Category Archives: Methods

Visual and Auditory Senses

For this assignment, we were asked to take a concept or theory and explain how it applied to an experience in our life.  The experience that stands out the most to me and is applicable to the principles of sensation and perception occurred when I was in the process of joining the military. Prior to be sent to basic military training, each individual is screened to ensure they are medically clear to pursue the endeavors encompassed in serving our nation. As a result, there are several tests an individual must take to determine their physical ability to include those pertaining to visual and auditory senses.

The first test, I recall taking is the visual test. The test was taken in a medium sized room that had separated cubicles, each with a chair and a computer. The medical technician instructed me that I was to sit in front of the computer and tell her the numbers that I saw within an image. There were several images presented, however they differed in color in the context of the numbers and surrounding (Example 1). After I took the test, the medical technician informed me that I did very well and was visually cleared.  When I asked the technician what the test was looking for, she informed me the test was looking for color blindness. This test relates closely to the concept of retinal information processing. Although, there are five neuron sections within the retina that effect processing; the primary focus is the photoreceptors. There are two primary types of photoreceptors within the retina, which are rods and cones. Cones are specialized for color vision and contain three types of photopigment: short wavelength-sensitive cones (S-cones), medium wavelength-sensitive cones (M-cones), and long wavelength-sensitive cones (L-cones) (Wolfe, 2012). Thus, the absence of any of the cone photopigments would result in color blindness (Wolfe, 2012). Therefore, the test is seeking to find the status/health of the cones within the retina. After taking the visual test, I was then directed to take a test that examined my auditory senses.

Like the visual test, an auditory test was administered by a medical technician in a medium sized room. However, the within the room was a single enclosed cubicle that was well-insulated. The test required that I wear headphones and hold an electronic remote. The technician administering the test explained the procedures to me that compromised of the following:  1) Listen for a beep tone 2) Press the button on the electronic remote once you hear the tone. At first it seemed like the tone started off faint before becoming louder but as the test went on I realized that the tone was in random order. This auditory test, relates strongly to Gustav Fechner’s concept of psychophysical methods.

Fechner’s psychophysical methods revolve around the consensus that there must be a threshold or minimum amount of stimulation needed to detect a stimulus (Wolfe, 2012). In order to measure this threshold, Fechner created the psychophysical methods: 1) method of constant stimuli 2) method of limits 3) method of adjustment (Wolfe, 2012).  Since I was presented the beeping tone (stimulus) multiple times, in random order, one at a time; the auditory test correlates strongly to the method of constant stimuli. The purpose of the auditory test was to detect my hearing ability and as such the medical technician had to find where my threshold was through the tones loudness (measured in decibels). As a result of my responses, the medical technician was able to determine not only my threshold but whether I had good hearing or not.

 

References

http://en.wikipedia.org/wiki/File:Ishihara_11.PNG

Wolfe, J. M. (2012). Sensation & perception (3rd ed.). Sunderland, Mass.: Sinauer

Associates.

Example 1