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Biomedical subjects

L E Marks

Publications and source records attributed to L E Marks.

At least 37 records · Page 2Linked to original sources
PubMed1995

Binaural summation after learning psychophysical functions for loudness.

Do response-related processes affect perceptual processes? Sometimes they may: Algom and Marks (1990) produced different loudness exponents by manipulating stimulus range, and thereby also modified the rules of loudness summation determined by magnitude scaling. The present study manipulated exponents by having a dozen subjects learn prescribed power functions with exponents of 0.3, 0.6, or 1.2 (re sound pressure). Subjects gave magnitude estimates of the loudness of binaural signals during training, and of monaural and binaural signals after training. During training, subjects' responses followed the nominal functions reasonably well. Immediately following training, subjects applied the numeric response scales uniformly to binaural and monaural signals alike; the implicit monaural-binaural loudness matches, and thus the basic rules underlying binaural summation, were unaffected by the exponent learned. Comparison of these results with those of Algom and Marks leads us to conclude that changing stimulus range likely influences underlying perceptual events, whereas "calibrating" a loudness scale through pretraining leaves the perceptual processes unaffected.

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PubMed1994

"Recalibrating" the auditory system: the perception of loudness.

Listening to relatively intense tones at 1 frequency and weak tones at another makes the latter relatively louder. The auditory system's relative response to low-frequency (f1) and high-frequency (f2) tones depends on the separation between f1 and f2. When f1 and f2 differ little, loudness matches change little with shifts in mean sound pressure levels (SPLs) at each frequency; but when f1 and f2 differ more, matches change markedly, showing how the auditory system "recalibrates" its responses to f1 and f2. The magnitude of recalibration and its frequency bandwidth also depend to a modest degree on the range of SPLs, their mean level, and the experimental paradigm. The representation of loudness reflects the processing and recalibration of multidimensional peripheral inputs within a higher level, context-sensitive (adaptationlike) mechanism. Other perceptual modalities show evidence of analogous mechanisms.

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PubMed1993

Contextual processing of multidimensional and unidimensional auditory stimuli.

Stimulus context (the distribution of stimulus values) can strongly affect both perception and judgment. In 14 experiments, the method of magnitude estimation revealed 2 fundamentally different kinds of context effect in loudness. An assimilative effect dominated when stimuli varied unidimensionally (in intensity only). But a contrasting, or adaptation-like, effect dominated when stimuli varied multidimensionally (in frequency and intensity). In Experiment 15, direct loudness comparison revealed a potent, adaptational process specific to the signal frequency. Taken together, these and other results are compatible with the view that loudness perception and judgment reflect the net outcome of 2 different contextual processes: a relatively early (though probably not peripheral) process of perceptual adaptation and a later process of response-dependent assimilation.

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PubMed1993

Primacy of dimensions in color perception.

In this study, we used a procedure called selective/divided rotation to investigate the role of dimensions in the perception of color. Ss performed either selective-attention or divided-attention tasks to paired dimensions created from each of 3 orientations of axes in color space: 0 degree, 22.5 degrees, and 45 degrees. We evaluated a Euclidean hypothesis, namely, that speeded classification of interacting dimensions is invariant to rigid rotation of stimulus axes. All experiments obtained evidence against this Euclidean hypothesis. Experiments 1 to 4 showed that selective attention was best at the orientation corresponding to saturation and brightness, suggesting primacy of these dimensions. The results were replicated with the pairs hue-saturation (Experiment 7) and hue-brightness (Experiment 8). We conclude that interacting dimensions can be primary and that dimensional primacy characterizes much of perceptual experience.

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PubMed1992

Effects of context on sweet and bitter tastes: unrelated to sensitivity to PROP (6-n-propylthiouracil).

In a double-shifting context paradigm, subjects gave magnitude estimates of the perceived intensity of qualitatively dissimilar taste substances (saccharin and quinine, sucrose and quinine) or qualitatively similar ones (saccharin and sucrose), with each pair of substances taking on different contextual sets of concentrations in different sessions. The dissimilar pairs produced substantial differential effects of context (e.g., a particular concentration of saccharin or sucrose was judged more intense than a particular quinine in one contextual setting, less intense in another), but the similar pair did not. This result accords with the hypothesis that differential context effects depend on qualitative similarity. Contrary to expectations, however, the magnitude of the context effect did not differ in tasters and nontasters of the bitter substance 6-n-propylthiouracil (PROP), groups previously shown to differ in sensitivity to bitterness in saccharin. Similarity judgments suggest that saccharin and sucrose were qualitatively alike for all subjects, regardless of sensitivity to PROP.

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PubMed1992

Optional processes in similarity judgments.

This research investigates the nature of similarity relations among three pairs of interacting dimensions: (1) the integral dimensions of auditory pitch and loudness, (2) the configural dimensions of paired parentheses, and (3) the cross-modally corresponding dimensions of visual position and auditory pitch. We evaluated the rules by which information from each dimension combines in similarity judgments. Our claim is that, when judging similarity, processes that are obligatory, or what we call mandatory processes, can commingle with processes of choice, or what we call optional processes. By varying instructions, we found strong evidence of optional processing. Instructions to rate overall similarity encouraged subjects to attend to stimuli as wholes and led to a Euclidean rule in similarity scaling. Instructions to focus on dimensions encouraged subjects to consider each stimulus dimension separately and led to a city-block rule. We argue that optional processes may obscure mandatory ones, and so need to be identified before mandatory processes can be understood.

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PubMed1992

The slippery context effect in psychophysics: intensive, extensive, and qualitative continua.

When subjects gave magnitude estimates of 500- and 2500-Hz tones at various SPLs, they judged a 500-Hz tone of 60 dB to be as loud as a 2500-Hz tone of 57 dB in one context (low SPLs at 500 Hz, high SPLs at 2500 Hz), but as loud as a 2500-Hz tone at 40 dB in another context (high SPLs at 500 Hz, low at 2500 Hz) (Marks, 1988). Such shifts in matches derived from judgments of multidimensionally varying stimuli are termed slippery context effects. The present set of seven experiments showed that slippery effects were absent from judgments of pitch of tones at different loudnesses, duration of tones at different pitches, and length of lines at different colors, though a small effect emerged in judgments of duration of tones and lights. Slippery context effects were substantial when subjects gave magnitude estimates of loudness of 500- and 2500-Hz tones under conditions in which the pitch at each trial either was cued visually beforehand or could be known through the regular stimulus sequence, and with instructions to make absolute magnitude estimates. The results are consistent with the view that slippery context effects occur automatically and "preattentively."

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PubMed1991

Slippery context effect and critical bands.

This article explored the slippery context effect: When Ss judge the loudness of tones that differ in sound frequency as well as intensity, stimulus context (relative intensity levels at the 2 frequencies) can strongly influence the levels that are judged equally loud. It is shown that the size of the slippery context effect depends on the frequency difference between the tones: Small frequency differences (less than a critical bandwidth) produced essentially no slippery effect; much larger differences produced substantial effects. These results are consistent with a model postulating the existence of a central attentional or preattentive "filter-like" process whose weighting coefficients represent the size of the absolute as opposed to the relative (contextual) component of loudness perception and judgment.

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PubMed1991

Reliability of magnitude matching.

In each of four experimental sessions, each of 16 subjects gave magnitude estimates of the taste intensities of NaCl and the loudness of noise on a single, common scale--the method of magnitude matching. In all sessions, the intensity levels of the noises were identical; but in two sessions, the concentrations of NaCl were low, and in two they were high. Cross-modality matches (magnitude matches) between NaCl and noise were derived from the judgments, revealing two main findings: First, given constant NaCl concentrations, individual subjects showed reliably different magnitude matches. Second, changing the NaCl concentrations (context) strongly affected the magnitude matches. These findings suggest that magnitude matching may be useful in assessing interindividual as well as intergroup differences, though caution must be taken to minimize effects of context: Context effects are pervasive; they suggest the presence of a complex relativistic process operating when people judge the intensities of qualitatively different stimuli.

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PubMed1990

Perceptual primacy of dimensions: support for a model of dimensional interaction.

Do Ss always process multidimensional stimuli according to psychologically primary dimensions? Our hypothesis is that they do: Primary dimensions provide one component of a new model of dimensional interaction, a model that distinguishes information processed at the level of attributes from information processed at the level of the stimulus. By using sound stimuli created from the dimensions pitch-loudness (Experiments 1 and 2), pitch-timbre (Experiment 3), and loudness-timbre (Experiment 4), we tested performance in selective- and divided-attention tasks at each of three orientations of axes: 0 degrees, 22.5 degrees, and 45 degrees. Each experiment revealed strong evidence of primacy: As axes rotated from 0 degrees to 45 degrees, selective attention deteriorated, but divided attention improved, producing a distinct pattern of convergence. Each experiment also revealed effects of congruity: Attributes from corresponding poles of a dimension (e.g., high pitch and loud) were classified faster than those from noncorresponding poles. The results fit well with our new conception but are inconsistent with other current models of dimensional interaction.

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PubMed1990

Range and regression, loudness scales, and loudness processing: toward a context-bound psychophysics.

How does context affect basic processes of sensory integration and the implicit psychophysical scales that underlie those processes? Five experiments examined how stimulus range and response regression determine characteristics of (a) psychophysical scales for loudness and (b) 3 kinds of intensity summation: binaural loudness summation, summation of loudness between tones widely spaced in frequency, and temporal loudness summation. Context affected the overt loudness scales in that smaller power-function exponents characterized larger versus smaller range of stimulation and characterized magnitude estimation versus magnitude production. More important, however, context simultaneously affected the degree of loudness integration as measured in terms of matching stimulus levels. Thus, stimulus range and scaling procedure influence not only overt response scales, but measures of underlying intensity processing.

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PubMed1990

Dimensional interactions in language processing: investigating directions and levels of crosstalk.

In this article we evaluate current models of language processing by testing speeded classification of stimuli comprising one linguistic and one nonlinguistic dimension. Garner interference obtains if subjects are slower to classify attributes on one dimension when an irrelevant dimension is varied orthogonally than when the irrelevant dimension is held constant. With certain linguistic-nonlinguistic pairings (e.g., Experiment 1: the words high and low spoken either loudly or softly), significant Garner interference obtained when either dimension was classified; this indicated two-directional crosstalk. With other pairings (e.g., Experiment 3: spoken vowels and loudness), only the nonlinguistic dimension (e.g., loudness) displayed interference, suggesting unidirectional crosstalk downstream from a phonemic/graphemic level of analysis. Collectively, these results indicate the interaction can occur either within or across levels of information processing, being directed toward either more advanced or more primitive processes. Although poorly explained by all current models of language processing, our results are strikingly inconsistent with models that posit autonomy among levels of processing.

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PubMed1990

Processes underlying dimensional interactions: correspondences between linguistic and nonlinguistic dimensions.

In six experiments, we examined speeded classification when one dimension was linguistic and the other was nonlinguistic. In five of these, attributes on the dimensions corresponded meaningfully, having in common the concepts "high" and "low." For example, in Experiment 1, the visually presented words HI and LO were paired with high- or low-pitched tones; in Experiment 2, the dimensions were visual words and vertical position, in Experiment 3, they were spoken words and position, and in Experiments 4 and 5, spoken words and pitch. For each dimension in each pair, subjects suffered Garner interference when dimensions were varied orthogonally. Garner interference remained constant across 15 blocks of trials (Experiment 5). Subjects also showed significant congruity effects in all experiments, with attributes from congruent stimuli (e.g., HI/high pitch) classified faster than attributes from incongruent stimuli (e.g., HI/low pitch). These results differ from those obtained previously with noncorresponding pairs of linguistic-nonlinguistic dimensions. The results also differ from those obtained with traditional Stroop dimensions (colors and color words; Experiment 6), which showed minimal Garner interference and diminishing congruity effects across blocks of trials. We conclude that the interactions found here represent cross-talk between channels within a semantic level of processing. We contrast our view with current models of dimensional interaction.

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PubMed1990

Interaction among auditory dimensions: timbre, pitch, and loudness.

In two experiments, we examined whether or not pairs of auditory dimensions--timbre-loudness (Experiment 1) and timbre-pitch (Experiment 2)--interact in speeded classification. Subjects classified values from one dimension while the other dimension was (1) held constant (baseline), (2) varied orthogonally (filtering), or (3) correlated linearly. The subjects showed substantial Garner interference when classifying all dimensions--that is, poor performance at filtering relative to baseline. Timbre and loudness displayed redundancy gain (i.e., performance faster than baseline) when correlated positively, but redundancy loss (i.e., interference) when correlated negatively. Timbre and pitch displayed redundancy gain however dimensions were correlated. Both pairs of dimensions showed substantial effects of congruity: Attributes from one dimension were classified faster when paired with "congruent" attributes from the other dimension. The results are interpreted in terms of an interactive multichannel model of auditory processing.

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PubMed1990

Hard and soft interacting dimensions: differential effects of dual context on classification.

In this article, we extend Garner's speeded classification procedure to investigate processes underlying the interaction of the auditory dimensions pitch, loudness, and timbre. In the experiments reported here, subjects classified attributes on these three auditory dimensions. Our extended procedure, called multiclass, is based conceptually on our model of how such dimensions interact; the model explains the perception of attributes from an attended dimension through the action of contextual constraints created by variation along an unattended dimension. Two forms of context are present simultaneously in each multiclass task: intraclass context, variation along the unattended dimension that interferes with the classification of attributes, and redundant context, variation along the unattended dimension that enhances classification. We find that such dual-context situations reliably distinguish two kinds of interacting dimensions. Subjects classifying hard dimensions, here pitch and timbre, resist the ill effects of intraclass context and reap gains from redundant context. Subjects classifying soft dimensions, here loudness, show interference because the attributes are veiled perceptually in dual context. These findings, we argue, demonstrate the power of the multiclass procedure and fit well our view that dimensional interaction entails processing both at the level of the stimulus whole and at the level of stimulus attributes.

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PubMed1989

On cross-modal similarity: the perceptual structure of pitch, loudness, and brightness.

Examined how pitch and loudness correspond to brightness. In the Experiment 1, 16 Ss identified which of 2 lights more resembled each of 16 tones; in Experiment 2, 8 of the same 16 Ss rated the similarity of lights to lights, tones to tones, and lights to tones. (1) Pitch and loudness both contributed to cross-modal similarity, but for most Ss pitch contributed more. (2) Individuals differed as to whether pitch or loudness contributed more; these differences were consistent across matching and similarity scaling. (3) Cross-modal similarity depended largely on relative stimulus values. (4) Multidimensional scaling revealed 2 perceptual dimensions, loudness and pitch, with brightness common to both. A simple quantitative model can describe the cross-modal comparisons, compatible with the view that perceptual similarity may be characterized through a malleable spatial representation that is multimodal as well as multidimensional.

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