Most of us were taught five senses at school: sight, hearing, smell, taste, and touch. These are the external senses — they detect the world around us. But there are at least three more internal senses that are equally important, particularly for understanding sensory processing differences in children with ADHD and autism. Here is a complete guide to all eight.
Key Takeaways
- There are 8 senses, not 5 — the additional three are internal body senses
- Proprioception (sense 6): body position and movement — provides calming, regulating input
- Vestibular (sense 7): balance and spatial orientation — connected to alertness and coordination
- Interoception (sense 8): internal body states — hunger, heartbeat, emotional feeling
- The "hidden" senses are often most affected in sensory processing differences
- A chew necklace targets sense 6 (proprioception) via the jaw muscles
All Eight Senses
| # | Sense | What It Detects | Sensory Organ | Role in Regulation |
|---|---|---|---|---|
| 1 | Vision | Light, colour, movement, depth | Eyes | Spatial orientation; can be overwhelming in bright/busy environments |
| 2 | Hearing | Sound frequency, volume, direction | Ears | Communication; often hyperactive in autism — background noise can cause overload |
| 3 | Smell | Chemical molecules in air | Nose | Emotion and memory; strong smells can trigger anxiety or overload |
| 4 | Taste | Chemical compounds on tongue | Tongue | Food acceptance and rejection; taste differences common in autism |
| 5 | Touch (Tactile) | Pressure, temperature, pain, texture | Skin | Safety sense; seam sensitivity, label aversion common in sensory differences |
| 6 | Proprioception | Body position, muscle load, joint pressure | Muscles, tendons, joints | The most regulating sense — deep pressure, heavy work, chewing provide regulating input |
| 7 | Vestibular | Head position, acceleration, gravity | Inner ear (semicircular canals) | Balance and spatial orientation; rocking and spinning are vestibular stims |
| 8 | Interoception | Internal body states (hunger, heartbeat, temperature, emotion) | Internal organs, autonomic nervous system | Emotional awareness; difficulties here can make it hard to identify feelings or physical needs |
Why Does This Matter?
Understanding all eight senses helps explain behaviours that otherwise seem puzzling. A child who cannot sit still is often seeking vestibular or proprioceptive input. A child who chews everything is seeking proprioceptive input from the jaw. A child who covers their ears at ordinary sounds may be hypersensitive in the auditory channel. A child who seems not to notice pain may be hyposensitive in the tactile channel.
Knowing which sensory channel is involved helps identify the right support tool. For proprioceptive seeking, chew necklaces and heavy work activities help. For vestibular seeking, wobble cushions and movement breaks help. For tactile hypersensitivity, managing clothing seams and textures helps.
Sense 6: Proprioception — The Most Important for Chew Necklaces
Proprioception is detected by specialised receptors called mechanoreceptors in the muscles, tendons, and joints. These receptors respond to stretch, compression, and pressure. They send continuous signals to the brain about where every part of the body is and how much load it is carrying — without any conscious effort or visual input.
The jaw contains some of the most powerful proprioceptive receptors in the body. The muscles of mastication (chewing) generate enormous proprioceptive signals when engaged. Occupational therapists have long known that activities involving jaw use — chewing, blowing, sucking through a straw — are among the most effective calming and regulating strategies available. A chew necklace delivers this input on demand, in a controlled and socially acceptable way.
See: proprioception explained in depth
Sense 7: Vestibular — Why Some Children Need to Move
The vestibular system is housed in the inner ear and detects head position and movement. It tells the brain whether the body is upright, tilted, accelerating, or spinning. It is closely connected to the cerebellum (which coordinates movement) and to systems that regulate arousal and attention.
Children who seek vestibular input rock, spin, bounce, climb, and find sitting still particularly difficult. Vestibular input can be calming for some and alerting for others. Tools like wobble cushions allow a child to receive gentle vestibular input while seated. See: the vestibular system explained
Sense 8: Interoception — The Emotional Sense
Interoception is perhaps the least understood of the eight senses. It is the sense of internal body states: hunger, thirst, heartbeat, bladder fullness, temperature, and — critically — the physical sensations associated with emotions. When you feel anxiety as a tight chest, or happiness as a warmth in your body, that is interoception at work.
Difficulties with interoception are common in autism and can make it hard for a person to identify their own emotions ("I know I feel something, but I don't know what"), recognise hunger or thirst, or understand why they feel overwhelmed. Supporting interoceptive awareness is an increasingly important part of sensory-based occupational therapy.