Sensory and cognitive factors in judgments of loudness

One thousand Hertz tones were presented at equal or unequal intensities to the two ears. In a binaural-summation experiment, the presentation of components was simultaneous, the auditory system integrated the components automatically, and the subjects judged the loudness of the unitary sensation. In two cognitive-summation experiments, the presentation of components was successive, and the subjects had to integrate the two sensations consciously to judge their "total loudness." Results of all three experiments are consistent with models of linear summation of "loudness," but the loudness scales differ in the two tasks: The scales that underlie binaural summation and cognitive summation are nonlinearly related. This outcome suggests two nested processes: First, the auditory system transduces stimulus energy to loudness sensations by means of a nonlinear function; second, tasks that require subjects to judge combinational relations between sensations may impose additional nonlinear transformations on the sensations before the latter are combined.     

Sequential effects in absolute judgments of loudness

The effects of preceding stimuli on the judgments of current stimuli were examined in a study using absolute judgments of loudness with feedback. It was found that the response on a given trial was dependent on the stimuli in the preceding sequence of at least five trials. Both assimilation and contrast effects were observed. The form of the dependency of a response on a prior stimulus was a function of the ordinal position of the stimulus in the preceding sequence of trials. The stimulus on the immediately preceding trial had an assimilative effect on the response and preceding stimuli two to five trials removed all showed a contrast effect on a given response. The extent to which these preceding stimuli contributed to the contrast effect was an increasing function of their recency. The reversal of the dependency of the response, from assimilation to the stimulus one trial back, to contrast with the stimuli two and more trials back, indicates a unique function of the immediately preceding stimulus in this task. Since there was a reduction in the variance of responses to those stimuli similar in value to the immediately preceding stimulus, it is proposed that the stimulus and feedback on the last trial were remembered and used asa standardin judging the presented stimulus. A model is presented in which it is assumed that the memory of the magnitude of the immediately preceding stimulus is contaminated in specified ways by prior stimuli in the series. The empirical findings of assimilation and contrastare expected consequences of the proposed memorial processes.     

The perceptual basis of loudness ratio judgments

In Experiment 1, subjects were required to estimateloudness ratios for 45 pairs of tones. Ten 1,200-Hz tones, differing only in intensity, were used to generate the 45 distinct tone pairs. In Experiment 2, subjects were required to directly compare two pairs of tones (chosen from among the set of 45) and indicate which pair of tones had the greaterloudness ratio. In both Experiments 1 and 2, the subjects’ judgments were used to rank order the tone pairs with respect to their judged loudness ratios. Nonmetric analyses of these rank orders indicated that both magnitude estimates of loudness ratios and direct comparisons of loudness ratios were based on loudnessintervals ordifferences where loudness was a power function of sound pressure. These experiments, along with those on loudness difference judgments (Parker & Schneider, 1974; Schneider, Parker, & Stein, 1974), support Torgerson’s (1961) conjecture that there is but one comparative perceptual relationship for ioudnesses, and that differences in numerical estimates for loudness ratios as opposed to loudness intervals simply reflect different reporting strategies generated by the two sets of instructions.     

Semantic congruity effects in judgments of loudness

This research uses comparative judgments of the relative loudness of sounds to make a critical test of one theory of the mental representation of continuous physical attributes. The first two experiments find a semantic congruity effect, which is an interaction such that subjects can pick the louder of two loud sounds faster than the softer, and the softer of two quiet sounds faster than the louder. According to the theory under test, physical quantities are stored as points on a representational continuum, with a variance as well as a mean placement on it. The theory predicts the semantic congruity effect by assuming that the variance of placement of intensities on the representational continuum is a function of the direction of judgment: a soft sound will have less variance than a loud one when judged for softness and more when judged for loudness. Since the speed of making a judgment increases as variance decreases, the theory predicts a semantic congruity effect. However, for loudness, it can be shown that variance does not change in the manner assumed. The finding of a semantic congruity effect therefore disconfirms the theory. Alternative models are discussed. This research was supported by NSF Grant BNS 78-17442.     

Response requirements and the contrast effect in loudness judgments

Ss responded to a series of soft tones via category judgments, reaction time responses, or simple nonquantitative discrimination judgments. An evaluation was then made of the contrast effects obtained in the category judgments of these same soft tones when subsequently presented along with a series of loud tones. A control group was also used which did not receive the initial trials with the soft tones. The results indicated: (1) equivalent contrast effects for all four groups for the soft tones and (2) significantly greater judgments of the loud tones in the group that had used category judgments on the initial trials with soft tones. These results, alonR with a trend analysis, were used to argue for a joint semantic shift and equalization of category usage process underlying the contrast effect when Ss are required to denote the stimuli initially by means of category judgments.     

Multisensory numerosity judgments for visual and tactile stimuli

To date, numerosity judgments have been studied only under conditions of unimodal stimulus presentation. It is therefore unclear whether the same limitations on correctly reporting the number of unimodal visual or tactile stimuli presented in a display might be expected under conditions in which participants have to count stimuli presented simultaneously in two or more different sensory modalities. In Experiment 1, we investigated numerosity judgments using both unimodal and bimodal displays consisting of one to six vibrotactile stimuli (presented over the body surface) and one to six visual stimuli (seen on the body via mirror reflection). Participants had to count the number of stimuli regardless of their modality of presentation. Bimodal numerosity judgments were significantly less accurate than predicted on the basis of an independent modality-specific resources account, thus showing that numerosity judgments might rely on a unitary amodal system instead. The results of a second experiment demonstrated that divided attention costs could not account for the poor performance in the bimodal conditions of Experiment 1. We discuss these results in relation to current theories of cross-modal integration and to the cognitive resources and/or common higher order spatial representations possibly accessed by both visual and tactile stimuli.     

Effects of range on category scaling of loudness judgments

In two experiments subjects judged the loudness of a 1000-Hz tone within a range of three loudnesses. The first used a within-subjects design with ranges of 1-2 sones, 1-4 sones, and 1-8 sones. The second used a between-subjects design with ranges of 1-2 sones, 1-8 sones, and 1-16 sones. Except for two values in the 1- to 2-sone range the two experiments produced comparable results. As range was increased the tendency to round away from the end points increased and the judged mid-point occurred at a higher value. Comparisons are made with rounding patterns that occur in studies of linear scales. The present results are interpreted to support Poulton's (1975) position, that the mid-point of subjective estimates depends on the range of stimuli judged, rather than that of Stevens (1975), that the mid-point on a prosthetic scale is assigned to a value that is lower than the mid-point on the subject's subjective scale.     

Similarity and preference judgments of musical stimuli

Two experiments were performed comparing similarity (technical-structural) and preference personal-affective) judgments of jazz improvizations (Experiment 1) and of classical, pop-rock, and jazz music (Experiment 2). A multidimensional scaling paradigm (INDSCAL) was used for pairwise comparisons of the 12 musical pieces in each experiment. Each 2 minute piece was subdivided into 10 second segments in order to reduce fatigue or boredom and provide better sampling across comparison trials. In general, similarity dimensions reflected greater agreement among the subjects that did preference dimensions and were hierarchically ordered. The dominant dimensions for both similarity and preference judgments of jazz improvizations were: Tempo, Dominant Instrument (Horns-guitar), and Articulation. The dominant dimensions for similarity judgments involving all three genres were: Classical-Contemporary, Jazz-Rock, and Tempo. The dominant dimensions for preference judments were: Rock-Classical, Jazz-Classical, and Tempo. In general, the preference judgments of musically sophisticated subjects were less constrained by salient dimensions.     

Temporal-order judgments and reaction time for stimuli of different modalities

Summary Reaction times and the relative latency evaluated by the temporal-order-judgment method for two stimuli of different modalities (visual and auditory) were measured. The difference between reaction times for visual and auditory stimuli was about 40 ms. The relative latency was slightly shorter, however; in conflict with Rutschmann and Link's (1964) previous result, the auditory stimulus must be delayed to be perceived simultaneously with the visual one.     

Some new hypotheses on the mediation of loudness judgments 1

A new solution to the problem of relating equal-interval and ratio scales is proposed. It is shown that it is also possible, with the type of theory proposed, to predict results of cross-modality matching experiments.     

A dynamic model of loudness adaptation

Previous research on loudness adaptation has provided heterogeneous and partly contradictory results. One major reason seems to be the inconsistent use of the term 'adaptation', which is due to differing operational definitions. Here, a measurement-theoretic definition of loudness adaptation is introduced, which also comprises a new method for the identification of certain linear dynamic systems. This is of particular interest, since there is a lack of dynamic models describing loudness adaptation. An experiment with sinusoidal sound stimuli (3000 Hz) was performed to test whether loudness adaptation can be modeled by such a linear system. The results of the system identification indicate that this is possible. Therefore, it can be concluded that the given definition of loudness adaptation might be appropriate and that the method of system identification is an applicable research tool.     

Temporal judgments and contextual change

Three experiments investigated effects of environmental context on temporal memory judgments. An equal number of items occurred within each of two equal durations (D1 and D2). Subjects subsequently were asked to judge the length of a given duration in comparison with the other, then to discriminate the correct list and serial position for each recognized item on a test. If environmental context was unchanged, D1 was remembered as being longer than D2; if the context was disrupted during the interval separating D1 and D2, this effect was reduced; and if the context prevailing during D2 also was changed, the effect was eliminated. List discrimination was improved only if the context was changed. Serial-position judgment was not affected by either manipulation. Changes in process context--the internal context produced by the performance of specific cognitive processes--lengthened remembered duration, but the effect did not simply add on to the effects of environmental context. Results are discussed in terms of a contextual-change hypothesis.