Comprehensive Notes on Child Development Themes
Nature and Nurture: How Do Nature and Nurture Together Shape Development?
Basic definitions
Nature = our biological endowment and genes; includes broad traits (physical appearance, personality, intellect, mental health) and specific predispositions (e.g., political attitudes, thrill-seeking).
Nurture = environments that influence development (prenatal environment, family, schools, communities, people we interact with).
The common misconception is to treat nature and nurture as an either/or choice. Development is the product of their constant, bidirectional interaction; asking which is more important misses the joint process.
Example to illustrate interaction: schizophrenia shows strong genetic risk but substantial environmental modulation.
Classic empirical illustration: the Kauai Longitudinal Study (Werner, 2005)
Sample: 698 children born in 1955 on the Hawaiian island of Kauai; followed for ~40 years.
Data sources:
Prenatal/birth complications from physicians’ records.
Home environment: nurse/social-worker observations; maternal interviews at age 1 and age 10.
School factors: teacher reports on academic performance and classroom behavior.
Juvenile justice/services: police, family court, and social-service records.
Cognitive/psychological measures: standardized IQ and personality tests at ages 10 and 18; self-reports at ages 18, 32, and 40.
Major takeaway: biological risks (prenatal/birth problems) increase risk for problems, but outcomes depend heavily on the home environment (income, education, parental mental health, and the quality of parental relationships).
Key findings:
By age 2, toddlers with severe prenatal/birth issues in harmonious middle-income families were nearly as advanced in language and motor skills as peers without early problems.
By age 10, prenatal/birth problems related to psychological difficulties mainly when rearing conditions were poor.
Children facing both biological and environmental challenges tended to develop serious learning or behavior problems by age 10; by 18, many had police records, mental health issues, or were unmarried parents — yet ~⅓ showed remarkable resilience and grew up to be caring, self-confident adults (Werner, 1989).
This study highlights resilience and the important moderator role of the environment.
The Michael case: resilience in adversity
Premature birth and low birth weight to teenage parents.
Early family disruption (parents separated, mother deserted, siblings raised by father and grandparents).
By age 18, achieved school success, high self-esteem, social popularity, and a positive outlook.
Illustrates that many children can flourish despite early biological risk and adverse family circumstances.
Why study child development? Practical and intellectual reasons
Raising children: everyday parenting questions (pregnancy diet, outdoor exposure in cold weather, early schooling, anger management, etc.)
Research-informed strategies to manage anger without spanking:
In Canada, about 25 rac{\%}{100} of parents report spanking; spanking linked to increased aggression and ongoing conflict across races/ethnicities, and above/controlling for income and education factors.
Alternatives shown to be effective: showing sympathy, helping children find positive outlets for anger, time-outs, and caregiver strategies in daycare/school settings (Denham, 2006; Feindler & Schira, 2022).
Demonstrations of emotion-recognition and anger-control curricula (3- to 4-year-olds) improving outcomes; the turtle technique encourages stepping away and thinking before acting; evidence of long-term benefits (up to 4–5 years post-intervention) (Denham & Burton, 1996; Jennings & Greenberg, 2009).
Building empathy for diverse populations
Empathy = capacity to understand and share others’ feelings; increasingly crucial as societies diversify.
Professionals across fields (teachers, health-care workers, social workers, therapists, counselors, pediatricians, school psychologists, etc.) must understand how trauma and stress affect development to provide effective care.
Choosing social policies
Quantitative evidence is essential for policy decisions (e.g., violent video games and aggression): meta-analyses quantify small effects rather than large causal impacts.
Ferguson (2015) meta-analysis of 101 studies found the effect of video games on aggression is minimal, though not nonexistent; a small increase in aggression was detected but not as a major causal factor.
Singapore study of >3{,}000 children found no relation between violent-game exposure and later aggression after controlling for gender, impulse control, and prior violence (Ferguson & Wang, 2019); see other research (Greitmeyer, 2022) with alternative views.
Risk assessment in child testimony: tens of thousands of Canadian children testify in court; in 2012, about 40 ext{%} of sexual offence victims were 11 years old or younger (Statistics Canada, 2014). Ensuring reliable testimony requires careful question design to avoid false reports and to avoid under-detecting true abuse.
Enduring Philosophical Issues in Child Development
From ancient Greece to modern times, why do individuals develop as they do? The central questions in the field have long roots.
Plato and Aristotle on nature and nurture
Plato emphasized self-control and discipline as central educational goals; he warned that boys are particularly difficult to rear because of their strong intelligence and wildness.
Quote: “Now of all wild things, a boy is the most difficult to handle… a fount of intelligence in him which has not yet ‘run clear’” (The Laws, bk. 7).
Aristotle argued for tailoring education to the individual, aligning instruction with each child’s character and needs.
Quote: “a study of individual character is the best way of making education perfect” (Nicomachean Ethics, bk. 10, ch. 9).
Plato vs. Aristotle differed on how children acquire knowledge: innate knowledge (Plato) versus knowledge from experience (Aristotle).
Locke and Rousseau: early modern re-centering of the nurture question
Locke: tabula rasa — the infant’s mind is a blank slate; development primarily reflects nurture; the key goal is character formation through role modeling, honesty, stability, and gentleness; authority should be relaxed as children age and demonstrate good behavior.
Rousseau (as discussed in subsequent literature) emphasized natural development and stages, with society shaping development in both beneficial and harmful ways.
Enduring Themes in Child Development (Table 1.1 concepts)
Nature and nurture: how both together shape development.
The active child: how children contribute to their own development.
Continuity/discontinuity: which aspects of development are steady vs. undergoing abrupt changes.
Mechanisms of change: how changes occur over time.
Sociocultural context: how cultural and social environments influence development.
Individual differences: why children differ from one another.
Research and children’s welfare: how research informs policy and practice to improve child welfare.
1 Nature and Nurture: How Do Nature and Nurture Together Shape Development?
Core concept: Development results from the joint action of genetics and environment; not a simple hierarchy of importance.
Genetic influences and environment interact through several mechanisms
Schizophrenia as a case study of nature-nurture interaction:
Genetic relatedness and risk: identical twins show a substantially higher concordance than the general population.
If one identical twin has schizophrenia, the other’s risk is about 40 ext{%} \sim 50\%; the general population risk is about 1\% (approximate values in the cited studies).
The closer the biological relation, the stronger the risk for relatives with schizophrenia (Figure 1.1).
Environment modifies risk: roughly 50\%–60\% of identical twins do not develop schizophrenia; living in troubled homes increases risk.
Adoption studies show a robust gene-by-environment interaction: children with a schizophrenic parent who are raised in a troubled family have substantially higher risk than those not exposed to such environments (Tienari et al., 2004; follow-up 21 years later, 2006).
Biological mechanisms: gene expression is regulated by the genome; environments can alter gene activity without changing DNA sequence—epigenetics.
Epigenetics = study of stable changes in gene expression mediated by the environment; changes in gene expression can persist and influence cognition, emotion, and behavior.
Epigenetic processes include DNA methylation, histone modification, and other chromatin changes that can turn genes on or off in response to experiences.
Methylation as a key example:
Stress experienced by mothers during infancy correlates with higher methylation in children’s genomes 15 years later (Essex et al., 2013).
Increased methylation detected in cord blood DNA of newborns from depressed mothers (Oberlander et al., 2008).
Methylation patterns found in adults who experienced childhood abuse (McGowan et al., 2009).
These methylation changes can heighten risk for depression and other outcomes later in life (Palma-Gudiel et al., 2015).
The genome interacts with experience, creating enduring developmental trajectories; this supports a bidirectional view of nature and nurture rather than a strict hierarchy.
Epilogue on the Trudeau example
A human example of how early experiences and biological predispositions can interact to influence life outcomes (e.g., political leadership pathways), illustrating the complexity of nature-nurture pathways in real lives.
The Active Child: How Do Children Shape Their Own Development?
Concept: Children actively contribute to their development from infancy onward, not just as passive recipients of environment.
Early forms of active influence: selective attention and social engagement
Infants show preferences that direct learning: they attend to moving/sounding objects more than to static ones, and they preferentially attend to faces, especially their mother’s.
At around 1 month, infants prefer Mom’s face over strangers; by the end of the second month, smiling and cooing become more pronounced when focusing on mom.
The mother–infant feedback loop reinforces social interaction: infant smiles/coos elicit maternal responses, which in turn reinforce infant social engagement and bonding (Lavelli & Fogel, 2013).
Early self-driven language practice
When toddlers (1–2 years) talk alone in a room (crib speech), this internal motivation supports language development even without immediate social feedback.
This practice likely accelerates linguistic acquisition by providing more rehearsal and feedback cycles.
Evidence from infancy to toddlerhood
The preference for mother’s face and maternal responses helps establish social and language foundations.
Toddlers’ self-initiated vocalizations demonstrate internal motivation to learn language and practice communication skills.
Implications for development
Emphasizes the agency of children in shaping attention, social interaction, and language learning from very early in life.
Connections to previous lectures and real-world relevance
The nature–nurture framework informs parenting practices, education, and social policy by highlighting the moderating role of environment on biological risk.
Epigenetics provides a mechanistic link showing how experiences can alter biological pathways that influence development across the lifespan.
The active child perspective supports interventions that leverage children’s own interests and explorations to promote healthy development.
Ethical, philosophical, and practical implications
Policy design should consider that environmental improvements can reduce biological risks, not just treat them as fixed traits.
In legal contexts (e.g., child testimony), understanding developmental stages helps in designing fair evaluation processes that minimize misreporting.
Programs that foster empathy, self-regulation, and supportive home and school environments can have long-term benefits, potentially offsetting early risk factors.
Key numerical and methodological references (highlights)
Classic study details
Sample size: 698 children; duration: 40 years; data points across ages: 1, 10, 18, 32, 40.
Schizophrenia-related genetics-and-environment data
Concordance in identical twins: approx. 40\%\text{ to }50\% if one twin has schizophrenia; population baseline: 1\%.
Adoption studies show interaction effects: exposure to a troubled family environment increases risk for those with schizophrenic biology.
Epigenetics and methylation findings
Maternal stress during infancy linked to methylation changes in child genome after 15\text{ years} (Essex et al., 2013).
Cord-blood DNA methylation higher in newborns of depressed mothers (Oberlander et al., 2008).
Adult methylation changes associated with childhood abuse (McGowan et al., 2009).
Policy-relevant evidence
Meta-analysis of violent video games: 101 studies; overall effect: minimal but present.
Large cohort in Singapore: >3000 children; no long-term relation after accounting for confounds (Ferguson & Wang, 2019).
Testimony in courts
In Canada, tens of thousands of children testify; in 2012, about 40\% of sexual offence victims were aged 11\text{ or younger} (Statistics Canada, 2014).
Intrinsic lifespan questions
Seven foundational questions guiding the study of child development (Nature and nurture; The active child; Continuity/discontinuity; Mechanisms of change; Sociocultural context; Individual differences; Research and children’s welfare).
Summary synthesis
Development is best understood as the product of ongoing, bidirectional interactions between biology and the environment.
Children are active agents shaping their own development, selecting experiences and engaging in learning processes that influence later outcomes.
Historical and philosophical perspectives inform contemporary methods and questions, but modern research emphasizes integrative, evidence-based explanations that consider both genetic predispositions and environmental contexts.
Practical implications span parenting, education, clinical practice, and public policy, including approaches to anger management, empathy development, and courtroom procedures for child testimony.
Table 1.1: Basic Questions About Child Development (themes)
Nature and Nurture: How do nature and nurture together shape development?
The Active Child: How do children shape their own development?
Continuity/Discontinuity: In what ways is development continuous, and in what ways is it discontinuous?
Mechanisms of Change: How does change occur?
The Sociocultural Context: How does the sociocultural context influence development?
Individual Differences: How do children become so different from one another?
Research and Children’s Welfare: How can research promote children’s well-being?
Final note: The material encourages a holistic view of development, integrating empirical data, theoretical perspectives, and real-world applications to understand how humans grow, adapt, and flourish across the lifespan.