The eight senses your child is actually using

You learned five senses at school. Touch, taste, sound, smell, vision. There are actually eight. The three you probably haven't heard of are the ones that matter most for understanding your child's behaviour, and they're the ones that develop first.

When I sat down with Jacqui, founder of Kids in Sync and a specialist in sensory integration, she started here. Not with my daughter's specific difficulties, but with how sensory integration actually works. "This is the foundation," she said. "You can't go further without understanding this."

The five senses you already know

These are quick because you already understand them. But it's worth noting that for many autistic and neurodivergent children, even these familiar senses can be over-sensitive, under-sensitive, or both at the same time:

• Touch (tactile): pressure, texture, temperature on the skin. The child who can't bear labels, seams, or certain fabrics
• Taste and smell (gustatory and olfactory): why the lunch hall is overwhelming and why food selectivity often has a sensory basis
• Sound (auditory): the hand dryer, the assembly hall, the classroom with 29 children talking at once
• Vision: flickering fluorescent lights, cluttered displays, busy patterns

These are "higher-level" senses in the developmental hierarchy. They need the three foundational senses below them to be working well before they can be processed efficiently.

The three senses behind sensory integration

The vestibular system: balance, movement, and muscle tone

"The vestibular system is located in the inner ear," Jacqui explained, "and it dictates muscle tone throughout the entire body."

That surprised me. I'd associated the inner ear with balance, full stop. But the vestibular system controls muscle tone in every muscle, including:

• Eye muscles (affects eye tracking; relevant to reading and copying from the board)
• Hand and finger muscles (affects pencil grip and fine motor skills)
• Core muscles (affects whether your child can sit upright without slumping)

It also controls what Jacqui called gravitational security: how safe you feel with your feet off the ground.

• Some children climb everything and jump off with zero fear
• Others won't go near a climbing frame
• Some hate sitting on the toilet because without anything to hold onto, they're essentially suspended, and their brain doesn't feel safe about it

You feed information into the vestibular system through movement, particularly head movements: jumping, spinning, crashing about, rocking, sliding. When you see a child doing these things constantly, their brain is trying to get the sensory input it needs. They're not being wild; they're self-regulating.

My daughter didn't walk downstairs until she was five. She bumped down on her bottom. When Jacqui explained that walking downstairs means stepping off into the unknown, that your foot is going to land somewhere and your vestibular system needs to tell you when, it suddenly made sense. Standing up and walking down puts you in a position of gravitational insecurity if that system isn't well integrated.

The proprioceptive system: muscles and joints talking to the brain

The proprioceptive system is information coming through your muscles and joints to the brain. It tells the brain which muscles are contracted and which are relaxed, and it controls muscle strength. Both the proprioceptive and vestibular systems need to work together for coordinated, controlled movement.

Something I found interesting: slow, graded movement is harder than fast movement. It's harder to walk carefully than to run, because running gives you gravitational force and momentum working with you. The child who's always hurtling around isn't necessarily more energetic; they may find that kind of movement easier than the controlled alternative.

The most important thing about proprioceptive input: it calms the central nervous system. This explains a huge number of behaviours:

• Seeking hugs and wanting to be held tightly
• Hanging off monkey bars and door frames
• Pushing, pulling, leaning against furniture
• Squeezing into tight spaces
• Chewing on sleeves, pencils, fingernails, shirt collars

Your jaw muscles are the strongest muscles in your body. Chewing or biting down on things is a child getting proprioceptive input to calm themselves. They're self-regulating, not misbehaving. For more on building this kind of input into the day, see our guide on sensory diets for children.

Interoception: what's happening inside the body

Interoception is your brain picking up signals from your internal organs: hunger, thirst, bladder fullness, temperature, heart rate, pain, and the physical sensations that underpin emotions.

"All these things we assume happen automatically," Jacqui said. "You feel the cue, you respond. That's interoception."

For children whose interoception isn't reliable, signals get missed, arrive late, or arrive as vague discomfort the child can't identify. This is a big enough topic that it has its own article, but the short version: if your child doesn't realise they're thirsty until they have a headache, doesn't know they need the toilet until it's an emergency, or says "something is wrong but I don't know what," interoception is likely involved.

How sensory integration develops: the triangle

Now that you know what the eight senses are, the next question is how they work together. Jacqui drew me a triangle. It's the most useful thing I took away from our conversation, because it explains why difficulties at the top (writing, concentration, social skills) trace back to gaps at the base.

Base layer: vestibular, proprioceptive, tactile. These foundational senses start integrating from the moment a baby lifts their head against gravity. The crawling phase is critical: four-point crawling builds hip and shoulder strength, develops core stability, and establishes bilateral coordination (using both sides of the body together).

Middle layer: auditory, visual, olfactory. These need the foundation in place. This is why speech develops later — the brain has to decode pitches, tones, sounds and volumes, then reorganise all of that to produce speech. Children who aren't speaking well often get sent for a hearing test and can hear perfectly fine. It's not a hearing problem; it's a processing problem.

Upper layer: praxis. The ability to conceive of a task and implement it — ideation plus execution, requiring all the systems below to be well integrated.

Top: academic learning and social communication. Everything schools focus on sits at the very top, built on all the layers beneath.

When I told Jacqui that Annabel doesn't have much praxis, she said: "That's because it's the integration of those sensory systems. That's the area that needs work."

Why sensory integration matters for learning and behaviour

The triangle explains why a child might struggle with writing: not because they're not clever enough, but because their proprioceptive and vestibular systems aren't giving them the core stability, bilateral coordination and pencil pressure control they need to physically do it.

Writing requires:

• Core stability to sit upright (vestibular)
• Bilateral coordination to hold the paper and write simultaneously (vestibular + proprioceptive)
• Correct pencil grip and pressure (proprioceptive; the brain needs feedback on how hard the pencil is pressing)
• Visual-motor coordination to stay on the line (visual + proprioceptive + vestibular working together)
• Attention and motivation to sustain it (which requires being in the calm zone, which requires sensory regulation, which requires the sensory foundation)

No amount of handwriting practice will fix a problem that sits in the vestibular and proprioceptive systems. You have to go to the foundation.

How sensory integration therapy addresses the foundation

If the foundation is where the gaps are, that's where support needs to start. SI therapy targets the foundational senses through guided movement in a specialist clinic. As those pathways strengthen and become more automatic, the brain has more capacity for everything built on top: higher-level sensory processing, praxis, academic learning, social communication, and interoception.

Jacqui put it simply: "Behaviour is at the end point of something. You have to get beneath the surface."

For what therapy involves practically, see what SI therapy looks like. For how to support sensory needs at home and school, see sensory diets for children. For how sensory overload connects to anxiety, see our dedicated guide.

Don't know where to start? Jacqui offers a one-off parent consultation for £55 to talk through your child's difficulties and get advice on what to do next. Book a parent consultation at Kids in Sync →

Jacqui is the founder of Kids in Sync, an award-winning children's therapy centre specialising in sensory integration, with clinics in Borehamwood and Twickenham. She is quoted throughout with her permission.