Measurement in psychology
In psychology, there are two main schools of metrology: psychophysics and psychometrics. The former is grounded in physics and the latter in statistics, but both presume that attributes of psychological experience may be viewed as quantities, which, in turn, may be represented by numbers. In practice, psychophysics has utilized the assumption of a “standard observer.” This would mean that single individuals are in principle viewed as measuring instruments (persons) that may be used for measuring certain perceptual/evaluative features of the environment or of other persons (e.g., detection, discrimination, perceived intensity, pleasantness, naturalness, friendliness, and so on; “measurement with person(s)”). In practice, psychometrics has utilized the idea of a “standard stimulus.” Stimuli or sets of test items are in principle viewed as a measuring instrument (psychological test) that may be used for measuring mainly mental processes of single and unique individuals (e.g., emotions, personality, political attitudes, psychomotor skills, etc.; “measurement of person(s)”).