The new psychophysics: Six models for magnitude estimation.

For convenience in testing, the product axiom may be written in its logarithmic form:A special feature of these axioms is that they are applied before any scale is constructed, and a subset of the data is used to predict the residual data. Tests based on scales constructed from all the data are more likely to obscure possible violations ApparatusThe apparatus, described in detail elsewhere (Eskildsen, 1963), provided four luminous white circular targets 13 mm in diam, placed horizontally and separated by 90 mrn, center to center. The apparatus was located in a light-tight visual tunnel, and Ss were seated at a distance of 12 ft from the targets in an ordinary classroom desk seat. S reported his estimations orally. A brief dark-adaptation period of 15 min preceded each experimental session. METHOD SubjectsSubjects were two male and four female undergraduates at the University of Oregon, and were paid $1.50 per hour for their time. ProcedureThree of the Ss (randomly selected) did the difference estimation task first and the ratio task second, and the other three Ss performed the tasks in reverse order.Difference estimation task. Each trial began with the presentation of the standard pair, which consisted of two adjacent lights, one set at 30 (always on the left) and the other at 100 ft-L. By pushing a button S could then move a shutter to view the comparison pair which was always to the left of the standard pair. The S was told to call the difference in brightness for the standard pair 100, and to assign a number to the difference in brightness for the comparison pair in accord with usual magnitude estimation instructions. The S could move the shutter back and forth as many times as he wished to compare the two pairs. The trial ended when S responded and E turned out the lights. The following instructions were read for the difference estimation task:

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“…Steps in this direction have been taken, e.g., by Mashhour (1961), Sjoberg (1965), Akesson (1966,1967), and Poulton (1968).…”

Section: Methodsmentioning

confidence: 99%

Tests of product and additive scaling axioms

Fagot

Stewart

1969

Perception & Psychophysics

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“…(approximately 0 to 1.0 m/s 2 ), the power exponent was, of mathematical necessity (Laming, 1997), greater in the case of magnitude estimation since the subjective response values ranged from approximately 4 to 400, as opposed to the span of 0 to 10 for the CR-10. Poulton (1968) has suggested six factors that may influence the psychological processes involved in judging sensory magnitude. Of these, he suggested that the magnitude range of the stimulus accounted for up to 33% of the total variation in the power exponents.…”

Section: Discussionmentioning

confidence: 99%

“…The test participant is asked to assign numbers to the test stimuli such that the stimulus attribute of interest bears a ratio relationship with that of the reference. In magnitude estimation, it is known (Poulton, 1968) that the choice of the reference stimulus plays a role in determining the value of the power exponents that are obtained. For the set of 13 acceleration stimuli ranging from 0.01 to 0.86 m/s 2 in the current experiment, the median stimuli, which had an r.m.s.…”

Section: Procedures Of the Magnitude Estimation Experimentsmentioning

confidence: 99%

“…The psychophysical method of magnitude estimation (Stevens 1957) was chosen since it has been used in most previous research. Magnitude estimation has, however, come under some criticism (Poulton, 1968;Gregory and Colman, 1995) due to the tendency on the part of test participants to logarithmically distribute their numerical responses. For this reason, an alternative method was also used which yielded a subjective discomfort scale with ratio properties.…”

Section: Introductionmentioning

confidence: 99%

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Subjective response to seated fore-and-aft direction whole-body vibration

Hacaambwa

Giacomin

2007

International Journal of Industrial Ergonomics

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Subjective response to seated, fore-and-aft direction, whole-body vibration of the type experienced in automobiles was investigated. Fore-and-aft acceleration was measured at the seat guide of a small automobile when driving over two representative road surfaces, and was replicated in a laboratory setting using a whole-body vibration test rig and rigid seat. A single 15-second section of each of the two acceleration time histories was band-pass filtered to the frequency interval from 0.5 to 50.5 Hz, and was used as a base stimulus. Thirteen test stimuli were then constructed for each base stimulus by rescaling to BS 6841 W d frequency-weighted r.m.s. amplitudes from 0.01 to 0.86 m/s 2 . Two groups of 16 participants (8 male and 8 female in each case) rated the discomfort of the test stimuli. The first group was asked to use the psychophysical method of magnitude estimation while the second used a Borg CR-10 scale. The order of presentation of the test stimuli was fully randomised and each was repeated 3 times. For each group of participants, regression analysis was used to determine both the individual and the group mean Stevens' Power Law exponent describing the relationship between stimulus amplitude and subjective response. All mean power exponents were found to be less than unity, with the CR-10 scale having produced smaller exponents than magnitude estimation. The power exponents ranged from 0.66 to 0.91, corroborating the value of 0.84 obtainable from the guidelines of standard BS 6841.The results suggest that the numerical response scale provided in the BS 6841 guidelines is appropriate for use in the case of automobile fore-andaft vibration, but that the semantic labels under-represent the actual human subjective response in this direction. Psychophysical test method, vibration stimulus range and test participant gender were all found to affect the Stevens' Power Law exponent achieved from subjective testing. Each factor may therefore require control when attempting to compare human responses to vibration originating from different automobiles. Keywords

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“…A hipótese da amplitude dos estímulos Poulton (1968) deu outra interpretação muito diferente para o expoente da função de potência. A hipótese de Poulton é que este expoen-te não reflete o funcionamento dos diferentes sistemas sensoriais, mas somente certas características do experimento.…”

Section: José Aparecido Da Silva Nilton Pinto Ribeiro-filhounclassified

Avaliação psicofísica da percepção de dor

Silva

Ribeiro-Filho

2011

Psicol. USP

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Resumo: Dor é uma experiência pessoal e subjetiva influenciada por fatores culturais, situacionais, atentivos e outras variáveis psicológicas. Abordagens para a mensuração de dor incluem variados instrumentos, tais como, escalas verbais, numéricas, observacionais, questionários, autorregistros e respostas fisiológicas. Nesta revisão, descrevemos e analisamos como as sofisticadas técnicas psicofísicas podem ser designadas para mensurar separadamente as dimensões sensoriais e afetivas da percepção de dor. Destacamos que estas técnicas produzem mensurações válidas e fidedignas da percepção de dor, com propriedades de escalonamento de razão e, também, podem ser usadas, facilmente, em ambientes clínicos.Palavras-chave: Percepção de dor. Dor. Avaliação da dor.Que significado tem a função de potência? Uma vez que seu princípio são razões iguais entre os estímulos produzindo razões subjetivas iguais, podemos propor uma situação. Vejamos: suponha que o expoente (n) de uma função de potência seja 0,50 (e K = 1). Se um estímulo vale 100, a sensação correspondente será igual a 10, e se o estímulo vale 110, a sensação valerá 10,5; por conseguinte, se o estímulo aumenta em 10%, a sensação aumentará em 5%. Com a mesma função de potência, se o estímulo vale 200, a sensação valerá 14,14, e se o estímulo au-

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The new psychophysics: Six models for magnitude estimation.

Cited by 635 publications

References 66 publications

Tests of product and additive scaling axioms

Tests of product and additive scaling axioms

Subjective response to seated fore-and-aft direction whole-body vibration

Avaliação psicofísica da percepção de dor

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