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This study explores the effects of native prosodic system and segmental context on the perception of Cantonese tones by Mandarin and Japanese listeners. In Experiment 1, 13 Mandarin and 13 Japanese subjects took part in a two-alternative forced-choice discrimination test of Cantonese tones in different segmental contexts (familiar vs unfamiliar). In Experiment 2, 20 Mandarin listeners participated in a perceptual assimilation task that examined the cross-language perceptual similarity between Mandarin and Cantonese tones. Results showed that Mandarin listeners were comparable to Japanese counterparts in discriminability, but the former attended more to pitch contour differences while the latter were more sensitive to pitch height. Moreover, the effect of segmental context was significant exclusively in the Mandarin group, whereas the Japanese group performed stably across syllables in discriminating Cantonese tones. It seemed that unfamiliar context rendered lower perceptual similarity, which further hindered corresponding discrimination by the Mandarin group. In addition, segmental effects were mainly observed in the assimilation patterns of category goodness or uncategorized-categorized. These findings suggested that non-native tone perception could be modulated by listeners' native prosodic structures in a finer way.

[EN] Human-machine interaction is increasingly dependent on speech communication, mainly due to the remarkable performance of Machine Learning models in speech recognition tasks. However, these models can be fooled by adversarial examples, which are inputs in-tentionally perturbed to produce a wrong prediction without the changes being noticeable to humans. While much research has focused on developing new techniques to generate adversarial perturbations, less attention has been given to aspects that determine whether and how the perturbations are noticed by humans. This question is relevant since high fool-ing rates of proposed adversarial perturbation strategies are only valuable if the perturba-tions are not detectable. In this paper we investigate to which extent the distortion metrics proposed in the literature for audio adversarial examples, and which are commonly applied to evaluate the effectiveness of methods for generating these attacks, are a reliable mea-sure of the human perception of the perturbations. Using an analytical framework, and an experiment in which 36 subjects evaluate audio adversarial examples according to different factors, we demonstrate that the metrics employed by convention are not a reliable measure of the perceptual similarity of adversarial examples in the audio domain. This work was supported by the Basque Government (PRE_2019_1_0128 predoctoral grant, IT1244-19 and project KK-2020/00049 through the ELKARTEK program); the Spanish Ministry of Economy and Competitiveness MINECO (projects TIN2016-78365-R and PID2019-104966GB-I00); and the Spanish Ministry of Science, Innovation and Universities (FPU19/03231 predoctoral grant). The authors would also like to thank to the Intelligent Systems Group (University of the Basque Country UPV/EHU, Spain) for providing the computational resources needed to develop the project, as well as to all the participants that took part in the experiments.

Hops, the flowers of the Humulus lupus plant, are almost exclusively used in beer production, where they add important flavor qualities, such as bitter taste and a variety of aromas, to the finished product. Depending on concentration, variety, and time of addition, different beer styles are created, appealing to a broad range of consumer needs. Consumers of different beer styles both state and reveal a strong preference for their respective preferred style, presumably due to their familiarity with unique aromas and flavors experienced with different beer styles. Here we use several rapid profiling methods – free sorting (FS) in combination with check-all-that-apply (CATA) – to perceptually characterize nine samples of hops (7 varieties; 2 blind duplicates; all whole hops cones) with naive participants who had been segmented by their typical beer consumption habits (craft versus light beer consumers). The ‘light’ group (n = 30) exclusively consumed light, American lager beer styles while the ‘craft’ group (n = 32) exclusively consumed what they considered ‘craft’ or ‘micro-brew’ beers, which are typically associated with more intense hop flavors. All participants were asked to first sort the whole hop cone samples into groups based solely on perceptual similarity; they were then asked to endorse a list of 24 common hops aroma descriptors in a CATA task. Sorting data were used to generate perceptual maps via DISTATIS. Inspection of the perceptual maps indicate participants successfully differentiated between hop samples, and no differences in the number of groups formed between the two consumer groups were found; however, the two cohorts grouped hops samples differently, and resulting maps showed little agreement. Further, the light beer drinkers checked significantly fewer attributes in the CATA task to describe their groupings of hop cones and were also less discriminating between the hops cones relative to the craft beer consumers. These data suggest free sorting can be used to profile hops, and observed differences between types of beer drinkers are both perceptual and linguistic in nature.

Perceptual similarities between a specific stimulus and other stimuli of the same modality provide valuable information about the structure and geometry of sensory spaces. While typically a subject of behavioral experiments in humans, perceptual similarities, or distances, are rarely measured in other species. However, understanding the neural computations responsible for sensory representations requires the monitoring and sometime manipulating of neural activity, which is more readily achieved in other experimental models. Here we develop a behavioral paradigm that allows for the quantifying of perceptual similarity between sensory stimuli using mouse olfaction as a model system.

Perceptual quality enhancement of heavily compressed videos is a difficult, unsolved problem because there still not exists a suitable perceptual similarity loss function between two video pairs. Motivated by the fact that it is hard to design unified training objectives which are perceptual-friendly for enhancing regions with smooth content and regions with rich textures simultaneously, in this paper, we propose a simple yet effective novel solution dubbed "Adaptive Spatial-Temporal Fusion of Two-Stage Multi-Objective Networks" (ASTF) to adaptive fuse the enhancement results from networks trained with two different optimization objectives. Specifically, the proposed ASTF takes an enhancement frame along with its neighboring frames as input to jointly predict a mask to indicate regions with high-frequency textual details. Then we use the mask to fuse two enhancement results which can retain both smooth content and rich textures. Extensive experiments show that our method achieves a promising performance of compressed video perceptual quality enhancement.

With the growing use of camera devices, the industry has many image datasets that provide more opportunities for collaboration between the machine learning community and industry. However, the sensitive information in the datasets discourages data owners from releasing these datasets. Despite recent research devoted to removing sensitive information from images, they provide neither meaningful privacy-utility trade-off nor provable privacy guarantees. In this study, with the consideration of the perceptual similarity, we propose perceptual indistinguishability (PI) as a formal privacy notion particularly for images. We also propose PI-Net, a privacy-preserving mechanism that achieves image obfuscation with PI guarantee. Our study shows that PI-Net achieves significantly better privacy utility trade-off through public image data.

International audience; In this paper an experimental method to quantify perceptual differences between acoustic stimuli is presented. The experiments are implemented as a signal-in-noise task, where two sounds are to be discriminated. By adjusting the signal-to-noise ratio (SNR) the difficulty of the sound discrimination is manipulated. If two sounds are very similar already, a low level of added noise (high SNR) makes the discrimination task difficult. For more dissimilar sounds, a higher amount of noise (lower SNR) is needed to affect discriminability. In other words, a strong correlation between SNR and similarity is expected. The experimental noises are generated to have similar spectro-temporal properties to those of the test stimuli. As a study case, the suggested method was used to evaluate recordings of one note played on seven Viennese pianos using (1) non-reverberant sounds (as recorded) and (2) reverberant sounds, where reverberation was added by means of digital convolu- tion. The experimental results of the suggested method were compared with a similarity experiment using the method of triadic comparisons. The results of both methods were significantly correlated with each other.

Korean loanwords borrowed from English that end in voiceless stops frequently undergo vowel insertion. This vowel insertion is interesting since voiceless stops are permissible in final position in Korean native words. The perceptual similarity approach claims that this seemingly unnecessary vowel insertion is motivated by perceptual similarity between English and Korean forms. The current study reports on a perception experiment designed to examine whether Korean listeners actually judge English forms to be similar to Korean forms. In an AXB similarity judgment experiment, Korean learners of English listened to a triplet, consisting of an English stop-final form (CVC) and two Korean forms, one ending in a stop (CVC) and the other ending in stop-vowel (CVCV), and indicated which of the two Korean forms the English form sounded more similar to. The experimental result showed that Korean listeners were more likely to judge Korean CVCV as more similar to English CVC than Korean CVC when the English form ended in a released stop, and that final stress did not have a significant effect. This finding turns out to be consistent with the perceptual similarity approach, indicating that the English form could be acoustically similar to the Korean pronunciation.

This study tests whether Australian English (AusE) and European Spanish (ES) listeners differ in their categorisation and discrimination of Brazilian Portuguese (BP) vowels. In particular, we investigate two theoretically relevant measures of vowel category overlap (acoustic vs. perceptual categorisation) as predictors of non-native discrimination difficulty. We also investigate whether the individual listener’s own native vowel productions predict non-native vowel perception better than group averages. The results showed comparable performance for AusE and ES participants in their perception of the BP vowels. In particular, discrimination patterns were largely dependent on contrast-specific learning scenarios, which were similar across AusE and ES. We also found that acoustic similarity between individuals’ own native productions and the BP stimuli were largely consistent with the participants’ patterns of non-native categorisation. Furthermore, the results indicated that both acoustic and perceptual overlap successfully predict discrimination performance. However, accuracy in discrimination was better explained by perceptual similarity for ES listeners and by acoustic similarity for AusE listeners. Interestingly, we also found that for ES listeners, the group averages explained discrimination accuracy better than predictions based on individual production data, but that the AusE group showed no difference.

Subsequent search misses (SSM) refer to the decrease in accuracy of second target detection in dual-target visual search. One of the theoretical explanations of SSM errors is similarity bias – the tendency to search for similar targets and to miss the dissimilar ones. The current study focuses on both perceptual and categorical similarity and their individual roles in SSM. Five experiments investigated the role of perceptual and categorical similarity in subsequent search misses, wherein perceptual and categorical similarities were manipulated separately, and task relevance was controlled. The role of both perceptual and categorical similarity was revealed, however, the categorical similarity had greater impact on second target detection. The findings of this research suggest the revision of the traditional perceptual set hypothesis that mainly focuses on perceptual target similarity in multiple target visual search.

Supplementary information available online at https://jeb.biologists.org/lookup/doi/10.1242/jeb.227611.supplemental.; International audience; How animals perceive and learn complex stimuli, such as mixtures of odorants, is a difficult problem, for which the definition of general rules across the animal kingdom remains elusive. Recent experiments conducted in human and rodent adults as well as newborn rabbits suggested that these species process particular odor mixtures in a similar, configural manner. Thus, the binary mixture of ethyl isobutyrate (EI) and ethyl maltol (EM) induces configural processing in humans, who perceive a mixture odor quality (pineapple) that is distinct from the quality of each component (strawberry and caramel). Similarly, rabbit neonates treat the mixture differently, at least in part, from its components. In the present study, we asked whether the properties of the EI.EM mixture extend to an influential invertebrate model, the honey bee Apis mellifera. We used appetitive conditioning of the proboscis extension response to evaluate how bees perceive the EI.EM mixture. In a first experiment, we measured perceptual similarity between this mixture and its components in a generalization protocol. In a second experiment, we measured the ability of bees to differentiate between the mixture and both of its components in a negative patterning protocol. In each experimental series, the performance of bees with this mixture was compared with that obtained with four other mixtures, chosen from previous work in humans, newborn rabbits and bees. Our results suggest that when having to differentiate mixture and components, bees treat the EI.EM in a robust configural manner, similarly to mammals, suggesting the existence of common perceptual rules across the animal kindgdom.

Wavelength is a physical measure of light, and the intricate understanding of its link to perceived colour enables the creation of perceptual entities such as metamers—non-overlapping spectral compositions that generate identical colour percepts1. By contrast, scientists have been unable to develop a physical measure linked to perceived smell, even one that merely reflects the extent of perceptual similarity between odorants2. Here, to generate such a measure, we collected perceptual similarity estimates of 49,788 pairwise odorants from 199 participants who smelled 242 different multicomponent odorants and used these data to refine a predictive model that links odorant structure to odorant perception3. The resulting measure combines 21 physicochemical features of the odorants into a single number—expressed in radians—that accurately predicts the extent of perceptual similarity between multicomponent odorant pairs. To assess the usefulness of this measure, we investigated whether we could use it to create olfactory metamers. To this end, we first identified a cut-off in the measure: pairs of multicomponent odorants that were within 0.05 radians of each other or less were very difficult to discriminate. Using this cut-off, we were able to design olfactory metamers—pairs of non-overlapping molecular compositions that generated identical odour percepts. The accurate predictions of perceptual similarity, and the ensuing creation of olfactory metamers, suggest that we have obtained a valid olfactory measure, one that may enable the digitization of smell. By collecting nearly 50,000 perceptual estimates of smell, a reliable physicochemical measure that links odorant structure to odorant perception at a resolution that enables the creation of olfactory metamers was derived.

Previous false memory research has suggested that older adults' false memories are based on an overreliance on gist processing in the absence of item-specific details. Yet, false memory studies have rarely taken into consideration the precise role of item-item similarity on the cognitive and neural mechanisms underlying perceptual false memories in older adults. In addition, work in our laboratory has suggested that when investigating the neural basis of false memories in older adults, it is equally as critical to take into account interindividual variability in behavior. With both factors in mind, the present study was the first to examine how both controlled, systematic differences in perceptual relatedness between targets and lures and individual differences in true and false recognition contribute to the neural basis of both true and false memories in older adults. Results suggest that between-subject variability in memory performance modulates neural activity in key regions associated with false memories in aging, whereas systematic differences in perceptual similarity did not modulate neural activity associated with false memories.

The overinvestment account of the attentional blink (AB) posits that the AB results from the allocation of more resources than necessary to encode a first target (T1), which in turn lowers the resources available to encode a second target (T2) shortly thereafter. Across two experiments, we examined whether resource allocation to T1, and thus overinvestment that results in an AB effect, might be limited by perceptual mechanisms that evaluate the need for encoding resources. The key result observed in both experiments was that a relatively easy to encode T1 can nonetheless result in an AB when it is perceptually similar to a more difficult to encode T1. The importance of experimental context as an influence on the allocation, or overinvestment, of attentional resources to T1 is highlighted by these findings.

The 20th Annual Conference of the International Speech Communication Association (Interspeech 2019), Graz, Austria, 15-19 September 2019

Recent studies have demonstrated the effectiveness of the voice for communicating sonic ideas, and the accuracy with which it can be used to imitate acoustic instruments, synthesised sounds and environmental sounds. However, there has been little research on vocal imitation of percussion sounds, particularly concerning the perceptual similarity between imitations and the sounds being imitated. In the present study we address this by investigating how accurately musicians can vocally imitate percussion sounds, in terms of whether listeners consider the imitations ‘more similar’ to the imitated sounds than to other same–category sounds. In a vocal production task, 14 musicians imitated 30 drum sounds from five categories (cymbals, hats, kicks, snares, toms). Listeners were then asked to rate the similarity between the imitations and same–category drum sounds via web based listening test. We found that imitated sounds received the highest similarity ratings for 16 of the 30 sounds. The similarity between a given drum sound and its imitation was generally rated higher than for imitations of another same–category sound, however for some drum categories (snares and toms) certain sounds were consistently considered most similar to the imitations, irrespective of the sound being imitated. Finally, we apply an existing auditory image based measure for perceptual similarity between same–category drum sounds, to model the similarity ratings using linear mixed effect regression. The results indicate that this measure is a good predictor of perceptual similarity between imitations and imitated sounds, when compared to acoustic features containing only temporal or spectral features.

Learning new identities is crucial for effective social interaction. A critical aspect of this process is the integration of different images from the same face into a view-invariant representation that can be used for recognition. The representation of symmetrical viewpoints has been proposed to be a key computational step in achieving view-invariance. The aim of this study was to determine whether the representation of symmetrical viewpoints in face-selective regions is directly linked to the perception and recognition of face identity. In Experiment 1, we measured fMRI responses while male and female human participants viewed images of real faces from different viewpoints (−90, −45, 0, 45, and 90° from full-face view). Within the face regions, patterns of neural response to symmetrical views (−45 and 45° or −90 and 90°) were more similar than responses to nonsymmetrical views in the fusiform face area and superior temporal sulcus, but not in the occipital face area. In Experiment 2, participants made perceptual similarity judgements to pairs of face images. Images with symmetrical viewpoints were reported as being more similar than nonsymmetric views. In Experiment 3, we asked whether symmetrical views also convey an advantage when learning new faces. We found that recognition was best when participants were tested with novel face images that were symmetrical to the learning viewpoint. Critically, the pattern of perceptual similarity and recognition across different viewpoints predicted the pattern of neural response in face-selective regions. Together, our results provide support for the functional value of symmetry as an intermediate step in generating view-invariant representations.SIGNIFICANCE STATEMENTThe recognition of identity from faces is crucial for successful social interactions. A critical step in this process is the integration of different views into a unified, view-invariant representation. The representation of symmetrical views (e.g., left profile and right profile) has been proposed as an important intermediate step in computing view-invariant representations. We found view symmetric representations were specific to some face-selective regions, but not others. We also show that these neural representations influence the perception of faces. Symmetric views were perceived to be more similar and were recognized more accurately than nonsymmetric views. Moreover, the perception and recognition of faces at different viewpoints predicted patterns of response in those face regions with view symmetric representations.

Animals can effortlessly adapt their behavior by generalizing from past aversive experiences, allowing to avoid harm in novel situations. We studied how visual information was sampled by eye-movements during this process called fear generalization, using faces organized along a circular two-dimensional perceptual continuum. During learning, one face was conditioned to predict a harmful event, whereas the most dissimilar face stayed neutral. This introduced an adversity gradient along one specific dimension, while the other, unspecific dimension was defined solely by perceptual similarity. Aversive learning changed scanning patterns selectively along the adversity-related dimension, but not the orthogonal dimension. This effect was mainly located within the eye region of faces. Our results provide evidence for adaptive changes in viewing strategies of faces following aversive learning. This is compatible with the view that these changes serve to sample information in a way that allows discriminating between safe and adverse for a better threat prediction.

In this chapter, I reconstruct Quine’s attempts to accommodate the privacy of stimulus meaning in his naturalized epistemology. These attempts span three decades and equally many monographs as well as a number of articles. Furthermore, I delineate his final proposal to solve it, which relies on natural selection to guarantee a preestablished harmony of innate perceptual similarity standards, and I discuss the extent to which this final solution still agrees with the basic doctrines that Quine defended in the 1960s (and never explicitly retracted). Finally, I develop an internal critique of two central aspects of Quine’s mature account, one focused on his use of natural selection, the other on his conception of pleasure through approval.

Talkers imitate the speech of others through phonetic convergence. The current study examined the influence of dialect-specific features and dialect familiarity on the extent and perceptibility of phonetic convergence. Talkers with Mid-Atlantic and General American dialects repeated words after model talkers with Mid-Atlantic and General American dialects in a shadowing task. Half of the target words contained phonetic variables differing between the two dialects, including /ɔ/, /aeɹ/, and word-initial /stɹ/, and half contained no distinguishing dialect features. In an AXB task, listeners from the Mid-Atlantic region with greater exposure to the Mid-Atlantic dialect and listeners from the Midwestern United States with less exposure to the Mid-Atlantic dialect assessed the perceptual similarity of the two shadowing productions to the original productions of the model talkers. Together, acoustic analyses of the shadowing productions and the results of the AXB task revealed that dialect-specific features facilitated phonetic convergence. This facilitation was stronger for Mid-Atlantic shadowers and model talkers, suggesting that dialect familiarity increases the magnitude of convergence in speech production. However, no differences were observed between listener groups, indicating that greater experience with a dialect may not affect the perception of phonetic convergence.

The COVID-19 pandemic underscored the importance of telepractice in the care of voice disorders. Acoustic analyses are routinely conducted for determining the presence and severity of voice disorders. In the in-person voice evaluation, the recording environment is carefully controlled as the recording's quality can affect the acoustic analyses' output. Telepractice environment does not allow such control, challenging this aspect of voice evaluation. In order to capture the nature of this challenge, this study examined the feasibility of using remotely collected voice recordings for the acoustic evaluation of disordered voice. Thirteen students in Vocal Performance and Theater studies were trained to perform individuals with voice disorders as standardized patients (SPs) and underwent a remote voice evaluation. Recordings of sustained vowels and sentences were collected via Zoom and the SP's personal computers. The fundamental frequency, cepstral peak prominence, and harmonic-to-noise ratio were calculated from these recordings. A listening experiment was also conducted to examine the perceptual similarity between the Zoom and computer recordings. The preliminary data analyses indicated that the mode of voice recording significantly affects the listener's perception and acoustic analyses of dysphonic voice. Clinical implications and possible strategies for future studies will be discussed.

Recent research has demonstrated that ascribing minds to humanlike stimuli is a product of both their perceptual similarity to human faces and whether they engaged configural face processing. We present the findings of two experiments in which we both manipulate the amount of humanlike features in faces (in a doll-to-human morph continuum) and manipulate perceivers’ ability to employ configural face processing (via face inversion) while measuring explicit ratings of mind ascription (Study 1) and the spontaneous activation of humanlike concepts (Study 2). In both studies, we find novel evidence that ascribing minds to entities is an interactive product of both having strong perceptual similarity to human faces and being processed using configural processing mechanisms typical of normal face perception. In short, ascribing mind to others is bounded jointly by the featural cues of the target and by processes employed by the perceiver.

Perceptual and semantic similarity have an impact on object-based attention for the geometric objects. However, no previous studies have disassociated perceptual properties from the semantic ones of real objects that combine perceptual and semantic properties. It is unclear whether the perceptual and semantic similarity of real objects jointly or independently guides attentional deployment. The aim of the present study was to explore the influence of object similarity on object-based attention by using a variant of the two-rectangle paradigm and disassociating the perceptual and semantic similarity of real objects. The results indicated that when the semantic of objects was similar, the object-based effect was larger for the perceptually dissimilar condition than for the perceptually similar condition, because of slower response to invalid different-object location in a dissimilar condition. Moreover, when the perception of objects was similar, the object-based effect was larger for the semantically dissimilar condition than for the semantically similar condition, due to slower response to invalid different-object location in a dissimilar condition. These results suggest that perceptual and semantic similarity can independently guide attentional allocation to real objects and the similarity may constrain the object-based attention in a way of grouping. The current study implies that the attentional prioritization hypothesis is more flexible and effective to explain the real object-based attention and also has some implication to advertising design.

Perceptual grouping contributes to the resolution of visual ambiguity of multiple spatially separate regions in view by enhancing their perceptual similarity. Here, the same ambiguous neural representations are shown also to enhance perceived dissimilarity among the regions. Two separated equiluminant gratings were made ambiguous by introducing rivalry for one of two of their features: orientation or chromaticity. Observers perceived two gratings (above and below fixation) to be different in both color and orientation more often than chance. Overall, a disambiguating process was found to select often for maximal perceived dissimilarity between two objects.

Older adults consistently show elevated rates of false recognition of new items that are related to studied items. This finding has been largely attributed to a greater tendency for older adults to rely on conceptual gist during memory recognition tasks. However, perceptual factors may also be implicated considering that related items are not only conceptually but also perceptually similar. While some findings do suggest that age-related increases in false recognitions can be driven by perceptual factors, little is known about the nature and circumstances under which these factors operate. To address this gap, we measured basic visual ability as well as false recognition for four different image categories (upright faces, inverted faces, chairs, houses) in younger (n = 34) and older (n = 34) adults. Each image category represented different levels of variability in perceptual similarity and pre-experimental exposure. Perceptual similarity was objectively defined on the basis of the low-level properties of the images. We found evidence that perceptual similarity can contribute to elevated rates of false recognition in older adults. Our results also suggest that declines in basic visual abilities influence elevated false recognition in older adults for perceptually similar but not perceptually dissimilar items. We conclude that both perceptual and conceptual similarity can drive age-related differences in false recognition.

Lightness constancy is the ability to perceive surface reflectance correctly despite substantial changes in lighting intensity. A classic view is that lightness constancy is the result of a "discounting" of lighting intensity, and this continues to be a prominent view today. Logvinenko and Maloney (2006) have proposed an alternative approach to understanding lightness constancy, in which observers do not make explicit estimates of reflectance, and lightness constancy is instead based on a perceptual similarity metric that depends on both the reflectance and the illuminance of surfaces viewed under different lighting conditions. Here we compare these two views using a novel, free-adjustment reflectance-matching task. We test whether observers can match reflectance in a task where they are free to adjust both the illuminance and the reflectance of the match stimulus over a wide range. We find that observers can match reflectance under these conditions, which supports the view that observers make explicit estimates of reflectance. We also compare performance in this free adjustment task using physical objects and computer-rendered images as stimuli. We find that lightness constancy is good in both cases, but with some evidence of a glow-related artifact with computer-rendered stimuli.

Copycats often choose brand names that mimic perceptual, conceptual, or both elements of leading brand names. Yet little is known about how perceptual and conceptual similarities of a copycat interact to affect consumers' evaluations, especially in logographic language systems (e.g., Chinese). Three laboratory experiments demonstrate that perceptual similarity alone leads to negative evaluations of copycat brand names; this negative effect, however, can be mitigated when conceptual similarity is added. The underlying mechanism for this effect can be traced to consumers' persuasion knowledge. Perceptual (vs. conceptual) similarity activates consumers' persuasion knowledge about the insincere motives of the copycat brand, which in turn shapes their brand evaluations. However, this effect can become less prominent when conceptual similarity is added because it alleviates use of persuasion knowledge, or when a consumer is in a happy mood because it neutralizes persuasion knowledge. These findings shed light on how different types of copycat strategies interact to affect copycat brand name evaluations and offer important implications for marketing practice. Copyright © 2015 John Wiley & Sons, Ltd.

Whether infants initially learn object labels by mapping them onto similarity-defining perceptual features or onto concepts of object kinds remains under debate. We addressed this question by attempting to teach infants words for behaviorally defined action roles. In a series of experiments, we found that 14-month-olds could rapidly learn a label for the role played by the chaser in a chasing scenario, even when the different instances of chasers did not share perceptual features. Furthermore, when infants could choose, they preferred to interpret a novel label as expressing the agent’s role within the observed interaction rather than as being associated with the agent’s appearance. These results demonstrate that infants can learn labels as easily (or even more easily) for concepts identified by abstract behavioral characteristics as for objects identified by perceptual features. Thus, at early stages of word learning, infants already expect that novel words express concepts.

Almost all nonhuman animals can recognize when one item is the same as another item. It is less clear whether nonhuman animals possess abstract concepts of "same" and "different" that can be divorced from perceptual similarity. Pigeons and monkeys show inconsistent performance, and often surprising difficulty, in laboratory tests of same/different learning that involve only two items. Previous results from tests using multi-item arrays suggest that nonhumans compute sameness along a continuous scale of perceptual variability, which would explain the difficulty of making two-item same/different judgments. Here, we provide evidence that rhesus monkeys can learn a two-item same/different discrimination similar to those on which monkeys and pigeons have previously failed. Monkeys' performance transferred to novel stimuli and was not affected by perceptual variations in stimulus size, rotation, view, or luminance. Success without the use of multi-item arrays, and the lack of effect of perceptual variability, suggests a computation of sameness that is more categorical, and perhaps more abstract, than previously thought.

Nonnative listeners are less accurate than native listeners at identifying, categorizing, and classifying native talkers’ accents, suggesting a decrement in nonnative listeners’ representation of native variation. Nonnative listeners’ representation of nonnative variation, however, may be as robust as, or more robust than, that of native listeners. To compare native and nonnative listeners’ representations of linguistic variation, the current study examined native English, Korean, and Spanish listeners’ classification of native and nonnative talkers by native language. Overall, the listener groups performed with similar accuracy, but they exhibited different perceptual similarity spaces. Specifically, listener groups demonstrated heightened perceptual sensitivity to talkers with whom they share a native language. The results suggest that listeners’ linguistic experiences significantly shape their perceptual representation of nonnative varieties.

Purpose In this investigation, the construct of perceptual similarity was explored in the dysarthrias. Specifically, we employed an auditory free-classification task to determine whether listeners could cluster speakers by perceptual similarity, whether the clusters mapped to acoustic metrics, and whether the clusters were constrained by dysarthria subtype diagnosis. Method Twenty-three listeners blinded to speakers' medical and dysarthria subtype diagnoses participated. The task was to group together (drag and drop) the icons corresponding to 33 speakers with dysarthria on the basis of how similar they sounded. Cluster analysis and multidimensional scaling (MDS) modeled the perceptual dimensions underlying similarity. Acoustic metrics and perceptual judgments were used in correlation analyses to facilitate interpretation of the derived dimensions. Results Six clusters of similar-sounding speakers and 3 perceptual dimensions underlying similarity were revealed. The clusters of similar-sounding speakers were not constrained by dysarthria subtype diagnosis. The 3 perceptual dimensions revealed by MDS were correlated with metrics for articulation rate, intelligibility, and vocal quality, respectively. Conclusions This study shows (a) feasibility of a free-classification approach for studying perceptual similarity in dysarthria, (b) correspondence between acoustic and perceptual metrics to clusters of similar-sounding speakers, and (c) similarity judgments transcended dysarthria subtype diagnosis.

Although young children often rely on salient perceptual cues, such as shape, when categorizing novel objects, children eventually shift towards deeper relational reasoning about category membership. This study investigates what information young children use to classify novel instances of familiar categories. Specifically, we investigated two sources of information that have the potential to facilitate the classification of novel exemplars: (1) comparison of familiar category instances, and (2) attention to function information that might direct children’s attention to functionally relevant perceptual features. Across two experiments, we found that comparing two perceptually similar category members—particularly when function information was also highlighted—led children to discover non-obvious relational features that supported their categorization of novel category instances. Together, these findings demonstrate that comparison may aid in novel object categorization by heightening the salience of less obvious, yet functionally relevant, relational structures that support conceptual reasoning.

We present a content-based surface material retrieval (CBSMR) system for tool-mediated freehand surface exploration that relies on features motivated by the main psychophysical dimensions of tactile surface texture perception. The proposed approach does not require explicit scan force and scan velocity measurements. The perceptual features used in our CBSMR engine cover the tactile dimensions of friction, hardness, macroscopic roughness, microscopic roughness and warmth. We examine 108 surface materials recorded by different users and present the results of a free-sorting grouping experiment with 30 subjects which we conducted to determine the perceptual similarity of the surface materials in our database, providing a ground truth data set for perceived tactile similarity. The outcome of this experiment is used to demonstrate that the proposed CBSMR engine is able to determine the perceptually most similar surface materials for a test query. The proposed set of 8 features leads to a classification precision of 86% and a similarity precision-at-one of 30% when combined with a Euclidean Distance-based classifier.

Auditory displays are currently used in many medical, automotive and aviation settings. Although there are many existing guidelines for developing effective auditory signals, there is a need for more research considering the interaction between signals within a display, especially when sounds originate from conceptually distinct referent systems. Identifying the parameters that are most relevant to auditory similarity can facilitate acoustic branding and the development of guidelines that ensure signals for different systems are distinct without requiring standardisation. Twenty-seven undergraduate students judged the similarity of a set of abstract sounds varying in tempo, or pulse rate, fundamental frequency and burst density. Results indicate that no single parameter is entirely responsible for determining auditory similarity, but temporal characteristics are most salient. These findings have implications for acoustic branding and suggest that designers intending to ensure perceptual similarity and sep...

Summary The tendency to confuse witnessed and suggested information can result in inaccurate eyewitness testimonies and convictions of innocent people. Studies that tested how similarities between witnessed and suggested information affect the tendency to confuse them reached inconsistent results. Here, we claim that there is a more complex and not necessarily linear relationship between similarity and memory distortions. Participants (164) viewed two subsequent stories, which varied in the conceptual and perceptual similarities between them. We found a significant interaction between conceptual and perceptual similarities. When we presented two conceptually different stories, perceptual similarity increased the suggestibility effect compared with perceptual dissimilarity. Conversely, when we presented two conceptually similar stories, perceptual similarity decreased suggestibility compared with perceptual dissimilarity. Accordingly, we suggest that similarity between two events may increase the suggestibility effect. However, counter-intuitively, once similarity reaches a certain threshold, the coherence level between the events reduces the tendency to confuse them. Copyright © 2014 John Wiley & Sons, Ltd.

Recent studies suggest that perceptual similarity among sounds can be used to predict accuracy in perceptual tasks (Dickerson & Gaston, 2014; Gaston, et al., 2017). We operationalize this similarity as distance in a 2D similarity space generated using multidimensional scaling (MDS) on pair-wise similarity stimulus ratings. We tested listeners’ ability to categorize mechanical environmental sounds, and modeled the relationship between stimulus categorization and similarity. Stimuli were 18 mechanical sounds selected hierarchically from three broad categories (vehicles, power tools, and household appliances), and three subcategories. Thirty-five normal hearing listeners completed pair-wise similarity rating and categorization tasks. Perceptual similarity ratings from all paired stimuli were used to develop an MDS solution. Stimuli in the solution generally were segregated by broad category membership, with some exceptions. Categorization performance for each broad category varied, with vehicles being the easiest and household appliances being the most difficult to categorize. MDS distances among the stimuli were used in a simple regression model to predict performance in the categorization task and explain confusions in categorization. The results of this study indicate that perceptual similarity is a strong predictor of variance in listeners’ judgments of complex environmental sounds.Recent studies suggest that perceptual similarity among sounds can be used to predict accuracy in perceptual tasks (Dickerson & Gaston, 2014; Gaston, et al., 2017). We operationalize this similarity as distance in a 2D similarity space generated using multidimensional scaling (MDS) on pair-wise similarity stimulus ratings. We tested listeners’ ability to categorize mechanical environmental sounds, and modeled the relationship between stimulus categorization and similarity. Stimuli were 18 mechanical sounds selected hierarchically from three broad categories (vehicles, power tools, and household appliances), and three subcategories. Thirty-five normal hearing listeners completed pair-wise similarity rating and categorization tasks. Perceptual similarity ratings from all paired stimuli were used to develop an MDS solution. Stimuli in the solution generally were segregated by broad category membership, with some exceptions. Categorization performance for each broad category varied, with vehicles being the ea...

The paper presents the results of a Perceptual Assimilation Task whose aim was to assess and establish the perceptual similarity of SSBE and Bulgarian vowel categories as heard by experienced Bulgarian tertiary-level students and to relate them to those predicted by the articulatory-phonetic similarities between the vowel systems of the two languages. The PAT showed that the participants were able to fit all English vowels into Bulgarian categories, using any detected quantitative, qualitative or feature similarities. The results showed that PAM accounts for the assimilation patterns of most English vowels, which were mapped to PAM assimilation types. The study is designed to help further research that examines the production patterns of SSBE and Bulgarian vowels by these same students to determine to what extent the perceptual assimilation patterns can predict difficulties L2 learners encounter in the acquisition of the vowel sounds of Standard Southern British English.

Perceptual similarity between stimuli is often assessed via generalization, the response to stimuli that are similar to the one which was previously conditioned. Although conditioning procedures are variable, studies on how this variation may affect perceptual similarity remain scarce. Here, we use a combination of behavioural and computational analyses to investigate the influence of olfactory conditioning procedures on odour generalization in ants. Insects were trained following either absolute conditioning, in which a single odour (an aldehyde) was rewarded with sucrose, or differential conditioning, in which one odour (the same aldehyde) was similarly rewarded and another odour (an aldehyde differing in carbon-chain length) was punished with quinine. The response to the trained odours and generalization to other aldehydes were assessed. We show that olfactory similarity, rather than being immutable, varies with the conditioning procedure. Compared with absolute conditioning, differential conditioning enhances olfactory discrimination. This improvement is best described by a multiplicative interaction between two independent processes, the excitatory and inhibitory generalization gradients induced by the rewarded and the punished odour, respectively. We show that olfactory similarity is dramatically shaped by an individual's perceptual experience and suggest a new hypothesis for the nature of stimulus interactions underlying experience-dependent changes in perceptual similarity.

Maljkovic and Nakayama (1994) demonstrated memory influences in singleton search from one trial to the next, an effect they termed priming of pop-out (PoP). This effect was described as resulting from the persistence of an implicit memory trace, the influence of which could be observed for around five to eight subsequent trials. The seemingly short-lived nature of this priming effect has been attributed to decay of the underlying memory representation that occurs when attention is directed to intervening search items, even when such items are perceptually dissimilar from the search trials upon which PoP is measured (Maljkovic & Nakayama, 2000). The present study reexamines the role of perceptual similarity as a mechanism of interference by examining the influence on PoP of rare search trials that were perceptually distinct with respect to the other, common trials. Long-lasting (n - 16) PoP was observed for rare trials that were composed of distinct target/distractor colors, suggesting that PoP can be observed across at least twice as many trials as has previously been reported. Thus, the time span across which PoP can be measured depends heavily on the nature of the intervening search displays, a result that must be accommodated by current theoretical accounts of PoP.

Artists have long explored the way in which we see the world, and they have developed their own tools to portray their vision. The present study investigated whether the compositional information in paintings, an artistic device invented by artists, is utilized when people view paintings. In Experiment 1, we categorized paintings depending on their compositions through experts’ ratings. Using the stimuli from Experiment 1, Experiment 2 tested if the compositional information interferes with a target detection task. We found that the false alarms increased when the targets and distracters had the same composition compared to when they were different. Finally, Experiments 3A and 3B examined whether composition information influences the perceptual similarity of paintings. Through a multi-dimensional scaling analysis, we first showed that paintings with the same composition were proximately located in the mental space (Experiment 3A). Using this distance from the MDS analysis, we found that performance on the target detection task decreased as this distance became close (Experiment 3B). These results suggest that people make use of compositions in paintings, thus providing a possible link between artworks and the human visual system.

Previous studies have found that talkers converge or diverge in phonetic form during a single conversational session or as a result of long-term exposure to a particular linguistic environment. In the current study, five pairs of previously unacquainted male roommates were recorded at four time intervals during the academic year. Phonetic convergence over time was assessed using a perceptual similarity test and measures of vowel spectra. There were distinct patterns of phonetic convergence during the academic year across roommate pairs, and perceptual detection of convergence varied for different linguistic items. In addition, phonetic convergence correlated moderately with roommates' self-reported closeness. These findings suggest that phonetic convergence in college roommates is variable and moderately related to the strength of a relationship.

This paper presents evidence from a series of perception experiments that non-local restrictions on laryngeal features are restrictions on contrast. First, I present results from two perception experiments and show that the perceptual strength of a contrast in ejection or aspiration correlates with the typology of long-distance restrictions on these segments. I then claim that a language may disallow roots with two ejectives because roots of this type are judged too perceptually similar to a root with only one ejective. Second, I claim that non-local laryngeal restrictions involve restrictions on auditory properties. A third experiment supports the idea that long VOT is relevant in explaining the interaction of ejectives and aspirates in Quechua, thus supporting the proposal that auditory dimensions of contrast are relevant to phonology ( Flemming, 1995; Steriade, 1997 ).

Various factors could conceivably promote the accuracy of guesses during a recognition test. Two that we identified in previous studies are forced-choice testing format and high perceptual similarity between the repeat target and novel foil. In restricted circumstances, the relative perceptual fluency of the target can be compared with that of the foil and used as a reliable cue to guide accurate responses that occur without explicit retrieval—a phenomenon we referred to as “implicit recognition.” In this issue, Jeneson and colleagues report a failure to replicate accurate guesses and also a tendency on the part of subjects to hazard guesses infrequently, even though testing circumstances were very similar to those that we used. To resolve this discrepancy, we developed a simple manipulation to encourage either guessing or confident responding. Encouraging guessing increased both the prevalence of guesses and the accuracy of guesses in a recognition test, relative to when confident responding was encouraged. When guessing was encouraged, guesses were highly accurate (as in our previous demonstrations of implicit recognition), whereas when confident responding was encouraged, guesses were at chance levels (as in Jeneson and colleagues' data). In light of a substantial literature showing high accuracy despite low confidence in certain circumstances, we infer that both the prevalence and accuracy of guessing can be influenced by whether subjects adopt guessing-friendly strategies. Our findings thus help to further characterize conditions likely to promote implicit recognition based on perceptual fluency.

In a perceptual assimilation task, 16 Russian speakers categorized American English (AE) vowels [i[see text], I, epsilon, ae[see tedxt], a[see text], u[see text]] in /Vp/ disyllables into Russian (RU) response categories and rated their perceived goodness on a 9-point Likert scale. Cross-language discriminant analysis established acoustic similarities to Russian vowels. For all but AE [epsilon], acoustic similarity predicted modal assimilation responses. Russian listeners consistently assimilated AE point vowels to their Russian counterparts, whereas assimilation of the remaining vowels was less consistent. These acoustic and perceptual similarity patterns provide a baseline for future studies of AE vowel discrimination by Russian learners of English.

Perception entails not only sensory input (e.g., merely seeing), but also subsidiary motor processes (e.g., moving the eyes); such processes have been neglected in research on aesthetic preferences. To fill this gap, the present research manipulated the fluency of perceptual motor processes independently from sensory input and predicted that this increased fluency would result in increased aesthetic preference for stimulus movements that elicited the same motor movements as had been previously trained. Specifically, addressing the muscles that move the eyes, I trained participants to follow a stimulus movement without actually seeing it. Experiment 1 demonstrated that ocular-muscle training resulted in the predicted increase in preference for trained stimulus movements compared with untrained stimulus movements, although participants had not previously seen any of the movements. Experiments 2 and 3 showed that actual motor matching and not perceptual similarity drove this effect. Thus, beauty may be not only in the eye of the beholder, but also in the eyes’ movements.

Certain odours and certain tastes appear to share common perceptual properties. One example is sweetness, a perceptual experience that results from stimulation of taste receptors on the tongue typically by sugars. The experiment here examined for evidence of this perceptual similarity using a novel and indirect test. Participants were exposed six times each, to three odours (strawberry, caramel, and oregano) and three tastes (sucrose, saline, and citric acid). Following a 10-min interval, participants were given a surprise frequency estimation task, in which they had to judge how often each stimulus had occurred. If sweet-smelling strawberry and caramel odours really do share this perceptual characteristic in common with sweet tasting sucrose, then frequency estimates for sucrose should be overestimated relative to non-sweet tastes. Not only was this observed, but frequency estimates for sweet tastes were also found to correlate with (1) evaluations from a later test of similarity between these sweet smells and sucrose, and (2) the degree to which these odours smelled sweet. These findings suggest a shared perceptual feature between such odours and sucrose - sweetness - under conditions where no judgment of perceptual quality was required.

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 fun...