Interoception, Exteroception, Proprioception and Nociception: Understanding Your Body's Four Sensory Systems
What Is Interoception?
Interoception refers to the process by which the brain senses, interprets, integrates, and regulates signals arising from within the body (Chen et al., 2021). These signals include heartbeat, breathing rate, hunger, thirst, bladder fullness, temperature, pain, and the subtle physiological shifts that underlie emotional experience.
What is Exteroception?
Exteroception is the processing of sensory information from the outside world, and it encompasses the five senses, namely, vision, hearing, smell, taste, and touch, along with skin-surface temperature sensing (thermoception). Nociception, the detection of potentially harmful stimuli, is closely tied to exteroception. However, due to its unique neural pathways and clinical significance, it will be addressed separately in the section below.
Where Exteroception and Interoception Overlap
While exteroception and interoception are conceptually separate, their boundary can overlap. For instance, sensory systems like temperature sensing (thermoception) serve both internal and external functions. An article by Toussaint et al. (2024) offers a clear framework to distinguish them based on purpose, noting that signals regulating internal states (like body temperature) are interoceptive, whereas signals orienting a person to their surrounding environment are exteroceptive.
This framework has direct clinical value. For instance, a person who is sensitive to external inputs like sounds, textures, or lighting may have exteroceptive processing differences that are separate from, though often co-occurring with, interoceptive differences. Knowing which system is active lets us give our bodies the right kind of support.
How Our Brain Shapes External Sensing
Our sense of the outside world isn't just a passive feed, because our brains actively use past memories and context to interpret what we see, hear, and feel. For those of us with sensory processing differences, common across autistic and ADHD experiences, our brains often weigh past expectations against incoming sensory data differently than neurotypical brains do.
What Is Proprioception?
Proprioception is the sensory system through which our nervous system gathers information about the position, movement, and force of our own limbs, muscles, and joints. Sometimes called the "sixth sense," it allows us to know where our hand is without looking at it, to walk without watching our feet, and to catch a falling object before consciously processing the event. A review by Proske and Gandevia (2012) describes proprioception as our sense of body position and movement, along with our awareness of effort, force, and heaviness.
Proprioception Across the Lifespan
Our proprioceptive acuity is not static, with research demonstrating that proprioceptive sensitivity declines as we age and can be disrupted by musculoskeletal injury, neurological conditions, or prolonged inactivity. Valdes et al. (2023) identify active movement training as the most evidence-supported approach for improving our proprioceptive function following injury, with intervention periods of six to eight weeks showing measurable gains, which has direct relevance for occupational therapy, physiotherapy, and somatic movement practices.
What Is Nociception?
Nociception is the sensory system our nervous systems use to pick up on anything that could potentially damage our tissues. The word comes from the Latin nocere, which simply means to harm. Specialised nerve endings called nociceptors are spread throughout our skin, muscles, joints, and internal organs. They respond when mechanical pressure, temperature changes, or chemical signals cross a threshold into potentially dangerous territory. When triggered, these sensors send two types of signals up our spinal cords to our brains. One pathway delivers immediate, sharp warnings, while a slower pathway carries the lingering, dull ache that follows.
People often mix up nociception with pain, but they aren't the same thing. Nociception is the automatic sensory detection process, which often happens beneath our conscious awareness. Pain, on the other hand, is the conscious experience our brains create when they interpret that nociceptive input in context.
Just like with our other senses, our brains shape pain using past memories, attention, emotion, context, and expectation. This difference matters a lot for how we understand our bodies. We can have active nociceptive signals without feeling pain, such as when an athlete stays focused during a match and notices a injury only afterward. Conversely, we can experience very real pain without active nociceptive signals, as seen in phantom limb experiences or central sensitisation.
Nociception and the other sensory systems
Nociception intersects with interoception, exteroception, and proprioception in ways that directly impact our health and support needs. For instance, visceral nociception consists of pain signals arising from our internal organs that are processed alongside interoceptive signals in our insular cortex and brainstem, helping explain why conditions such as irritable bowel syndrome and functional pain disorders often overlap with interoceptive differences and emotional dysregulation.
For those of us who are neurodivergent, processing differences are well-documented. Autistic people may experience either heightened pain sensitivity or reduced pain responsiveness that can shift depending on context or capacity, while also navigating challenges with pinpointing where pain is coming from or untangling harm signals from other internal bodily sensations. For ADHDers, how our attention interacts with pain signals often follows different patterns, as our brain's capacity to dial down or turn up pain signals based on focus works differently than in neurotypical brains, reflecting neurological variation in how our brains detect, weigh, and make sense of warning signals.
Interoception, Exteroception, and Proprioception in Neurodivergent People
A growing body of research has examined how interoceptive, exteroceptive, and proprioceptive processing differ neurodivergent people.
Autistic People and Interoception
A systematic review by Williams et al. (2023) found that autistic participants showed significantly reduced interoceptive accuracy on heartbeat counting tasks, while research by Garfinkel et al. (2015) demonstrated that autistic people also showed higher confidence in our heartbeat counting performance despite lower accuracy, mirroring the pattern between interoceptive accuracy and interoceptive awareness.
What this means for us is that reduced interoceptive accuracy can make it harder to identify and name our emotional states (alexithymia), recognize our body's hunger and fullness cues, or navigate unexpected internal bodily shifts.
Conclusion
Interoception, exteroception, proprioception, and nociception are four fundamental channels through which our nervous system constructs our sense of self in relation to the world. For neurodivergent individuals, autistic people, ADHDers, and others with sensory processing differences in how our interoception, exteroception, proprioception, and nociception function are significant, pervasive, and often unrecognized by surrounding systems. The evidence consistently points to the importance of interoceptive awareness in emotional regulation, mental health, and daily functioning, alongside our interconnected proprioceptive, exteroceptive, and nociceptive processing.
References
Chen, W. G., Schloesser, D., Arensdorf, A. M., Simmons, J. M., Cui, C., Valentino, R., Gnadt, J. W., Nielsen, L., Hillaire-Clarke, C. S., Spruance, V., Horowitz, T. S., Vallejo, Y. F., & Langevin, H. M. (2021). The emerging science of interoception: Sensing, integrating, interpreting, and regulating signals within the self. Trends in Neurosciences, 44(1), 3–16. https://doi.org/10.1016/j.tins.2020.10.007
Garfinkel, S. N., Tiley, C., O'Keeffe, S., Harrison, N. A., Seth, A. K., & Critchley, H. D. (2016). Discrepancies between dimensions of interoception in autism: Implications for emotion and anxiety. Biological Psychology, 114, 117–126. https://doi.org/10.1016/j.biopsycho.2015.12.003
Proske, U., & Gandevia, S. C. (2012). The proprioceptive senses: their roles in signaling body shape, body position and movement, and muscle force. Physiological Reviews, 92(4), 1651–1697. https://doi.org/10.1152/physrev.00048.2011
Toussaint, B., Heinzle, J., & Stephan, K. E. (2024). A computationally informed distinction of interoception and exteroception. Neuroscience and Biobehavioral Reviews, 159, Article e105608. https://doi.org/10.1016/j.neubiorev.2024.105608
Valdes, K., Manalang, K. C., & Leach, C. (2023). Proprioception: An evidence-based review. Journal of Hand Therapy, 37(2), 269-272. https://doi.org/10.1016/j.jht.2023.09.015
Williams, Z. J., Suzman, E., Bordman, S. L., Markfeld, J. E., Kaiser, S. M., Dunham, K. A., Zoltowski, A. R., Failla, M. D., Cascio, C. J., & Woynaroski, T. G. (2023). Characterizing interoceptive differences in autism: A systematic review and meta-analysis of case-control studies. Journal of Autism and Developmental Disorders, 53(3), 947–962. https://doi.org/10.1007/s10803-022-05656-2
