Sensory Systems
All information our brain takes in is sensory in nature. If brains attended to 100% of the information coming it, we would be constantly overwhelmed. Because of this, humans come with filtering systems to decrease the amount of information coming in. The filtering system of neurodivergent brains can be different from those of neurotypical/allistic brains in two ways:
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The filter lets in comparatively more sensory information
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The filter lets in comparatively less sensory information
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Visually, we can view this filter as a mesh screen. The screen in the allistic filter lets in a pre-determined amount of sensory info (A). The neurodivergent screen can be: (A) the same as the allistic filter; (B) finer, in that it has smaller holes and lets in less info; or (C) coarser, in that it has larger holes and lets in more info
For example, the allistic filter lets in a predetermined amount of sensory info from the environment, as demonstrated in the figure ->
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Depending on the person, some neurodivergent (ND) individuals may have a filter that lets in less information than allistic folks, as seen in the middle picture ->
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In contrast, other ND individuals may let in more sensory information than allistic folks, as seen in the bottom picture ->
ND filters can be thought of as Hypo versus Hyper depending on how much sensory info they let in to be processed
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The filter lets in less sensory information = hyposensitive
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The filter that lets in more sensory information = hypersensitive
What do these filtering systems look like? Let’s use the auditory (sounds) system to illustrate:
Hyposensitive filters look like
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Less aware of sensory info(e.g., may not hear noise)
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Needs more sensory info (e.g., need louder or repetitive noises)
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Does not or is slower to respond to info (e.g., may need more prompts)
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May seek out sensory info (e.g., make noises)
Hypersensitive filters look like
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A small amount of info is activating (e.g., may hear noises others cannot)
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May go into fight or flight mode (e.g., overwhelmed or ‘meltdown’)
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Ongoing info may be uncomfortable (e.g., repetitive noise is grating)
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May avoid out sensory info (e.g., stay away from areas with certain noises)
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YET, there is more complexity at work here.
Each sensory system may have its own filter. So, one could be either hyper- or hypo-sensitive across each domain. When we think of sensory systems, the 5 senses come to mind: sight, sound, touch, taste, and smell. Yet, the number of sensory systems we have is higher, with some arguing that we have 8, 21, or even 53 different senses. That’s complex!
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The 5 we are taught in elementary school was first described by Aristotle (in De Anima) but most neurologists suggest there are 8 senses. The additional 3 senses include interoception (sense of internal systems, e.g., hunger), vestibular (sense of balance), and proprioception (sense of body awareness). The senses can be even further categorized if you like all the differences and details (for example, within interoception, we could break that down into senses of hunger, thirst, temperature, pain) (Francis, 2020).
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When considering how the 8 senses play a role in making our way through the world, we can see how being hyper-sensitive to even one sense can cause distress in one’s life. Imagine if you were hypersensitive to two or more senses, and how they additive effects may lead to overwhelming feelings, meltdowns, or burnouts.
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​​​​​​​Want to explore how each of these sensory systems may be showing up in your life? Check out this resource:​​​​​​​
