How Children Invented Humanity

Family Context, Parenting and Child Development: An Epigenetic Approach

This paper presents an essay that uses an epigenetic approach to attain an inclusive and in-depth understanding of the influence of family context and quality of parenting on children’s psychological development. Based on the identification of a key developmental process in which interactions are continuously internalised, the approach draws attention to the bidirectional and systemic nature of intrafamily and parenting interactions and highlights the multiple factors that influence them, which are linked to the developmental history of the species, the individual characteristics of both the child and their parents, and contextual variables. In response to these internalised interactions, the body activates epigenetic mechanisms, such as DNA methylation, which may affect the phenotypic expression of the genome. Theoretical and methodological implications are discussed in light of the current process of identifying the biological profiles underlying negative and positive parenting practices. Some insights are offered regarding the challenges and opportunities that parents and policymakers should address in the 21st century in connection with the promotion of positive parenting, taking into account the epigenetic processes triggered by adverse environments for children and their families.

Dyslexia as an adaptation to cortico-limbic stress system reactivity

A new school of thought in evolutionary developmental biology, combined with research in the neurobiology of stress, suggest that early exposure to stressful circumstances may be a cause of dyslexia. A balance between epigenetic, stress-induced and cognitive-growth genetic programs modulates the brain's cellular, regional, and network homeostasis. This balance is essential for adaptability to the normative range of everyday stress. However, even mild chronic stress exposition may overactivate the hypothalmic-pituitary-adrenal stress axis, upsetting the homeostatic balance between these programs, and exposing the brain to harmful levels of stress hormones. A protective strategy to sustained disequilibrium precociously advances maturation at the cost of neuroplasticity, which blunts stress axis reactivity but also compromises learning potential in the prefrontal cortex and networks associated with dyslexia. Stress exceeding an individual's range of resilience: (1) reduces levels of TFEB and BDNF, gene regulatory factors prolonging maturation and neuroplasticity; (2) interferes with the insular cortex, amygdala and hippocampus in coordinating afferent visceral signals with cognitive performance; (3) over-recruits the brain's Default Mode network; and (4) amplifies release from the Locus coeruleus/norepinephrine system which impairs the entrainment of oscillations in the lower phonological frequencies of speech. Evidence supporting a stress-growth imbalance is preliminary, but holds promise for reconceptualizing the neurobiology of dyslexia and reducing its prevalence.

Frontal brain maturation and the stability of children's shyness

Recent evidence suggests that relative to nonshy children, shy children exhibit a lower overall frontal EEG alpha/delta ratio (ADR) during middle childhood, possibly reflecting relatively less frontal brain maturation at this age. We examined this same ADR measure in relation to the stability of observed shyness and parent-reported child social anxiety measured across two laboratory visits separated by approximately 1 year during late childhood in 51 children (33% female, age range 10-16 years). We found that the overall frontal ADR score was significantly lower among children with high, stable observed shyness and parent-reported child social anxiety compared to children in the low, stable class. Findings provide convergent evidence suggesting that the stability of shyness in late childhood may be linked to relatively less overall frontal brain maturation at this age. We speculate on the adaptive function of delaying frontal brain maturation in the origins and maintenance of children's shyness.