Neuroscientist Charles Spence and philosopher of mind Casey O’Callaghan are among a growing group of researchers who argue that the schoolbook list of five senses is badly out of date. Drawing on work in psychology, neuroscience and philosophy, they say humans rely on many more ways of sensing the world and the body, possibly numbering in the dozens. Their claims build on research published by O’Callaghan in 2014 and on later reporting that popularized a headline-grabbing estimate of 33 senses.
This newer view does not simply tack a few extra senses onto the old list. Instead, it suggests that the body runs on a network of specialized detectors for balance, pain, temperature, body position and internal organs. Some writers, including journalist Ashley Fike, have reported that scientists now talk about “as many as 33” distinct senses. That exact number, however, comes from coverage published after 2014, while the contemporary academic work speaks more cautiously about “potentially dozens” of separate sensory systems.
How science broke the five-sense myth
The familiar five-sense story dates back to Aristotle, not to modern biology. He focused on the obvious ways we connect with the outside world: light for seeing, sound waves for hearing, and chemicals for smelling and tasting, plus pressure on the skin for touch. For centuries, this simple list shaped teaching and popular science. Doctors and physiologists, though, have long known that people can also detect temperature, balance, pain and many other signals. The puzzle has been whether to treat these abilities as full senses or as subtypes of the classic five.
To sort this out, philosophers have asked what makes something a distinct sense. In a 2014 issue of The Monist, O’Callaghan analyzes criteria such as the kind of receptor involved, the type of stimulus and the way the brain processes the information. Using those tests, he argues that humans have far more than five senses, and that the total may reach into the dozens. On this view, systems like proprioception, which tracks body position, and nociception, which signals tissue damage and pain, each count as their own sense rather than as mere branches of touch.
Interoception and the hidden senses inside
Another challenge to the five-sense picture comes from looking inward at how we monitor our own bodies. A widely cited review in Nature Reviews Neuroscience describes interoception as the sense of the body’s internal state. Interoceptive signals include feelings of hunger, thirst and heartbeat, as well as subtler cues such as gut tension, breathing effort and the urge to use the bathroom. The authors argue that this internal monitoring system is a primary sense in its own right, not a side effect of other processes.
Placing interoception on the same level as vision or hearing has big consequences. It means that our inner body signals are part of perception, not just background noise. The review notes that interoceptive pathways use their own receptors and brain circuits, and that they can strongly shape mood and awareness. Once interoception is counted, the total number of senses already grows beyond five, because it bundles many separate channels for tracking different organs and processes inside the body.
Where the “33 senses” number comes from
In later years, some writers tried to put a specific number on this expanded list. One popular claim is that humans do not have five senses but “as many as 33.” Journalist Ashley Fike helped spread this idea in a feature for VICE, where she reported that humans may use to track everything from food to movement to emotion. That article draws on interviews with sensory scientists who study how we perceive the body and the outside world.
An institutional write-up later echoed this figure, stating that new work “reveals humans could have as many as 33 senses,” and linking the estimate to conversations with Spence. In that summary, which appeared in a ScienceDaily-style release, Spence is described as a long-term collaborator who directs a lab at Oxford that studies how senses such as sight and proprioception interact. This reporting is dated 2026, however, and as of 2014 the peer-reviewed work it cites supports a broader claim of “potentially dozens” of senses rather than a precise total of 33.
Philosophy’s role in counting senses
Behind any specific number sits a deeper question: how should we carve up sensory experience? The analysis in The Monist paper does not try to fix a final count, but it does explain why the total could be very high. If different receptors respond to different kinds of energy and send signals along distinct pathways, then each type can qualify as a separate sense. Under that rule, thermal sensing, balance, pain, itch and body position all become their own modalities, even though everyday language often folds them into “touch.”
This philosophical framing helps explain why estimates vary. Some scientists group related receptors together and end up with a shorter list. Others, including those quoted in later coverage that mentions 33 senses, split the systems more finely. The key point is that once you accept the criteria laid out by O’Callaghan and other theorists, the old five-sense model no longer matches what the body actually does. Perception instead looks like a web of specialized detectors, each tuned to a narrow slice of the outside world or the body’s interior.
How extra senses shape perception
Expanding the list of senses is not just a matter of labels. It changes how researchers think about perception as a whole. Reporting that cites the 33-sense claim notes that senses constantly influence one another and change how we see, hear and feel. An explainer in The News Digital describes how signals like hunger or heart rate can alter the way we interpret sights and sounds, tying this effect to research on interoception and cross-sensory integration.
Spence’s own specialty, crossmodal perception, offers clear examples of this mixing. In Fike’s VICE feature, Spence is described who directs a lab that explores how senses from food to movement to emotion interact. His team studies how sight and proprioception shape each other, and how subtle changes in sound or color can alter the taste of food or the feeling of body ownership. This kind of work turns the abstract idea of “extra senses” into something we can see in restaurants, virtual reality systems and everyday choices.
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*This article was researched with the help of AI, with human editors creating the final content.
