The Story of the Senses

Share

As children, we were taught that we only have “five senses” to guide us through life; I am sure every one of us can recite them: sight, hearing, smell, taste, and touch. As early as Kindergarten, we are taught that these are the only sensory systems that we have to perceive information and discover the world around us. We are later taught that anything beyond these five senses would be paranormal, totally outside the realm of the scientific.

Since most of us take the facts we learn at school for granted, the idea of the “five senses” may have remained with us well into adulthood. It turns out that what we were taught at school was inaccurate.

Ask any contemporary neurologist about the number of senses a human being possesses; the answer would be that they are more than five. The majority count between 14 and 21 actual senses, most of which we were not taught earlier at school.

So how many senses do we really have? Scientists are still unable to give a definite answer to this question, although they all assert that there are more than five. The reason for the general lack of consensus among scientists as to the exact number of senses a human being actually possesses is the difference in opinion on what constitutes a sense.

While they all agree on the classical five senses, some scientists believe that they should be split into subgroups. They assume that sight, for instance, may be divided into perceptions of brightness, color, and depth. Other researchers argue that true senses must not only respond to a specific physical phenomenon, but also correspond to a particular region in the brain. Using this classification, most neurologists recognize at least five additional senses, in addition to another six if interoceptive senses—those that react to stimuli originating inside of the body—are also considered.

  1. Equilibrioception: it corresponds to the sixth sense organ in the human body; the vestibular system. Although vision plays a role in equilibrioception, the vestibular labyrinthine system found in both of the inner ears is the main responsible organ for balance. Also known as the sense of balance, it allows an organism to sense body movement, direction, and acceleration, and to attain and maintain postural equilibrium.
  2. Nociception: contrary to popular belief, the sense of pain is not connected to the sense of touch. There are three distinct types of pain receptors: cutaneous (skin), somatic (bones and joints), and visceral (body organs). These special sensors react to certain types of stimuli. Once the stimuli reach a given point called “the pain threshold”, a signal of varying strength is sent to the brain via the spinal column, causing us to feel the sensation we recognize as pain.
  3. Proprioception (Sense of body awareness): is the sense that gives us the ability to tell where our body parts are relative to other body parts. Even with our eyes closed, we have a sense of body position; where our arms and legs are, for example, and whether we are moving them or not. Muscles, tendons, joints and the inner ear contain “proprioceptors”, which relay positional information to our brains. Our brains then analyze this information and provide us with a sense of body orientation and movement.
  4. Thermoception: it informs us to put on an extra layer when there is a chill, and to take it off when it gets warm. It is the sense of heat and the absence of it, which relies on temperature sensors, aka “thermoreceptors”, in the skin that detect the movement of thermal energy.
  5. Temporal Perception: refers to how the passage of time is perceived and experienced. Although it is not associated with a specific sensory system, neuroscientists research indicates that human brains do have a system governing the perception of time, composed of a highly distributed structure involving the cerebral cortex; the cerebellum and basal ganglia.

While the previous list is not conclusive, it serves to show that the “five senses” of Aristotle are only just a fraction of the senses that we, human beings, possess. They might be the most obvious senses we have, but they are not by any means more important than all our other senses. So, perhaps it is time to do away with the “five senses” paradigm, and give humans more credit for their fascinating abilities.

References

Eugene T. Gendlin PhD., “Line by Line Commentary on Aristotle’s De Anima, Book III”, University of Chicago

jhupressblog.com

articles.mercola.com

www.ncbi.nlm.nih.gov


Cover image source.

*Published in the PSC Newsletter, Come to Your Senses (Summer 2013) issue.

About Us

SCIplanet is a bilingual edutainment science magazine published by the Bibliotheca Alexandrina Planetarium Science Center and developed by the Cultural Outreach Publications Unit ...
Continue reading

Contact Us

P.O. Box 138, Chatby 21526, Alexandria, EGYPT
Tel.: +(203) 4839999
Ext.: 1737–1781
Email: COPU.editors@bibalex.org

Become a member

© 2021 | Bibliotheca Alexandrina