Sight, hearing, smell, touch and taste. These are five senses everyone knows about. But did you know that there are actually quite a few more senses that humans have and regularly use, but do not know about? The total number of senses that humans possess is not clear, with estimates varying from 9 to 21. Two additional senses that have been almost universally acknowledged by scientists are the sense of balance and the sense of proprioception (spatial understanding of the position of one’s body parts).
Balance is probably not acknowledged as a separate sense because the organ that controls it – the ear – is also responsible for another sense – hearing. It is difficult to accept that one organ controls two senses. This is not actually the case though, as there are separate parts within the ear that control the senses of hearing and balance. The two are not related in any way except their close proximity in the ear.
Proprioception is the mind’s understanding of the location and orientation of one’s body parts. Have you ever wondered how you manage to put on your clothes in the dark, or write without looking? This is how. Even if you do not realize it, your mind always knows where your arms or legs are, and how they are positioned. This sense is provided by proprioceptors present in muscles, tendons and joints. These proprioceptors send continuous messages to the brain informing it about the location of various body parts. When one is drunk, these receptors are disabled and the mind partly loses awareness of the body. This sense has not been acknowledged because it is a little difficult to visualize. There is no clear sensory organ associated with the sense. Some people say that it is not a true sense because it exists only in the mind. But if that were the case, none of the sense would be accepted because technically they are all only in the mind.
Besides these two, there are several other examples of senses that are beginning to gain recognition, including the sense of one’s internal conditions such as hunger and thirst. Scientists are hopeful of discovering and recognizing even more senses that have so far evaded our five original senses.