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

Sustained looking at faces at 5 months of age is associated with socio-communicative skills in the second year of life

Efficiently processing information from faces in infancy is foundational for nonverbal communication. We studied individual differences in 5-month-old infants' (N = 517) sustained attention to faces and preference for emotional faces. We assessed the contribution of genetic and environmental influences to individual differences in these gaze behaviors, and the association between these traits and other concurrent and later phenotypes. We found an association between the mean duration of looking at a face (before looking away from it) at 5 months and socio-communicative abilities at 14 months (β = 0.17, 95% CI: 0.08; 0.26, p < 0.001). Sustained attention to faces predicted socio-communicative abilities over and above variance captured by mean fixation duration. We also found a statistically significant but weak tendency to prefer looking at smiling faces (relative to neutral faces), but no indication that variability in this behavior was explained by genetic effects. Moderate heritability was found for sustained attention to faces (A = 0.23, CI: 0.06; 0.38), while shared environmental influences were non-significant for both phenotypes. These findings suggest that sustained looking at individual faces before looking away is a developmentally significant 'social attention' phenotype in infancy, characterized by moderate heritability and a specific relation to later socio-communicative abilities.

Infant perception of causal motion produced by humans and inanimate objects

Both the movements of people and inanimate objects are intimately bound up with physical causality. Furthermore, in contrast to object movements, causal relationships between limb movements controlled by humans and their body displacements uniquely reflect agency and goal-directed actions in support of social causality. To investigate the development of sensitivity to causal movements, we examined the looking behavior of infants between 9 and 18 months of age when viewing movements of humans and objects. We also investigated whether individual differences in gender and gross motor functions may impact the development of the visual preferences for causal movements. In Experiment 1, infants were presented with walking stimuli showing either normal body translation or a "moonwalk" that reversed the horizontal motion of body translations. In Experiment 2, infants were presented with unperformable actions beyond infants' gross motor functions (i.e., long jump) either with or without ecologically valid body displacement. In Experiment 3, infants were presented with rolling movements of inanimate objects that either complied with or violated physical causality. We found that female infants showed longer looking times to normal walking stimuli than to moonwalk stimuli, but did not differ in their looking time to movements of inanimate objects and unperformable actions. In contrast, male infants did not show sensitivity to causal movement for either category. Additionally, female infants looked longer at social stimuli of human actions than male infants. Under the tested circumstances, our findings indicate that female infants have developed a sensitivity to causal consistency between limb movements and body translations of biological motion, only for actions with previous visual and motor exposures, and demonstrate a preference toward social information.

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.

Do Animals Engage Greater Social Attention in Autism? An Eye Tracking Analysis

BACKGROUND

Visual atypicalities in autism spectrum disorder (ASD) are a well documented phenomenon, beginning as early as 2-6 months of age and manifesting in a significantly decreased attention to the eyes, direct gaze and socially salient information. Early emerging neurobiological deficits in perceiving social stimuli as rewarding or its active avoidance due to the anxiety it entails have been widely purported as potential reasons for this atypicality. Parallel research evidence also points to the significant benefits of animal presence for reducing social anxiety and enhancing social interaction in children with autism. While atypicality in social attention in ASD has been widely substantiated, whether this atypicality persists equally across species types or is confined to humans has not been a key focus of research insofar.

METHODS

We attempted a comprehensive examination of the differences in visual attention to static images of human and animal faces (40 images; 20 human faces and 20 animal faces) among children with ASD using an eye tracking paradigm. 44 children (ASD n = 21; TD n = 23) participated in the study (10,362 valid observations) across five regions of interest (left eye, right eye, eye region, face and screen).

RESULTS

Results obtained revealed significantly greater social attention across human and animal stimuli in typical controls when compared to children with ASD. However in children with ASD, a significantly greater attention allocation was seen to animal faces and eye region and lesser attention to the animal mouth when compared to human faces, indicative of a clear attentional preference to socially salient regions of animal stimuli. The positive attentional bias toward animals was also seen in terms of a significantly greater visual attention to direct gaze in animal images.

CONCLUSION

Our results suggest the possibility that atypicalities in social attention in ASD may not be uniform across species. It adds to the current neural and biomarker evidence base of the potentially greater social reward processing and lesser social anxiety underlying animal stimuli as compared to human stimuli in children with ASD.

How Large Are Gender Differences in Toy Preferences? A Systematic Review and Meta-Analysis of Toy Preference Research

It is generally recognized that there are gender-related differences in children's toy preferences. However, the magnitude of these differences has not been firmly established. Furthermore, not all studies of gender-related toy preferences find significant gender differences. These inconsistent findings could result from using different toys or methods to measure toy preferences or from studying children of different ages. Our systematic review and meta-analysis combined 113 effect sizes from 75 studies to estimate the magnitude of gender-related differences in toy preferences. We also assessed the impact of using different toys or methods to assess these differences, as well as the effect of age on gender-related toy preferences. Boys preferred boy-related toys more than girls did, and girls preferred girl-related toys more than boys did. These differences were large (d ≥ 1.60). Girls also preferred toys that researchers classified as neutral more than boys did (d = 0.29). Preferences for gender-typical over gender-atypical toys were also large and significant (d ≥ 1.20), and girls and boys showed gender-related differences of similar magnitude. When only dolls and vehicles were considered, within-sex differences were even larger and of comparable size for boys and girls. Researchers sometimes misclassified toys, perhaps contributing to an apparent gender difference in preference for neutral toys. Forced choice methods produced larger gender-related differences than other methods, and gender-related differences increased with age.

How Large Are Gender Differences in Toy Preferences? A Systematic Review and Meta-Analysis of Toy Preference Research

It is generally recognized that there are gender-related differences in children's toy preferences. However, the magnitude of these differences has not been firmly established. Furthermore, not all studies of gender-related toy preferences find significant gender differences. These inconsistent findings could result from using different toys or methods to measure toy preferences or from studying children of different ages. Our systematic review and meta-analysis combined 113 effect sizes from 75 studies to estimate the magnitude of gender-related differences in toy preferences. We also assessed the impact of using different toys or methods to assess these differences, as well as the effect of age on gender-related toy preferences. Boys preferred boy-related toys more than girls did, and girls preferred girl-related toys more than boys did. These differences were large (d ≥ 1.60). Girls also preferred toys that researchers classified as neutral more than boys did (d = 0.29). Preferences for gender-typical over gender-atypical toys were also large and significant (d ≥ 1.20), and girls and boys showed gender-related differences of similar magnitude. When only dolls and vehicles were considered, within-sex differences were even larger and of comparable size for boys and girls. Researchers sometimes misclassified toys, perhaps contributing to an apparent gender difference in preference for neutral toys. Forced choice methods produced larger gender-related differences than other methods, and gender-related differences increased with age.

The effect of the still-face paradigm on infant behavior: A cross-cultural comparison between mothers and fathers

Most still-face paradigm (SFP) studies have been done in Western families with infant-mother dyads. The present study investigated the SFP pattern in 123 Dutch and 63 Chinese 4-month-old infants with mothers and fathers. The classic SFP effect was found for positive affect and gaze in both countries. For negative affect, Chinese infants showed a different SFP pattern than Dutch infants. With fathers, infants displayed a less pronounced SFP pattern for positive affect and an increase from the still face to the reunion for negative affect. Only a minority of infants showed the expected SFP pattern across episodes. Our findings support that infant emotion expression is influenced by parent gender and cultural context. An interesting avenue for further study is the exploration of the origins of within- and between-gender and culture differences in affective communication between parents and infants.

Parents' Autistic Personality Traits and Sex-Biased Family Ratio Determine the Amount of Technical Toy Choice

We investigated the effect of parents' autism quotient (AQ), their sex and the sex of their children on their toy preference. In a computerized forced-choice shopping task, adults selected from cuddly and social role-playing toys (social toys), academic, music and sports toys (educational toys) and construction sets as well as cars (technical toys). A sex-balanced high and low AQ sample of 160 adults consisted of groups of parents of sons only, daughters only, sons and daughters, as well as of a group of adults without children (non-parents). The standard toy preference was social toys < educational toys < technical toys. Low AQ women were the only group to make a significantly higher amount of educational and a lower amount of technical toy choices. The mere presence of just sons increased technical toy choice in this experiment, while the mere presence of just daughters reduced technical toy choice both in men and high AQ individuals.

Visual attention to faces in children with autism spectrum disorder: are there sex differences?

Background

The male bias in autism spectrum disorder (ASD) diagnoses is well documented. As a result, less is known about the female ASD phenotype. Recent research suggests that conclusions drawn from predominantly male samples may not accurately capture female behavior. In this study, we explore potential sex differences in attention to social stimuli, which is generally reported to be diminished in ASD. Population-based sex differences in attention to faces have been reported, such that typically developing (TD) females attend more to social stimuli (including faces) from infancy through adulthood than TD males. It is yet unknown whether population-based sex differences in the face domain are preserved in ASD.

Methods

A dynamic, naturalistic infrared eye-tracking paradigm measured attention to social stimuli (faces) in 74 school-aged males and females with ASD (male N = 23; female N = 19) and without ASD (male N = 16; female N = 16). Two kinds of video stimuli were presented that varied in social content: rich social scenes (dyadic play between two children) and lean social scenes (parallel play by two children).

Results

Results revealed a significant 3-way interaction between sex, diagnosis, and condition after controlling for chronological and mental age. ASD females attended more to faces than ASD males in the socially lean condition. This effect was not found in the typically developing (TD) group. ASD males attended less to faces regardless of social context; however, ASD females only attended significantly less to faces compared to TD females in the socially rich condition. TD males and ASD females did not differ in their attention to faces in either condition.

Conclusions

This study has implications for how the field understands core social deficits in children with ASD, which should ideally be benchmarked against same-sex peers (male and female). Social attention in ASD females fell on a continuum—greater than their ASD male peers, but not as great as TD females. Overall, their social attention mirrored that of TD males. Improved understanding of the female social phenotype in ASD will enhance early screening and diagnostic efforts and will guide the development of sex-sensitive experimental paradigms and social interventions.

Parents' Influence on Infants' Gender-Typed Toy Preferences

Gender socialization influences children at early ages, shaping their developing identities. The toys provided by parents deliver some of the earliest gender-based messages by encouraging children to engage in activities associated with, for example, dolls and trucks. In the current study, we measured the influence of parental socialization by assessing 5- and 12 ½-month-old infants' exposure to dolls and trucks and by experimentally manipulating parents' encouragement to play with these toys. We found that infants displayed gender-typical toy preferences at 12 ½, but not 5 months, a pattern characteristic of previous studies. However, brief encouragement by a parent to play with toys from each category was ineffective in altering infants' preferences. Rather, the types of toys present in the home predicted preferences, suggesting that at-home exposure to toys may be influential in the development of toy preferences. These findings reveal that socialization processes may indeed play a role in the formation of early gender-typical toy preferences and highlight the importance of equal toy exposure during infancy to ensure optimal development.

Infant attention to same- and other-race faces

We recorded visual attention to same- and other-race faces in Hispanic and White 11-month-old infants, an age at which face processing is presumably biased by an own-race recognition advantage. Infants viewed pairs of faces differing in race or ethnicity as their eye movements were recorded. We discovered consistently greater attention to Black over Hispanic faces, to Black faces over White faces, and to Hispanic over White faces. Inversion of face stimuli, and infant ethnicity, had little effect on performance. Infants' social environments, however, differed sharply according to ethnicity: Hispanic infants are almost exclusively exposed to Hispanic family members, and White infants to White family members. Moreover, Hispanic infants inhabit communities that are more racially and ethnically diverse. These results imply that race-based visual attention in infancy is closely aligned with the larger society's racial and ethnic composition, as opposed to race-based recognition, which is more closely aligned with infants' immediate social environments.

Sex differences in autism spectrum disorder based on DSM-5 criteria: evidence from clinician and teacher reporting

In the absence of intellectual impairment autism spectrum disorder (ASD) is diagnosed both less and later in females. This study used clinician and teacher report to explore sex differences in the behavioural presentation of 69 girls and 69 boys all diagnosed with high-functioning ASD. Evidence from DSM-IV-TR and DSM-5 are presented. Sex differences in teacher concerns were also explored. While no sex differences were found in the broad social criteria presented in the DSM-IV-TR or DSM-5, numerous differences were evident in how boys and girls came to meet each criterion. For example, girls were more likely to show an ability to integrate non-verbal and verbal behaviours, maintain a reciprocal conversation, and be able to initiate, but not maintain friendships. Moreover, girls presented with both less and different restricted interests. Teachers also reported substantially fewer concerns for girls than boys, including for externalising behaviours and social skills. Results suggest girls with ASD may present with a surface-level 'look' different from the 'classic' presentation of ASD, and present as less impaired when in a school setting. Consequently, results provide insight in to why the disorder may be more difficult to detect in cognitively-able girls.

Visual search and attention to faces during early infancy

Newborn babies look preferentially at faces and face-like displays, yet over the course of their first year much changes about both the way infants process visual stimuli and how they allocate their attention to the social world. Despite this initial preference for faces in restricted contexts, the amount that infants look at faces increases considerably during the first year. Is this development related to changes in attentional orienting abilities? We explored this possibility by showing 3-, 6-, and 9-month-olds engaging animated and live-action videos of social stimuli and also measuring their visual search performance with both moving and static search displays. Replicating previous findings, looking at faces increased with age; in addition, the amount of looking at faces was strongly related to the youngest infants' performance in visual search. These results suggest that infants' attentional abilities may be an important factor in facilitating their social attention early in development.