but the drive to deal with the imbalance lessens. We learn not to stim because others tell us it is weird. We learn to ‘bottle up’ our stress at sensory overload because others seem to be able to cope, therefore we should too. We learn to ignore all the warning signals our brain is sending us, because others have told us that those signals aren’t real. However, while our conscious brain may be less aware, the effect on the nervous system is still there. Day by day, failing to listen to and respond to our sensory needs causes more and more damage, until finally, we break. We burn out. Anxiety and depression become so severe that we can no longer function.

Desensitising techniques may force us to mask our response (fawn response), to ‘tune out’ the signals we are getting, but they don’t stop the trauma underneath. It is like persuading someone that knives are safe by repeatedly stabbing them in the leg and rewarding them when they don’t scream or flinch. Our brain is not fooled, and anxiety will get worse and worse each time the trauma is repeated and the brain becomes more and more hard wired into seeing that event as dangerous. There will come a point that we cannot mask any more and no amount of positive safe experiences after that will be able to undo the aversion that has been trained in.

There are times, such as when we are over-tired, overwhelmed, in pain or in burnout, that we are no longer able to ‘tune out’ our sensory signals. They come in full force, full intensity. It is like having severely burned skin. Now the lightest touch sends pain spiralling, where it would not even have been noticed on healthy skin.

We see this escalation of response in a small way on a daily basis. Every time a sensory stressor is triggered, it is like a small drop of boiling water flicked on the skin. If these stressors are few and far between, then the skin has plenty of time to recover. It stays a minor annoyance. However, if you increase the frequency of these stressors, then each flick adds to the damage of the previous flick. Now boiling water isn’t landing on healthy skin, it is landing on raw, blistered skin. It is becoming increasingly difficult to ignore the stressors now as each damage adds to the damage before. Finally, if there is no time to recover and there are too many stressors, one after the other, that boiling water is landing on severely burned skin – each flick makes you want to scream. One more flick and you are straight into meltdown, no warning, no lead up, just boom – Dino brain large and in charge.

This is why understanding the individual’s sensory profile and actively seeking to balance it is so important for our mental well-being. Unbalanced senses are not ‘a little annoying’ and responding to those warning signals isn’t ‘over-reacting’ or ‘being over-sensitive’. It is critical to the welfare of our nervous system and we are being done a great dis-service when we are encouraged, or actively trained, to tune it out.

The Sensory Profile

If we imagine our senses as a control board on a graphic equaliser, for most neurotypicals (NTs), senses sit around the middle. For most autistics, however, senses sit too high or too low. And these senses can be pushed higher and lower by stress, anxiety, processing overwhelm, tiredness, hormones or a dozen other environmental factors. In order to stay regulated, it is important to increase feedback on the low senses where possible and decrease feedback on the high senses where possible.

Where those senses are high and where they are low are unique to the individual. It is common to see autistic children described as either sensory seekers or sensory avoidant, when the truth is they’re generally both, it just depends on which sense you are looking at.

It takes detective work to see where the highs and lows are with the individual and is a lot more complex than just looking at the five well-known senses. Identifying where the child is hyper-sensitive (high senses) and where they are hypo-sensitive (low senses) takes time. And how far away those senses are from the central line depends very much on the environment and how stressed the child is. So, if they are calm and regulated, you may see very little variation at all, and if they are overwhelmed, highs become unbearable and low senses almost vanish entirely. However, learning to identify the profile of the individual and working to support it pays huge dividends in reducing stress and anxiety and increasing processing capacity. It is also a highly valuable tool going forward in enabling us to be pro-active in looking after our own nervous system.

Most of us were taught there were five senses – sight, sound, smell, touch and taste. In reality, there are many more and even the five ‘basic’ senses send different signals depending on what is being sensed. In this post we will discuss the ‘big five’ and in the next post – Part 2 – we will discuss the less well-known senses grouped under Interoception and Proprioception. Note, some sources separate Vestibular from Proprioception making an eighth group of senses, some group it under Proprioception to give you seven groups of senses. Given how complicated understanding the senses already are, I prefer to include it with Proprioception.

Sight – tells us about colour, light intensity, movement, shape, spatial organisation (where things are placed around you), it even pattern matches shape with previous experiences. And our feedback can be high in one area and low in another. For instance, lights can be too bright and so will need sunglasses to reduce the intensity, but the sense of movement or colour may be low which then leads to visual stimming, seeking out moving images and lights such as visual games, lava lamps, spinning tops etc. Or we can recognise animals from the briefest glimpse but have zero or limited pattern recognition for faces – prosopagnosia, common for a lot of autistics.

Another element that is really important to consider around sight, is eye contact. This visual input can range from intensely overwhelming, to painful, to uncomfortably intimate. Not all autistics struggle with this, but if we are aversive, there is a really good reason for this and should be respected. Eye contact isn’t needed to listen well, and often it badly impedes our ability to listen.

Sound – is one of our biggest alerts for danger and we can be hypersensitive to all alarm sounds because of this – beeping machines, alarm clocks, fire alarms, school bells etc. – triggering a massive surge of anxiety prepping us for the fight/flight response. It is also a very hard one to filter because for many of us, most sound comes in at the same ‘volume’ whether it is background noise or the speaker we are supposed to be listening to. The air-traffic controller has to work hard manually turning down the volume on background and turning up the volume on ‘important’ sounds. While still maintaining an ‘alert’ for the sabre-tooth tiger our Dino brain is convinced is sneaking up behind us.

Sound is also often extremely complex and hard work to process. Many autistics struggle with live music because of the complexity of live voices and instruments. Not all, for some autistics, music is very much part of their language and they can be more comfortable with sung communication than spoken.

One area where sound sensitivity can cause massive challenges is in eating. Many autistics have misophonia, which is an anxiety response often triggered by the sounds of other people eating. Eating may not be the only sound trigger, but can be the most problematic. Noise-cancelling headphones do not tend to help because, while they block the sounds of external eating, they then amplify the sounds of you eating. Having music on or the TV can help to drown out the sounds instead.

You will often see autistics who struggle with sound sensitivity making a lot of noise themselves, choosing to listen to loud music or have the TV on, even though they aren’t watching it. This is because this is noise that we can control and are familiar with. It takes little processing and drowns out the multitude of smaller noises that most NTs are completely unaware of such as the buzzing of electricity and lights, the whirr of motors, the children playing three doors down, the dog barking three streets away. Noise-cancelling headphones can make a huge difference as can noise-dampening earplugs, taking out a lot of the background frequencies.

Smell – another sense that tends to be hyperactive as a defense mechanism. Familiar scents register as safe and can be very comforting, unfamiliar scents often register as unsafe and can increase anxiety. This is why changing clothes detergents and fabric softeners can increase anxiety and why having a cloth with a familiar smell in an unfamiliar environment can help reduce anxiety.

In addition to this, there are some scents we will be very attracted to and some we are extremely averse to. This varies from individual to individual. For instance, strong perfumes and many aromatherapy products increase my anxiety enormously, and when I was a teacher, I had to stop drinking coffee once a week as the smell of coffee was triggering to one of my students. However, natural flower and herb scents in the garden are a pleasurable sensory stim for me and I find it calming.

Touch – this is an extremely complex area of the nervous system and an area that is commonly very affected by the high/low phenomenon. Our nervous system registers touch in multiple different areas – light touch registers differently to deep pressure, skin temperature registers differently to internal temperature, pain registers differently depending on the area of the body the feedback is coming from. This means that someone can have a highly sensitive scalp and yet bang into furniture hard enough to leave bruises and barely register it. Or really enjoy a deep pressure hug but gets two thousand icks if someone strokes their arm lightly.

One area that touch can have a major impact on an autistic’s life is clothing. If our sense for light touch is high then the feeling of certain fabrics and clothing tags can be intensely overwhelming. Unless the clothes are very soft and seamless, it can feel like wearing a monk’s hair shirt or a suit of barbed wire. If clothes are uncomfortable, not only does it push our stress levels through the roof, it makes it nearly impossible to focus on anything else.

The fact that some autistics senses go high, while some go low, is why body brushing can be an extremely traumatic therapy if someone has high feedback on light touch – the child learns to submit and not complain but the distress is still there underneath. Conversely, if our feedback on light touch is low, then body brushing can improve feedback and be very regulating. It is not a one size fits all therapy.

Similarly, a deep pressure hug or a weighted blanket can be soothing if our sense for deep pressure is set low, as it increases feedback and promotes a feeling of security. However, if the sense for deep pressure is high, then the hug is overwhelming and will make the indivudual feel trapped and threatened.

Taste – like touch, taste is also more complex than considering flavour. Even flavour breaks down into different elements – sweet, salty, sour, bitter and umami. When eating food there is also feedback on look, scent and texture to take into consideration. What is the bite – how crispy, tough, soft, yielding is it? What is the mouthfeel – smooth, slimy, squishy, rough, crunchy? There is a LOT of information for the brain to process here and sometimes it prefers to reduce processing load by reducing the options down to a few safe and familiar foods that give the same feedback every single time, and avoiding flavour combinations. This is often why autistics have a limited diet and struggle with food touching – it creates an unwanted taste combination to deal with. Forcing children to expand their range is likely to backfire if they are not ready or their processing or anxiety is running high. It then adds a trauma link to the food, so not only is it too complex to process, the brain now registers the food as dangerous and one to avoid. And sneaking food into current ‘safe foods’ is a VERY big no. The chances are very high we will pick up the tiny change in taste and now, not only is our safe food no longer safe, the person who served the food is no longer safe either. They have broken trust in a very big way.

In addition, in some autistics the poison sense does not switch off. This is a sense that all young children have to prevent them inadvertently eating things that will make them ill. As we get older, for most of us, our brain now knows how to recognise safe foods and this sense switches off. However, when it doesn’t switch off, the brain becomes highly alert and aversive to certain tastes and textures. You get a highly negative feedback, in the way you would if you tried to eat live slugs.

In both these situations ‘They will eat when they are hungry’ is a false belief. If it is a processing issue and we are hungry, we don’t have the energy to increase processing capacity, so the brain will refuse because it will cause overload. If it is a poison sense issue – would you knowingly eat poison, even if you were starving?

Instead, new foods should be introduced away from the table, in a zero pressure, zero demand environment, letting the child explore (or not) in any way they choose. Look, touch, sniff, lick, chew and spit. It gives a chance for the brain to learn about the new food and process all its elements in a no threat, low processing environment. In time, the brain may decide it is a safe food and add it to the list, or it may not. We all have foods we really dislike.

This aversion is not true for all autistics. For some of us, we have the opposite issue. Food is a sensory stim for us. So we actively seek it out to manage our anxiety, or to address other underlying regulating issues that we may not be consciously aware of. This can lead to us seriously over-eating if the underlying causes of the drive to eat aren’t addressed. The table below shows how drives for certain foods can indicate the underlying cause beneath.

As you can see, understanding and managing even the ‘big five’ senses is more complicated than many people understand. And managing our senses can have an enormous impact on the mental well-being of autistics.

Here are four common scenarios below with potential sensory challenges and their solutions. The list is not exhaustive but covers the most common struggles. As you learn more about the sensory profile of the individual autistic and become more adept in incorporating management of it into everyday life, you will not only reduce our stress in day to day life, you will equip us with a lifelong tool for regulation going forward.