Infant Preferences Research Articles

Infant preference for specific phonetic cue relations in the contrast between voiced and voiceless stops.

Acoustic variability in the speech input has been shown, in certain contexts, to be beneficial during infants' acquisition of sound contrasts. One approach attributes this result to the potential of variability to make the stability of individual cues visible. Another approach suggests that, instead of highlighting individual cues, variability uncovers stable relations between cues that signal a sound contrast. Here, we investigate the relation between Voice Onset Time and the onset of F1 formant frequency, two cues that subserve the voicing contrast in German. First, we verified that German-speaking adults' use of VOT to categorize voiced and voiceless stops is dependent on the value of the F1 onset frequency, in the specific form of a so-called trading relation. Next, we tested whether 6-month-old German learning infants exhibit differential sensitivity to stimulus continua in which the cues varied to an equal extent, but either adhered to the trading relation established in the adult experiment or adhered to a reversed relation. Our results present evidence that infants prefer listening to speech in which phonetic cues conform to certain cue trading relations over cue relations that are reversed.

Prevalence of Postpartum Depression and Its Sociodemographic and Obstetric Determinants among Mothers Attending a Maternity Hospital in Kenya: A Cross-Sectional Study

Postpartum depression (PPD) is a significant global public health concern affecting 17.7% and 18.7% of mothers globally and in Kenya respectively. The study aimed to assess the prevalence of postpartum depression and to explore its sociodemographic and obstetric determinants among mothers attending the postnatal and maternal and child health clinics at Eldoret West Maternity Hospital in Kenya. Unfortunately, postpartum depression and its determinants often go undiagnosed or untreated, leading to inadequate documentation of its impacts. A descriptive cross-sectional study design was employed, involving 257 women aged 18-49 years with infants aged 6-14 weeks postpartum. Participants were randomly selected using a simple random sampling method. Data was collected using a modified version of the Edinburgh Postnatal Depression Scale (EPDS) translated to Swahili. Descriptive analysis, Chi-squared analysis, and odds ratios were used to assess associations between sociodemographic factors, obstetric variables, and postpartum depression. The study found a prevalence of postpartum depression among participants to be 17.5%, with a higher likelihood of postpartum depression among mothers who were; older (aged 31-49 years) (68.9%), married (77.8%), with higher education levels (80%), lower income (82.2%), and those not formally employed (82.2%). Obstetric factors such as parity of greater than two (53.3%), unplanned pregnancy (53.3%) preference for male infants (62.2%) with having had unresolved issues (p-value < 0.01) in the past month and a parity of greater than two (p-value<0.05) were found to be significantly associated with higher odds of PPD. The prevalence of maternal postpartum depression among mothers 6-14 weeks postpartum at Eldoret West maternity Hospital, Uasin Gishu County was found to be 17.5%. Several sociodemographic and obstetric factors are linked and predispose women to PPD. Based on the conclusions, we recommend early intervention and support for young mothers, prenatal and postnatal complication screening, mental health education, and awareness.

Vowel harmony preferences in infants growing up in multilingual Ghana (Africa).

Infants' preference for vowel harmony (VH, a phonotactic constraint that requires vowels in a word to be featurally similar) is thought to be language-specific: Monolingual infants learning VH languages show a listening preference for VH patterns by 6 months of age, while those learning non-VH languages do not (Gonzalez-Gomez et al., 2019; Van Kampen et al., 2008). We investigated sensitivity to advanced tongue root (ATR) harmony in Akan (Kwa, Niger-Congo) in 40 six-month-old multilingual infants (21 girls) in Ghana, West Africa (an understudied population), all learning Akan, Ghanaian English, and most of them several other understudied African languages (e.g., Ga, Ewe). We hypothesized that infants learning both ATR harmony and nonharmony languages would demonstrate sensitivity to ATR harmony. Using the central fixation procedure, infants were presented with disyllabic nonwords that were either harmonic (e.g., puti) or nonharmonic (e.g., petɔ) based on their ATR features. Infants demonstrated sensitivity to ATR harmony with a familiarity preference, listening longer to harmonic syllable sequences than nonharmonic ones. The relative amount of exposure to (an) ATR harmony language(s) did not modulate the preference. These results shed light on our understanding of early multilingualism: they suggest that early sensitivity to VH in multilinguals may be similar to monolingual infants learning other types of VH, irrespective of simultaneous experience with non-VH languages. We conclude with reflections on studying infant language acquisition in multilingual Africa. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Supplemental Material for Vowel Harmony Preferences in Infants Growing up in Multilingual Ghana (Africa)

Supplemental Material for Vowel Harmony Preferences in Infants Growing up in Multilingual Ghana (Africa)

Visual stimulus structure, visual system neural activity, and visual behavior in young human infants.

In visual perception and information processing, a cascade of associations is hypothesized to flow from the structure of the visual stimulus to neural activity along the retinogeniculostriate visual system to behavior and action. Do visual perception and information processing adhere to this cascade near the beginning of life? To date, this three-stage hypothetical cascade has not been comprehensively tested in infants. In two related experiments, we attempted to expose this cascade in 6-month-old infants. Specifically, we presented infants with two levels of visual stimulus intensity, we measured electrical activity at the infant cortex, and we assessed infants' preferential looking behavior. Chromatic saturation provided a convenient stimulus dimension to test the cascade because greater saturation is known to excite increased activity in the primate visual system and is generally hypothesized to stimulate visual preference. Experiment 1 revealed that infants prefer (look longer) at the more saturated of two colors otherwise matched in hue and brightness. Experiment 2 showed increased aggregate neural cortical excitation in infants (and adults) to the more saturated of the same pair of colors. Thus, experiments 1 and 2 taken together confirm a cascade: Visual stimulation of relatively greater intensity evokes relatively greater levels of bioelectrical cortical activity which in turn is associated with relatively greater visual attention. As this cascade obtains near the beginning of life, it helps to account for early visual preferences and visual information processing.

Who spoke that language? Assessing early face-language associations in monolingual and bilingual infants.

In bilingual communities, knowing the language each speaker uses may support language separation and, later, guide language use in a context-appropriate manner. Previous research has shown that infants begin to form primary associations between the face and the language used by a speaker around the age of 3 months. However, there is still a limited understanding of how robust these associations are and whether they are influenced by the linguistic background of the infant. To answer these questions, this study explores monolingual and bilingual infants' ability to form face-language associations throughout the first year of life. A group of 4-, 6-, and 10-month-old Spanish and/or Catalan monolingual and bilingual infants were tested in an eye-tracking preferential-looking paradigm (N = 156). After the infants were familiarized with videos of a Catalan and a Spanish speaker, they were tested in two types of test trials with different task demands. First, a Silent test trial assessed primary face-language associations by measuring infants' visual preference for the speakers based on the language they had previously used. Then, two Language test trials assessed more robust face-language associations by measuring infants' ability to match the face of each speaker with their corresponding language. When measuring primary face-language associations, both monolingual and bilingual infants exhibited language-based preferences according to their specific exposure to the languages. Interestingly, this preference varied with age, with a transition from an initial familiarity preference to a novelty preference in older infants. Four-month-old infants showed a preference for the speaker who used their native/dominant language, while 10-month-old infants preferred the speaker who used their non-native/non-dominant language. When measuring more robust face-language associations, infants did not demonstrate signs of consistently matching the faces of the speakers with the language they had previously used, regardless of age or linguistic background. Overall, the results indicate that while both monolingual and bilingual infants before the first year of life can form primary face-language associations, these associations remain fragile as infants seemed unable to maintain them when tested in a more demanding task.

Implicit and explicit responses to infant sounds: A cross-sectional study among parents and non-parents

This research investigates the infant schema in auditory perception by examining how different demographics, including males, females, parents, and non-parents, respond implicitly and explicitly to baby vocalizations in comparison to adult, cat, and kitten sounds. Utilizing a single category implicit association task (SC-IAT) and a detailed questionnaire, we analyzed participants' responses to synthesized vowel sounds from infants, adults, cats, and kittens. The questionnaire focused on participants' liking and perception of cuteness for these sounds. Findings reveal a universal positive implicit preference for baby vocalizations across all groups (p = 0.01), without a similar effect for other sound sources. In contrast, explicit responses varied significantly. While all groups showed a preference for the sounds of cats, babies, and kittens over adults, only mothers demonstrated a statistically significant explicit preference for infant sounds over those of cats and kittens. This study highlights the discrepancy between unconscious and conscious attitudes towards infant sounds. It underscores that while an implicit affinity for baby vocalizations is widespread, explicit preferences, particularly in terms of cuteness and likeability, are markedly stronger in mothers. These insights contribute to our understanding of the auditory dimension of the infant schema, emphasizing the role of gender and parental status in shaping responses.

Assessing the motivational value of infant video clips on chimpanzees through discrimination learning task.

The motivational value of visual infant stimuli in humans is considered to encourage parental behavior. To explore the evolutionary roots of this preference for infants, we examined the reward value of conspecific infant videos compared to adult ones in nine chimpanzees. We employed a novel approach, a simultaneous discrimination task with differential sensory reinforcement. In Experiments 1 and 2, we tested if watching conspecific infant videos is more rewarding than watching adult ones. Participants were required to discriminate between two visual stimuli by a touch panel task. In video reward trials, a video clip featuring a chimpanzee infant followed a correct choice, while one featuring an adult followed an incorrect choice. However, the percentage of correct choices did not significantly differ from chance except in one chimpanzee, indicating that chimpanzees did not exhibit a preference for watching infant videos over those of adult. In Experiment 3, we tested if chimpanzees prefer conspecific videos over a blank screen; however, we did not find evidence either at a group level. These results suggest that the incentive salience of infant stimuli may not be universally compelling across species. Additionally, we discuss the limitations of the task using sensory reinforcement.

A Mobile App to Promote Breastfeeding Self-Efficacy in Preterm Infants' Mothers: Development and Validation.

Improving breastfeeding rates is a global goal. To achieve it, actions targeting modifiable factors that influence the breastfeeding experience, such as maternal self-efficacy, could be a promising path, especially with preterm infants' mothers. Considering the current ubiquitous technology, we developed a mobile application for mothers of preterm infants to constitute a breastfeeding information and support platform. The study was developed in three phases: a survey to determine characteristics and preferences of preterm infants' mothers; the app development by an interdisciplinary team, following the principles of Disciplined Agile Delivery; and the face and content validation by 10 professionals. The app contains 80 screens and 11 strategies to address prematurity, lactation, breastfeeding, peer support, maternal emotions, resilience, and motivation. Nurses can apply their expertise by designing mHealth-based interventions, employing scientific evidence, and considering the interests and preferences of the target population. Future studies will assess the user experience, the effect on breastfeeding self-efficacy, and breastfeeding rates, and develop a culturally adapted English version of the app for women in Canada.

Clinician Management Practices for Infants With Hypothermia in the Emergency Department.

Young infants with serious bacterial infections (SBI) or herpes simplex virus (HSV) infections may present to the emergency department (ED) with hypothermia. We sought to evaluate clinician testing and treatment preferences for infants with hypothermia. We developed, piloted, and distributed a survey of ED clinicians from 32 US pediatric hospitals between December 2022 to March 2023. Survey questions were related to the management of infants (≤60 days of age) with hypothermia in the ED. Questions pertaining to testing and treatment preferences were stratified by age. We characterized clinician comfort with the management of infants with hypothermia. Of 1935 surveys distributed, 1231 (63.6%) were completed. The most common definition of hypothermia was a temperature of ≤36.0°C. Most respondents (67.7%) could recall caring for at least 1 infant with hypothermia in the previous 6 months. Clinicians had lower confidence in caring for infants with hypothermia compared with infants with fever (P < .01). The proportion of clinicians who would obtain testing was high in infants 0 to 7 days of age (97.3% blood testing for SBI, 79.7% for any HSV testing), but declined for older infants (79.3% for blood testing for SBI and 9.5% for any HSV testing for infants 22-60 days old). A similar pattern was noted for respiratory viral testing, hospitalization, and antimicrobial administration. Testing and treatment preferences for infants with hypothermia varied by age and frequently reflected observed practices for febrile infants. We identified patterns in management that may benefit from greater research and implementation efforts.

94 Understanding Parental Behaviours Related to Infant Sleep Environment

Abstract Introduction/Background Sudden unexplained death in infants continues to make up a significant proportion of infant deaths. Despite wide dissemination of Canadian Paediatric Society and American Academy of Paediatrics safe sleep recommendations, studies demonstrate significant caregiver nonadherence to the recommendations. Few studies have examined caregiver reasons for low uptake of recommendations. There is an urgent need to understand these issues not only for individual providers counseling about sleep, but also for implementation of public health initiatives which attempt to target parental behaviour change. Objectives Our study aimed to explore parental perceptions, beliefs and influences regarding safe infant sleep environment and factors contributing to parental behaviour related to sleep environment. Design/Methods A qualitative study utilizing ground theory methodology was conducted with in-depth individual interviews of 14 parents of infants less than six months admitted to a large paediatric hospital in Toronto, Canada. Data collection occurred from November 2017 to January 2018, until a saturation of themes was reached. Interview transcripts were analyzed for recurrent and emergent themes and a coding structure was developed. Results Interviews with caregivers were completed, and a range of sleep locations and environments were described. Most caregivers reported that a bassinet or crib was the main sleeping location, but most infants were also placed in other locations at various times, including infant swings, couches, and bed-sharing with caregivers. Three dominant themes affecting decision-making about sleep location were identified: 1. safety, 2. feasibility and convenience and, 3. perception of infant preference and developmental needs. These factors were often present simultaneously in parental decision-making, frequently acting in opposition to one another. Caregivers’ methods of mitigating harm were often counter to recommendations, such as using pillows to prevent rolling. Information sources regarding sleep choices typically included family, friends, healthcare providers and media. Most caregivers placed greater significance on healthcare recommendations than the advice of family members. Conclusion This study identified key factors that impact caregivers’ decision-making regarding infant sleep. These results can inform healthcare providers counselling about safe sleep recommendations and public health interventions aimed at increasing adherence to safe sleep recommendations and reducing preventable infant deaths.

Development of Hand and Paw Preferences and Their Association with Other Patterns of Behaviour and Cognition

Hand preference in non-human primates has been studied extensively with the aim of understanding the evolution of hemispheric asymmetry and hand preferences in humans. However, the focus has been on hand preferences expressed in adulthood, with a surprising lack of studies on hand preferences in infants and changes that occur during the development of other, potentially associated, asymmetries in the brain and behaviour. This paper reports on the development of hand preference for grasping food and taking it to the mouth in common marmosets. It considers the development of other types of behaviour, such as head cocking and anogenital licking, that parallel and might influence the development of hand preferences during the first months of life. It then discusses behavioural differences between left- and right-handed adult marmosets, including response to novel stimuli, social behaviour and cognitive bias. The need to study the development of hand preferences together with the development of these other expressions of cognitive function is highlighted. The question to be addressed by empirical studies is whether hand preference is a downstream manifestation of the development of hemispheric differences in sensory processing and cognition, or whether it is instrumental in the development of functional differences between the hemispheres. Comparison is made to paw preference and associated behaviour in non-primate species.

Molecular and cellular mechanisms of the first social relationship: A conserved role of 5-HT from mice to monkeys, upstream of oxytocin

Maternal affiliation by infants is the first social behavior of mammalian animals. We report here that elimination of the Tph2 gene essential for serotonin synthesis in the brain reduced affiliation in mice, rats, and monkeys. Calcium imaging and c-fos immunostaining showed maternal odors activation of serotonergic neurons in the raphe nuclei (RNs) and oxytocinergic neurons in the paraventricular nucleus (PVN). Genetic elimination of oxytocin (OXT) or its receptor reduced maternal preference. OXT rescued maternal preference in mouse and monkey infants lacking serotonin. Tph2 elimination from RN serotonergic neurons innervating PVN reduced maternal preference. Reduced maternal preference after inhibiting serotonergic neurons was rescued by oxytocinergic neuronal activation. Our genetic studies reveal a role for serotonin in affiliation conserved from mice and rats to monkeys, while electrophysiological, pharmacological, chemogenetic, and optogenetic studies uncover OXT downstream of serotonin. We suggest serotonin as the master regulator upstream of neuropeptides in mammalian social behaviors.

Recognition of humans from biological motion in infants.

Infant studies have suggested that the detection of biological motion (BM) might be an innate capacity, based on newborns' spontaneous preference for BM. However, it is unclear if, like adults, infants recognize humans from BM and are able to build the representation of bodies and faces. To address this issue, we tested whether exposure to BM influences subsequent face recognition in 3- to 8-month-old infants. After familiarization with a point-light walker (PLW) of either a female or a male, the infant's preference for female and male faces was measured. If infants can build the representation of not only the body but also the face from PLWs, the familiarization effect of gender induced by the PLW might be generalized to faces. We found that infants at 7 to 8 months looked for longer at the face whose gender was opposite to that of the PLW, whereas 3- to 4- and 5- to 6-month-old infants did not. These results suggest that infants can access the representation of humans from BM and extract gender, which is shared across bodies and faces, from at least 7 to 8 months of age.

Infant sensitivity to age-based social categories in full-body displays

This study examined 3.5- and 6-month-old infants’ visual preferences for individuals from different age groups: adults versus infants. Unlike previous studies that only studied faces, here we included bodies, which are as frequent as faces in our environment, and highly salient, and in consequence, may play a role in identifying social categories and driving social preferences. In particular, we studied three salient dimensions along which individuals of different ages differ: body length, body typology, and face typology. In Experiment 1, adult and infant stimuli were presented in real proportions, differing both in body length and face typology, and infants preferred the adult stimuli. Experiment 2 demonstrated that given identical adult stimuli, which differ only in body length, infants attended more to the longer stimuli. In Experiment 3, infant and adult stimuli were matched on body length with the infant stimuli having larger heads, and infants preferred the infant stimuli. Experiment 4 measured infant visual preference for infant or adult bodies in the absence of face information, and found that 4-month-olds attended more to the infant bodies. Experiment 5 measured infants’ sensitivity to matching or mismatching faces and bodies based on age, and infants demonstrated a preference for the incongruent stimuli (i.e., adult head with an infant body). Altogether these studies show that while face typology and body size are main drivers of infant visual preference for adults, when body typology information is provided for bodies matched in size, infant preference shifts towards their peers. Thus, our results suggest that infants have early developing age-based body representations, and that body information shifts their pattern of visual behavior from a visual preference for adult faces, to a visual preference for full-body peers.

Effects of interracial experience on the race preferences of infants

Over their first year of life, infants express visual preferences for own- versus other-race faces. This developmental transition has primarily been investigated in monoracial societies where infants have limited personal or societal contact with other races. We investigated whether previously reported visual preferences for race generalize to a multiracial society (i.e., Singapore). In addition, we investigated effects of caregiver race on visual preferences for race. In Experiment 1, race preferences were measured at 3, 6, and 9 months of age for own-race (Chinese) versus other-race (Indian) faces in infants with no regular interaction with Indian-race individuals. Singaporean infants displayed a significant visual preference for Indian-race faces at each age group. Furthermore, infants raised with other-race caregivers demonstrated an age-related increase in other-race visual preferences. The visual preferences of infants for other-race faces were predicted by the extent of other-race contact. In Experiment 2, we confirmed that an other-race visual preference was not exclusive to Indian faces in a sample of 6-month-old Singaporean Chinese infants who demonstrated a similar other-race visual preference for Caucasian faces over Chinese faces. Findings are discussed in terms of the influence of other-race contact on visual preferences for race in infants.

Setting the Stage for Speech Production: Infants Prefer Listening to Speech Sounds With Infant Vocal Resonances.

Current models of speech development argue for an early link between speech production and perception in infants. Recent data show that young infants (at 4-6 months) preferentially attend to speech sounds (vowels) with infant vocal properties compared to those with adult vocal properties, suggesting the presence of special "memory banks" for one's own nascent speech-like productions. This study investigated whether the vocal resonances (formants) of the infant vocal tract are sufficient to elicit this preference and whether this perceptual bias changes with age and emerging vocal production skills. We selectively manipulated the fundamental frequency (f0 ) of vowels synthesized with formants specifying either an infant or adult vocal tract, and then tested the effects of those manipulations on the listening preferences of infants who were slightly older than those previously tested (at 6-8 months). Unlike findings with younger infants (at 4-6 months), slightly older infants in Experiment 1 displayed a robust preference for vowels with infant formants over adult formants when f0 was matched. The strength of this preference was also positively correlated with age among infants between 4 and 8 months. In Experiment 2, this preference favoring infant over adult formants was maintained when f0 values were modulated. Infants between 6 and 8 months of age displayed a robust and distinct preference for speech with resonances specifying a vocal tract that is similar in size and length to their own. This finding, together with data indicating that this preference is not present in younger infants and appears to increase with age, suggests that nascent knowledge of the motor schema of the vocal tract may play a role in shaping this perceptual bias, lending support to current models of speech development. https://doi.org/10.23641/asha.17131805.

Back Cover: Cover Image, Volume 25, Issue 1

The cover image is based on the Paper Observing inefficient action can induce infant preference and learning by Masahiro Hirai, Yasuhiro Kanakogi, and Ayaka Ikeda., https://doi.org/10.1111/desc.13152.

Observing inefficient action can induce infant preference and learning.

'Motionese' can be defined as an exaggerated and repetitive action. It induces preference and learning in infants. However, which action component of motionese promotes infants' preference and learning remains largely unknown. In this study, we focused on inefficiency and toward-ness of action. Our study demonstrates that observing an inefficient holding out action can induce a visual preference in 4-month-old infants and learning in 10-month-old infants through eight experiments (N=192). We found that when infants observe inefficient holding out action, the action attracts their attention and facilitates learning about the identity of the toy object accompanying it, especially when people direct inefficient actions towards them. Our findings indicate that both action efficiency and toward-ness may be key factors in infant learning.

Making the World Behave: A New Embodied Account on Mobile Paradigm.

In this review article, we describe the mobile paradigm, a method used for more than 50 years to assess how infants learn and remember sensorimotor contingencies. The literature on the mobile paradigm demonstrates that infants below 6 months of age can remember the learning environment weeks after when reminded periodically and integrate temporally distributed information across modalities. The latter ability is only possible if events occur within a temporal window of a few days, and the width of this required window changes as a function of age. A major critique of these conclusions is that the majority of this literature has neglected the embodied experience, such that motor behavior was considered an equivalent developmental substitute for verbal behavior. Over recent years, simulation and empirical work have highlighted the sensorimotor aspect and opened up a discussion for possible learning mechanisms and variability in motor preferences of young infants. In line with this recent direction, we present a new embodied account on the mobile paradigm which argues that learning sensorimotor contingencies is a core feature of development forming the basis for active exploration of the world and body. In addition to better explaining recent findings, this new framework aims to replace the dis-embodied approach to the mobile paradigm with a new understanding that focuses on variance and representations grounded in sensorimotor experience. Finally, we discuss a potential role for the dorsal stream which might be responsible for guiding action according to visual information, while infants learn sensorimotor contingencies in the mobile paradigm.