The Science Behind the Senses
by Timothy D. Davis, Ph.D.
Most kids love to move. As they move, they constantly receive sensory information from their environment. In fact, we all do. But what we do with that information in our brain can be affected by a whole host of factors.
For most of us, processing the excessive amount of sensory information we receive from the environment happens unconsciously. Managing loud noises, bright lights, crowded hallways, or textures we don’t like is just part of our day. We have learned to manage or discriminate the information we need to know from the information that is not necessary. However, for kids with sensory processing issues, the ability to process and actually discriminate sensory input often is overwhelming.
Some children have trouble organizing information the brain receives from the senses. When we talk about senses, we usually mean the five traditional ones: sight, smell, hearing, taste, and touch. But there are actually three additional senses that are often overlooked, but are critical to development!
The sixth sense, proprioception, control bodily awareness. This helps a child know where they are at in relationship to other things. The seventh sense is vestibular. The vestibular sense helps us with balance and spatial awareness and is essential to any form of movement we choose to do. Finally, the eighth sense is interoception. Interoception sends information to the brain through soft tissue and organs, essentially letting us know when we have to go to the bathroom, or if we have a stomach ache or even if we are hungry.
Having sensory processing issues can affect kids’ motor skills in several ways. For example, if a child is uncomfortable touching things, they may be reluctant to play with and manipulate objects. If they are reluctant to go on a swing or don’t like to lean backward or hang upside down, this could limit their vestibular system and ultimately affect their balance. Finally, difficulty with processing proprioceptive information (the information that comes from our muscles and joints) can lead to difficulties with self-regulating behavior in new situations or environments. We often describe these responses as being over or under-responsive to particular sensory stimuli.
Over responsivity and under responsivity is a condition that describes how a child responds to a particular sense they experience in their environment. Some children will be over-responsive to bright lights, loud noises, or certain smells/tastes, but maybe under-responsive to things such as their vestibular (likes swings) or proprioceptive systems (enjoys big hugs/pressure).
For example, when children experience noises that are too loud or light that is too bright, it is not uncommon for them to cry or try to avoid the sensation by covering their ears or shielding their face or eyes. A similar response can occur when a child is over-responsive to their vestibular system. Children who are over-responsive to the vestibular sense are often fearful when moving quickly, jumping down from a height, or will avoid activities such as swings or other playground activities. They often prefer sedentary activities and may act shy or anxious when asked to play a group game.
Under responsivity is often observed in children who have difficulty controlling their own body and are often impulsive. Under-responsive children seek out specific sensory inputs such as activities like swings and spinning (vestibular) and textures (tactile), often wanting to touch something even when told not to. Under-responsiveness with proprioception is commonly observed in children who often push into things with their bodies, run their hand along the wall when walking, or who like to crawl into small spaces.
In either case, children who are over-responsive may avoid specific situations and become emotionally insecure in their ability to try new things. Children who are under-responsive may seek out specific proprioceptive stimuli through rough play, making loud noises, touching and/or pushing others and/or acting inappropriately for the task or the environment.
Delays in both proprioception and vestibular senses can impede motor skill development, affecting more advanced perceptual motor skills (hand-eye coordination), create unwanted anxiety, and limit social-emotional engagement.