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.

This study investigated if non-nutritive suck (NNS) at 3 months is related to subsequent oral motor and motor skills using caregiver-reported scores on the Child Oral and Motor Proficiency Scale (ChOMPS) at 12 months in a cohort of 69 full-term infants and their caregivers. Longer NNS burst durations were associated with lower oral motor coordination and total ChOMPS scores. More NNS cycles per minute was associated with lower complex motor movement scores. More NNS bursts, cycles per burst, and cycles per minute were related with lower total ChOMPS scores. Early NNS outcomes can provide valuable insight in future neuromotor development.

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.

Any experiment brings about results and conclusions that necessarily have a component of uncertainty. Many factors influence the degree of this uncertainty, yet they can be overlooked when drawing conclusions from a body of research. Here, we showcase how subjective logic could be employed as a complementary tool to meta-analysis to incorporate the chosen sources of uncertainty into the answer that researchers seek to provide to their research question. We illustrate this approach by focusing on a body of research already meta-analyzed, whose overall aim was to assess if human infants prefer prosocial agents over antisocial agents. We show how each finding can be encoded as a subjective opinion, and how findings can be aggregated to produce an answer that explicitly incorporates uncertainty. We argue that a core feature and strength of this approach is its transparency in the process of factoring in uncertainty and reasoning about research findings. Subjective logic promises to be a powerful complementary tool to incorporate uncertainty explicitly and transparently in the evaluation of research.

Previous work has shown that caregiver attention shapes visual cognition in infants through dyadic interactions. Is this association measurable when visual cognition is objectively measured in caregivers and infants using comparable experimental paradigms? In the current study, we presented infants (N = 86) and caregivers (N = 78) with age-specific variants of the same preferential looking visual cognition task to investigate whether caregiver visual cognition was associated with their infants’ visual cognition. In each trial of the task, two side-by-side flashing displays of coloured shapes were presented. On the ‘unchanging’ side, the colours of the shapes remained the same. On the ‘changing’ side, the colour of one shape changed after each flash. Load was varied by changing the number of shapes across trials (low, medium, and high loads). We extracted looking dynamics using video recordings and brain function using functional near-infrared spectroscopy as both infants and caregivers engaged with the task. Change preference (CP) score, which represented the amount of time spent looking at the changing side divided by the total looking duration, showed a load-dependent modulation for both infants and caregivers. Both groups showed the highest CP scores at the low load. Further, higher caregiver CP scores was associated with higher infant CP scores at the low load. Both infants and caregivers engaged canonical regions of the fronto-parietal network involved in visual cognition. Critically, higher caregiver CP scores were associated with greater activation in the left superior parietal lobule in younger infants, a region involved in allocating visuo-spatial attention and working memory maintenance. Further, there was spatial overlap between performance-dependent regions in the right parietal cortex in caregivers and younger infants. Our findings provide first evidence of a heritability-related visual neurocognitive association between caregivers and their children in the first year of life.