Perception is the elaboration, interpretation and assignment of meaning to sensory experiences. There are over six billion people in the world today, and each one of these individuals has a different perception and opinion on life. It is these differing perceptions that cause some people to form tunnel vision, basing judgments of people on first, or past, impressions. In the show Northern Exposure many of the character's tunnel vision caused them to misinterpret or misunderstand the importance of people and situations.
Career and background are two aspects that can greatly effect one's perception. In Northern Exposure, Maurice discovered an old Guarnieri violin. To Maurice, as a powerful businessman and investor, the violin was a gold mine worth about two million dollars. He did not have significant appreciation for music or the unique tone of the violin. However, Cal, whom Maurice had hired to appraise the Guarnieri, had a deep appreciation and talent for music. To Cal, there was no real monetary value to the violin, he viewed it as a rare, and extremely valuable, musical find. Cal then fell deeply in love with the woodwork and sound of the Guarnieri. Eventually Maurice realized that Cal's talent and passion for music was worth more than any amount of money and allowed Cal to keep the Guarnieri. .
Another example of tunnel vision due to background and career is shown through Joel, a local doctor and scientist who discovered the body of a wooly mammoth, and Walt, a backwoods survivalist who is also interested in the mammoth. When Joel discovered the mammoth, he realized that finding such a prehistoric creature well preserved and in one piece was an amazing find. Little was known about the mammoths and this discovery was extremely valuable. Unlike Joel, Walt was not interested in the historical value of the creature; he was interested in the edible value. As a survivalist, Walt saw that the animal could yield and exceptional amount of meat.