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Language development during the 1st year of life is characterized by perceptual attunement: following language-general perception, a decline in the perception of non-native phonemes and a parallel increase in or maintenance of the perception of native phonemes. While this general pattern is well established, there are still many gaps in the literature. First, most evidence documenting these patterns comes from "Minority world countries" with only a limited number of studies from "Majority world countries", limiting the range of languages and contrasts assessed. Second, few studies test both the developmental patterns of native and non-native speech perception in the same group of infants, making it hard to draw conclusions on simultaneous decline in non-native and increase in native speech perception. Such limitations are in part due to the effort that goes into testing developing speech sound perception, where usually only discrimination of one contrast per infant can be tested at a time. The present study thus set out to assess the feasibility of assessing a given infant on their discrimination of two speech sound contrasts during the same lab visit. It leveraged the presence of documented patterns of the improvement of native and the decline of non-native phoneme discrimination abilities in Japanese, therefore assessing native and non-native speech perception in Japanese infants from 6 to 12 months of age. Results demonstrated that 76 % of infants contributed discrimination data for both contrasts. We found a decline in non-native speech perception evident in discrimination of the non-native /ɹ/-/l/ consonant contrast at 9–11, but not at 11–13 months of age. Additionally, a parallel increase in native speech perception was demonstrated evident in an absence of native phonemic vowel length discrimination at 6–7 and 9–11 months and a discrimination of this contrast at 11–13 months of age. These results, based on a simultaneous assessment of native and non-native speech perception in Japanese-learning infants, demonstrate the feasibility of assessing the discrimination of two contrasts in one testing session and corroborate theoretical proposals on two hallmarks of perceptual attunement: a decrease in non-native and a facilitation in native speech perception during the first year of life. ● Native and non-native sounds discrimination was tested in Japanese infants. ● Non-native speech perception declined from 9 to 12 months of age. ● Native speech perception increased from 6 to 12 months of age. ● Results confirm theoretical proposals on perceptual alignment during early infancy. [ABSTRACT FROM AUTHOR]

The developmental trajectories of tone perception among tone and non-tone language learning infants have received wide attention and discussion in recent decades under the perceptual attunement framework. Nevertheless, tone perception in infants from pitch accent and bilingual language backgrounds has not been well understood. The present study examined monolingual and bilingual Norwegian-learning infants' discrimination of two Cantonese tone contrasts at 5 and 10 months, ages corresponding to the onset and offset of perceptual attunement. Results showed that while monolingual infants were sensitive to the salient contrast, bilingual infants showed sensitivity to both contrasts at 10 months. In sum, infant age and bilingual language background affected discrimination. Pitch accent language experience or contrast salience may also play a role. The finding that early bilingual experience facilitated tone perception is of particular interest. It suggests that infant perception could be enhanced by a more complex linguistic environment on a broader level. As this was observed only at 10 months, cumulative exposure may be required for infants in a complex bilingual environment. Future studies should disambiguate explanations generated from the current finding, ranging from neurocognitive plasticity to perceptual salience, and from experience-dependent to independent possibilities., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Young infants can discriminate many non-native sounds, but the discrimination ability is thought to decrease within the first year of life due to perceptual attunement. However, most studies tested infants' perception cross-sectionally, without examining within-group change. To this end, the current study tested German infants' discrimination of the English /æ/-/ɛ/ contrast both cross-sectionally and longitudinally using the visual habituation technique. In Experiment 1, 96 German-learning infants were tested cross-sectionally at 5-6, 8-9 and 12-13 months. Linear mixed-effects models revealed that while the 5-6-month-olds did not discriminate the contrast, the 8-9- and 12-13-month-olds showed signs of discrimination only when they were habituated with /ɛ/, in line with previous findings suggesting that changes from central to peripheral vowels in the F1/F2 vowel space are more noticeable than in the reverse direction. Moreover, the 8-9-month-olds showed a novelty preference, while the 12-13-month-olds showed a familiarity preference. In Experiment 2, the infants tested at 5-6 months in Experiment 1 were tested again at 8-9 and 12-13 months. Fifteen infants completed the three experiments. Here, only the 12-13-month-olds discriminated the contrast by showing a novelty preference but only when habituated with /æ/. Overall, both experiments showed gradual development of discrimination ability across the first year, which challenges the assumptions of perceptual attunement. We propose that the perceptual sensitivity for a non-native vocalic contrast can improve during development. The change in perceptual asymmetry tells us that the direction of asymmetry is not universal and can be altered by linguistic experience. The change from novelty to familiarity preference may be due to the emerging preference for the more native-like vowel as well as the effect of repeating experiments with the same infants. In sum, our cross-sectional and longitudinal results overlap broadly, but the potential effect of repeating experiments must be considered when interpreting longitudinal studies., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Comparisons of the beneficial effects of nature-based versus indoor physical activity have been extensively reported, but existing research addresses mainly aerobic activity (running, jogging), not resistance or mixed (aerobic and resistance) exercise. It is unclear if the psychological benefits extend to functionality, i.e., if participants perform their activities better in nature, and how movement is expressed in nature-based and indoor environments, during similar exercise. The present registered report was a randomized controlled trial investigating how engaging in similar resistance-based exercise (calisthenics) in nature-based and indoor settings differed in affective valence, perceived exertion, visual attention, movement adaptability, heart rate variability, and performance. Nature-based exercisers (N = 51) showed increased performance output than indoor exercisers (N = 53) (p < 0.001). There were no group differences in affective valence, perceived exertion, or visual attention. However, psychological states of nature-based exercisers showed stronger associations to performance output (r < 0.33) than those of indoor exercisers (r < 0.03). Nature-based exercisers' movement variability and structure, measured with non-linear and fractal techniques (Sample Entropy and Detrended Fluctuation Analysis), were more regular (p < 0.001) and more functionally adaptive (long-term Detrended Fluctuation Analysis, p = 0.022) to achieve better performance output. Heart rate variability measures were not different between groups. Distinct environments can influence movement adaptability in a calisthenics exercise routine, and ultimately contribute to better performance. These results show how action is specific to task environment, and how action implies not only the task, but also the characteristics of the environment. NCT05090501 (Clinicaltrials.gov). Registered October 21, 2021. [ABSTRACT FROM AUTHOR]

Infants learn their native language(s) at an amazing speed. Before they even talk, their perception adapts to the language(s) they hear. However, the mechanisms responsible for this perceptual attunement and the circumstances in which it takes place remain unclear. This paper presents the first attempt to study perceptual attunement using ecological child-centered audio data. We show that a simple prediction algorithm exhibits perceptual attunement when applied on unrealistic clean audio-book data, but fails to do so when applied on ecologically-valid child-centered data. In the latter scenario, perceptual attunement only emerges when the prediction mechanism is supplemented with inductive biases that force the algorithm to focus exclusively on speech segments while learning speaker-, pitch-, and room-invariant representations. We argue these biases are plausible given previous research on infants and non-human animals. More generally, we show that what our model learns and how it develops through exposure to speech depends exquisitely on the details of the input signal. By doing so, we illustrate the importance of considering ecologically valid input data when modeling language acquisition. [ABSTRACT FROM AUTHOR]

• Infants and adults detect human faces efficiently, even in visually complex environments. • We observed own-species bias in face detection in 3–5-month-olds, 10–11-moth-olds, and adults. • Infants' face detection was influenced by low-level manipulations in a species-specific way. • Adults' face detection was broadly impacted by low-level manipulations equally across species. • Distinct face properties may underlie own-species face processing differences in infants and adults. Humans rapidly locate and recognize human faces, even in complex environments. In the current study, we explored some of the social and perceptual features of faces that may contribute to this ability. We measured infant and adult attention to complex, heterogeneous image arrays containing human and animal faces. Arrays were upright or inverted 180° and in color or grayscale. Infants, aged 3–5 months (n = 51) and 10–11 months (n = 34), viewed 6-item arrays (Experiment 1), whereas adults (n = 120) searched 64-item arrays (Experiment 2). We found that 3- to 5-month-olds already displayed strong own-species biases in face detection—in attention capture, attention holding, and overall detection—suggesting a surprisingly early specialization for human face detection. Furthermore, this remarkable ability was robust, evident even when color and orientation were disrupted, and grew stronger with age. Interestingly, infants' face detection was reduced by low-level manipulations in a species-specific way, negatively affecting only animal face detection but not affecting human face detection. In contrast, adults' face detection efficiency was equally reduced by low-level manipulations across species, suggesting potential age differences in own-species face detection. For infants, social relevance (species) may play a more important role than low-level perceptual features, ensuring that infants attend to, connect with, and learn from the people around them. Efficient human face detection during infancy may reflect the uniqueness of own-species faces as a category, perhaps due to their social relevance. [ABSTRACT FROM AUTHOR]

This study investigates the role of language background and bilingual status in the perception of foreign lexical tones. Eight groups of participants, consisting of children of 6 and 8 years from one of four language background (tone or non-tone) × bilingual status (monolingual or bilingual)—Thai monolingual, English monolingual, English-Thai bilingual, and English-Arabic bilingual were trained to perceive the four Mandarin lexical tones. Half the children in each of these eight groups were given auditory-only (AO) training and half auditory-visual (AV) training. In each group Mandarin tone identification was tested before and after (pre- and post-) training with both auditory-only test (ao-test) and auditory-visual test (av test). The effect of training on Mandarin tone identification was minimal for 6-year-olds. On the other hand, 8-year-olds, particularly those with tone language experience showed greater pre- to post-training improvement, and this was best indexed by ao-test trials. Bilingual vs. monolingual background did not facilitate overall improvement due to training, but it did modulate the efficacy of the Training mode: for bilinguals both AO and AV training, and especially AO, resulted in performance gain; but for monolinguals training was most effective with AV stimuli. Again this effect was best indexed by ao-test trials. These results suggest that tone language experience, be it monolingual or bilingual, is a strong predictor of learning unfamiliar tones; that monolinguals learn best from AV training trials and bilinguals from AO training trials; and that there is no metalinguistic advantage due to bilingualism in learning to perceive lexical tones.

Although statistical learning has been shown to be a domain-general mechanism, its constraints, such as its interactions with perceptual development, are less well understood and discussed. This study is among the first to investigate the distributional learning of lexical pitch in non-tone-language-learning infants, exploring its interaction with language-specific perceptual attunement during the first 2 years after birth. A total of 88 normally developing Dutch infants of 5, 11, and 14 months were tested via a distributional learning paradigm and were familiarized on a unimodal or bimodal distribution of high-level versus high-falling tones in Mandarin Chinese. After familiarization, they were tested on a tonal contrast that shared equal distributional information in either modality. At 5 months, infants in both conditions discriminated the contrast, whereas 11-month-olds showed discrimination only in the bimodal condition. By 14 months, infants failed to discriminate the contrast in either condition. Results indicate interplay between infants' long-term linguistic experience throughout development and short-term distributional learning during the experiment, and they suggest that the influence of tonal distributional learning varies along the perceptual attunement trajectory, such that opportunities for distributional learning effects appear to be constrained in the beginning and at the end of perceptual attunement. The current study contributes to previous research by demonstrating an effect of age on learning from distributional cues. [ABSTRACT FROM AUTHOR]

By the end of their first year of life, infants have become experts in discriminating the sounds of their native language, while they have lost the ability to discriminate non-native contrasts. This type of phonetic learning is referred to as perceptual attunement. In the present study, we investigated the emergence of a context-dependent form of perceptual attunement in infancy. Indeed, some native contrasts are not discriminated in certain phonological contexts by adults, due to the presence of a language-specific process that neutralizes the contrasts in those contexts. We used a mismatch design and recorded high-density Electroencephalography (EEG) in French-learning 14-month-olds. Our results show that similarly to French adults, infants fail to discriminate a native voicing contrast (e.g., [f] vs. [v]) when it occurs in a specific phonological context (e.g. [ofbe] vs. [ovbe], no mismatch response), while they successfully detected it in other phonological contexts (e.g., [ofne] vs. [ovne], mismatch response). The present results demonstrate for the first time that by the age of 14 months, infants’ phonetic learning does not only rely on the processing of individual sounds, but also takes into account in a language-specific manner the phonological contexts in which these sounds occur. [ABSTRACT FROM AUTHOR]

This study explores the influence of bilingualism on the cognitive processing of language and music. Specifically, we investigate how infants learning a non-tone language perceive linguistic and musical pitch and how bilingualism affects cross-domain pitch perception. Dutch monolingual and bilingual infants of 8-9 months participated in the study. All infants had Dutch as one of the first languages. The other first languages, varying among bilingual families, were not tone or pitch accent languages. In two experiments, infants were tested on the discrimination of a lexical ( N = 42) or a violin ( N = 48) pitch contrast via a visual habituation paradigm. The two contrasts shared identical pitch contours but differed in timbre. Non-tone language learning infants did not discriminate the lexical contrast regardless of their ambient language environment. When perceiving the violin contrast, bilingual but not monolingual infants demonstrated robust discrimination. We attribute bilingual infants' heightened sensitivity in the musical domain to the enhanced acoustic sensitivity stemming from a bilingual environment. The distinct perceptual patterns between language and music and the influence of acoustic salience on perception suggest processing diversion and association in the first year of life. Results indicate that the perception of music may entail both shared neural network with language processing, and unique neural network that is distinct from other cognitive functions. [ABSTRACT FROM AUTHOR]

Adults detect conspecific faces more efficiently than heterospecific faces; however, the development of this own-species bias (OSB) remains unexplored. We tested whether 6- and 11-month-olds exhibit OSB in their attention to human and animal faces in complex visual displays with high perceptual load (25 images competing for attention). Infants (n=48) and adults (n=43) passively viewed arrays containing a face among 24 non-face distractors while we measured their gaze with remote eye tracking. While OSB is typically not observed until about 9 months, we found that, already by 6 months, human faces were more likely to be detected, were detected more quickly (attention capture), and received longer looks (attention holding) than animal faces. These data suggest that 6-month-olds already exhibit OSB in face detection efficiency, consistent with perceptual attunement. This specialization may reflect the biological importance of detecting conspecific faces, a foundational ability for early social interactions. [ABSTRACT FROM AUTHOR]

A major focus of research on visually guided action is the identification of control strategies that map optical information to actions. The traditional approach has been to test the behavioral predictions of a few hypothesized strategies against subject behavior in environments in which various manipulations of available information have been made. While important and compelling results have been achieved with these methods, they are potentially limited by small sets of hypotheses and the methods used to test them. In this study, we introduce a novel application of data-mining techniques in an analysis of experimental data that is able to both describe and model human behavior. This method permits the rapid testing of a wide range of possible control strategies using arbitrarily complex combinations of optical variables. Through the use of decision-tree techniques, subject data can be transformed into an easily interpretable, algorithmic form. This output can then be immediately incorporated into a working model of subject behavior. We tested the effectiveness of this method in identifying the optical information used by human subjects in a collision-avoidance task. Our results comport with published research on collision-avoidance control strategies while also providing additional insight not possible with traditional methods. Further, the modeling component of our method produces behavior that closely resembles that of the subjects upon whose data the models were based. Taken together, the findings demonstrate that data-mining techniques provide powerful new tools for analyzing human data and building models that can be applied to a wide range of perception-action tasks, even outside the visual-control setting we describe. [ABSTRACT FROM AUTHOR]

Abstract: The adoption of egocentric and allocentric frameworks in the perception of other people’s reachability was investigated. In study 1, 24 adults (12 experienced and 12 inexperienced dealing with children) judged vertical reachability for themselves and for two children. In study 2, 37 parents judged vertical reachability for themselves and their children. Absolute errors (|estimate-actual reachability|), absolute percent errors (|1-judgement/actual reachability|×100), and error tendency (underestimations, right judgments, or overestimations) were calculated. Adults were quite accurate in perceiving their own reachability (absolute percent errors ranging from 2.20% in study 1 to 3.12% in study 2) and clearly less precise when estimating children’s reachability. Results indicated a tendency for adults to overestimate reachability of the younger child (study 1) and a tendency for parents to overestimate their children’s reachability (study 2). No correlation between judgement errors for the self and for the children in any of the studies was observed. Results support the existence of an allocentric and not an egocentric framework when evaluating other people’s affordances. [Copyright &y& Elsevier]

Three experiments investigated the ability to perceive the maximum height to which another actor could jump to reach an object. Experiment 1 determined the accuracy of estimates for another actor's maximal reach-with-jump height and compared these estimates to estimates of the actor's standing maximal reaching height and to estimates of the perceiver's own maximal reaching and reach-with-jump height. Perception of another actor's maximum reach-with-jump height was less accurate than the other estimates, but still accurate to within 8% error. The actor's reach-with-jump height was modified in Experiment 2 by attaching weights around the actor's ankles. Perceivers, who were explicitly aware of the manipulation, adjusted their maximum reach-with-jump estimates for the actor accordingly. In Experiment 3, perceivers were not explicitly aware of the weight manipulation, but provided significantly lower maximum reach-with-jump estimates after watching the actor walk while wearing the weights compared to estimates obtained after watching the actor walk while not wearing the weights. The results suggest that the actor's walking pattern was informative about the actor's capacity to produce a different action, jumping to reach an object. [ABSTRACT FROM AUTHOR]

• We tested bilingual infants at 10–11 months on native and non-native speech perception. • Their vocabulary development was later assessed at 2 and 3 years of age. • Native speech perception was a significant predictor of English vocabulary at 2 years. • Native speech perception was a marginally significant predictor of English vocabulary at 3 years. • Non-native speech perception did not predict later vocabulary. One of the most significant transitions reported in infant psychological development is perceptual narrowing whereby infants orient towards their native language. In monolingual infants, the progress made by infants in perceptual narrowing positively predicts later vocabulary size. The relationship between infant speech perception and later language development has not been thus far reported in bilingual populations. The present study investigated infant speech perception in relation to later vocabulary development in a prospective longitudinal study of bilingual infants over the first three years of life. Our study revealed three primary findings. First, unlike monolingual infants, bilingual infants demonstrated a positive correlation between native and non-native phonetic discrimination. Second, native speech perception at 10–11 months predicted single-language (English) vocabulary at 2 years, but not second language (Mandarin), nor total conceptual vocabulary. Third, infants with a native language orientation relative to a non-native orientation in phonetic discrimination at 10–11 months tended towards higher English vocabulary scores at 3 years of age. When placed in the context of prior research with monolingual infants, results with bilingual infants point to distinct relationships between native and non-native speech perception in infancy, but to a similar continuity between infant speech discrimination and later vocabulary growth. [ABSTRACT FROM AUTHOR]