Infant Preferences Research Articles

A Novel Method to Investigate How Dimensions Interact to Inform Perceptual Salience in Infancy

How physical dimensions govern children's perception, language acquisition, and cognition is an important question in developmental science. Here, we use the psychophysical technique of maximum likelihood conjoint measurement (MLCM) as a novel approach to investigate how infants combine information distributed along two or more dimensions. MLCM is based on a signal detection model of decision that allows testing of several models of how observers integrate information to make choices. We tested 6‐month‐old infants’ preferential looking to “green” stimuli that covaried in lightness and chroma and analyzed infant preferences using MLCM. The findings show that infant looking is driven primarily by lightness, with darker stimuli having a greater preference than lighter, plus a small but significant positive contribution of chroma. This study demonstrates that the technique of MLCM can be used in conjunction with preferential looking to investigate the salience of physical dimensions during development. The technique could now be applied to investigate the role of physical dimensions in key aspects of perceptual and cognitive development such as face recognition, language acquisition, and object recognition.

Impact of a Modified Version of Baby-Led Weaning on Dietary Variety and Food Preferences in Infants.

The aim of this study was to determine whether food variety and perceived food preferences differ in infants following baby-led instead of traditional spoon-feeding approaches to introducing solids. A total of 206 women (41.3% primiparous) were recruited in late pregnancy from a single maternity hospital (response rate 23.4%) and randomized to Control (n = 101) or BLISS (n = 105) groups. All participants received government-funded Well Child care. BLISS participants also received support to exclusively breastfeed to 6 months and three educational sessions on BLISS (Baby-Led Weaning, modified to reduce the risk of iron deficiency, growth faltering, and choking) at 5.5, 7, and 9 months. Food variety was calculated from three-day weighed diet records at 7, 12, and 24 months. Questionnaires assessed infant preference for different tastes and textures at 12 months, and for ‘vegetables’, ‘fruit’, ‘meat and fish’, or ‘desserts’ at 24 months. At 24 months, 50.5% of participants provided diet record data, and 78.2% provided food preference data. BLISS participants had greater variety in ‘core’ (difference in counts over three days, 95% CI: 1.3, 0.4 to 2.2), ‘non-core’ (0.6, 0.2 to 0.9), and ‘meat and other protein’ (1.3, 0.8 to 1.9) foods at 7 months, and in ‘fruit and vegetable’ foods at 24 months (2, 0.4 to 3.6). The only differences in perceived food preferences observed were very small (i.e., <5% difference in score, at 12 months only). Infants following the modified Baby-Led Weaning were exposed to more varied and textured foods from an early age, but only an increased variety in ‘fruit and vegetable’ intake was apparent by two years of age.

Observing Others' Gaze Direction Affects Infants' Preference for Looking at Gazing- or Gazed-at Faces.

Eye gaze is an important signal in social interactions, and it plays an important role to understand what others looking in joint attention (JA) situations. JA has been examined in situations involving two people gazing at objects; however, ecologically, infants observe not only faces that gaze at objects but also those that gaze at other people. Here, we examined how eye gaze directed toward another face affect face preferences in infants. A total of 19 children were observed during a JA situation and a no-JA situation. In the JA situation, an adult face in the central position of the screen shifted her gaze to look at another adult face at a lateral position on the screen. However, during the no JA situation, the central face shifted her eye gaze away from the adult face presented on the screen. At test, for the centrally presented faces, infant looking times were longer at faces in the no JA condition. At test, for the laterally presented faces, looking times were longer at the faces in the JA condition. Thus, the adult’s eye gaze biased the duration of the gaze of the infants at either the central faces or the lateral-cued faces in the preferential looking tests. These results suggest that 10-month-old infants may interpret adult gazing behavior and that this can affect the gazing behavior of infants.

Consumer preference for infant milk‐based formula with select food safety information attributes: Evidence from a choice experiment in China

AbstractThe melamine milk powder incident in China undermined consumers’ confidence in dairy products including infant milk‐based formula (IMF). In this study, three quality IMF product attributes are considered in a choice experiment survey in China including organic label, traceability information, and country of origin (COO). Results reveal that consumers have the highest willingness to pay (WTP) for an organic label from the United States. Traceability information regarding milk production was preferred the most. Consumers prefer IMF originated from the United States and New Zealand over China. Consumer heterogeneity was revealed through a latent class model. Compared to price‐sensitive consumers, certification‐inclined consumers had significantly higher WTP for organic labels. Origin‐preferred consumers displayed higher WTP for IMF produced in the United States and New Zealand, and concerned consumers had higher WTP for all food safety informational attributes. The conclusions of this paper should not only aid Chinese domestic producers and policy makers, they should also provide references for organic certification bodies and dairy enterprises from around the world for their business decision making.

Is infant-directed speech interesting because it is surprising? – Linking properties of IDS to statistical learning and attention at the prosodic level

The exaggerated intonation and special rhythmic properties of infant-directed speech (IDS) have been hypothesized to attract infants’ attention to the speech stream. However, there has been little work actually connecting the properties of IDS to models of attentional processing or perceptual learning. A number of such attention models suggest that surprising or novel perceptual inputs attract attention, where novelty can be operationalized as the statistical (un)predictability of the stimulus in the given context. Since prosodic patterns such as F0 contours are accessible to young infants who are also known to be adept statistical learners, the present paper investigates a hypothesis that F0 contours in IDS are less predictable than those in adult-directed speech (ADS), given previous exposure to both speaking styles, thereby potentially tapping into basic attentional mechanisms of the listeners in a similar manner that relative probabilities of other linguistic patterns are known to modulate attentional processing in infants and adults. Computational modeling analyses with naturalistic IDS and ADS speech from matched speakers and contexts show that IDS intonation has lower overall temporal predictability even when the F0 contours of both speaking styles are normalized to have equal means and variances. A closer analysis reveals that there is a tendency of IDS intonation to be less predictable at the end of short utterances, whereas ADS exhibits more stable average predictability patterns across the full extent of the utterances. The difference between IDS and ADS persists even when the proportion of IDS and ADS exposure is varied substantially, simulating different relative amounts of IDS heard in different family and cultural environments. Exposure to IDS is also found to be more efficient for predicting ADS intonation contours in new utterances than exposure to the equal amount of ADS speech. This indicates that the more variable prosodic contours of IDS also generalize to ADS, and may therefore enhance prosodic learning in infancy. Overall, the study suggests that one reason behind infant preference for IDS could be its higher information value at the prosodic level, as measured by the amount of surprisal in the F0 contours. This provides the first formal link between the properties of IDS and the models of attentional processing and statistical learning in the brain. However, this finding does not rule out the possibility that other differences between the IDS and ADS also play a role.

A Longitudinal Investigation of Preferential Attention to Biological Motion in 2- to 24-Month-Old Infants

Preferential attention to biological motion is an early-emerging mechanism of adaptive action that plays a critical role in social development. The present study provides a comprehensive longitudinal mapping of developmental change in preferential attention to biological motion in 116 infants at 7 longitudinal time points. Tested repeatedly from 2 until 24 months of age, results reveal that preferential attention to biological motion changes considerably during the first months of life. Previously reported preferences in both neonates and older infants are absent in the second month but do reemerge by month 3 and become increasingly pronounced during the subsequent two years. These results highlight the second month of life as a potentially critical transition period in social visual engagement.

Impact of Bilingualism on Infants’ Ability to Learn From Talking and Nontalking Faces

AbstractTo probably overcome the challenge of learning two languages at the same time, infants raised in a bilingual environment pay more attention to the mouth of talking faces than same‐age monolinguals. Here we examined the consequences of such preference for monolingual and bilingual infants’ ability to perceive nonspeech information coming from the eyes or the mouth region of talking faces. Using a learning procedure, we recorded 15‐month‐olds’ and 18‐month‐olds’ gaze while watching, at each trial, a speaker producing a sentence systematically followed by a nonspeech movement (eyebrow raise vs. lip protrusion). Differences were obtained for infants in the eyebrow‐raise condition. While 15‐month‐old monolinguals and 18‐month‐old bilinguals learned to anticipate the eyebrow‐raise movement before its appearance, 15‐month‐old bilinguals did not (i.e., they continued to look at the mouth region). Thus, bilingualism appears to impact not only how infants explore talking faces but also how they learn from them.

Evaluation and management of nonsyndromic congenital hearing loss.

Nonsyndromic congenital hearing loss represents the largest proportion of paediatric sensorineural hearing loss. The optimal evaluation and management of affected patients remains clinically challenging. Current controversies in the diagnostic work-up of nonsyndromic congenital hearing loss are presented in this review. The improved diagnostic yield of comprehensive genetic testing due to new sequencing technologies is changing the diagnostic for congenital hearing loss. Concerns for both ionizing radiation and general anaesthetic exposure are also driving shifts in imaging modality preferences for infants and toddlers. A thoughtful systematic, targeted approach taking into consideration the audiologic phenotype of the patient is recommended for the work-up of nonsyndromic congenital hearing loss.

Early expression of manual lateralization in bipedal marsupials.

Robust lateralization in forelimb use has recently been found in bipedal, but not quadrupedal, marsupial mammals. The link between bipedality and handedness, occurring in both marsupials and primates, remains to be investigated. To shed light on the developmental origins of marsupial manual lateralization, infants of macropod marsupials were examined before and shortly after the acquisition of habitual bipedal posture and locomotion. Forelimb preferences were assessed in natural, not artificially evoked, behaviors of infant red-necked wallaby in the wild and infant eastern gray kangaroo in free-ranging captivity. Pouch young of both species showed population-level left-forelimb preference when manipulating food objects, such as leaves and grass blades. This result provides the first report of lateralization in pouch young marsupials and rare evidence of lateralized manual activity in early mammalian ontogenesis. Young-at-foot juveniles of eastern gray kangaroo preferred to use the left forelimb to manipulate the mother's pouch edge as previously shown for red-necked wallaby. In both species, the direction of biases in manipulative behavior for young-at-foot and pouch young was the same as in adults. Forelimb preferences in offspring were positively correlated with the forelimb preferences of their mothers. Our results strongly suggest that the emergence of individual and population-level forelimb preferences in macropod infants precedes the onset of independent standing and locomotion. In all probability, manual lateralization in bipedal marsupials, such as kangaroos and wallabies, is not determined by the acquisition of habitual bipedality in the course of ontogenesis. (PsycINFO Database Record

How Infants and Young Children Learn About Food: A Systematic Review.

Early childhood is a critical time for establishing food preferences and dietary habits. In order for appropriate advice to be available to parents and healthcare professionals it is essential for researchers to understand the ways in which children learn about foods. This review summarizes the literature relating to the role played by known developmental learning processes in the establishment of early eating behavior, food preferences and general knowledge about food, and identifies gaps in our knowledge that remain to be explored. A systematic literature search identified 48 papers exploring how young children learn about food from the start of complementary feeding to 36 months of age. The majority of the papers focus on evaluative components of children's learning about food, such as their food preferences, liking and acceptance. A smaller number of papers focus on other aspects of what and how children learn about food, such as a food's origins or appropriate eating contexts. The review identified papers relating to four developmental learning processes: (1) Familiarization to a food through repeated exposure to its taste, texture or appearance. This was found to be an effective technique for learning about foods, especially for children at the younger end of our age range. (2) Observational learning of food choice. Imitation of others' eating behavior was also found to play an important role in the first years of life. (3) Associative learning through flavor-nutrient and flavor-flavor learning (FFL). Although the subject of much investigation, conditioning techniques were not found to play a major role in shaping the food preferences of infants in the post-weaning and toddler periods. (4) Categorization of foods. The direct effects of the ability to categorize foods have been little studied in this age group. However, the literature suggests that what infants are willing to consume depends on their ability to recognize items on their plate as familiar exemplars of that food type.

A Review of Attractiveness Preferences in Infancy: From Faces to Objects

Despite some interpersonal variability, judgments of facial attractiveness are largely shared by most individuals, both within and between cultures. Infants are also sensitive to attractive faces even before being influenced by cultural standards of beauty. The intercultural agreement on this matter and its emergence during infancy suggest an evolutionary basis for facial attractiveness. Sensitivity to facial attractiveness is typically understood through evolutionary-based frameworks, either reflecting mate selection mechanisms or emerging as by-products of brain processing and perceptual sensory biases. In the current article, we review data on the emergence and the development of attractiveness preferences in infants, focusing on mechanisms that may explain or contribute to these preferences such as familiarity or fluency in processing. We further discuss the possibility that infants’ preference for attractiveness could extend to other stimuli than faces like objects or visual art. Potential directions for future research are proposed for developmental and comparative approaches.

I like it by mere association: Conditioning preferences in infants

Preferences have a profound impact on our behavior; however, relatively little is known about how preference formation works early in life. Evaluative conditioning occurs when the valence of an initially neutral object changes when it is paired with a positively or negatively valenced stimulus. It is possible that evaluative conditioning may account for early preference learning; however, the extent to which this kind of learning operates during infancy has not been empirically tested. The aim of the current studies was to assess whether infants’ preferences for neutral objects is influenced by pairing them with affective stimuli (Experiment 1: happy vs. angry faces, N=20; Experiment 2: mother vs. stranger faces, N=22). Infants’ preferences were tested using both looking time and behavioral choice measures. The results showed that infants tended to choose the object that had been paired with the positive stimulus (Experiment 1: 13/20; Experiment 2: 14/22). Gaze behavior at test did not differentiate between the two objects; however, gaze behavior during conditioning predicted infants’ behavioral preference. Only infants who looked longer at the affective stimulus than at the object during learning chose the object that had been paired with positive valence more often than chance. These results suggest that infants’ preferences may be influenced by learned associations between objects and affective stimuli, a process akin to evaluative conditioning in adults.

Attachment Avoidance Is Significantly Related to Attentional Preference for Infant Faces: Evidence from Eye Movement Data.

Objective: To determine the influence of adult attachment orientations on infant preference.Methods: We adopted eye-tracking technology to monitor childless college women’s eye movements when looking at pairs of faces, including one adult face (man or woman) and one infant face, with three different expressions (happy, sadness, and neutral). The participants (N = 150; 84% Han ethnicity) were aged 18–29 years (M = 19.22, SD = 1.72). A random intercepts multilevel linear regression analysis was used to assess the unique contribution of attachment avoidance, determined using the Experiences in Close Relationships scale, to preference for infant faces.Results: Women with higher attachment avoidance showed less infant preference, as shown by less sustained overt attentional bias to the infant face than the adult face based on fixation time and count.Conclusion: Adult attachment might be related to infant preference according to eye movement indices. Women with higher attachment avoidance may lack attentional preference for infant faces. The findings may aid the treatment and remediation of the interactions between children and mothers with insecure attachment.

Development of category formation for faces differing by age in 9- to 12-month-olds: An effect of experience with infant faces.

We examined category formation for faces differing in age in 9- and 12-month-olds, and the influence of exposure to infant faces on such ability. Infants were familiarized with adult or infant faces, and then tested with a novel exemplar from the familiarized category paired with a novel exemplar from a novel category (Experiment 1). Both age groups formed discrete categories of adult and infant faces, but exposure to infant faces in everyday life did not modulate performance. The same task was conducted with child versus infant faces (Experiment 2). Whereas 9-month-olds preferred infant faces after familiarization with child faces, but not child faces after familiarization with infant faces, 12-month-olds formed discrete categories of child and infant faces. Moreover, more exposure to infant faces correlated with higher novel category preference scores when infants were familiarized with infant faces in 12-month-olds, but not 9-month-olds. The 9-month-old asymmetry did not reflect spontaneous preference for infant over child faces (Experiment 3). These findings indicate that 9- and 12-month-olds can form age-based categories of faces. The ability of 12-month-olds to form separate child and infant categories suggests that they have a more exclusive representation of face age, one that may be influenced by prior experience with infant faces.

An adult face bias in infants that is modulated by face race

The visual preferences of infants for adult versus infant faces were investigated. Caucasian 3.5- and 6-month-olds were presented with Caucasian adult vs. infant face pairs and Asian adult vs. infant face pairs, in both upright and inverted orientations. Both age groups showed a visual preference for upright adult over infant faces when the faces were Caucasian, but not when they were Asian. The preference is unlikely to have arisen because of low-level perceptual features because: (1) no preference was observed for the inverted stimuli, (2) no differences were observed in adult similarity ratings of the upright infant–adult face pairs from the two races, and (3) no differences between the infant and adult faces were observed across races in an image-based analysis of salience. The findings are discussed in terms of the social attributes of faces that are learned from experience and what this implies for developmental accounts of a recognition advantage for adult faces in particular and models of face processing more generally.

Commentary: Cats prefer species-appropriate music.

Commentary: Cats prefer species-appropriate music.

Taste Preferences in Infants: What Defines Them?

Breast milk is the best food for a baby of the first year of life. To pass successfully from feeding by breast milk or formula tothe introduction of complementary food, a child need to learn to perceive the taste of new products offering to him. We have evaluated mouthfeel of complementary food in 30 children aged between 4 and 12 months of life, which were divided into 3 groups according to the administered complementary food. The observation period was 30 days. The accounting of the perception of new complementary food was carried out basing on the assessment of the child's emotional status and tolerability of the complementary food product. As a result, in the first group of children the refusal of the vegetable intake (broccoli, squash) occurred to 4.1 ± 0.94 days from the start of the product administration. Intestinal colic and defecation disorders were observed in 2 (16.6%) children of this group, but they were not registered after the re-examination of infants. In the second group, the positive perception of buckwheat dairy-free porridge rich in 3 polyunsaturated fatty acids was observed ranging from 3.0 ± 0.97 days from the start of its administration. In this group 1 (8.3%) child responded by the appearance of posseting and 2 (16.6%) — by defecation disorders. After 2 weeks 1 (8.3%) child still had defecation disorders. In the third group, children, starting from the 2nd day of the intake of pureed meat, ate this product with pleasure, disorders of the gastrointestinal tract have not been reported. Thus, studied complementary food has a good taste, hypoallergenic balanced composition and allows to diversify the diet of infants.

Outcome of in vitro fertilization procedure at a private fertility center in Nnewi, South-East Nigeria

Background: Infertility has grown to be a major health and social challenge in our environment that a childless marriage is regarded as a failed marriage. Couples are therefore ready to do all within their power to achieve pregnancy and have a baby of their own. This is the yawning gap assisted reproductive technology is fulfilling. Objective: To determine the outcome of in vitro fertilization (IVF) procedures 2 years after the commencement of the IVF program in a private hospital setting in Nnewi, Nigeria. Methods: From October 1, 2010 to September 30, 2012, 115 couples had conventional IVF procedures in batches of 10-15 couples. The outcome measures were clinical pregnancy rate, miscarriage rate, live birth rate, and sex ratio following one or two cycles of treatment. The results were analyzed using Epi info software 2013 version 7.0. Results: The mean age of the participants was 43.7 ± 3.5 years. The maximum number of embryos transferred per woman was four and minimum was one. The rates of clinical pregnancy, live births and multiple pregnancies were 30%, 18.3%, and 6.0%, respectively. Of the 31 women who conceived, 21 (67.7%) delivered live infants and 10 (32.3%) aborted in the first trimester. There was no case of ectopic pregnancy. The male:female sex ratio was 2:1. The mean endometrial thickness at embryo transfer (ET) was 8.9 ± 2.3 mm. Conclusion: The success rate of IVF-ET was good even in low resource settings and optimal endometrial thickness prior to ET may be one of the key success factors. The preponderance of male sex infants in our IVF births is acceptable to the couples who ordinarily have a preference for male infant.

Prevalence and Characteristics of Infant's Unexplained Breast Preference for Nursing One Breast: A Self-Administered Survey.

Breastfeeding is recommended by international bodies as the only source of infant nutrition during the first 6 months of life. Sometimes infants prefer to nurse on one breast for no obvious reason (hereafter called infant's unexplained breast preference [IUBP]). IUBP might reduce the rate of exclusive breastfeeding. The prevalence of IUBP is unknown because most of the literature on IUBP so far has been anecdotal. This study's objective was to investigate the prevalence and characteristics of IUBP among healthy infants in Al-Ahsa, Saudi Arabia. We conducted a population-based, cross-sectional study between March and August 2013 in the Al-Ahsa area, Eastern Province, Saudi Arabia. Healthy infants who had been born at full term (≥37 weeks of gestation) and were 2-24 months of age were included. We distributed 600 self-administered surveys to mothers who attended vaccination clinics in nine primary healthcare centers. Of 478 mothers who responded to the survey, 121 (25.3%) reported unilateral breastfeeding. IUBP was the most common reason for unilateral breastfeeding, with a prevalence of 13.6% (65/478). IUBP developed at a median age of 1 month (range, 1 day-9 months) and was familial in 42.9% of cases. It was the only reason for formula feeding during the first 6 months of life in 18.5% of cases. IUBP is common, develops very early in life, and can be familial and a reason for formula feeding. However, these findings need to be confirmed in other studies of other populations.

Predictors of the time to attain full oral feeding in late preterm infants.

The aim of this study was to determine the factors that predict the timing and age at which preterm infants (born 32-36 weeks gestation) commenced and attained full oral feeding. We conducted a retrospective review of medical records of 647 preterm infants born 2005-2011. Infants were from six neonatal intensive care units in New Zealand, all World Health Organisation Baby-friendly Hospital Initiative accredited. Median time to the first oral feed offered was one day, and median time to the time of full oral feeding was 12 days. No infants attained full oral feeding before 33(+3) weeks postmenstrual age. Gestational age, birthweight, medical conditions and location of the neonatal unit were significantly associated with the time taken to commence and attain full oral feeding. This study highlights the factors that are associated with the rate at which late preterm infants commence oral feeding and progress to full oral feeding. These findings offer important considerations not only for clinical practice but also discharge planning given the preference for preterm infants reaching full oral feeds before discharge from hospital. Prospective experimental research is required to confirm infant, maternal and environmental factors that influence feeding milestones in late preterm infants.