Understanding Psychology (10th Ed)

R E C A P / E V A L U A T E / R E T H I N K
K E Y T E R M S
R E C A P
What is sensation, and how do psychologists study it?
• Sensation is the activation of the sense organs by any 
source of physical energy. In contrast, perception is the 
process by which we sort out, interpret, analyze, and in-
tegrate stimuli to which our senses are exposed. (p. 99) 
What is the relationship between a physical stimulus and the 
kinds of sensory responses that result from it?
• Psychophysics studies the relationship between the 
physical nature of stimuli and the sensory responses 
they evoke. (p. 99)
• The absolute threshold is the smallest amount of physi-
cal intensity at which a stimulus can be detected. Under 
ideal conditions absolute thresholds are extraordinarily 
sensitive, but the presence of noise (background stimuli 
that interfere with other stimuli) reduces detection capa-
bilities. (p. 100)
• The difference threshold, or just noticeable difference, is 
the smallest change in the level of stimulation required 
to sense that a change has occurred. According to 
Weber’s law, a just noticeable difference is a constant 
proportion of the intensity of an initial stimulus. (p. 101)
• Sensory adaptation occurs when we become accustomed 
to a constant stimulus and change our evaluation of it. 
Repeated exposure to a stimulus results in an apparent 
decline in sensitivity to it. (p. 102)
sensation p. 99
perception p. 99
stimulus p. 99
psychophysics p. 99
absolute threshold p. 100
difference threshold (just 
noticeable difference) p. 101
Weber’s law p. 102
adaptation p. 102
E VA LU AT E
1.
is the stimulation of the sense organs; 
is the sorting out, interpretation, analysis, and 
integration of stimuli by the sense organs and the brain.