Psychophysical Scaling

Marks, Lawrence Ε.; Gescheider, George A.

doi:10.1002/0471214426.pas0403

Cited by 22 publications

(18 citation statements)

References 109 publications

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“…According to Ganel et al, the basis for this technique is drawn from the classic method of adjustment in which variance provides a measure of visuomotor uncertainty “… for which the observer is unable to tell the difference between the size of the comparison and the target object” (p. 600). Such an approach supports Fechnerian principles of Weber functions (see Marks and Algom, 1998), and we interpret linear scaling of JNDs to increasing object size (i.e., the Weber function) as adherence to the psychophysical properties of Weber's law.…”

Section: Methodssupporting

confidence: 77%

Grasping time does not influence the early adherence of aperture shaping to Weber's law

Heath¹,

Holmes²,

Mulla³

et al. 2012

Front. Hum. Neurosci.

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The “just noticeable difference” (JND) represents the minimum amount by which a stimulus must change to produce a noticeable variation in one's perceptual experience (i.e., Weber's law). Recent work has shown that within-participant standard deviations of grip aperture (i.e., JNDs) increase linearly with increasing object size during the early, but not the late, stages of goal-directed grasping. A visually based explanation for this finding is that the early and late stages of grasping are respectively mediated by relative and absolute visual information and therefore render a time-dependent adherence to Weber's law. Alternatively, a motor-based explanation contends that the larger aperture shaping impulses required for larger objects gives rise to a stochastic increase in the variability of motor output (i.e., impulse-variability hypothesis). To test the second explanation, we had participants grasp differently sized objects in grasping time criteria of 400 and 800 ms. Thus, the 400 ms condition required larger aperture shaping impulses than the 800 ms condition. In line with previous work, JNDs during early aperture shaping (i.e., at the time of peak aperture acceleration and peak aperture velocity) for both the 400 and 800 ms conditions scaled linearly with object size, whereas JNDs later in the response (i.e., at the time of peak grip aperture) did not. Moreover, the 400 and 800 ms conditions produced comparable slopes relating JNDs to object size. In other words, larger aperture shaping impulses did not give rise to a stochastic increase in aperture variability at each object size. As such, the theoretical tenets of the impulse-variability hypothesis do not provide a viable framework for the time-dependent scaling of JNDs to object size. Instead, we propose that a dynamic interplay between relative and absolute visual information gives rise to grasp trajectories that exhibit an early adherence and late violation to Weber's law.

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Section: Methodssupporting

confidence: 77%

Grasping time does not influence the early adherence of aperture shaping to Weber's law

Heath¹,

Holmes²,

Mulla³

et al. 2012

Front. Hum. Neurosci.

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“…Continuity with these studies was desirable, both of which employed a rating task. Additionally, Ellis and Jones (2009) explained that this methodology extends the magnitude matching paradigm of Stevens and Marks (Marks & Gescheider, 2002;Stevens & Marks, 1980), in which participants used the same ordinal scale to rate the dimensions of brightness and loud ness (independently). The present research furthers this extension.…”

Section: Princementioning

confidence: 99%

Pitch structure, but not selective attention, affects accent weightings in metrical grouping.

Prince¹

2014

Journal of Experimental Psychology: Human Perception and Perfor

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Among other cues, pitch and temporal accents contribute to grouping in musical sequences.However, exactly how they combine remains unclear, possibly because of the role of structural organisation. In three experiments, participants rated the perceived metrical grouping of sequences that either adhered to the rules of tonal Western musical pitch structure (musical key), or did not (atonal). The tonal status of sequences did not provide any grouping cues and was irrelevant to the task. Experiment 1 established equally strong levels of pitch leap accents and duration accents in baseline conditions, which were then recombined in subsequent experiments. Neither accent type was stronger or weaker for tonal and atonal contexts. In Experiment 2, pitch leap accents dominated over duration accents, but the extent of this advantage was greater when sequences were tonal. Experiment 3 ruled out an attentional origin of this effect by replicating this finding while explicitly manipulating attention to pitch or duration accents between participant groups. Overall, the presence of tonal pitch structure made the dimension of pitch more salient at the expense of time. These findings support a dimensional salience framework in which the presence of organisational structure prioritises the processing of the more structured dimension regardless of task relevance, independent from psychophysical difficulty, and impervious to attentional allocation.

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“…Since Fechner's seminal work, the “measurement of sensation magnitude”—nowadays typically referred to as “psychophysical scaling”—has been one of the central aims of psychophysics ( Gescheider, 1988 ). 1 Psychophysical scaling is formally defined as the problem of quantifying the magnitude of sensation induced by a physical stimulus ( Marks & Gescheider, 2002 ; Krantz, Luce, Suppes, & Tversky, 1971 ).…”

Section: Introductionmentioning

confidence: 99%

Estimation of perceptual scales using ordinal embedding

2020

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In this article, we address the problem of measuring and analyzing sensation, the subjective magnitude of one's experience. We do this in the context of the method of triads: The sensation of the stimulus is evaluated via relative judgments of the following form: "Is stimulus S i more similar to stimulus S j or to stimulus S k ?" We propose to use ordinal embedding methods from machine learning to estimate the scaling function from the relative judgments. We review two relevant and well-known methods in psychophysics that are partially applicable in our setting: nonmetric multidimensional scaling (NMDS) and the method of maximum likelihood difference scaling (MLDS). Considering various scaling functions, we perform an extensive set of simulations to demonstrate the performance of the ordinal embedding methods. We show that in contrast to existing approaches, our ordinal embedding approach allows, first, to obtain reasonable scaling functions from comparatively few relative judgments and, second, to estimate multidimensional perceptual scales. In addition to the simulations, we analyze data from two real psychophysics experiments using ordinal embedding methods. Our results show that in the one-dimensional perceptual scale, our ordinal embedding approach works as well as MLDS, while in higher dimensions, only our ordinal embedding methods can produce a desirable scaling function. To make our methods widely accessible, we provide an R-implementation and general rules of thumb on how to use ordinal embedding in the context of psychophysics.

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Psychophysical Scaling

Cited by 22 publications

References 109 publications

Grasping time does not influence the early adherence of aperture shaping to Weber's law

Grasping time does not influence the early adherence of aperture shaping to Weber's law

Pitch structure, but not selective attention, affects accent weightings in metrical grouping.

Estimation of perceptual scales using ordinal embedding

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