Sensory adaptation Essay Example

Sensory adaptation Essay Example Sensory adaptation Paper Sensory adaptation Paper Behavior rests on an understanding of the biological basis of the nervous system – the receptors. Efforts should be made to understand the relations between stimuli and sense organs and the processes associated with sense organs and their connectors, as well as the selective input called perception (Atkinson et al., 2000). While an individual gets his information about the world around him from his sense organs, his interpretation of these stimuli impinging on his senses will depend on his perception (Coren and Ward, 1989). Sensory adaptation is any reduction in sensitivity to stimulus as stimulation persists through time. Sense organs have the capacity to adapt to stimulus when such stimulus persists for quite a time (Coren and Ward, 1989; Atkinson et al., 2000). Sensory adaptation affects all of the individual’s sensing areas. For example in visual adaptation, this is due to the difference in the action between the rods and the cones. After five minutes in the dark, for instance, the sensitivity of the cones decreases. The rods continue to adapt and increasingly become more sensitive. Hence after about thirty minutes, one can distinguish things quite clearly in the dark. After coming from a dark movie theater, one may temporarily be blinded by the glare of the light from outside. Adaptation to light takes shorter than adaptation to the dark. Adaptation to light is called photopia while adaptation to dark is called scotopia (Andreassi, 1989; Atkinson et al., 2000). Theories of color vision include the Young Helmholtz theory which encompasses the Three-fiber theory and the theory of photo-chemical substances. Another is the Hering theory which is also called Opponent-colors theory, Wundt’s theory, the Von Kries theory and the Ladd-Franklin theory which help elucidate the visual phenomenon. The Young Helmholtz theory assumed that colors are but the result of combining three fundamental or primary colors – red, blue and green. Young assumed the existence of three different kinds of nervous fibers in the retina that react specifically to these colors with their corresponding preceptors in the brain center. This theory was further developed by Ludwig von Hemholtz. This was later revised to the theory of photo-chemical substances (Andreassi, 1989). On the other hand, in the auditory phenomena, several theories help explain how this occurs. Loudness for instance, according to the Place theory of pitch, is associated with spread of excitation – a more intense stimulus affecting more of the basilar membrane than a weaker one (Andreassi, 1989). In the olfactory sense aspect, not all gases react with the organ of smell to set up sensation of odor – hence, only those gases that do react are called odors or smells. The stronger the sensation of odor, the more odorous gases comes into contact with the organ of smell. Hence, one has to take a big sniff in order that the odors can penetrate up to the olfactory epithelium (Coren and Ward, 1989). While the sense of smell is highly developed in animals, it is relatively mildly developed in human beings (Coren and Ward, 1989).