Approximately what percent of the total sensory receptors of the body are in the eyes?

Myopia is a very common condition. What is myopia and which type of lens can correct it?

Signal detection studies measure an individual’s ability to detect certain stimuli. They involve exposure to stimuli at varying magnitudes and ask subjects to detect any changes in their perceptual experience of the stimuli (i.e. the just-noticeable difference). Perceiving magnitude differences in stimuli depends on the type of sensory experience (e.g. touch or sound) and is based on proportional rather than absolute amounts.

Imagine a hypothetical study that asked participants to perceive changes in amplitude of a sound stimulus. In this experiment, the researchers wanted to know how much the amplitude needed to change in order for an individual to detect a difference. They decided to test the just-noticeable difference at three different amplitudes: low, medium, and high. Participants in each category listened to the initial sound, and then the amplitude was increased or decreased slightly until participants detected a difference.

The researchers found that the absolute difference in amplitude that needed to occur in order for participants to detect a difference varied by condition (i.e. low, medium, high amplitude). This observation best illustrates which of the following?