Why do children have 7 sensory systems and not just 5?

Most people are taught about the five traditional senses — sight, hearing, touch, taste, and smell — in school. However, occupational therapists and neuroscientists recognise at least seven sensory systems. The vestibular system (responsible for balance and movement) and the proprioceptive system (responsible for body awareness and pressure) are just as important for daily functioning as the classic five. Some frameworks also include an eighth sense called interoception, which is awareness of internal body states like hunger, thirst, and heartbeat. Understanding all seven systems helps parents and educators better support children with sensory processing differences.

How do I know which sensory systems my child is struggling with?

A paediatric occupational therapist can conduct a formal sensory assessment using tools such as the Sensory Profile 2 or the Sensory Processing Measure, which evaluate each sensory system individually. At home, you can observe patterns: does your child struggle with light touch but seek heavy pressure (proprioceptive seeking, tactile sensitivity)? Do they get car sick easily (vestibular sensitivity)? Are they extremely picky eaters (gustatory sensitivity)? Keeping a diary of your child's sensory reactions over one to two weeks can be very helpful to share with an OT.

What is the proprioceptive system and why does my child keep crashing into things?

The proprioceptive system uses receptors in muscles, joints, and tendons to tell the brain where the body is in space and how much force is being applied. Children with poor proprioceptive processing often appear clumsy, use too much or too little force (breaking pencils, hugging too hard), and seek heavy input through crashing, jumping, and rough play. This behaviour is the nervous system's attempt to get the proprioceptive feedback it needs. Heavy work activities — carrying books, pushing a trolley, climbing — are OT-recommended strategies for providing this input in a controlled way.

What tools help with vestibular (balance and movement) sensory issues?

The vestibular system is stimulated by movement, particularly linear movement (swinging back and forth), rotary movement (spinning), and changes in head position. For children who are vestibular-seeking, swings, rocking chairs, wobble cushions, balance boards, and trampolines are excellent tools that provide the movement input they crave in a safe way. For children who are vestibular-sensitive (get dizzy or distressed by movement), avoiding rapid or unexpected movement, using stable seating, and providing slow rhythmic movement rather than fast unpredictable input can help regulate their system.

What is interoception and how does it relate to emotional regulation?

Interoception is sometimes called the eighth sense and refers to awareness of internal body states — hunger, thirst, heart rate, temperature, bladder fullness, pain, and emotional feelings. Many children with sensory processing differences have poor interoceptive awareness, meaning they cannot accurately identify what their body is feeling internally. This is strongly linked to difficulty identifying and regulating emotions — if a child cannot feel that their heart is racing or their muscles are tense, they struggle to identify that they are anxious or angry before it becomes a full meltdown. OT and mindfulness-based interventions can support interoceptive development.

The 7 Sensory Systems Explained — Complete Parent Guide

Why 7 Sensory Systems?

Most of us grew up learning about five senses: sight, hearing, touch, taste, and smell. While these are real and important, occupational therapists and sensory processing researchers recognise that human beings actually have at least seven sensory systems — and some frameworks include an eighth, called interoception. Understanding all seven systems is essential for parents and educators trying to support children with sensory processing differences, because it explains why a child may be perfectly comfortable with loud music but unable to tolerate the feel of sock seams, or why they need to swing constantly but become distressed in a busy shopping centre.

Each sensory system has receptors that detect specific types of input and send signals to the brain for processing. When this processing works smoothly, we move through the world comfortably. When any system is over-responsive, under-responsive, or seeking, the effects can be significant — affecting behaviour, learning, emotional regulation, and relationships.

1. Tactile System (Touch)

The tactile system processes information received through the skin — temperature, pressure, pain, texture, and light touch. It serves two functions: the discriminative function helps us identify what we are touching without looking, while the protective function alerts us to potential harm (hot surfaces, sharp objects).

Signs of over-sensitivity: Avoids messy play (sand, glue, finger paints), distressed by light touch or unexpected contact, refuses certain clothing textures or sock seams, dislikes having hair washed or cut.

Signs of under-sensitivity: May not notice when their hands are dirty, high pain threshold, unaware of temperature extremes, touches objects or people frequently.

Tools that help: Seamless socks and clothing, tagless labels, deep pressure massage, sensory bins with varied textures for gradual desensitisation, fidget toys with different textures.

2. Visual System (Sight)

The visual system processes light, colour, movement, depth, and spatial relationships. For children with visual sensitivity, busy visual environments — cluttered classrooms, bright fluorescent lights, screens — can be extremely overwhelming.

Signs of over-sensitivity: Squinting or covering eyes in normal lighting, distracted by movement in peripheral vision, difficulty in busy or visually cluttered environments, prefers dim light.

Signs of under-sensitivity: Difficulty tracking objects, poor spatial awareness, moves very close to screens or books, misses visual information.

Tools that help: Sunglasses or tinted lenses for outdoor use, decluttered study spaces, reading overlays, task lighting rather than overhead fluorescent lights.

3. Auditory System (Hearing)

The auditory system processes sound — volume, pitch, tone, rhythm, and the ability to distinguish speech from background noise. Many children with sensory processing differences are highly sensitive to auditory input, and ordinary environments like school hallways, shopping centres, and sporting events can be genuinely painful.

Signs of over-sensitivity: Covering ears, distress at unexpected or loud sounds, difficulty concentrating with background noise, avoids crowded public places.

Signs of under-sensitivity: Frequently asks for things to be repeated, makes loud vocalisations, unaware of environmental sounds, may appear to have hearing difficulties.

Tools that help: Noise-cancelling headphones (such as the Loop or Puro Sound options available in Australia), quiet study spaces, ear defenders for crowded events, white noise machines for sleep.

4. Olfactory System (Smell)

The olfactory system is uniquely connected to the limbic system — the brain's emotional centre — which explains why smells can trigger strong emotional responses and memories. Children with olfactory sensitivity may find perfumes, cleaning products, or certain foods genuinely overwhelming, while those with low olfactory sensitivity may have trouble detecting odours others find obvious.

Signs of over-sensitivity: Gagging or retching at ordinary smells, refusing to eat foods based on smell rather than taste, distress in environments with strong cleaning products or perfumes.

Signs of under-sensitivity: May not notice unpleasant odours, seeks strong smells, difficulty discriminating between smells.

Tools that help: Fragrance-free cleaning and personal care products, using a small amount of a calming scent (e.g., lavender) as a regulation strategy, serving food with reduced smell when necessary.

5. Gustatory System (Taste)

The gustatory system processes taste — sweet, sour, bitter, salty, and umami — as well as the texture and temperature of food in the mouth (oral tactile input). Children with gustatory sensitivity are often described as "extreme picky eaters," but this is not a behavioural choice — it reflects genuine neurological differences in how the mouth and tongue process sensory input.

Signs of over-sensitivity: Extremely limited food repertoire based on texture, temperature, or taste, gagging on foods with mixed textures, refuses new foods with strong resistance.

Signs of under-sensitivity: Mouths or chews non-food items (pencils, clothing), prefers very spicy, sour, or strong-flavoured foods, seeks oral sensory input.

Tools that help: Chewable jewellery and chewy necklaces (OT-recommended for oral seekers), food chaining approaches (introducing gradual variations of preferred foods), specialist feeding OT intervention.

6. Vestibular System (Movement and Balance)

The vestibular system is located in the inner ear and detects movement, gravity, and changes in head position. It is fundamental to balance, coordination, posture, and the ability to keep the eyes focused on a moving target. The vestibular system also has a powerful regulatory effect on the nervous system — the right kind of movement can calm or alert the brain.

Signs of over-sensitivity: Easily dizzy or motion sick, avoids playground equipment (swings, slides), distressed by having head tilted back (e.g., hair washing), anxious about feet leaving the ground.

Signs of under-sensitivity / seeking: Constantly moving, spinning, rocking, or swinging; difficulty sitting still; craving fast or intense movement; does not get dizzy from spinning.

Tools that help: Wobble cushions, balance boards, indoor swings or rocking chairs, trampolines, movement breaks built into the daily schedule. See our sensory tools guide for Australian-available options.

7. Proprioceptive System (Body Awareness and Pressure)

The proprioceptive system receives input from receptors in muscles, joints, and tendons to tell the brain where the body is in space, how much force is being used, and the position of body parts without looking. It is profoundly linked to emotional regulation — proprioceptive input (heavy work, deep pressure) is one of the most powerful ways to calm the nervous system.

Signs of over-sensitivity: Uncommon — proprioceptive over-sensitivity typically presents as a dislike of intense physical contact or resistance activities.

Signs of under-sensitivity / seeking: Crashes into furniture, hugs too hard, breaks items by using excessive force, chews on objects, loves rough-and-tumble play, appears to need constant physical contact.

Tools that help: Weighted blankets and lap pads, compression clothing, heavy work activities (carrying books, pushing a trolley, digging in sand), resistance bands, fidget toys that require squeezing. Visit our fidget toys guide for options suited to proprioceptive seekers.

Understanding Your Child's Unique Sensory Profile

It is rare for a child to be uniformly over-responsive or under-responsive across all seven systems. Most children with sensory processing differences have a unique sensory profile — perhaps hypersensitive in the auditory and tactile systems while simultaneously seeking proprioceptive input. This is why a thorough OT assessment is so valuable: it maps the specific pattern across all systems and allows for targeted, personalised strategies rather than a one-size-fits-all approach.

Understanding all seven sensory systems also helps parents and educators respond with empathy rather than frustration. When a child melts down at a birthday party, a crowded canteen, or a shopping centre, it is rarely about behaviour — it is a nervous system overwhelmed by sensory input it cannot process effectively. Knowing which systems are involved is the first step toward meaningful support.