SENSATION AND PERCEPTION

                      
 

Sensation and perception are fundamental topics in psychology because behavior is the reflection of how one receives, interprets and reacts to stimuli. Sensations regarded as pre-awareness and perceptions regarded as a window to outside world and a preparation for appropriate behavior. Sensation is very simple process and is raw material for perception. Perception is a complex and complete cognitive process. To understand the process of perception it is essential to understand the process sensation. Sensation is regarded as the primary and perception as secondary process. Without sensation perception is not possible

Environment stimulus as such does not enter in the brain directly.  Stimulus is a physical energy and when this physical energy stimulates the sense organs the receptor cells of the sense organs are activated. Each sense organ is programmed to receive a unique form of stimulus. It is termed as appropriate stimuli. For example, eye will never be stimulated by sounds. To receive the physical by sense organs energy conversion process is activated. This process is known as transduction. The receptor cells transduce the physical energy into neural impulses and transmit to the brain via neurons. Usually neural impulses pass through the spinal cord to specific brain centers depending upon the location of sense organs. Simple mental process occurs in the brain center. This process is primary and is called sensation. Thus, sensation is the detection of information about external and internal environment and the transmission of that information to the brain.

Generally, stimulus can excite more than one sense organ e.g., food excites the visual sensory receptor cells of the olfactory cells and gustatory cells. If one touches the food it also excites the cutaneous cell. We get a sensation only when some sense organ is stimulated. A stimulus is any change in outside or inside energy (e.g., muscle pain or hunger) that arouses a sense organ and its receptors. I is a stimulus only when it stimulates. Light is not a stimulus to a blind man or sound to a deaf man.