Senses are abilities of an organism that are needed for perception and interpretation. Each sense has a sensory organ or system particularly placed in various areas of the human nervous system Senses, their properties and characteristics are extensively studied in many fields of science, particularly in cognitive psychology and neuroscience.
A widely accepted definition of sense [3] is: "a system that consists of a group of sensory cell types that responds to a specific physical phenomenon, and that corresponds to a particular group of regions within the brain where the signals are received and interpreted." (TodayIFoundOut.com, 2010).
From this definition, we can say that there are three important aspects of sense – physical phenomenon or stimulus, sensory organ or system and sensory areas in the brain.
There are many types of senses in humans. Aristotle is highly regarded for his classification of the five traditional senses. The five traditional senses include vision or sight, hearing, taste, smell and touch. Vision or sight is the ability of the eye to capture images of visible light via the photoreceptors of the retina in the eyes.
The sense of sound perception is called hearing or audition, in which the ears convert sound waves into vibrations and then into nerve impulses for brain processing. Taste or gestation is the ability to detect the taste of various substances via the tongue. The sense of taste should not be mistaken for "flavour sense", as the latter is a mixture of taste and smell perception.
The five basic tastes include sweet, sour, salty, bitter and umami. On the other hand, olfaction or smell is the ability to detect odor molecules through olfactory receptors.
Finally, the sense of touch or tactition/ mechanoperception, includes the sensory receptors in the skin and other parts of the body to determine tactile stimulation.
Other senses that are important for human survival and development include temperature, kinaesthetic sense, acceleration, balance and pain. Balance and acceleration are managed by the vestibular system. Internal senses include any sense within the body that is normally stimulated.
These are comprised of pulmonary stretch receptors in the lungs, peripheral chemoreceptors in the brain, and others. Yet a number of senses overlap with one another such that they cannot be safely classified as different senses unless thorough physiological examinations are conducted.
As sensory neuroscience developed through the years, humans have been attributed to additional senses such as sense of time, pain, balance, motion, acceleration and more. Current research studies try to examine the possibility of sense of direction or magnetoception in humans.