3.1 How the physical world relates to the psychological world

Question 1

absolute threshold

Answer 1

The minimum amount of energy in a sensory stimulus detected 50% of the time.

Question 2

signal detection theory

Answer 2

A theory that assumes that the detection of faint sensory stimuli depends not only upon a person’s physiological sensitivity to a stimulus but also upon his decision criterion for detection, which is based on non sensory factors.

Question 3

difference threshold

Answer 3

The minimum difference between two sensory stimuli detected 50% of the time. The difference threshold is also sometimes referred to as the just noticeable difference, or jnd.

Question 4

Stevens’s power law

Answer 4

The perceived magnitude of a stimulus is equal to its actual physical intensity raised to some constant power. The constant power varies across the types of sensory judgment.

Question 4

Weber’s law

Answer 4

For each type of sensory judgment that we can make, the measured difference threshold is a constant fraction of the standard stimulus value used to measure it. This constant fraction varies across the types of sensory judgment.

Question 5

sensory adaptation

Answer 5

Our sensitivity to unchanging and repetitious stimuli disappears over time.