Sensation

Everything we experience comes to us by means of our sense organs. These may be thought of as receiving stations for stimuli which come from outside and from within our body. Human beings and other higher animals are distinguished by the fact that the sense organs highly specialized for receiving specific kinds of stimuli. We have eyes for seeing, ears for hearing and the tongue for taste. To psychologists , “Sensation is the process by which an organism’s sense organs respond to a stimulus”.

If sensation is to occur, a stimulus must activate receptor cell, from which nerve impulses travel through the nervous system to the sensory areas of the brain. Only stimuli that are above the threshold can activate the receptors. In other words, energy strong enough to produce a response is said to be above the absolute threshold. Sensory sensitivity is also measured by different limen– the smallest difference in stimulus intensity that a particular sense can detect.

It has been traditional to speak of man’s five sense– seeing, hearing, smelling, touching and tasting. Psychological experimentation, however, has expanded our knowledge about sensory functions. We can now identify possibly eleven sensory mechanisms. A knowledge of the way in which these senses function provides an understanding of some very common, although interesting, variations of everyday human reactions.

Vision is a very important sense in humans. The stimulus for vision is light and the sense organs are the eyes. Hearing, or audition, depends on sound and the sense organs are the ears. Smell and taste are called the chemical senses because the sensory stimulation of the receptors involves contact with chemical substances.

The somatic, or body senses include the skin sense of pressure, pain, warmth and cold, and the proprioceptive sense: Kinesthesis and vestibular. The skin senses are sensitive to stimuli on the body surface.