Optional processes in similarity judgments

A conceptual-perceptual distinctiveness processing account of the superior recognition memory of pictures over environmental sounds

Researchers have proposed a coarser or gist-based representation for sounds, whereas a more verbatim-based representation is retrieved from long-term memory to account for higher recognition performance for pictures. This study examined the mechanism for the recognition advantage for pictures. In Experiment 1A, pictures and sounds were presented in separate trials in a mixed list during the study phase and participants showed in a yes-no test, a higher proportion of correct responses for targets, exemplar foils categorically related to the target, and novel foils for pictures compared with sounds. In Experiment 1B, the picture recognition advantage was replicated in a two-alternative forced-choice test for the novel and exemplar foil conditions. For Experiment 2A, even when verbal labels (i.e., written labels) were presented for sounds during the study phase, a recognition advantage for pictures was shown for both targets and exemplar foils. Experiment 2B showed that the presence of written labels for sounds, during both the study and test phases did not eliminate the advantage of recognition of pictures in terms of correct rejection of exemplar foils. Finally, in two additional experiments, we examined whether the degree of similarity within pictures and sounds could account for the recognition advantage of pictures. The mean similarity rating for pictures was higher than the mean similarity rating for sounds in the exemplar test condition, whereas mean similarity rating for sounds was higher than pictures in the novel test condition. These results pose a challenge for some versions of distinctiveness accounts of the picture superiority effect. We propose a conceptual-perceptual distinctiveness processing account of recognition memory for pictures and sounds.

Avoiding Conflict: When Speaker Coordination Does Not Require Conceptual Agreement

In this paper we discuss the socialization hypothesis-the idea that speakers of the same (linguistic) community should share similar concepts given that they are exposed to similar environments and operate in highly-coordinated social contexts-and challenge the fact that it is assumed to constitute a prerequisite to successful communication. We do so using distributional semantic models of meaning (DSMs) which create lexical representations via latent aggregation of co-occurrence information between words and contexts. We argue that DSMs constitute particularly adequate tools for exploring the socialization hypothesis given that 1) they provide full control over the notion of background environment, formally characterized as the training corpus from which distributional information is aggregated; and 2) their geometric structure allows for exploiting alignment-based similarity metrics to measure inter-subject alignment over an entire semantic space, rather than a set of limited entries. We propose to model coordination between two different DSMs trained on two distinct corpora as dimensionality selection over a dense matrix obtained via Singular Value Decomposition This approximates an ad-hoc coordination scenario between two speakers as the attempt to align their similarity ratings on a set of word pairs. Our results underline the specific way in which linguistic information is spread across singular vectors, and highlight the need to distinguish agreement from mere compatibility in alignment-based notions of conceptual similarity. Indeed, we show that compatibility emerges from idiosyncrasy so that the unique and distinctive aspects of speakers' background experiences can actually facilitate-rather than impede-coordination and communication between them. We conclude that the socialization hypothesis may constitute an unnecessary prerequisite to successful communication and that, all things considered, communication is probably best formalized as the cooperative act of avoiding conflict, rather than maximizing agreement.

Brightness perception for musical instrument sounds: Relation to timbre dissimilarity and source-cause categories

Timbre dissimilarity of orchestral sounds is well-known to be multidimensional, with attack time and spectral centroid representing its two most robust acoustical correlates. The centroid dimension is traditionally considered as reflecting timbral brightness. However, the question of whether multiple continuous acoustical and/or categorical cues influence brightness perception has not been addressed comprehensively. A triangulation approach was used to examine the dimensionality of timbral brightness, its robustness across different psychoacoustical contexts, and relation to perception of the sounds' source-cause. Listeners compared 14 acoustic instrument sounds in three distinct tasks that collected general dissimilarity, brightness dissimilarity, and direct multi-stimulus brightness ratings. Results confirmed that brightness is a robust unitary auditory dimension, with direct ratings recovering the centroid dimension of general dissimilarity. When a two-dimensional space of brightness dissimilarity was considered, its second dimension correlated with the attack-time dimension of general dissimilarity, which was interpreted as reflecting a potential infiltration of the latter into brightness dissimilarity. Dissimilarity data were further modeled using partial least-squares regression with audio descriptors as predictors. Adding predictors derived from instrument family and the type of resonator and excitation did not improve the model fit, indicating that brightness perception is underpinned primarily by acoustical rather than source-cause cues.

Acoustic and Categorical Dissimilarity of Musical Timbre: Evidence from Asymmetries Between Acoustic and Chimeric Sounds

This paper investigates the role of acoustic and categorical information in timbre dissimilarity ratings. Using a Gammatone-filterbank-based sound transformation, we created tones that were rated as less familiar than recorded tones from orchestral instruments and that were harder to associate with an unambiguous sound source (Experiment 1). A subset of transformed tones, a set of orchestral recordings, and a mixed set were then rated on pairwise dissimilarity (Experiment 2A). We observed that recorded instrument timbres clustered into subsets that distinguished timbres according to acoustic and categorical properties. For the subset of cross-category comparisons in the mixed set, we observed asymmetries in the distribution of ratings, as well as a stark decay of inter-rater agreement. These effects were replicated in a more robust within-subjects design (Experiment 2B) and cannot be explained by acoustic factors alone. We finally introduced a novel model of timbre dissimilarity based on partial least-squares regression that compared the contributions of both acoustic and categorical timbre descriptors. The best model fit (R² = 0.88) was achieved when both types of descriptors were taken into account. These findings are interpreted as evidence for an interplay of acoustic and categorical information in timbre dissimilarity perception.

Polarity correspondence effect between loudness and lateralized response set

Performance is better when a high pitch tone is associated with an up or right response and a low pitch tone with a down or left response compared to the opposite pairs, which is called the spatial-musical association of response codes effect. The current study examined whether polarity codes are formed in terms of the variation in loudness. In Experiments 1 and 2, in which participants performed a loudness-judgment task and a timbre-judgment task respectively, the correspondence effect was obtained between loudness and response side regardless of whether loudness was relevant to the task or not. In Experiments 3 and 4, in which the identical loudness- and timbre-judgment tasks were conducted while the auditory stimulus was presented only to the left or right ear, the correspondence effect was modulated by the ear to which the stimulus was presented, even though the effect was marginally significant in Experiment 4. The results suggest that loudness produced polarity codes that influenced response selection (Experiments 1 and 2), and additional spatial codes provided by stimulus position modulated the effect, generating the stimulus eccentricity effect (Experiments 3 and 4), which is consistent with the polarity correspondence principle.

Selective attention to pitch amid conflicting auditory information: context-coding and filtering strategies

An auditory Eriksen-flanker task was used to study how conflicting information interferes with selective attention to task-relevant differences in pure-tone frequency. Across the observation intervals of the discrimination task, the relevant frequency differences between target tones were positive, but within an observation interval, they could appear to be small or negative relative to conflicting differences in flanker tones leading or trailing the target. Being correct required attending to the between-target and ignoring the target-flanker pitch relation (across and within observation-interval, respectively). The interference index was an elevation of conflict-laden frequency discrimination thresholds (FDTs), relative to no-conflict FDTs. When conflicting differences in frequency or level (but not in duration) trailed the relevant differences, interference (i.e., FDT elevation) was large and persistent, increased with the target-flanker time proximity, but decreased with extensive training. Interference occurs when the target-flanker pitch relation is more prominent than the one between targets, and the physical and/or perceptual effects of relevant and conflicting differences tend to cancel one another, as with the above conflicting differences. With untrained participants, the target-flanker pitch relation is most prominent in conditions fostering both the perceptual grouping of the target and flanker (e.g., close time proximity), and the recency and salience of the conflicting differences (e.g., trailing conflicting difference); conversely, by lessening such grouping and salience, prolonged training decreases or nullifies the interference. The interference observed herein does not arise because the relevant and the conflicting differences each prompt separate decisions or responses that are in mutual conflict; instead, it arises from the early-stage interaction between their perceptual effects.

The role of a change heuristic in judgments of sound intensity

Leboe and Mondor (2008) demonstrated that participants will apply a change heuristic when making duration judgments. In this study we investigated whether participants would apply this same change heuristic when making judgments about the perceived intensity of a sound. In two experiments, participants were presented with two consecutive sounds on each of a series of trials and their task was to judge whether the second sound was louder or quieter than the first. In Experiment 1, participants were more likely to judge sounds that increased in frequency as louder in intensity than sounds that maintained a constant frequency. In Experiment 2, participants were more likely to judge sounds that either increased or decreased in frequency as louder in intensity than sounds that maintained a constant frequency. We interpret these results as evidence that reliance on a change heuristic leads to the illusion of increased intensity.

Behavioral and electrophysiological effects of distractor variation on auditory selective attention

Two experiments investigated the effects on auditory selection of varying distractor values in memory. Participants performed a set of control (single distractor) and distractor-variation (multiple distractors) tasks, classifying targets by pitch (Experiments 1A and 2) or loudness (Experiment 1B) while ignoring previously presented (and spatially separate) distractors. When both targets and distractors varied in pitch, the degree of variation among the distractors increasingly disrupted classification accuracy and reaction time to the targets. Physiologically, the degree of distractor variation boosted the N1 response to distractors, the P2 response to both targets and distractors, and the slow-wave response to targets (400-600 ms after stimulus onset). The results suggest that target representations are diminished in distinctiveness as distractors activate a wider range of the task-relevant continuum in working memory.

Interactive processing of timbre dimensions: a Garner interference study

Timbre characterizes the identity of a sound source. Psychoacoustic studies have revealed that timbre is a multidimensional perceptual attribute with multiple underlying acoustic dimensions of both temporal and spectral types. Here we investigated the relations among the processing of three major timbre dimensions characterized acoustically by attack time, spectral centroid, and spectrum fine structure. All three pairs of these dimensions exhibited Garner interference: speeded categorization along one timbre dimension was affected by task-irrelevant variations along another timbre dimension. We also observed congruency effects: certain pairings of values along two different dimensions were categorized more rapidly than others. The exact profile of interactions varied across the three pairs of dimensions tested. The results are interpreted within the frame of a model postulating separate channels of processing for auditory attributes (pitch, loudness, timbre dimensions, etc.) with crosstalk between channels.

Odor/taste integration and the perception of flavor

Perceptions of the flavors of foods or beverages reflect information derived from multiple sensory afferents, including gustatory, olfactory, and somatosensory fibers. Although flavor perception therefore arises from the central integration of multiple sensory inputs, it is possible to distinguish the different modalities contributing to flavor, especially when attention is drawn to particular sensory characteristics. Nevertheless, our experiences of the flavor of a food or beverage are also simultaneously of an overall unitary perception. Research aimed at understanding the mechanisms behind this integrated flavor perception is, for the most part, relatively recent. However, psychophysical, neuroimaging and neurophysiological studies on cross-modal sensory interactions involved in flavor perception have started to provide an understanding of the integrated activity of sensory systems that generate such unitary perceptions, and hence the mechanisms by which these signals are "functionally united when anatomically separated". Here we review this recent research on odor/taste integration, and propose a model of flavor processing that depends on prior experience with the particular combination of sensory inputs, temporal and spatial concurrence, and attentional allocation. We propose that flavor perception depends upon neural processes occurring in chemosensory regions of the brain, including the anterior insula, frontal operculum, orbitofrontal cortex and anterior cingulate cortex, as well as upon the interaction of this chemosensory "flavor network" with other heteromodal regions including the posterior parietal cortex and possibly the ventral lateral prefrontal cortex.

Odor/taste integration and the perception of flavor

Perceptions of the flavors of foods or beverages reflect information derived from multiple sensory afferents, including gustatory, olfactory, and somatosensory fibers. Although flavor perception therefore arises from the central integration of multiple sensory inputs, it is possible to distinguish the different modalities contributing to flavor, especially when attention is drawn to particular sensory characteristics. Nevertheless, our experiences of the flavor of a food or beverage are also simultaneously of an overall unitary perception. Research aimed at understanding the mechanisms behind this integrated flavor perception is, for the most part, relatively recent. However, psychophysical, neuroimaging and neurophysiological studies on cross-modal sensory interactions involved in flavor perception have started to provide an understanding of the integrated activity of sensory systems that generate such unitary perceptions, and hence the mechanisms by which these signals are "functionally united when anatomically separated". Here we review this recent research on odor/taste integration, and propose a model of flavor processing that depends on prior experience with the particular combination of sensory inputs, temporal and spatial concurrence, and attentional allocation. We propose that flavor perception depends upon neural processes occurring in chemosensory regions of the brain, including the anterior insula, frontal operculum, orbitofrontal cortex and anterior cingulate cortex, as well as upon the interaction of this chemosensory "flavor network" with other heteromodal regions including the posterior parietal cortex and possibly the ventral lateral prefrontal cortex.

Driven by information: a tectonic theory of Stroop effects

The goal of avoiding distraction (e.g., ignoring words when naming their print colors in a Stroop task) is opposed intrinsically by the penchant to process conspicuous and correlated characteristics of the environment (e.g., noticing trial-to-trial associations between the colors and the words). To reconcile these opposing forces, the authors propose a tectonic theory of selective attention in which 2 memory-based structures--dimensional imbalance and dimensional uncertainty--drive selection by processing salient, surprising, and/or correlated information contained within and across stimulus dimensions. Each structure modulates the buildup of excitation to targets and the buildup of inhibition to distractors and to memories of previous stimuli. Tectonic theory is implemented to simulate the impact of 4 types of context on the presence, magnitude, and direction of congruity effects and task effects in the Stroop paradigm. The tectonic model is shown to surpass other formal models in explaining the range and diversity of Sroop effects.

Similarity in context

Similarity comparisons are highly sensitive to judgment context. Three experiments explore context effects that occur within a single comparison rather than across several trials. Experiment 1 shows reliable intransitivities in which a target is judged to be more similar to stimulus A than to stimulus B, more similar to B than to stimulus C, and more similar to C than to A. Experiment 2 explores the locus of Tversky's (1977) diagnosticity effect in which the relative similarity of two alternatives to a target is influenced by a third alternative. Experiment 3 demonstrates a new violation of choice independence which is explained by object dimensions' becoming foregrounded or backgrounded, depending upon the set of displayed objects. The observed violations of common assumptions to many models of similarity and choice can be accommodated in terms of a dynamic property-weighting process based on the variability and diagnosticity of dimensions.

The role of congruency and pleasantness in odor-induced taste enhancement

Although odorants and tastants are perceived by two different senses, the rated intensity of a tastant may increase if an odorant is added. The size of the odor-induced taste enhancement is said to depend on the perceptual similarity between the tastant and the odorant, and on the task instruction which affects subjects' working concepts of attribute categories. It is investigated whether congruency or pleasantness (halo-effects) can replace perceptual similarity in accounting for odor-induced taste enhancement. Sweetness intensity, pleasantness, and degree of congruency are determined for three sucrose/odorant combinations. Odor-induced enhancement is found only for congruent mixtures (sucrose/strawberry and sucrose/lemon). In addition, highly congruent mixtures are more pleasant than expected under additivity. The pleasantness judgments for incongruent combinations (sucrose/ham) follow a subtractive rule. The congruency ratings can account for a significant part of the pleasantness ratings, but not for the degree of sweetness enhancement. Also, the pleasantness ratings are not related to the degree of enhancement. Therefore, congruency or pleasantness ratings cannot replace similarity ratings in accounting for odor-induced taste enhancement.

Determinants of cumulative successive contrast in saltiness intensity judgments

When all stimuli elicit the same taste quality, solutions preceded by a high concentration level are judged to be significantly less intense than solutions preceded by a low concentration level. After repetitious stimulation with a different tasting stimulus, the intensity of the present stimulus is over-estimated. This phenomenon is called "successive contrast." In the present study, the cumulative effects of three identical stimuli on the saltiness ratings for a test stimulus are investigated. The preceding stimuli are manipulated with regard to taste quality, saltiness intensity, total taste intensity, and complexity. Whether the size of the cumulative contrast effect is associated with the degree of dissimilarity between preceding stimuli and test stimulus, or with the saltiness or total taste intensity of the preceding stimuli, is investigated. The size of the contrast effect depends on the type of preceding stimulus, its intensity, and the type of test stimulus. No association was found with judgments of the degree of dissimilarity between the preceding stimuli and the test stimulus. For nonsalty preceding stimuli, the contrast effects are independent of concentration level. When the preceding stimuli taste at least partly salty, the total intensity appears to determine the size of the contrast for an unmixed salty test stimulus.

Visual-auditory interaction in speeded classification: role of stimulus difference

An experiment examined cross-modal interference and congruence in speeded classification: Subjects had to identify compound (visual-auditory) stimuli as either low or high in spatial position (visual judgment) or low or high in pitch (auditory judgment), in 16 conditions, each of which combined one of four possible pairs of tones, varying in frequency difference, with one of four possible pairs of dots, varying in positional difference. Both classification by position and classification by pitch revealed Garner interference (poorer performance than baseline, with orthogonal variation in the irrelevant dimension) and congruence effects (better performance with congruent than with incongruent stimulus combinations), but pitch classification showed more. Furthermore, the size of the pitch difference strongly affected classification by pitch and less strongly affected classification by position, but the size of the position difference affected neither. The findings are consistent with the view that Garner interference and congruence effects are closely related, perhaps arising from a common source, and suggest that the asymmetries could depend in part on the degree of dimensional overlap between stimuli and responses.

The role of similarity in categorization: providing a groundwork

The relation between similarity and categorization has recently come under scrutiny from several sectors. The issue provides an important inroad to questions about the contributions of high-level thought and lower-level perception in the development of people's concepts. Many psychological models base categorization on similarity, assuming that things belong in the same category because of their similarity. Empirical and in-principle arguments have recently raised objections to this connection, on the grounds that similarity is too unconstrained to provide an explanation of categorization, and similarity is not sufficiently sophisticated to ground most categories. Although these objections have merit, a reassessment of evidence indicates that similarity can be sufficiently constrained and sophisticated to provide at least a partial account of many categories. Principles are discussed for incorporating similarity into theories of category formation.

Contextual influences on interactive processing: effects of discriminability, quantity, and uncertainty

Three contextual factors--(1) the discriminability of stimuli in pitch, (2) the number of stimuli differing in pitch, and (3) the uncertainty regarding which stimuli or tasks would appear--were manipulated as subjects performed speeded loudness classifications in each of six experiments. The magnitude of Garner interference and effects of congruity were used to gauge the degree of interactive processing. Enhancing pitch discriminability caused monotonic increases in interference and congruity. Stimulus-task uncertainty mediated the changes in Garner interference wrought by increased discriminability. Uncertainty also caused a surprising shift in congruity from strongly positive to strongly negative as uncertainty grew. Increasing stimulus quantity lowered interference, but had inconsistent effects on congruity. Regression analyses suggested that, collectively, these three contextual variables underlie most failures of selective attention in speeded classification.

Selective attention to Stroop dimensions: effects of baseline discriminability, response mode, and practice

The framework of dimensional interaction was used to test the hypothesis that the Stroop effect is partially rooted in mismatches in baseline discriminability, with stimulus differences along the word dimension typically exceeding stimulus differences along the color dimension. Subjects made speeded classifications, with either keypresses or vocalizations, of either words or colors. Stroop congruity and Garner interference were measured under conditions in which discriminabilities were (1) matched (Experiments 1 and 4), (2) mismatched in favor of colors (Experiment 2), or (3) mismatched in favor of words (Experiment 3). When matched, colors and words appeared separable, with small interactive effects being reduced or eliminated through practice. When mismatched, asymmetric Stroop and Garner effects emerged, with the more discriminable dimension disrupting classification of the less discriminable dimension. Asymmetric effects were obtained in both response modes, and were not alleviated by practice. We conclude that (1) the Stroop effect is an optional effect, and (2) unequal discriminability causes a mandatory failure of selective attention.