Psychophysical Scaling Research Articles

5角形の類似性

5角形の類似性

Mixed-modality psychophysical scaling: inter- and intramodality sequential dependencies as a function of lag.

In mixed-modality psychophysical scaling, stimuli from different modalities are presented alternately for judgment on the same scale. This paper reports the results of two experiments using a variant of the standard technique that allowed investigation of inter- and intramodality sequential dependencies as a function of lag. Derived cross-modality matching functions from magnitude- and category-matching experiments were highly similar, with exponents around 1.6, as is the case for the standard technique. In both experiments, significant inter- and intramodality assimilation of responses to previous responses was found for lags of up to four trials back in the sequence of stimuli, whereas contrast of current responses to previous stimulus values occurred only within a modality, but also for lags of up to four trials. Second-order dependency of the correlation between current and previous responses as a function of the separation of their stimuli has the usual form (inverted v) for lags of up to four trials, both within and across modalities. Dependency of the coefficient of variation of the ratio of current to previous responses on the separation of their stimuli was found only within a stimulus modality, and only for a lag of one trial. These results strengthen the case for different sources for assimilative and contrastive sequential dependencies, and for the two second-order dependencies.

Perceptual aspects of synthesized approximations to melody.

A procedure is described for synthesizing tone sequences that contain a high proportion of events that are likely to be found in melodies that occur in music. This is done by using a random-number generator with probability weightings that favor the selection of certain notes and intervals. The form of the probability weightings derives from constraints on the "semitone span" of the intervals, the "fifth span" of the intervals, and the occurrence of "scale" notes. The role of "redundancy" is also considered. In this way it is possible to obtain melodies that obey various combinations of the different constraints. Other melody variables are either fixed, randomized, or controlled. These experimental melodies were used in a test of the hypothesis that the more melodious tone sequences will be easier to organize perceptually and remember than less melodious sequences of equal redundancy. A psychophysical scaling procedure confirmed that the constraints generated tone sequences bearing degrees of perceptual similarity to "real" melodies. Melody discrimination was also measured. The "fifth span" and "scale" constraints increased the melodiousness of tone sequences. They also improved performance on tasks requiring the discrimination of unfamiliar, untransposed melodies, and the discrimination of transposed melodies after some familiarization. It is argued that general perceptual principles do not give a complete account of the perception of melody: A full description requires consideration of the listener's tacit musical "knowledge" and its interaction with perceptual processes.

Applications of the theory of meaningfulness to psychology

The theory of meaningfulness of statements using numerical scales is summarized. Applications of this theory are surveyed. These deal with average performance, importance ratings, statistical tests, indices of consumer confidence, psychophysical scaling, block modeling of social structure, structural modeling in decision making, and the analysis of order and matching experiments.

Perception of organization in a random stimulus

This paper describes an experimental test of the role of perceptual organization in the perception and reproduction of a visual stimulus. A perceptually random stimulus was presented to subjects who were to reproduce it. A procedure of serial reproductions was used and the perceptual organization inherent in the subjects' reproductions was quantified by a psychophysical scaling procedure. The prediction of increased organization in successive reproductions was confirmed. When there was little or no perceptual organization in the stimulus (as in the random stimulus), subjects imposed perceptual organization on the sensory input. When there was perceptual organization inherent in the stimulus, subjects perceived it and further emphasized the organization in their reproductions. Of particular interest was the investigation of the distinction between perceptual organization as a characteristic of the sensory input and perceptual organization as a characteristic of the processing operations of the visual system acting on the sensory input.

Perceptual controls for synthesizers: Relating synthesis parameters to perceived timbre

When faced with the task of producing a given range of timbres on a commercially available synthesizer, users must learn how the manipulation of the controls of the synthesizer affects the timbres produced by the synthesizer. The process of developing the desired palette of timbres usually involves making educated guesses at how the synthesis parameters must be varied and then proceeding with a trial and error search for the desired sound qualities. This process may be described as a method for the psychophysical scaling of synthetic timbres. With the advent of the standardized Musical Instrument Digital Interface (MIDI), an avenue has been opened for a more systematic approach to the problem of relating synthesis parameters and perceived timbre. At the Northwestern University Computer Music Studio, we have developed a software environment which applies the methods of modern psychoacoustics to determining this relation for MIDI‐controlled commercial synthesizers. The software supports the automatic perceptual scaling of synthesis parameters and is capable of providing control over synthetic timbres which is based strictly upon the perceptual features of the desired timbres.

The effects of mental imagery on skin temperature and skin temperature sensation.

In a series of six experimental sessions five subjects were instructed to imagine their hand in a hot and cold water stream. During the imagery period the subjects estimated with a psychophysical scale their subjective temperature sensations caused by the imagery. Skin temperature was measured from the thumb of the subjects' dominant hand. After each session the subjects were asked whether they had succeeded in producing an imagery. The skin temperature changes deviated significantly from the control level in the successful imagery experiments. Differences in the skin temperature changes between the successful and unsuccessful imagery experiments were significant. The skin temperature changes measured and the subjects' temperature sensations, produced by the imagery, were similar in the successful imagery experiments. The possible relationships between mental imagery and changes in skin temperature and skin temperature sensation are discussed.

Memory mechanisms and the psychophysical scaling of duration.

Two experiments were performed to examine the suggestion that underlying memory mechanisms may be revealed in the form of the psychophysical function for duration. In experiment 1 a broad range of durations, with fine spacing at the lower end, was employed to bring out any transition in function that might reflect a change from 'ionic' memory to short-term memory. Estimation in conventional time-units (Verbal Estimation) was also compared with unit-free estimation (Magnitude Estimation). In experiment 2 Verbal Estimation was compared with the Production method, for a different range of stimulus values, and with varying interval content. Contrary to earlier claims, memory mechanisms were not found to be reflected in the values of power exponents for subjective duration. The value of the search for such functions is questioned, as simple linear plots fit the data at least as well.

Evaluation of the chronic low back pain patient: Conceptual and clinical considerations

The purpose of this article is to provide a comprehensive review of the surprising and substantial breadth of currently available biomedical, physiological, and psychometric assessment methods for chronic low back pain (CLBP). Biomedical methods such as nuclear magnetic resonance may so revolutionize medical diagnosis that cases previously assumed to have psychogenic etiology may in fact be found to have been caused by spinal degenerative conditions, nerve compression, or spinal stenosis. The reviewers suggested that the traditional psychometric instrument, the MMPI, may be of dubious value in making treatment relevant diagnoses, in discriminating between organic and psychogenic etiologies, and in the prediction of treatment outcome. Several recent approaches in admittedly early stages of development seem to offer substantially more promise. To measure dimensions of cognition that may be important, investigators have assessed the kinds of coping styles patients employ to deal with pain and the attitude dimensions that may be affected by the chronic pain experience. The measurement of sensory, affective, and evaluative pain dimensions has been achieved via the McGill Pain Questionnaire, though a simple self-rating of pain intensity along a 100mm line may turn out to be just as useful clinically. Psychophysical scaling methods appear to be the most innovative to date, and quantify pain descriptors in terms of a patient's idiographic physiological response. Attempts to isolate physiological markers of chronic pain have been disappointing, but recent work suggests that the difference between right and left paraspinal EMG may be of diagnostic value in CLBP. Direct measures of pain behavior show great promise and include measurement of pain medication intake, “up time,” verbal complaints, and observer ratings of the frequency of grimacing, bracing and guarded movements. The construct validity of such behavioral measures has been demonstrated by successfully relating them to medical status variables (i.e., lumbar spine mobility limitation, hypalgesia). The authors conclude that further attempts to demonstrate the psychological involvement of the CLBP patient are redundant, and suggest that a multidimensional assessment strategy across physiological, cognitive, and behavioral domains may soon provide a treatment-relevant diagnostic and prognostic schema.

Stevens's exponent for psychophysical scaling of perceived, remembered, and inferred distance.

Analyse des resultats d'etudes utilisant l'exposant de Stevens pour evaluer les variations (et leurs sources) dans les relations entre distance physique et distance psychologique

Analysis and charcterization of FM imaging

The contrast sensitivity function describing the interrelated contrast and spatial response characteristics of the visual system was determined for sine-wave gratings. Three spatial frequencies were then selected for psychophysical scaling of apparent contrast using an intermodal matching technique. The perceptual contrast curves were to a fair approximation power functions of the physical contrast of the striped target. Power transformations as a function of spatial fequency were observed, i.e. with decreasing sensitivity the exponents of the apparent contrast functions increased. A reanalysis of evoked response data published by Campbell and Maffei confirmed these observations.

Stevens's exponent for psychophysical scaling of perceived, remembered, and inferred distance.

Stevens's exponent for psychophysical scaling of perceived, remembered, and inferred distance.

Angina pectoris and blood lactate concentration during graded exercise.

Nineteen patients with angina pectoris referred for preoperative evaluation were studied by psychophysical scaling of the chest pain according to Borg and blood lactate determination at rest and during a graded exercise test. The exercise tests consisted of stepwise increments of 10 W every min. Anginal pain, systolic blood pressure, heart rate (HR), and blood lactate concentration were determined at the end of each work load. The exercise test was interrupted at a rated anginal pain level (RAP) of 5-6/9 ("strong"), and this load was referred to as Wmax. The patients were divided into three groups: A with a Wmax less than or equal to 74 W, B 75-124 W, and C greater than or equal to 125 W. At submaximal loads HR was almost identical at the same absolute work load in all three groups. The heart rate at Wmax varied, however, and averaged 98 (A), 118 (B), and 136 (C), respectively. Corresponding peak values for RAP were 3.8, 4.5, and 4.8. Blood lactate at rest ranged from 1.0-1.6 mmol X 1-1 and increased curvilinearly with intensity, which was also the case for RAP. RAP was almost linearly related to blood lactate in all three groups suggesting a causal relationship between these two parameters.

A study of psychophysical scaling in chronic pain patients

Chronic pain patients were asked to psychophysically scale two sets of word descriptors (intensity and unpleasantness) using a crossmodality matching procedure with line length and numerical estimates. In 22 patients (group I) descriptor scaling was performed once, in another 20 patients (group II) the procedure was repeated 3 times. 72.7% of patients in group I obtained a correlation of 0.9 or higher when scaling intensity descriptors, but only 18.2% obtained this correlation when scaling unpleasantness words. In group II, an average of 85% of patients reliably scaled intensity words, but only 50% could do so for the unpleasantness descriptors. Patients who reliably judged unpleasantness descriptors generally exhibited a higher level of psychological distress (SCL-90 R). Numerical estimates assigned by patients to individual word descriptors showed a smaller range than obtained from experimental pain studies. There was unequal spacing of values of adjacent descriptors with clustering of words in the low and high ends of the continuum and large gaps in midrange. Results indicate that chronic pain patients in general show a higher incidence of impairment in rendering proportional judgments than a healthy population. In addition, they are more likely to judge pain reliably on an intensity than on an unpleasantness dimension. The difference in performance between scales persists in spite of training and could not be explained by medical history, drug intake, or demographic characteristics. Patients who are unable to render reliable judgments are easily identified. For optimal clinical use words clustering close together should be combined and additional words should be added describing midrange intensities. Conversely, psychophysical scaling techniques may be used to calibrate category or analogue scales of pain.

On the Psychophysics of Workload: Why Bother with Subjective Measures?

Psychophysical functions describe the relationship between variations in the amplitude of a defined physical quantity and the psychological perception of these changes. Examples are brightness, loudness, and pain. The regularities of these relationships have been formulated into psychophysical laws. The measurement methodology of psychophysical scaling has been refined by the Harvard group led by S. S. Stevens, who proposed a power function as a general form for such laws. The main argument of the present article is that a similar scaling approach can be adapted to the measurement of workload and task demands based upon subjective estimates. The rationale is that these estimates, like other psychophysical judgments, reflect the individual's perception of the amount of processing resources that the subject invests to meet the demand imposed by a task. This approach was successfully applied to the assessment of 21 experimental conditions given to a group of 60 subjects. The paper discusses the main results of this effort and their implications to theory and application in human performance.

Contributors To This Issue

Contributors To This Issue

Individual and group reliability of landscape assessments

The reliability of landscape quality assessments made by individual observers as well as their group consensus was examined using a test—retest procedure. After the elapse of more than a year, the individual observer reliability estimates averaged nearly 0.80. Group consensus values were derived using the Law of Comparative Judgment psychophysical scaling procedure. These derived group consensus values proved very reliable ( r > 0.95) after the elapse of a year. Individual rater reliability was good, but group reliability was excellent and should probably be used whenever possible, especially when used as an aid to long-term decision making.

Psychiatry Variation in meaning of pain descriptors of different headache types as revealed by psychophysical scaling: Headache, 22 (1982) 137–139

Psychiatry Variation in meaning of pain descriptors of different headache types as revealed by psychophysical scaling: Headache, 22 (1982) 137–139

Clinical evaluation of taste

Partial loss of taste function can take a variety of forms. Losses can be specific to one taste quality or to one tongue locus. In addition, the shapes of psychophysical functions can be altered so that taste intensity no longer grows normally with concentration. Magnitude matching, an efficient psychophysical scaling method (based on magnitude estimation of stimuli from two sensory continua), can provide a relatively quick assessment of a patient's ability to taste the four taste qualities--sweet, salty, sour, and bitter. When taste intensity and loudness are scaled in the same session, a person with normal hearing who has taste loss will match taste intensities to abnormally weak sounds. Spatial losses are detected by placing pieces of filter paper soaked in taste solutions on specific tongue loci. Dysgeusia, the presence of a chronic taste in the mouth, can result from abnormal substances in the mouth (e.g., via saliva or from poor oral hygiene) or can reflect disorders of the central nervous system.

COMPUTERIZED TESTING OF SIGNAL‐ENCODING STRATEGIES WITH ROUND‐WINDOW IMPLANTSa

After extensive testing of a patient with two bipolar modiolar electrodes connected to a percutaneous plug in 1977, we provided four patients with a single-channel monopolar round-window electrode connected to a tuned radio-frequency receiver coil. Loudness and pitch discrimination and results of psychophysical scaling experiments of extracochlear electrodes are comparable to those with intracochlear stimulation. Extensive testing with a computerized test system and with tape-recorded and live speech material showed that accurate vowel and speaker identification by stimulation alone is possible and that discrimination by lipreading is considerably improved. Interactive training sessions further improve discrimination results. Different signal-encoding algorithms can be used to generate in real time stimulation signals from prestored speech parameters (such as pitch, gain, formants, and zerocrossing intervals).