Psychophysics Essay

Psychophysics

Matthew Chavez

Del Mar College

Psychophysics Psychology has many fields that study different parts of the human brain. The branch of Psychology that studies the relationship between a stimulus and the perception of that stimulus is known as Psychophysics. Psychophysics has it’s foundation in the work of Gustav Theodor Fechner, a German scientist who studied the response to physical stimuli during the 1800’s. Currently, the two main areas that a Psychophysicists looks at when studying the brain's relationship to a stimulus are the absolute, minimum, and maximum thresholds. Psychophysics attempts to bridge the actual physical stimulus with the mind's perception of that stimulus. The study of psychophysics relies

Vision: A person holding a candle 30 miles away. Hearing: The ticking of a watch 20 feet away in a quiet environment. Taste: One drop of quinine sulfate in 250 gallons of water. Smell: One drop of perfume in a six-room house. Touch: The force of a bee’s wing onto a person’s cheek from one centimeter. In 1941, a vision scientist named Selig Hecht and his colleagues at Columbia university made a reliable measurement of the absolute threshold of the human eye. In this study, they found how many photons were needed to create an image. They began by putting subjects into complete darkness and waiting for the subject's eyes to adapt. They then flashed them with a blue-green light in order to get the most sensitive part of the human eye to react. The results of this study were that the absolute threshold of the human eye is between 54 and 148 protons. More recently, researchers have done complex experiments on the internet. Max-Planck-Institute for Biological Cybernetics conducted internet studies concerning absolute thresholds. One study asked 1089 subjects to judge pictures of faces and guess their genders. Out of 1089 subject, 374 made an error on one or more of the faces. Interestingly, 86% guessed the face belonged to a male when it was actually a female. This provided information about absolute threshold by showing that some people could see the difference between male and female features, but there were some people that could not see the differences. Another study conducted by this institute used six pictures with two heads. The pictures were taken with different lighting and orientations. In this study, 487 test subjects