A Short Method for Calculating the Adaptation-Level for Absolute and Comparative Rating Judgments

Helson, Harry; Himelstein, Philip

doi:10.2307/1418791

Cited by 22 publications

(13 citation statements)

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“…RESULTS AND DISCUSSION The 17S Ss' mean judgments for the 10 test runs were analyzed first by calculating the empirical ALs (Helson & Himelstein, 1955). Then the A L values for the different anchor conditions were investigated separately for the heavyand the light-weights series.…”

Section: Apparatus and Proceduresmentioning

confidence: 99%

Adaptation-level theory: Absolute or relative anchor effectiveness?

Sarris

1968

Psychon Sci

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Section: Apparatus and Proceduresmentioning

confidence: 99%

Adaptation-level theory: Absolute or relative anchor effectiveness?

Sarris

1968

Psychon Sci

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“…These psychophysical findings are consistent with the informal observation that humans are easily able to perceive global illumination changes, such as when a cloud passes overhead. It is important to note, however, that the scaling of local luminance to mean scene luminance has been proposed as a mechanism to underlie the tendency toward brightness constancy (Helson and Himelstein 1955;Robilotto and Zaidi 2004). In summary, understanding the roles of contrast and luminance processing may shed light on the nature of the cortical computations underlying surface perception.…”

Section: Introductionmentioning

confidence: 99%

Do Cortical Neurons Process Luminance or Contrast to Encode Surface Properties?

Vladusich¹,

Lucassen²,

Cornelissen³

2006

Journal of Neurophysiology

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Vladusich, Tony, Marcel P. Lucassen, and Frans W. Cornelissen. Do cortical neurons process luminance or contrast to encode surface properties ? J Neurophysiol 95: 2638 -2649, 2006. First published December 28, 2005 doi:10.1152/jn.01016.2005. On the one hand, contrast signals provide information about surface properties, such as reflectance, and patchy illumination conditions, such as shadows. On the other hand, processing of luminance signals may provide information about global light levels, such as the difference between sunny and cloudy days. We devised models of contrast and luminance processing, using principles of logarithmic signal coding and halfwave rectification. We fit each model to individual response profiles obtained from 67 surface-responsive macaque V1 neurons in a centersurround paradigm similar to those used in human psychophysical studies. The most general forms of the luminance and contrast models explained, on average, 73 and 87% of the response variance over the sample population, respectively. We used a statistical technique, known as Akaike's information criterion, to quantify goodness of fit relative to number of model parameters, giving the relative probability of each model being correct. Luminance models, having fewer parameters than contrast models, performed substantially better in the vast majority of neurons, whereas contrast models performed similarly well in only a small minority of neurons. These results suggest that the processing of local and mean scene luminance predominates over contrast integration in surface-responsive neurons of the primary visual cortex. The sluggish dynamics of luminance-related cortical activity may provide a neural basis for the recent psychophysical demonstration that luminance information dominates brightness perception at low temporal frequencies.

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“…Consequently, the calculations were done three times. A least squares estimate of PSE was obtained using the Helson-Himrnelstein model (Helson & Himmelstein, 1955). the reformulated Fechner law model (Michels & Helson.…”

Section: Resultsmentioning

confidence: 99%

Time error in lifted weights as affected by presentation order and judgment mode

Woodruff

Jennings

Rico

1975

Perception & Psychophysics

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In the method of constant stimulus differences, results obtained under two presentation orders (standard first and standard second) are commonly combined to eliminate time error. The present study shows that this technique is not adequate for controlling time error as the presentation orders have differential effects upon PSE. Using a two-handed technique, 96 subjects judged lifted weights on the comparative rating scale. The subjects lifted the standard before, with, or after the variable stimulus. They also either judged the standard in terms of the variable or the variable in terms of the standard (mode of judgment). Judgment mode, a previously uninvestigated confounding variable of presentation order was not an important factor in influencing the value of the PSE.In the method of constant stimulus differences, the observer is asked to judge if one member of a pair of stimuli is greater or less than the other member. One of the stimuli is the standard stimulus and the other is selected from a set of comparison stimuli. Each comparison stimulus is paired with the standard stimulus many times. From the judgments, a number of measures can be calculated. The point of subjective equality (PSE) specifies the value of the comparison stimulus which would be judged equal to the standard. Typically, the values of the PSE and standard stimulus are different and this difference is called the constant. error.Since the pair of stimuli are. separated in space or time, side effects of this separation can influence the judgments made by the observer. Space error is the aspect of constant error specifically related to changes in judgment caused by spatial separation. Space error is usually easily controlled by either counterbalancing conditions of presentation or by eliminating the spatial variable entirely. Time error (Fechner, 1860(Fechner, /1966 has to do with the influence on judgment of experiencing one stimulus before the other. Traditionally, a positive time error indicates underestimation of the second stimulus (PSE is greater than the standard); a negative time error indicates overestimation of the second stimulus (PSE is less than the standard) (Needham, 1934). Fechner suggested controlling for time error by using two presentation orders. For half the trials, present the standard stimulus first (S, presentation order), and in the other trials present the standard stimulus second (S2 presentation order). In this manner, the under-or overestimation of the second stimulus will affect both However, there is no reason that the variable and standard stimuli have to be equally affected by time error in the two presentation orders. In adaptation-level theory (Helson, 1964), the roles of the standard and variable are different, and consequently the presentation orders could well affect the two differentially. The Michels and Helson (1954) quantitative model of the effect of presentation order on PSE specifically allows for a differential effect as the usual state. Probably because presentation orders were a logical experim...

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A Short Method for Calculating the Adaptation-Level for Absolute and Comparative Rating Judgments

Cited by 22 publications

References 0 publications

Adaptation-level theory: Absolute or relative anchor effectiveness?

Adaptation-level theory: Absolute or relative anchor effectiveness?

Do Cortical Neurons Process Luminance or Contrast to Encode Surface Properties?

Time error in lifted weights as affected by presentation order and judgment mode

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