For centuries, human perception has been explained through Aristotle’s concept of the five senses: sight, sound, smell, taste, and touch. However, recent research shows that this traditional model does not fully capture the complexity of human sensory experience.
A recent article in The Conversation by Barry Smith, Director of the Institute of Philosophy at the University of London, suggests that humans may possess between 22 and 33 distinct senses, each contributing to perception through overlapping and interacting systems.
Beyond Aristotle’s Model
Neuroscientists and philosophers are re-examining Aristotle’s model by investigating how the brain processes sensory information. Instead of treating sight, sound, and smell as isolated experiences, research reveals that the brain integrates these signals into a unified perceptual whole.
Professor Charles Spence of the Crossmodal Laboratory at Oxford estimates that humans possess between 22 and 33 senses. These include the traditional five, as well as additional systems that constantly inform human awareness.
For example, a sense known as proprioception allows people to sense where their arms and legs are without looking. The vestibular system in the inner ear helps us maintain balance and perceive our position in space, while interoception is the sense that lets us notice things like hunger or changes in our heartbeat.
Scientists describe a “sense of agency” as the feeling that you are initiating your own movements, and a “sense of ownership” as the ability to recognize your limbs as your own. After certain neurological events, such as a stroke, these senses can be affected, making people feel as if someone else is moving their body. These sensory systems indicate that human perception is far more complex than the traditional five-sense model suggests.
Taste as a Team Effort
The perception of flavor provides a clear example of how multiple senses interact. When we say a food tastes like raspberry or mango, it’s not because we have special taste buds for those flavors. The tongue can only detect five basic tastes: sweet, sour, salty, bitter, and umami. The rest of what we call flavor comes from a mix of taste, smell, and touch.
When we chew, odor molecules move from our mouth to our nose through a passage called the nasopharynx. Smell then provides the majority of how we perceive flavor.
Texture also impacts our perception of flavor. The thickness of food or how its mouthfeel can alter how we interpret smells and tastes. Studies have found that adding certain smells to low-fat yogurt can make it feel richer and creamier, even if the ingredients don’t change. In the same way, the smell of shampoo can make you perceive hair as feeling silkier when you touch it.
When Balance Changes Vision
Vision is also influenced by other sensory systems. The vestibular system, for instance, can alter visual perception.
During airplane takeoff, passengers may perceive the cabin as tilted upward, even though the actual orientation of objects remains unchanged. This effect occurs because the inner ear detects a backward tilt, and the brain incorporates this information into the visual experience.
Experiments Reveal the Senses
Researchers at the Centre for the Study of the Senses at the University of London’s School of Advanced Study have explored how these combinations of senses overlap.
In one experiment, changing the sound of someone’s footsteps made participants feel lighter or heavier. In another experiment, audioguides at Tate Britain spoke as if a person in a portrait was talking, which helped visitors remember more details about what they saw.
Aircraft noise offers another notable example. Exposure to white noise diminishes the perception of sweet, salty, and sour tastes, while umami perception remains largely unaffected. As tomatoes are high in umami, tomato juice may taste more appealing during flight, likely explaining its popularity as an in-flight beverage.
A Network of Perception
Researchers continue to study how these senses interact through collaborative efforts across the fields of neuroscience, psychology, and philosophy. Interactive exhibits like Senses Unwrapped in London allow visitors to experience these sensory illusions firsthand.
One demonstration of the size-weight illusion involved participants lifting curling stones of different sizes, all with the same weight. Most people reported that the smallest stones felt heaviest, until a scale confirmed the actual weights.
Modern research indicates that Aristotle’s five-sense model is more historically significant than biologically accurate. Human perception operates as a densely interconnected network, continuously blending signals from the body and the environment into a unified experience.
Austin Burgess is a writer and researcher with a background in sales, marketing, and data analytics. He holds a Master of Business Administration, a Bachelor of Science in Business Administration, and a Data Analytics certification. His work combines analytical training with a focus on emerging science, aerospace, and astronomical research.