Sensation And Sensitivity

Each stimulus present outside of our body emits a certain amount of physical energy that is ultimately responsible for producing some effect in one or the other sensory organs of our body. For example, is working as a stimulus for producing some effects on our sense organs. It has a particular size and shape, colour and texture and its letters reflect a particular pattern. This effect produced on our sense organs for enabling us to become aware or conscious of the nature of a particular stimulus is known as sensation and the quality or tendency of a sense organ to help us in feeling some or the other type of sensation is known as sensitivity.

We as human beings neither respond indiscriminately nor are we capable of becoming aware or conscious of each and every stimulus available in our environment. We do not have the same power of smelling as our dog has. We can't see in the dark but our cat is capable of doing so. Similarly the light or sound waves that are beyond our sensation can be successfully caught by our television set. Not only in terms of detection but also in terms of discrimination we have our limitations. The degree to which we are capable of detecting a stimulus or discriminating between two or more stimuli for finding out the difference, we are said to be sensitive or are attributed to possess sensitivity to that stimulus or that difference.

Senses

Human senses are in fact the windows to the world - internal as well as external.These are the gateways of all information that our brain receives by interacting with the stimuli present inside and outside of our body. Our great ancient thinkers held that there were five human senses - Vision , Hearing , Taste , and Touch corresponding to the sense organs , Eyes , Ears , Nose , Tongue , and Skin of our body. During the subsequent ages there has been an addition of some more senses to this list.


These senses may be grouped into five categories as under:

Visual Senses - Sense of vision.
Auditory Senses - Sense of hearing.
Chemical Senses - Sense of small ans sense of taste.
Skin Senses - Sense of pressure , sense of temperature and pain.
Body Senses - Kinesthetic sense and Vestibular sense.

Understanding Instincts

From time immemorial , the term instinct has been used for an innate disposition or characteristic that makes an organism to respond or to act in such a way that helps him in his adjustment or adaptation including the survival of his species. Consequently instinctive behaviour has been understood as an unlearned species.

During the nineteenth century when Charles Darwin presented his theory that humans are linked to other species , it was also concluded that like their relatives , the behaviour of human beings is motivated by instincts. Inspired by the views of Charles Darwin in 1890 , William James , a Harvard psychologist tried to provide a long list of the human instincts and defined the term instincts in the following way:

"Instinct is usually defined as the faculty of acting in such a way as to produce certain ends , without foresight of the ends , and without previous education in the performance . "

(James , 1969)