Preference for attractive faces in human infants extends beyond conspecifics

Preschoolers' retrospective and prospective judgements of immanent justice following distributive actions

Prior research provided evidence for retrospective and prospective judgements of immanent justice in adults, but the developmental origins of judgements of immanent justice remain unknown. Both retrospective and prospective judgements were investigated in preschool age, using explicit and implicit measures. In Experiment 1, 2.5- and 4-year-olds were first shown events in which one agent distributed resources fairly or unfairly, and then they saw test events in which both distributors were damaged by a misfortune. Later, they were presented with a verbal task, in which they had to respond to two questions on evaluation of the deservingness, by using explicit measures. All children were likely to approve of deserved outcomes when deeds and outcomes were congruent (i.e., unfair distributor-misfortune), and only older ones were likely to disapprove when they were incongruent (i.e., fair distributor-misfortune). In Experiment 2, 4-year-olds after seeing familiarization events of Experiment 1, were presented with two verbal questions to explore prospective judgements of immanent justice, by using explicit measures. In Experiment 3, 4-year-olds were first shown familiarization events of Experiment 1 and listened to respective narratives, then before the outcome was revealed they were assessed with a reaching task to investigate prospective judgements of immanent justice, by using implicit measures. Children reached the image depicting a bad outcome for the unfair distributor, and that illustrated a good outcome for the fair distributor. The results of the last two experiments demonstrated a fine ability to make prospective judgements at 4 years of life, and found that they were to be more prone to apply immanent justice reasoning to positive outcomes following good actions. Taken together, these results provide new evidence for preschoolers' retrospective and prospective judgements of immanent justice.

Neural signatures to prosocial and antisocial interactions in young infants

Preverbal infants appear to be more attracted by prosocial characters and events, as typically assessed using preferential looking times and manual choice. However, infants' neural correlates of observed prosocial and antisocial interactions are still scarce. Here, we familiarized 5-month-old (N = 24) infants with a prosocial and antisocial scene (i.e., a character either helping or hindering) and infants' Event-Related Potentials (ERP) were recorded in response to the presentation of short video clips of the prosocial and antisocial interaction. On a neural level, results revealed that infants could discriminate between helping and hindering events at an early stage of processing, as shown by a larger N290 response to the former compared to the latter. Further, while the Nc - typically indexing attentional processes - was larger for antisocial over prosocial events, the LPP, indexing cognitive evaluation of the stimuli, was larger for prosocial over antisocial actions. Finally, infants' higher scores on the effortful control temperamental subscale were related to infants' increased N290 neural sensitivity to antisocial scenes. Together, these findings provide new evidence of the time course of infants' ERP responses during the observation of helping and hindering interactions, which involves both attentional and socially relevant processes.

Electrophysiological Evidence for Interhemispheric Connectivity and Communication in Young Human Infants

Little is known empirically about connectivity and communication between the two hemispheres of the brain in the first year of life, and what theoretical opinion exists appears to be at variance with the meager extant anatomical evidence. To shed initial light on the question of interhemispheric connectivity and communication, this study investigated brain correlates of interhemispheric transmission of information in young human infants. We analyzed EEG data from 12 4-month-olds undergoing a face-related oddball ERP protocol. The activity in the contralateral hemisphere differed between odd-same and odd-difference trials, with the odd-different response being weaker than the response during odd-same trials. The infants' contralateral hemisphere "recognized" the odd familiar stimulus and "discriminated" the odd-different one. These findings demonstrate connectivity and communication between the two hemispheres of the brain in the first year of life and lead to a better understanding of the functional integrity of the developing human infant brain.

A New Perspective on Assessing Cognition in Children through Estimating Shared Intentionality

This theoretical article aims to create a conceptual framework for future research on digital methods for assessing cognition in children through estimating shared intentionality, different from assessing through behavioral markers. It shows the new assessing paradigm based directly on the evaluation of parent-child interaction exchanges (protoconversation), allowing early monitoring of children’s developmental trajectories. This literature analysis attempts to understand how cognition is related to emotions in interpersonal dynamics and whether assessing these dynamics shows cognitive abilities in children. The first part discusses infants’ unexpected achievements, observing the literature about children’s development. The analysis supposes that due to the caregiver’s help under emotional arousal, newborns’ intentionality could appear even before it is possible for children’s intention to occur. The emotional bond evokes intentionality in neonates. Therefore, they can manifest unexpected achievements while performing them with caregivers. This outcome shows an appearance of protoconversation in adult-children dyads through shared intentionality. The article presents experimental data of other studies that extend our knowledge about human cognition by showing an increase of coordinated neuronal activities and the acquisition of new knowledge by subjects in the absence of sensory cues. This highlights the contribution of interpersonal interaction to gain cognition, discussed already by Vygotsky. The current theoretical study hypothesizes that if shared intentionality promotes cognition from the onset, this interaction modality can also facilitate cognition in older children. Therefore in the second step, the current article analyzes empirical data of recent studies that reported meaningful interaction in mother-infant dyads without sensory cues. It discusses whether an unbiased digital assessment of the interaction ability of children is possible before the age when the typical developmental trajectory implies verbal communication. The article develops knowledge for a digital assessment that can measure the extent of children’s ability to acquire knowledge through protoconversation. This specific assessment can signalize the lack of communication ability in children even when the typical trajectory of peers’ development does not imply verbal communication.

Infants look longer at colours that adults like when colours are highly saturated

The extent to which aesthetic preferences are ‘innate’ has been highly debated (Reber, Schwarz, & Winkielman, Personality and Social Psychology Review, 8(4), 364–382, 2004). For some types of visual stimuli infants look longer at those that adults prefer. It is unclear whether this is also the case for colour. A lack of relationship in prior studies between how long infants look at different colours and how much adults like those colours might be accounted for by stimulus limitations. For example, stimuli may have been too desaturated for infant vision. In the current study, using saturated colours more suitable for infants, we aim to quantify the relationship between infant looking and adult preference for colour. We take infant looking times at multiple hues from a study of infant colour categorization (Skelton, Catchpole, Abbott, Bosten, & Franklin, Proceedings of the National Academy of Sciences of the United States of America, 114(21), 5545–5550, 2017) and then measure adult preferences and compare these to infant looking. When colours are highly saturated, infants look longer at colours that adults prefer. Both infant looking time and adult preference are greatest for blue hues and are least for green-yellow. Infant looking and adult preference can be partly summarized by activation of the blue-yellow dimension in the early encoding of human colour vision. These findings suggest that colour preference is at least partially rooted in the sensory mechanisms of colour vision, and more broadly that aesthetic judgements may in part be due to underlying sensory biases.

Factors affecting infant toy preferences: Age, gender, experience, motor development, and parental attitude

In contrast to the anecdotal claim that "male infants like cars and female infants like dolls," previous studies have reported mixed findings for gender-related toy preferences in infancy. In Experiment 1, we explored the emergence of gender-related preferences using face-car pairs (Experiment 1a, n = 51, 6-20 months) or face-stove pairs (Experiment 1b, n = 54, 6-20 months). In Experiment 2 (n = 42, 14-16 months), we explore the effect of toy properties, infants' past toy exposure, activity levels, and parental attitudes on such preferences using a wider range of toys. For both studies, infants demonstrated a general preference for faced stimuli over other objects, except for male infants who showed no preference between dolls and cars at around 15 months. Infants' prior experience participating in motor-intensive activities, with wheeled toys and parental attitudes appeared to relate to female infants' preferences for dynamic toys. These results indicate a range of factors influence gendered toy preferences and suggest that nurture plays an important role.

Perceptual Advantage of Animal Facial Attractiveness: Evidence From b-CFS and Binocular Rivalry

Research has shown that attractive human faces enjoy an advantage in both conscious and preconscious processing. Here we examined whether this preference for attractiveness is exclusive to human faces by measuring participants’ sensitivity to the attractiveness of cat and tiger faces. Experiment 1 measured the time taken to break continuous flash suppression (b-CFS), whereas Experiment 2 measured the dominant time in binocular rivalry (BR). The results showed that attractive cat faces were detected more quickly (Experiment 1) and dominated for longer time in visual awareness (Experiment 2). However, no effect of attractiveness was found for tiger faces in Experiment 1, while attractive tiger faces also dominated for longer time in visual awareness in Experiment 2. The results provide first evidence that the preference for attractive animal faces can be shown involuntarily or without apparent conscious control. The findings suggest that human preference for facial attractiveness may contain an aesthetic element rather than being a purely adaptive means for mate choice.

Preference for facial averageness: Evidence for a common mechanism in human and macaque infants

Human adults and infants show a preference for average faces, which could stem from a general processing mechanism and may be shared among primates. However, little is known about preference for facial averageness in monkeys. We used a comparative developmental approach and eye-tracking methodology to assess visual attention in human and macaque infants to faces naturally varying in their distance from a prototypical face. In Experiment 1, we examined the preference for faces relatively close to or far from the prototype in 12-month-old human infants with human adult female faces. Infants preferred faces closer to the average than faces farther from it. In Experiment 2, we measured the looking time of 3-month-old rhesus macaques (Macaca mulatta) viewing macaque faces varying in their distance from the prototype. Like human infants, macaque infants looked longer to faces closer to the average. In Experiments 3 and 4, both species were presented with unfamiliar categories of faces (i.e., macaque infants tested with adult macaque faces; human infants and adults tested with infant macaque faces) and showed no prototype preferences, suggesting that the prototypicality effect is experience-dependent. Overall, the findings suggest a common processing mechanism across species, leading to averageness preferences in primates.

Six-month-old infant long sleepers prefer a human face

BACKGROUND

Sleep is known to influence socio-emotional regulation among children and preschoolers, whereas little is known about the association between sleep and social preference during infancy.

METHODS

In the current study, habitual sleep of 49 infants aged around six months old were surveyed by questionnaire, and their social preference was revealed by their preferential gaze in three conditions: (1) a human face paired with an object (ie, a cup), (2) a human face paired with an animal face (ie, a dog), and (3) a dog face paired with a cup.

RESULTS

In general, images with richer social information (ie, a human face and dog) attracted infants' gaze significantly more than nonsocial images (ie, cup). Infants with shorter sleep duration (ie, <13 h a day) show a significant reduction in their preference toward a human face when paired with a dog than infants with longer sleep duration.

CONCLUSIONS

Our findings suggest an early positive link between sleep duration and preference towards socially rich stimuli (eg, a human face) during infancy.

A foxy view of human beauty: implications of the farm fox experiment for understanding the origins of structural and experiential aspects of facial attractiveness

Within 20 years, experimental selection of quantified "not too aggressive, not too fearful" behavior to human approach was shown in silver foxes (Vulpes vulpes) to produce a neotenic package of traits in adults: ability to seek, induce, and sustain contact (called friendly or rapport behavior); relatively short limbs and foreshortened skull/face; and light pigmentation areas. Earlier sexual maturation, prolonged receptivity, and larger litters were also noted. The increased estradiol supporting these changes was apparently also responsible for faster skeletal maturation, including earlier fusion of the basicranium causing tooth crowding, but also paedomorphic craniofacial proportions that we find attractive in our own and other species. In this paper, these important findings of the farm fox experiment are juxtaposed with insights from social psychology, physical anthropology, and neuroscience about facial beauty and reaction to it. Since many unrelated species show some or all of the neotenic package or domestication profile when they have achieved rapport past the juvenile stage, craniofacial proportions considered attractive are discussed as genetically and hormonally linked to the evolution of rapport--social contact, trust, and cooperation--whether by natural, intuitive, intentional, or mixed paths of selection.

Sex-related preferences for real and doll faces versus real and toy objects in young infants and adults

Findings of previous studies demonstrate sex-related preferences for toys in 6-month-old infants; boys prefer nonsocial or mechanical toys such as cars, whereas girls prefer social toys such as dolls. Here, we explored the innate versus learned nature of this sex-related preferences using multiple pictures of doll and real faces (of men and women) as well as pictures of toy and real objects (cars and stoves). In total, 48 4- and 5-month-old infants (24 girls and 24 boys) and 48 young adults (24 women and 24 men) saw six trials of all relevant pairs of faces and objects, with each trial containing a different exemplar of a stimulus type. The infant results showed no sex-related preferences; infants preferred faces of men and women regardless of whether they were real or doll faces. Similarly, adults did not show sex-related preferences for social versus nonsocial stimuli, but unlike infants they preferred faces of the opposite sex over objects. These results challenge claims of an innate basis for sex-related preferences for toy real stimuli and suggest that sex-related preferences result from maturational and social development that continues into adulthood.

Left visual field biases when infants process faces: a comparison of infants at high- and low-risk for autism spectrum disorder

While it is well-known that individuals with autism spectrum disorder (ASD) have difficulties processing faces, very little is known about the origins of these deficits. The current study focused on 6- and 11-month-old infants who were at either high-risk (n = 43) or low-risk (n = 31) for developing ASD based on having a sibling already diagnosed with the disorder. Eye-tracking data were collected while the infants viewed color photographs of faces. Similar to previous studies with both typically developing adults and infants, low-risk infants demonstrated a preference for looking at the left side of the face (known as a left visual field bias) that emerged by 11 months of age. In contrast, high-risk infants did not demonstrate a left visual field bias at either age. Comparisons of the amount of attention given to the eye versus mouth regions indicated no differences between the two risk groups.

Visual recognition of age class and preference for infantile features: implications for species-specific vs universal cognitive traits in primates

Despite not knowing the exact age of individuals, humans can estimate their rough age using age-related physical features. Nonhuman primates show some age-related physical features; however, the cognitive traits underlying their recognition of age class have not been revealed. Here, we tested the ability of two species of Old World monkey, Japanese macaques (JM) and Campbell's monkeys (CM), to spontaneously discriminate age classes using visual paired comparison (VPC) tasks based on the two distinct categories of infant and adult images. First, VPCs were conducted in JM subjects using conspecific JM stimuli. When analyzing the side of the first look, JM subjects significantly looked more often at novel images. Based on analyses of total looking durations, JM subjects looked at a novel infant image longer than they looked at a familiar adult image, suggesting the ability to spontaneously discriminate between the two age classes and a preference for infant over adult images. Next, VPCs were tested in CM subjects using heterospecific JM stimuli. CM subjects showed no difference in the side of their first look, but looked at infant JM images longer than they looked at adult images; the fact that CMs were totally naïve to JMs suggested that the attractiveness of infant images transcends species differences. This is the first report of visual age class recognition and a preference for infant over adult images in nonhuman primates. Our results suggest not only species-specific processing for age class recognition but also the evolutionary origins of the instinctive human perception of baby cuteness schema, proposed by the ethologist Konrad Lorenz.

The Shaping of the Face Space in Early Infancy: Becoming a Native Face Processor

Face perception remains one of the most intensively researched areas in psychology and allied disciplines, and there has been much debate regarding the early origins and experiential determinants of face processing. This article reviews studies, the majority of which have appeared in the past decade, that discuss possible mechanisms underlying face perception at birth and document the prominent role of experience in shaping infants' face-processing abilities. In the first months of life, infants develop a preference for female and own-race faces and become better able to recognize and categorize own-race and own-species faces. This perceptual narrowing and shaping of the "face space" forms a foundation for later face expertise in childhood and adulthood and testifies to the remarkable plasticity of the developing visual system.

Bebês: o irresistível poder da graciosidade. Um estudo sobre o significado evolutivo dos traços infantis

Os bebês, em geral, despertam ternura e comportamentos de cuidado nas pessoas. O objetivo deste trabalho foi discutir a atração provocada pelos traços infantis, tendo como referencial teórico os quatro níveis de explicação de Tinbergen. Do ponto de vista dos mecanismos que desencadeiam essa atração neonatal, avaliamos a importância da aparência do infante para eliciar as respostas de cuidado parental. Considerando a função adaptativa desta característica, discutimos os processos evolutivos que moldaram as preferências pelos atributos infantis, além da história filogenética do favoritismo pelos sinais morfológicos de filhotes. Apresentamos, ainda, dados sobre o desenvolvimento deste traço comportamental ao longo da vida. Tomadas em conjunto, estas informações provêem uma análise de por que achamos os bebês tão irresistíveis.

Left-right facial orientation of familiar faces: developmental aspects of « the mere exposure hypothesis »

We investigated the developmental aspect of sensitivity to the orientation of familiar faces by asking 38 adults and 72 children from 3 to 12 years old to make a preference choice between standard and mirror images of themselves and of familiar faces, presented side-by-side or successively. When familiar (parental) faces were presented simultaneously, 3- to 5-year-olds showed no preference, but by age 5-7 years an adult-like preference for the standard image emerged. Similarly, the adult-like preference for the mirror image of their own face emerged by 5-7 years of age. When familiar or self faces were presented successively, 3- to 7-year-olds showed no preference, and adult-like preference for the standard image emerged by age 7-12 years. These results suggest the occurrence of a developmental process in the perception of familiar face asymmetries which is retained in memory related to knowledge about faces.

Sex differences in adults' relative visual interest in female and male faces, toys, and play styles

An individual's reproductive potential appears to influence response to attractive faces of the opposite sex. Otherwise, relatively little is known about the characteristics of the adult observer that may influence his or her affective evaluation of male and female faces. An untested hypothesis (based on the proposed role of attractive faces in mate selection) is that most women would show greater interest in male faces whereas most men would show greater interest in female faces. Further, evidence from individuals with preferences for same-sex sexual partners suggests that response to attractive male and female faces may be influenced by gender-linked play preferences. To test these hypotheses, visual attention directed to sex-linked stimuli (faces, toys, play styles) was measured in 39 men and 44 women using eye tracking technology. Consistent with our predictions, men directed greater visual attention to all male-typical stimuli and visual attention to male and female faces was associated with visual attention to gender conforming or nonconforming stimuli in a manner consistent with previous research on sexual orientation. In contrast, women showed a visual preference for female-typical toys, but no visual preference for male faces or female-typical play styles. These findings indicate that sex differences in visual processing extend beyond stimuli associated with adult sexual behavior. We speculate that sex differences in visual processing are a component of the expression of gender phenotypes across the lifespan that may reflect sex differences in the motivational properties of gender-linked stimuli.

Sex differences in infants' visual interest in toys

Evidence indicating that sex-linked toy preferences exist in two nonhuman primate species support the hypothesis that developmental sex differences such as those observed in children's object preferences are shaped in part by inborn factors. If so, then preferences for sex-linked toys may emerge in children before any self-awareness of gender identity and gender-congruent behavior. In order to test this hypothesis, interest in a doll and a toy truck was measured in 30 infants ranging in age from 3 to 8 months using eye-tracking technology that provides precise indicators of visual attention. Consistent with primary hypothesis, sex differences in visual interest in sex-linked toys were found, such that girls showed a visual preference (d > 1.0) for the doll over the toy truck and boys compared to girls showed a greater number of visual fixations on the truck (d = .78). Our findings suggest that the conceptual categories of "masculine" and "feminine" toys are preceded by sex differences in the preferences for perceptual features associated with such objects. The existence of these innate preferences for object features coupled with well-documented social influences may explain why toy preferences are one of the earliest known manifestations of sex-linked social behavior.