Bruce Schneider

The measurement of loudness using direct comparisons of sensory intervals.

Abstract Subjects were required in each trial to directly compare two pairs of tones and indicate which pair of tones had the greater loudness difference. Ten 1200 Hz tones differing only in intensity were employed. Subjects made binary comparisons among the 45 tone pairs which can be formed from the set of ten tones. The subjects binary comparisons of the tone pairs were found to satisfy the transitivity and monotonicity requirements of a positive difference structure. These comparisons of loudness intervals were used to construct a rank order of loudness difference. A loudness scale was constructed from a nonmetric analysis of the rank order of loudness difference for the 45 tone pairs and indicated that loudness was a power function of sound pressure with an exponent of 0.26.

Nomnetric scaling of loudness and pitch using similarity and difference estimates

In Experiment 1, nonmetric analyses of estimates of similarity and difference were used to generate a scale of loudness for 1,200-Hz tones varying in intensity. For both similarity and difference estimates, loudness was found to grow approximately as the 0.26 power of sound pressure. In Experiment 2, nomnetric analyses of estimates of similarity and difference were used to generate a scale of pitch for 83.3-dB pure tones varying in frequency. For both similarity and difference estimates, pitch was found to vary with frequency in accordance with the mel scale.

A scale for the psychological magnitude of number

A scale of the “psychological magnitude” of number was constructed from similarity ratings of the 45 number pairs that can be obtained from a set of 10 integers. A nonmetric analysis of these similarity ratings showed that “psychological number” was a power function of number.

Multidimensional scaling of color difference in the pigeon

Pigeons were required to discriminate between “identical” vs “different” pairs of lights in a yes/no signal-detection task with a symmetrical payoff matrix. If the two lights projected on the two halves of the bipartite field constituting the center response key in a three-key chamber were identical in wavelength composition, a single peck on the right key was reinforced with food. If the two lights differed in wavelength composition, then left-key pecks were reinforced. In Experiment 1, each of six pigeons experienced all possible pairs of 11 spectral lights and 1 purple light (66 pairs). In Experiment 2, the set of lights was expanded to 15 (105 pairs) and included a white light. The percentage of correct choices was taken as an index of the dissimilarity between the two lights constituting a pair. The rank-order information available in these dissimilarity measures was used to determine coordinate projections for each light in a two-dimensional Euclidean space. The configuration obtained in this manner was interpreted as a color circle for the pigeon.

The effects of adaptation to square-wave gratings as a function of grating orientation

An adaptation technique was used to measure the selectivity or tuning for grating orientation in the visual system for different orientations of the inspection stimulus. Duration thresholds for grating patterns of constant luminance were determined for 13 test gratings oriented from ±5 to 90 deg away from each of five adaptation gratings: 0, 22, 45, 67, and 90 deg. Threshold data obtained for test gratings without prior adaptation indicated higher sensitivity for gratings oriented along the horizontal and vertical axis than along the oblique axis. After adaptation, thresholds increased (sensitivity was reduced) for gratings having similar orientations as the test gratings. However, the functions relating sensitivity reduction to degree of angular disparity between test and adaptation grating did not vary across the five inpsection orientations, i.e., selectivity or tuning for grating orientation appeared to be independent of the orientation of the adapting stimulus.

Multidimensional Control of Fixed-Interval Responding by Light Intensity and Time

Pigeons were trained to respond on a multiple fixed-interval (FI) 60-sec/time-out 30-sec schedule with an added light whose intensity increased discretely every 10 sec during the 60-sec FI. During generalization testing in extinction, the light intensities were presented in pseudorandom order during the FI so that each light intensity appeared equally often during each 10-sec segment. A generalization surface was constructed for the 36 combinations of light intensity and 10-sec segment. The generalization surface showed that responding was a joint function of both light intensity and time since the beginning of the FI with light intensity exerting more control over responding than time since the beginning of the interval.

Magnitude estimation of loudness with a minimum 24-h interstimulus interval*

Magnitude estimates of the loudness of white noise were obtained in two conditions: in the first, the time between consecutive stimulus presentations was at least 24 h; in the second, the time was less than 2 min. In both conditions, the relationship between the reports of the Ss and the intensities of the stimuli was best described by a power function. The exponent of the function was lower and the variance was slightly greater in the 24-h interstimulus condition.