Sensation and Preception - Essay Example

The processes of sensation and perception are necessary in order to assure our survival. Just as the eagle has developed exceptional sight, which makes him an excellent hunter, humans have developed the appropriate sensory apparatus to assist us in deciphering from that which is potentially harmful, and that which is safe and beneficial. As humans, we depend on these processes in our everyday lives in a wide variety of circumstances, even though we are not always conscious of this. Each time we navigate up or down a staircase, we rely on sensation and perception to tell us precisely where our next step should be.

Driving is another instance where sensation and perception is vital to our well-being. Determining our distance in relation to a structure, or another vehicle, is particularly important for our safety, and the safety of others with whom we share the road. These are two instances, in which these processes are necessary to ensure our survival during our normal, everyday lives. During the viewing of this video, my perception of sensory stimuli was noticeably changed on numerous occasions. The most notable of these, was the screen that appeared to be a darker shade of gray on the left half.

This was most intriguing, because when the sensory stimuli was altered by simply covering the center boundary, the only area in which a difference in shade was actually present, both halves of the screen were proven to be identical in color. In retrospect, even though one is aware of there being no actual difference, aside from the center boundary, we still get the sensation that there is a slight difference in brightness or color. This phenomenon, referred to as subjective contours, is explained as the brain’s tendency to detect a slight difference in the sensory stimuli, in this case the slight color variation, and to over-extend that variation, therefore registering a pattern that does not exist.

This highlights the internal influences on our perception, such as prior experience, expectation, and bias, on what is external. Studies have revealed that previous experience and expectation play a significant role in sensation and perception of sensory stimuli. One research study, which placed particular importance on this internal influence, as presented in the video, is the Rat Man Illusion. In this study, subjects are shown a series of drawings—one group being shown a sequence of drawings of people, and the other a sequence of animal drawings—the subjects are then instructed to identify in quick succession, with no conscious effort, what it is they are viewing.

In each sequence, the drawings are easily identified as either an animal or a person; however, both sequences contain an identical, final image, which could be identified as either a rat or an old man wearing glasses. This study shows the tendency to see what we expect to see, depending on our prior experience and other internal factors. Not surprisingly, the subjects who were shown the sequence of drawings depicting people, tended to see the final image as an old man, and in the group of subjects, who had viewed the series of animal images, the opposite was perceived and recorded.

Works Cited “Program 7: Sensory and Perception.” Discovering Psychology. Web. 18 Jul 2011. http://www.learner.org/vod/vod_window.html?pid=1504.