Perceptual Similarity Judgments Research Articles

Perceptual similarity judgments do not predict the distribution of errors in working memory.

Population coding models provide a quantitative account of visual working memory (VWM) retrieval errors with a plausible link to the response characteristics of sensory neurons. Recent work has provided an important new perspective linking population coding to variables of signal detection, including d-prime, and put forward a new hypothesis: that the distribution of recall errors on, for example, a color wheel, is a consequence of the psychological similarity between points in that stimulus space, such that the exponential-like psychophysical distance scaling function can fulfil the role of population tuning and obviate the need to fit a tuning width parameter to recall data. Using four different visual feature spaces, we measured psychophysical similarity and memory errors in the same participants. Our results revealed strong evidence for a common source of variability affecting similarity judgments and recall estimates but did not support any consistent relationship between psychophysical similarity functions and VWM errors. At the group level, the responsiveness functions obtained from the psychophysical similarity task diverged strongly from those that provided the best fit to working memory errors. At the individual level, we found convincing evidence against an association between observed and best-fitting similarity functions. Finally, our results show that the newly proposed exponential-like responsiveness function has in general no advantage over the canonical von Mises (circular normal) function assumed by previous population coding models. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Perceptual similarity judgments predict the precision but not the distribution of errors in working memory

Perceptual similarity judgments predict the precision but not the distribution of errors in working memory

Perceptual similarity is not all: online perception of English coda stops by Korean listeners

AbstractThis study examines conscious judgments of perceptual similarity between foreign and native structures, focusing on vowel epenthesis following coda stops in English nonwords borrowed into Korean. In a similarity judgment experiment, Korean listeners heard a triplet consisting of an English stop-final form and two Korean forms, one ending in a stop and one ending in stop-vowel; then they indicated which of the two Korean forms the English form sounded more similar to. This study investigated six different predictors: release, voicing and place of coda stop, vowel tenseness, final stress, and word length. Similarity judgment choices showed that Korean CVCV is judged as more similar to English CVC than Korean CVC when the English final stop is released or dorsal or when the English word is monosyllabic. Although this result confirms that stop release is indeed a major factor explaining vowel insertion in this context, no effects of stop voicing and vowel tenseness are not compatible with the perceptual similarity hypothesis, which is surprising since they have been previously argued to involve acoustic cues affecting L2 speech perception. These findings support the need for further research that concentrates more on direct perception rather than judgments of perceptual similarity.

Visual stream connectivity predicts assessments of image quality.

Despite extensive study of early vision, new and unexpected mechanisms continue to be identified. We introduce a novel formal treatment of the psychophysics of image similarity, derived directly from straightforward connectivity patterns in early visual pathways. The resulting differential geometry formulation is shown to provide accurate and explanatory accounts of human perceptual similarity judgments. The direct formal predictions are then shown to be further improved via simple regression on human behavioral reports, which in turn are used to construct more elaborate hypothesized neural connectivity patterns. It is shown that the predictive approaches introduced here outperform a standard successful published measure of perceived image fidelity; moreover, the approach provides clear explanatory principles of these similarity findings.

Searching for perceptual similarity within, and between, the (chemical) senses.

In this narrative historical review, I want to take a closer look at the concept of perceptual similarity both as it applies within, and between, the chemical senses (specifically taste and smell). The discussion is linked to issues of affective similarity and connotative meaning. The relation between intramodal and crossmodal judgments of perceptual similarity, and the putatively special status of those odorants that happen to take on taste qualities will also be discussed. An important distinction is drawn between the interrelated, though sometimes distinct, notions of perceptual similarity and crossmodal congruency, specifically as they relate to the comparison of chemosensory stimuli. Such phenomena are often referred to as crossmodal correspondences, or by others (incorrectly in my view), as a kind of ubiquitous synesthesia.

Floral Categorization by Bumblebees: The Perceptual and the Functional

This study examines generalization and perceptual similarity judgments in bumblebees (Bombus impatiens) and addresses whether category formation of floral stimuli is based upon perceptual floral features alone or foraging experiences from reward associations. Previous experiments have found that bees transfer learning based on category membership, but little is known as to how membership is formed. Two experiments using twelve bumblebee colonies examined a) if bees were able to generalize between flowers with little or no perceptual similarity, and b) if bees were able to change which features of the flowers they generalize under different circumstances. All bees were given discrimination training in a radial arm maze using objects and corresponding photographs. Bees in Experiment 1 were trained to categorize stimuli based upon their reward associations while ignoring their perceptual features. Bees in Experiment 2 were trained to categorize either by floral type or dimensionality (2D vs 3D) of the stimuli. Results of tests using unrewarding stimuli revealed that bees were unable to group items without perceptual similarity cues. When perceptually similar flowers did not share the same reward, bees still generalized between them, regardless of experience. However, the reward values of the flowers were not spontaneously disregarded by the bees. Generalizations differed based on the bee’s experiences, although preferences for perceptual similarity remained. Bees grouped flowers based on the relevant features learned through experience rather than just relying on perceptual similarity, but also do not immediately discount similar flowers during foraging, giving a preliminary insight into the role of function in perceptual similarity judgments.

Predictive coding of natural images by V1 firing rates and rhythmic synchronization

SummaryPredictive coding is an important candidate theory of self-supervised learning in the brain. Its central idea is that sensory responses result from comparisons between bottom-up inputs and contextual predictions, a process in which rates and synchronization may play distinct roles. We recorded from awake macaque V1 and developed a technique to quantify stimulus predictability for natural images based on self-supervised, generative neural networks. We find that neuronal firing rates were mainly modulated by the contextual predictability of higher-order image features, which correlated strongly with human perceptual similarity judgments. By contrast, V1 gamma (γ)-synchronization increased monotonically with the contextual predictability of low-level image features and emerged exclusively for larger stimuli. Consequently, γ-synchronization was induced by natural images that are highly compressible and low-dimensional. Natural stimuli with low predictability induced prominent, late-onset beta (β)-synchronization, likely reflecting cortical feedback. Our findings reveal distinct roles of synchronization and firing rates in the predictive coding of natural images.

Dual coding of knowledge in the human brain.

How does the human brain code knowledge about the world? While disciplines such as artificial intelligence represent world knowledge based on human language, neurocognitive models of knowledge have been dominated by sensory embodiment, in which knowledge is derived from sensory/motor experience and supported by high-level sensory/motor and association cortices. The neural correlates of an alternative disembodied symbolic system had previously been difficult to establish. A recent line of studies exploring knowledge about visual properties, such as color, in visually deprived individuals converge to provide positive, compelling evidence for non-sensory, language-derived, knowledge representation in dorsal anterior temporal lobe and extended language network, in addition to the sensory-derived representations, leading to a sketch of a dual-coding knowledge neural framework.

Perceptual quality of BRDF approximations: dataset and metrics

AbstractBidirectional Reflectance Distribution Functions (BRDFs) are pivotal to the perceived realism in image synthesis. While measured BRDF datasets are available, reflectance functions are most of the time approximated by analytical formulas for storage efficiency reasons. These approximations are often obtained by minimizing metrics such as L2—or weighted quadratic—distances, but these metrics do not usually correlate well with perceptual quality when the BRDF is used in a rendering context, which motivates a perceptual study. The contributions of this paper are threefold. First, we perform a large‐scale user study to assess the perceptual quality of 2026 BRDF approximations, resulting in 84138 judgments across 1005 unique participants. We explore this dataset and analyze perceptual scores based on material type and illumination. Second, we assess nine analytical BRDF models in their ability to approximate tabulated BRDFs. Third, we assess several image‐based and BRDF‐based (Lp, optimal transport and kernel distance) metrics in their ability to approximate perceptual similarity judgments.

Age-Related Differences in Sensitivity to Facial Trustworthiness: Perceptual Representation and the Role of Emotional Development.

The ability to discriminate social signals from faces is a fundamental component of human social interactions whose developmental origins are still debated. In this study, 5-year-old (N=29) and 7-year-old children (N=31) and adults (N=34) made perceptual similarity and trustworthiness judgments on a set of female faces varying in level of expressed trustworthiness. All groups represented perceived similarity of the faces as a function of trustworthiness intensity, but such representation becomes more fine-grained with development. Moreover, 5-year-olds' accuracy in choosing the more trustworthy face in a pair varied as a function of children's score at the Test of Emotion Comprehension, suggesting that the ability to perform face-to-trait inferences is related to the development of emotional understanding.

Perceptual similarity judgments of voices: Effects of talker and listener language, vocal source acoustics, and time-reversal

Listeners demonstrate reliable perceptual biases favoring voices speaking their native language versus those speaking a foreign language. This “language-familiarity effect” for voice processing has been found even for perceptual similarity judgments: Voices speaking listeners’ native language sound less alike, even when those recordings have been rendered incomprehensible via time-reversal. Here, we sought to replicate and extend this finding of linguistic effects on voice similarity. Native English- and Mandarin-speaking listeners (both N = 40) rated the perceptual similarity of voices speaking English or Mandarin (both N = 20) for either time-reversed or forward speech. Both listener groups tended to find Mandarin-speaking voices more dissimilar, but this effect was reduced for English-speaking listeners, especially for forward speech. Perceptual similarity judgments of voices were always highly correlated between listener groups and between forward/time-reversed speech. Acoustic measurements (voice fundamental frequency mean and variance, local jitter, harmonics-to-noise ratio, speech rate, and formant dispersion) were also made to ascertain how listeners’ perceptual similarity judgments were related to speech acoustics and whether these relationships differed under time-reversal or across listeners’ or talkers’ native language. Overall, these data suggest that, while native language may influence perceptual dissimilarity of voices, the magnitude of these effects tend to be very small.

Auditory Frequency Representations in Human Somatosensory Cortex.

Recent studies have challenged the traditional notion of modality-dedicated cortical systems by showing that audition and touch evoke responses in the same sensory brain regions. While much of this work has focused on somatosensory responses in auditory regions, fewer studies have investigated sound responses and representations in somatosensory regions. In this functional magnetic resonance imaging (fMRI) study, we measured BOLD signal changes in participants performing an auditory frequency discrimination task and characterized activation patterns related to stimulus frequency using both univariate and multivariate analysis approaches. Outside of bilateral temporal lobe regions, we observed robust and frequency-specific responses to auditory stimulation in classically defined somatosensory areas. Moreover, using representational similarity analysis to define the relationships between multi-voxel activation patterns for all sound pairs, we found clear similarity patterns for auditory responses in the parietal lobe that correlated significantly with perceptual similarity judgments. Our results demonstrate that auditory frequency representations can be distributed over brain regions traditionally considered to be dedicated to somatosensation. The broad distribution of auditory and tactile responses over parietal and temporal regions reveals a number of candidate brain areas that could support general temporal frequency processing and mediate the extensive and robust perceptual interactions between audition and touch.

Perceptual similarity of visual patterns predicts dynamic neural activation patterns measured with MEG

Perceptual similarity is a cognitive judgment that represents the end-stage of a complex cascade of hierarchical processing throughout visual cortex. Previous studies have shown a correspondence between the similarity of coarse-scale fMRI activation patterns and the perceived similarity of visual stimuli, suggesting that visual objects that appear similar also share similar underlying patterns of neural activation. Here we explore the temporal relationship between the human brain's time-varying representation of visual patterns and behavioral judgments of perceptual similarity. The visual stimuli were abstract patterns constructed from identical perceptual units (oriented Gabor patches) so that each pattern had a unique global form or perceptual ‘Gestalt’. The visual stimuli were decodable from evoked neural activation patterns measured with magnetoencephalography (MEG), however, stimuli differed in the similarity of their neural representation as estimated by differences in decodability. Early after stimulus onset (from 50ms), a model based on retinotopic organization predicted the representational similarity of the visual stimuli. Following the peak correlation between the retinotopic model and neural data at 80ms, the neural representations quickly evolved so that retinotopy no longer provided a sufficient account of the brain's time-varying representation of the stimuli. Overall the strongest predictor of the brain's representation was a model based on human judgments of perceptual similarity, which reached the limits of the maximum correlation with the neural data defined by the ‘noise ceiling’. Our results show that large-scale brain activation patterns contain a neural signature for the perceptual Gestalt of composite visual features, and demonstrate a strong correspondence between perception and complex patterns of brain activity.

Clarifying the role of pattern separation in schizophrenia: The role of recognition and visual discrimination deficits

Patients with schizophrenia show marked memory deficits which have a negative impact on their functioning and life quality. Recent models suggest that such deficits might be attributable to defective pattern separation (PS), a hippocampal-based computation involved in the differentiation of overlapping stimuli and their mnemonic representations. One previous study on the topic concluded in favour of pattern separation impairments in the illness. However, this study did not clarify whether more elementary recognition and/or visual discrimination deficits could explain observed group differences. To address this limitation we investigated pattern separation in 22 schizophrenic patients and 24 healthy controls with the use of a task requiring individuals to classify stimuli as repetitions, novel or similar compared to a previous familiarisation phase. In addition, we employed a visual discrimination task involving perceptual similarity judgments on the same images. Results revealed impaired performance in the patient group; both on baseline measure of pattern separation as well as an index of pattern separation rigidity. However, further analyses demonstrated that such differences could be fully explained by recognition and visual discrimination deficits. Our findings suggest that pattern separation in schizophrenia is predicated on earlier recognition and visual discrimination problems. Furthermore, we demonstrate that future studies on pattern separation should include appropriate measures of recognition and visual discrimination performance for the correct interpretation of their findings.

Hip-hop rhymes reiterate phonological typology

In this paper, we analyze a database of rhymes from African-American English hip-hop. The analysis shows that rappers possess detailed implicit knowledge about speech sounds that is largely irrelevant to the sound pattern of their particular language, but has been argued to play a role in constraining possible sound systems across all human languages. We argue that rhyme data are related to phonological typology because many phonological patterns involve the neutralization of contrasts in contexts where they are less perceptible, and rhyme involves implicit judgments of perceptual similarity between sounds. The general finding is that sounds are more likely to mismatch in a rhyme in those contexts where the contrast between the sounds is more likely to neutralize cross-linguistically, even though the contrasts studied here do not neutralize in these contexts in English. The results contribute to the evidence for detailed implicit phonetic knowledge and bear on the issue of synchronic explanation in linguistic theory.

Is statistical learning constrained by lower level perceptual organization?

In order for statistical information to aid in complex developmental processes such as language acquisition, learning from higher-order statistics (e.g. across successive syllables in a speech stream to support segmentation) must be possible while perceptual abilities (e.g. speech categorization) are still developing. The current study examines how perceptual organization interacts with statistical learning. Adult participants were presented with multiple exemplars from novel, complex sound categories designed to reflect some of the spectral complexity and variability of speech. These categories were organized into sequential pairs and presented such that higher-order statistics, defined based on sound categories, could support stream segmentation. Perceptual similarity judgments and multi-dimensional scaling revealed that participants only perceived three perceptual clusters of sounds and thus did not distinguish the four experimenter-defined categories, creating a tension between lower level perceptual organization and higher-order statistical information. We examined whether the resulting pattern of learning is more consistent with statistical learning being “bottom-up,” constrained by the lower levels of organization, or “top-down,” such that higher-order statistical information of the stimulus stream takes priority over perceptual organization and perhaps influences perceptual organization. We consistently find evidence that learning is constrained by perceptual organization. Moreover, participants generalize their learning to novel sounds that occupy a similar perceptual space, suggesting that statistical learning occurs based on regions of or clusters in perceptual space. Overall, these results reveal a constraint on learning of sound sequences such that statistical information is determined based on lower level organization. These findings have important implications for the role of statistical learning in language acquisition.

Disentangling similarity judgments from pragmatic judgments: Response to Sloutsky and Fisher (2012).

Sloutsky and Fisher (2012) attempt to reframe the results presented in Noles and Gelman (2012) as a pure replication of their original work validating the similarity, induction, naming, and categorization (SINC) model. However, their critique fails to engage with the central findings reported in Noles and Gelman, and their reanalysis fails to examine the key comparison of theoretical interest. In addition to responding to the points raised in Sloutsky and Fisher's (2012) critique, we elaborate on the pragmatic factors and methodological flaws present in Sloutsky and Fisher (2004) that biased children's similarity judgments. Our careful replication of that study suggests that, rather than measuring the influence of labels on judgments of perceptual similarity, the original design measured sensitivity to the pragmatics of task demands. Together, the results reported in Noles and Gelman and the methodological problems highlighted here represent a serious challenge to the validity of the SINC model specifically and the words-as-features view more generally. (PsycINFO Database Record (c) 2012 APA, all rights reserved).

Effects of categorical labels on similarity judgments: a critical analysis of similarity-based approaches.

Our goal in the present study was to evaluate the claim that category labels affect children's judgments of visual similarity. We presented preschool children with discriminable and identical sets of animal pictures and asked them to make perceptual judgments in the presence or absence of labels. Our findings indicate that children who are asked to make perceptual judgments about identical items judge discriminable items less accurately when making subsequent similarity judgments. Thus, labels do not generally affect children's perceptual similarity judgments; rather, children's reliance on labels to make similarity judgments appears to be attributable to flaws in the methodological approaches used in prior studies. These results have implications for the role of perceptual and conceptual information in children's categorization and induction.

Effects of categorical labels on similarity judgments: A critical evaluation of a critical analysis: Comment on Noles and Gelman (2012).

Noles and Gelman (2012) attempt to critically reevaluate the claim that linguistic labels affect children's judgments of visual similarity. They report results of an experiment that used a modified version of Sloutsky and Fisher's (2004) task and conclude that "labels do not generally affect children's perceptual similarity judgments; rather, children's reliance on labels to make similarity judgments appears to be attributable to flaws in the methodological approaches used in prior studies" (p. 890). In this comment we demonstrate that these conclusions are based on inadequate analyses and reporting of statistics and are inconsistent with Noles and Gelman's own data. Instead, their data show a perfect replication of Sloutsky and Fisher (2004) and present further evidence that linguistic labels affect similarity judgment of young children.

Conversational role influences speech imitation

This study assessed the impact of a conscious imitation goal on phonetic convergence during conversational interaction. Twelve pairs of unacquainted talkers participated in a conversational task designed to elicit between-talker repetitions of the same lexical items. To assess the degree to which the talkers exhibited phonetic convergence during the conversational task, these repetitions were used to elicit perceptual similarity judgments provided by separate sets of listeners. In addition, perceptual measures of phonetic convergence were compared with measures of articulation rates and vowel formants. The sex of the pair of talkers and a talker's role influenced the degree of phonetic convergence, and perceptual judgments of phonetic convergence were not consistently related to individual acoustic-phonetic attributes. Therefore, even with a conscious imitative goal, situational factors were shown to retain a strong influence on phonetic form in conversational interaction.