Perceptual Tuning Research Articles

Examining the impact of cue similarity and fear learning on perceptual tuning

Past research on the effects of associative aversive learning on discrimination acuity has shown mixed results, including increases, decreases, and no changes in discrimination ability. An animal study found that the type of learning experience determined the direction and extent of learning-induced changes. The current preregistered web-based study aimed to translate these findings to humans. Experiment 1 (N = 245) compared changes in stimulus discrimination between simple learning (only one oriented grating cue), coarse differential conditioning (physically distinct cues), and fine differential conditioning (physically similar cues) as well as to their three respective control groups. The discrimination task consisted of a two-alternative-forced-choice task with oriented grating stimuli. During learning, a specific orientation was paired with unpleasant pictures. Our analysis using generative modeling demonstrated weak to moderate evidence that aversive learning did not alter discrimination acuity in any of the groups. In a follow-up experiment (N = 121), we replicated these findings despite successful learning trajectories in all three groups and a more detailed assessment of discrimination acuity. Contrary to prior assumptions, our findings indicate that aversive learning does not enhance perceptual discrimination, and the presence of additional safety cues does not appear to moderate this effect.

Using global feedback to induce learning of gist of abnormality in mammograms

Extraction of global structural regularities provides general ‘gist’ of our everyday visual environment as it does the gist of abnormality for medical experts reviewing medical images. We investigated whether naïve observers could learn this gist of medical abnormality. Fifteen participants completed nine adaptive training sessions viewing four categories of unilateral mammograms: normal, obvious-abnormal, subtle-abnormal, and global signals of abnormality (mammograms with no visible lesions but from breasts contralateral to or years prior to the development of cancer) and receiving only categorical feedback. Performance was tested pre-training, post-training, and after a week’s retention on 200 mammograms viewed for 500 ms without feedback. Performance measured as d’ was modulated by mammogram category, with the highest performance for mammograms with visible lesions. Post-training, twelve observed showed increased d’ for all mammogram categories but a subset of nine, labelled learners also showed a positive correlation of d’ across training. Critically, learners learned to detect abnormality in mammograms with only the global signals, but improvements were poorly retained. A state-of-the-art breast cancer classifier detected mammograms with lesions but struggled to detect cancer in mammograms with the global signal of abnormality. The gist of abnormality can be learned through perceptual/incidental learning in mammograms both with and without visible lesions, subject to individual differences. Poor retention suggests perceptual tuning to gist needs maintenance, converging with findings that radiologists’ gist performance correlates with the number of cases reviewed per year, not years of experience. The human visual system can tune itself to complex global signals not easily captured by current deep neural networks.

A flexible Python-based touchscreen chamber for operant conditioning reveals improved visual perception of cardinal orientations in mice.

Natural scenes are composed of a wide range of edge angles and spatial frequencies, with a strong overrepresentation of vertical and horizontal edges. Correspondingly, many mammalian species are much better at discriminating these cardinal orientations compared to obliques. A potential reason for this increased performance could be an increased number of neurons in the visual cortex that are tuned to cardinal orientations, which is likely to be an adaptation to the natural scene statistics. Such biased angular tuning has recently been shown in the mouse primary visual cortex. However, it is still unknown if mice also show a perceptual dominance of cardinal orientations. Here, we describe the design of a novel custom-built touchscreen chamber that allows testing natural scene perception and orientation discrimination performance by applying different task designs. Using this chamber, we applied an iterative convergence towards orientation discrimination thresholds for cardinal or oblique orientations in different cohorts of mice. Surprisingly, the expert discrimination performance was similar for both groups but showed large inter-individual differences in performance and training time. To study the discrimination of cardinal and oblique stimuli in the same mice, we, therefore, applied, a different training regime where mice learned to discriminate cardinal and oblique gratings in parallel. Parallel training revealed a higher task performance for cardinal orientations in an early phase of the training. The performance for both orientations became similar after prolonged training, suggesting that learning permits equally high perceptual tuning towards oblique stimuli. In summary, our custom-built touchscreen chamber offers a flexible tool to test natural visual perception in rodents and revealed a training-induced increase in the perception of oblique gratings. The touchscreen chamber is entirely open-source, easy to build, and freely available to the scientific community to conduct visual or multimodal behavioral studies. It is also based on the FAIR principles for data management and sharing and could therefore serve as a catalyst for testing the perception of complex and natural visual stimuli across behavioral labs.

Decoding the neural dynamics of within- and between-language lexical competition: A pediatric neurosurgical case report of a Spanish-English bilingual

Spoken word recognition proceeds by immediately activating items in the mental lexicon which match the incoming speech signal. These items compete for recognition over time. In multilinguals, the array of possible lexical competitors includes items across all their languages. Eye-tracking work indicates that the strength of early competitor activation relates to listeners’ proficiency: words from the dominant language outcompete those from the other(s). However, the neural mechanisms that give rise to this effect are not well known. We present a case study of a pediatric neurosurgical patient who was bilingual in English (nondominant) and Spanish (dominant). The participant passively listened to English and Spanish cohort competitors. We used machine learning techniques to decode within- and between-language lexical competition dynamics from the pattern of activity on the superior temporal plane. Spanish words were more robustly decodable than English words, regardless of their role as a target word (the actual word heard on a given trial) or as a competitor (the phonologically related word competing for activation). This is consistent with a Spanish-dominant system—corroborating evidence from eye-tracking—and suggests that activation of cohorts may be in part due to perceptual tuning of early auditory areas for the sounds of a language.

Exploring Environmental Influences on Infant Development and Their Potential Role in Processes of Cultural Transmission and Long-Term Technological Change

ABSTRACT Emerging understanding of the extent to which the childhood environment can influence long-term neural and cognitive development may justify greater attention to its role in prehistory. In this review, we attempt to identify a range of ways in which changes to the rearing environment might impact on cognitive function with the potential to modify processes of cultural transmission. We focus on the types of change to the infant environment that may arise when moving from mobile hunter-gather to more settled agrarian lifeways. We consider the evidence for such early environmental factors bringing about enduring effects on perceptual tuning, shared attention, behavioural regulation and observational learning, and how these might contribute to differences in processes of cultural transmission across lifeways. We conclude that the potential developmental significance of cultural changes to the infant environment suggests more attention should be paid by archaeologists to lines of evidence related to early childhood environments in prehistory.

Prosody facilitates learning the word order in a new language

One of the prominent ideas developed by Jacques Mehler and his colleagues was that perceptual tuning, present from birth on, enables infants, and language learners in general, to extract regularities from speech input. Here we discuss language learners’' ability to extract basic word order (VO or OV) structure from prosodic regularities in a language. The two are closely related: in phonological phrases of VO languages, the most prominent word is the rightmost one, and in OV languages, it is the leftmost one. In speech, this prominence is realized as extended duration, or as elevated pitch, sometimes combined with changes in intensity. When learning the first (L1) or the second language (L2), exposure to relevant rhythmic structure elicits implicit learning about syntactic structure, including the basic word order. However, it remains unclear whether triggering the learning process requires a certain level of familiarity with the relevant rhythm. It is moreover unknown whether prosodic information can help L2 learners to extract and learn the vocabulary of a new language. We tested Spanish- and Italian-speaking adults' ability to learn words from an artificial language with either non-native OV or native VO word order. The results show that learners used prosodic information to identify the most prominent words in short utterances when the artificial language was similar to the native language, with duration-based prominence in prosody and a VO word order. In contrast, when the artificial language had a non-native prominence marked by pitch alternations and an OV word order, prominent words were learned only after a three-day exposure to the relevant rhythmic structure. Thus, for adult L2 learners, only repeated exposure to the relevant prosody elicited learning new words from an unknown language with non-native prosodic marking, indicating that, with familiarity, prosodic cues can facilitate learning in L2.

The Learning Signal in Perceptual Tuning of Speech: Bottom Up Versus Top-Down Information.

Cognitive systems face a tension between stability and plasticity. The maintenance of long-term representations that reflect the global regularities of the environment is often at odds with pressure to flexibly adjust to short-term input regularities that may deviate from the norm. This tension is abundantly clear in speech communication when talkers with accents or dialects produce input that deviates from a listener's language community norms. Prior research demonstrates that when bottom-up acoustic information or top-down word knowledge is available to disambiguate speech input, there is short-term adaptive plasticity such that subsequent speech perception is shifted even in the absence of the disambiguating information. Although such effects are well-documented, it is not yet known whether bottom-up and top-down resolution of ambiguity may operate through common processes, or how these information sources may interact in guiding the adaptive plasticity of speech perception. The present study investigates the joint contributions of bottom-up information from the acoustic signal and top-down information from lexical knowledge in the adaptive plasticity of speech categorization according to short-term input regularities. The results implicate speech category activation, whether from top-down or bottom-up sources, in driving rapid adjustment of listeners' reliance on acoustic dimensions in speech categorization. Broadly, this pattern of perception is consistent with dynamic mapping of input to category representations that is flexibly tuned according to interactive processing accommodating both lexical knowledge and idiosyncrasies of the acoustic input.

Human Auditory-Frequency Tuning Is Sensitive to Tonal Language Experience.

Purpose The aim of this study is to investigate whether human auditory frequency tuning can be influenced by tonal language experience. Method Perceptual tuning measured via psychophysical tuning curves and cochlear tuning derived via stimulus-frequency otoacoustic emission suppression tuning curves in 14 native speakers of a tonal language (Mandarin) were compared to those of 14 native speakers of a nontonal language (English) at 1 and 4 kHz. Results Group comparisons of both psychophysical tuning curves (p = .046) and stimulus-frequency otoacoustic emission suppression tuning curves (p = .007) in the 4-kHz region indicated sharper frequency tuning in the Mandarin-speaking group relative to the English-speaking group. The auditory tuning was better at the higher (4 kHz) than the lower (1 kHz) probe frequencies (p < .001). Conclusions The sharper auditory tuning in the 4-kHz cochlear region is associated with long-term tonal language (i.e., Mandarin) experience. Experience-dependent plasticity of tonal language may occur before the sound signal reaches central neural stages, as peripheral as the cochlea.

Perceptual tuning through contact? Contact interacts with perceptual (not memory-based) face-processing ability to predict cross-race recognition

Perceivers generally exhibit better face processing with same-race rather than cross-race faces. To what extent is this deficit attenuated by a perceiver's ability to process faces, and to what extent does that face-processing ability need to be “tuned” by experience with cross-race faces? The current study examined the cross-race recognition deficit (CRD) as a function of participants' ability with faces (measured by one task that emphasizes memory-based ability and one task that measures perceptual ability) and cross-race contact. Our primary analyses involve 583 White participants, 45 of whom can be classified as “super-recognizers.” Results suggest that (a) participants with better memory-based face-processing ability generally show a reduction in the CRD, and (b) participants with better perceptual ability only show a reduction in the CRD if they also have cross-race contact. The latter effect suggests that perceptual face processing must be tuned through experience.

Adaptation to an Unfamiliar Accent by Child L2 Listeners.

The study examines school-aged L2 listeners' adaptation to an unfamiliar L2 accent and learner variables predicting such adaptation. Fourth-grade Mandarin L1 learners of English as a foreign language (N = 117) listened to a story twice in one of three accent conditions. In the single-talker condition, the story was produced by an Indian English (IE) speaker. In the multi-talker condition, the story was produced by two IE speakers. In the control condition, the story was produced by a Mandarin-accented speaker. Children's (re)interpretation of IE words/nonwords was assessed by referent selection tests administered before and after the first and the second exposures to the story. Repeated exposure to IE-accented speech forms influenced performance: the participants demonstrated better recognition of IE words across the referent selection tests but worse (re)interpretation of IE nonwords sounding similar to existing lexical items. Exposure to an IE-accented story yielded an additional advantage in word recognition, but the advantage was limited to words heard in the story. Furthermore, children's English phonological awareness, phonological memory, and vocabulary predicted their reinterpretation performance of the accented forms. These results suggest that school-aged L2 listeners with better phono-lexical representations develop better capacity in adapting to an unfamiliar accent of a foreign language by loosening their acceptability criteria for word recognition but the adaptation does not necessarily entail perceptual tuning to the specific phonological categories of the accent.

The role of sensory drive in floral evolution.

Sensory drive theory posits that the evolution of communication signals is shaped by the sensory systems of receivers and the habitat conditions under which signals are received. It has inspired an enormous body of research, advancing our understanding of signal evolution and speciation in animals. In plants, the extreme diversification of floral signals has fascinated biologists for over a century. While processes involved in sensory drive probably play out in plant-pollinator communication, the theory has not been formally synthesized in this context. However, it has untapped potential to explain mechanisms underlying variation in pollinator preferences across populations, and how environmental conditions impact floral signal transmission and perception. Here I develop a framework of sensory drive for plant-pollinator interactions, identifying similarities and differences from its original conception. I then summarize studies that shed light on how the primary processes of sensory drive - habitat transmission, perceptual tuning, and signal matching - apply to the evolution of floral color and scent. Throughout, I propose research avenues and approaches to assess how sensory drive shapes floral diversity. This framework will be important for explaining patterns of extant floral diversity and examining how altered signaling conditions under global change will impact the evolutionary trajectory of floral traits.

Infants\u2019 advances in speech perception shape their earliest links between language and cognition

The power of human language derives not only from the precision of its signal or the complexity of its grammar, but also from its links to cognition. Infants as young as 3 months have begun to link language and core cognitive capacities. At 3 and 4 months, this link is not exclusive to human language: listening to vocalizations of nonhuman primates also supports infant cognition. By 6 months, infants have tuned this link to human speech alone. Here we provide evidence that infants’ increasing precision in speech perception shapes which signals they will link to cognition. Infants listening to German, a nonnative language that shares key rhythmic and prosodic properties with their own native language (English), successfully formed object categories. In contrast, those listening to Cantonese, a language that differs considerably in these suprasegmental properties, failed. This provides the first evidence that infants’ increasingly precise perceptual tuning to the sounds of their native language sets constraints on the range of human languages they will link to cognition: infants begin to specify which human languages they will link to core cognitive capacities even before they sever the link between nonhuman primate vocalizations and cognition.

Contextual Influences on Phonetic Categorization in School-Aged Children.

Perceptual stability in adult listeners is supported by the ability to process acoustic-phonetic variation categorically and dynamically adjust category boundaries given systematic contextual influences. The current study examined the developmental trajectory of such flexibility. Adults and school-aged children (5-10 years of age) made voicing identification decisions to voice-onset-time (VOT) continua that differed in speaking rate and place of articulation. The results showed that both populations were sensitive to contextual influences; the voicing boundary was located at a longer VOT for the slow compared to the fast speaking rate continuum and for the velar compared to the labial continuum, and the magnitude of the displacement was slighter greater for the adults compared to the children. Moreover, the two populations differed in terms of the absolute location of the voicing boundaries and the categorization slopes, with slopes becoming more categorical as age increased. These results demonstrate that sensitivity to contextual influences on speech perception emerges early in development, but mature perceptual tuning requires extended experience.

Statistical and acoustic effects on the perception of stop consonants in Kaqchikel (Mayan)

This paper investigates the relationship between speech perception and linguistic experience in Kaqchikel, a Guatemalan Mayan language. Our empirical focus is the perception of plain, ejective, and implosive stops. Drawing on an AX discrimination task, a corpus of spoken Kaqchikel, and a text corpus, we make two claims. First, we argue that speech perception is mediated by phonemic representations which include acoustic detail drawn from prior phonetic experience, as in Exemplar Theory. Second, segmental distributions also condition speech perception: The perceptual distinctiveness of a pair of phonemes is affected by their functional load and relative contextual predictability. These top-down factors influence phoneme discrimination even at relatively fast response times. We take this result as evidence that distributional factors like functional load may affect speech perception by shaping perceptual tuning during linguistic development. This study replicates and extends some key findings in speech perception in the context of a language (Kaqchikel) which is structurally and sociolinguistically different from the majority languages (like English) which have served as the basis of most work in the speech perception literature. At the practical level, our research illustrates methods for conducting corpus-based laboratory phonology with lesser-studied and under-resourced languages.

Short-term perceptual tuning to talker characteristics

ABSTRACTWhen a listener encounters an unfamiliar talker, the ensuing perceptual accommodation to the unique characteristics of the talker has two aspects: (1) the listener assesses acoustic characteristics of speech to resolve the properties of the talker's sound production; and, (2) the listener appraises the talker's idiolect, subphonemic phonetic properties that compose the finest grain of linguistic production. A new study controlled a listener's exposure to determine whether the perceptual benefit rests on specific segmental experience. Effects of sentence exposure were measured using a spoken word identification task of Easy words (likely words drawn from sparse neighbourhoods of less likely words) and Hard words (less likely words drawn from dense neighbourhoods of more likely words). Recognition of words was facilitated by exposure to voiced obstruent consonants. Overall, these findings indicate that talker-specific perceptual tuning might depend more on exposure to phonemically marked consonants than to exposure distributed across the phoneme inventory.

Selective enhancement of orientation tuning before saccades.

Saccadic eye movements cause a rapid sweep of the visual image across the retina and bring the saccade's target into high-acuity foveal vision. Even before saccade onset, visual processing is selectively prioritized at the saccade target. To determine how this presaccadic attention shift exerts its influence on visual selection, we compare the dynamics of perceptual tuning curves before movement onset at the saccade target and in the opposite hemifield. Participants monitored a 30-Hz sequence of randomly oriented gratings for a target orientation. Combining a reverse correlation technique previously used to study orientation tuning in neurons and general additive mixed modeling, we found that perceptual reports were tuned to the target orientation. The gain of orientation tuning increased markedly within the last 100 ms before saccade onset. In addition, we observed finer orientation tuning right before saccade onset. This increase in gain and tuning occurred at the saccade target location and was not observed at the incongruent location in the opposite hemifield. The present findings suggest, therefore, that presaccadic attention exerts its influence on vision in a spatially and feature-selective manner, enhancing performance and sharpening feature tuning at the future gaze location before the eyes start moving.

Neural Tuning to Numerosity Relates to Perceptual Tuning in 3–6-Year-Old Children

Neural Tuning to Numerosity Relates to Perceptual Tuning in 3–6-Year-Old Children

Assessing neural tuning for object perception in schizophrenia and bipolar disorder with multivariate pattern analysis of fMRI data.

IntroductionDeficits in visual perception are well-established in schizophrenia and are linked to abnormal activity in the lateral occipital complex (LOC). Related deficits may exist in bipolar disorder. LOC contains neurons tuned to object features. It is unknown whether neural tuning in LOC or other visual areas is abnormal in patients, contributing to abnormal perception during visual tasks. This study used multivariate pattern analysis (MVPA) to investigate perceptual tuning for objects in schizophrenia and bipolar disorder.MethodsFifty schizophrenia participants, 51 bipolar disorder participants, and 47 matched healthy controls completed five functional magnetic resonance imaging (fMRI) runs of a perceptual task in which they viewed pictures of four different objects and an outdoor scene. We performed classification analyses designed to assess the distinctiveness of activity corresponding to perception of each stimulus in LOC (a functionally localized region of interest). We also performed similar classification analyses throughout the brain using a searchlight technique. We compared classification accuracy and patterns of classification errors across groups.ResultsStimulus classification accuracy was significantly above chance in all groups in LOC and throughout visual cortex. Classification errors were mostly within-category confusions (e.g., misclassifying one chair as another chair). There were no group differences in classification accuracy or patterns of confusion.ConclusionsThe results show for the first time MVPA can be used successfully to classify individual perceptual stimuli in schizophrenia and bipolar disorder. However, the results do not provide evidence of abnormal neural tuning in schizophrenia and bipolar disorder.

Perceptual narrowing towards adult faces is a cross-cultural phenomenon in infancy: a behavioral and near-infrared spectroscopy study with Japanese infants.

Recent data showed that, in Caucasian infants, perceptual narrowing occurs for own‐race adult faces between 3 and 9 months of age, possibly as a consequence of the extensive amount of social and perceptual experience accumulated with caregivers and/or other adult individuals of the same race of the caregiver. The neural correlates of this developmental process remain unexplored, and it is currently unknown whether perceptual tuning towards adult faces can be extended to other cultures. To this end, in the current study we tested the ability of 3‐ and 9‐month‐old Japanese infants to discriminate among adult and infant Asian faces in a visual familiarization task (Experiment 1), and compared 9‐month‐olds’ cerebral hemodynamic responses to adult and infant faces as measured by near‐infrared spectroscopy (NIRS) (Experiment 2). Results showed that 3‐month‐olds exhibit above‐chance discrimination of adult and infant faces, whereas 9‐month‐olds discriminate adult faces but not infant faces (Experiment 1). Moreover, adult faces, but not infant faces, induced significant increases in hemodynamic responses in the right temporal areas of 9‐month‐old infants. Overall, our data suggest that perceptual narrowing towards adult faces is a cross‐cultural phenomenon occurring between 3 and 9 months of age, and translates by 9 months of age into a right‐hemispheric specialization in the processing of adult faces.

Neural Tuning to Numerosity Relates to Perceptual Tuning in 3-6-Year-Old Children.

Here we test for the existence of neural tuning to numerosity in the developing brain in the youngest sample of children tested with fMRI to date. Although previous research shows evidence of numerical distance effects in the intraparietal sulcus of the developing brain, those effects could be explained by patterns of neural activity that do not represent neural tuning to numerosity. These data provide the first robust evidence that from as early as 3-4 years of age there is developmental continuity in how the intraparietal sulcus represents the values of numerosities. Moreover, the study goes beyond previous research by examining the relation between neural tuning and perceptual tuning in children.