Frequency of occurrence as a psychophysical continuum: Weber's fraction, Ekman's fraction, range effects, and the phi-gamma hypothesis

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Using the continuum of frequency of occurrence of words in English, it was found that: (1) errors in judgment are distributed lognormally rather than normally, and therefore the standard method of calculating Weber's fraction underestimates its definition, (2) Weber's fraction has an extremely large value of 3.3, (3)Ekman's fraction equals 1.81, not .03 as with sensory continua, and (4)the logarithm of the dynamic range times Stevens' law exponent equals 3.83, not 1.53 as with sensory continua. The last two results favor Teghtsoonian's underlying sensory scale interpretation over Poulton's range effects interpretation of the range-exponent relation. © 1976 Psychonomic Society, Inc.






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Rubin, DC (1976). Frequency of occurrence as a psychophysical continuum: Weber's fraction, Ekman's fraction, range effects, and the phi-gamma hypothesis. Perception & Psychophysics, 20(5). pp. 327–330. 10.3758/BF03199413 Retrieved from

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David C. Rubin

Juanita M. Kreps Distinguished Professor of Psychology and Neuroscience

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My main research interest has been in long-term memory, especially for complex (or "real-world") stimuli. This work includes the study of autobiographical memory and oral traditions, as well as prose. I have also studied memory as it is more commonly done in experimental psychology laboratories using lists. In addition to this purely behavioral research, which I plan to continue, I work on memory in clinical populations with the aid of a National Institute of Mental Health grant to study PTSD and on the underlying neural basis of memory the aid of a National Institute of Aging grant to study autobiographical memory using fMRI.

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