20 - Signal Detection Theory and Models for Trade-Offs in Decision Making

Summary

SIGNAL DETECTION THEORY

The first topic we will cover in this chapter is signal detection theory (SDT). Let's begin by considering an area of psychology closely associated with SDT – psychophysics. The first psychological experiments ever conducted were in psychophysics. Psychophysics describes how physical stimuli, such as light or sound waves, are translated into subjective impressions – what we see and hear. For example, we know that the wavelength of light determines the color we perceive.

But our subjective impressions do not map onto physical stimuli in a one-to-one fashion. There are several variables that can affect our subjective impression. Take the physical environment. Imagine that you are listening to another person at a cocktail party, and the party grows so loud that you have a difficult time hearing the person. This is an example of the physical environment interfering with your perception. The neural structure of the perceiver can make a difference as well; if the person has some sort of neural damage, it can interfere with or alter his or her perceptions of a physical stimulus. People who are red-green color-blind do not have the subjective impressions of green or red. Finally, the motivation of the perceiver can make a difference, especially when a task is difficult. Imagine that you are looking in a Where's Waldo puzzle.