Aristotle is credited with first classifying the five senses that we know best: touch, smell, taste, hearing, and vision. But as science has delved deeper into biology and the human brain, researchers have discovered several other forms of sensory perception that you probably didn’t even know you had..
We all have a basic understanding of the “Big 5,” as they are often called, because we are cognizant of the fact they help us navigate our daily lives. But we also tend to take our senses for granted until they stop working. “As people age and as our lifespans get longer, all of our senses get worse,” Paul Fuchs, PhD, co-director of the Center for Sensory Biology at Johns Hopkins University, told Yahoo Health. “We have to get glasses or hearing aids, and even our sense of touch gets worse.”
But there are many sensory preceptors throughout our bodies that perform many vital roles beyond the Big 5 – from controlling balance to telling us that our stomachs are empty. Here are five more senses to know about.
Equilibrioception. The fact that you can stand and walk without falling is attributed to your sense of balance, aka equilibrioception, and is regulated by fluid in the inner ear. It works with your sense of vision to help you move around safely. Spin around repeatedly, and you throw this system off, causing dizziness and, yes, loss of balance.
Proprioception. This one is the ability to know where your body parts are without looking. So if you close your eyes and raise your hand, you know where your hand is even without looking. This sounds pointless, but without proprioception, you would have to constantly look down at your feel to be able to walk. Police test proprioception when someone is suspected of drunk driving.
Thermoception. If you sit by a campfire, you feel the heat. Grab ice out of the freezer and you feel how cold it is. Thermoceptors in your skin are what sense those changes in temperature. The ability to detect heat and cold was once rolled up under the sense of touch. However, you don’t have to physically touch something to feel the heat (coming from that campfire, for example), so thermoception is in a category of its own. Separate thermoceptors in your brain help detect and regulate changes in core body temperature.
Nociception. This is your ability to sense pain. “Nociception and thermoception are usually lumped together because, to some extent, they use the same nerve cells in the skin,” said Fuchs. You have nociceptors in your skin, bones and joints, and internal organs.
Interoception: This is an umbrella term for senses that govern our internal organs. “Your body is full of internal receptors that trigger subconscious or reflexive reactions important for your health and well-being,” according to Fuchs. These receptors perform a wide range of involuntary tasks, such as triggering a cough, controlling respiratory rate, and telling you when you’re hungry or thirsty.