Absolute Judgment versus Absolute Magnitude Estimation to Convey Information through Symbol Magnitude Changes in CRT Displays.
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH
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Psychophysical scaling of symbol magnitude to convey information through CRT displays was evaluated in terms of information theory. Series of lines and ellipses each with four, eight and twelve intermediate sizes were presented to twelve subjects under absolute judgment scaling and to an additional twelve subjects under absolute magnitude estimation scaling. Under absolute judgment, information transmission is higher and equivocation and ambiguity measures are lower than those obtained under absolute magnitude estimation. The difference in information transmission represents an increase of about one stimulus alternative under absolute judgement scaling and in itself does not preclude the practical application of absolute magnitude estimation to encode information. Rather it is the wide variability in median magnitude estimations that makes it difficult to reach any common ground for symbol interpretation. Keyword Theses. Author