How Chatty Are Daddies? An Exploratory Study of Infants' Language Environments

Purpose Fathers play a critical but underresearched role in their children's cognitive and linguistic development. Focusing on two-parent families with a mother and a father, the present longitudinal study explores the amount of paternal input infants hear during the first 2 years of life, how this input changes over time, and how it relates to child volubility. We devote special attention to parentese, a near-universal style of infant-directed speech, distinguished by its higher pitch, slower tempo, and exaggerated intonation. Method We examined the daylong recordings of the same 23 infants at ages 6, 10, 14, 18, and 24 months, given English-speaking families. The infants were recorded in the presence of their parents (mother–father dyads), who were predominantly White and ranged from mid to high socioeconomic status (SES). We analyzed the effects of parent gender and child age on adult word counts and parentese, as well as the effects of maternal and paternal word counts and parentese on child vocalizations. Results On average, the infants were exposed to 46.8% fewer words and 51.9% less parentese from fathers than from mothers, even though paternal parentese grew at a 2.8-times faster rate as the infants aged. An asymmetry emerged where maternal word counts and paternal parentese predicted child vocalizations, but paternal word counts and maternal parentese did not. Conclusions While infants may hear less input from their fathers than their mothers in predominantly White, mid-to-high SES, English-speaking households, paternal parentese still plays a unique role in their linguistic development. Future research on sources of variability in child language outcomes should thus control for parental differences since parents' language can differ substantially and differentially predict child language.

Perceived Paternal and Maternal Parenting Attributes among Chinese Adolescents: A Meta-Analysis

This meta-analysis study examined perceived parental differences between Chinese mothers and fathers from the perspective of adolescents. A systematic search for relevant articles published up to 2019 was performed in electronic databases. The random-effect model was used to calculate the weighted and pooled effect size at the 95% confidence interval. This study was based on 43 studies in English peer-reviewed journals involving 55,759 Chinese adolescents aged between 11 and 18 years. We conducted subgroup analyses to explore whether differences in study designs (i.e., cross-sectional and longitudinal) and adolescent gender could explain perceived parental differences. The results showed that perceived maternal parenting attributes were more positive than perceived paternal parenting attributes in cross-sectional and longitudinal studies. Besides, perceived paternal parenting attributes showed slightly greater variability than did maternal parenting attributes. Subgroup analysis based on adolescent gender revealed that only adolescent girls perceived maternal parenting attributes to be more positive than paternal parenting attributes.

Balanced communication in mid-infancy promotes early vocabulary development: effects of play with mother and father in mono- and bilingual families

In this longitudinal study on Finnish and Finnish-Russian families, infants’ play interaction at 7 months with each parent was observed during 5-minute play sessions ( N = 96) and predictive relations between co-regulated communication in mid-infancy and language development at 14 months were examined. Parental differences in communication were greater within the culturally diverse Finnish-Russian families than within the culturally less diverse Finnish families. Four family-level communication profiles were identified that differed with respect to how balanced, or similar, infants’ co-regulation with each parent appeared. Three of the profiles were equally distributed across the families, whereas one of the unbalanced profiles was typical for the culturally diverse families. Language exposure and balance of the family-level communication profiles in mid-infancy predicted differences in children’s expressive and productive vocabulary size beyond infancy.

The genetic architecture necessary for transgressive segregation is common in both natural and domesticated populations

Segregating hybrids often exhibit phenotypes that are extreme or novel relative to the parental lines. This phenomenon is referred to as transgressive segregation, and it provides a mechanism by which hybridization might contribute to adaptive evolution. Genetic studies indicate that transgressive segregation typically results from recombination between parental taxa that possess quantitative trait loci (QTLs) with antagonistic effects (i.e. QTLs with effects that are in the opposite direction to parental differences for those traits). To assess whether this genetic architecture is common, we tabulated the direction of allelic effects for 3252 QTLs from 749 traits and 96 studies. Most traits (63.6%) had at least one antagonistic QTL, indicating that the genetic substrate for transgressive segregation is common. Plants had significantly more antagonistic QTLs than animals, which agrees with previous reports that transgressive segregation is more common in plants than in animals. Likewise, antagonistic QTLs were more frequent in intra– than in interspecific crosses and in morphological than in physiological traits. These results indicate that transgressive segregation provides a general mechanism for the production of extreme phenotypes at both above and below the species level and testify to the possible creative part of hybridization in adaptive evolution and speciation.