Moving Beyond Simple Dichotomies in Child Development – Key Vocabulary

Vocabulary flashcards summarizing the central terms and concepts from the lecture on moving beyond simple dichotomies in child development.

Heritability (h²)

Statistical estimate of how much variation in a trait within a population is attributable to genetic differences, not a measure of destiny for individuals.

Twin Study Paradigm

A naturalistic experiment comparing monozygotic and dizygotic twins to tease apart genetic (A), shared-environment (C), and unique-environment (E) influences on traits.

Monozygotic (MZ) Twins

Identical twins who share virtually 100 % of their genetic material.

Dizygotic (DZ) Twins

Fraternal twins who share, on average, 50 % of their segregating genes.

ACE Model

Behavior-genetic framework that partitions trait variance into Additive genetics (A), Common environment (C), and Unique environment (E).

Additive Genetics (A)

The cumulative effect of individual genes that add together to influence a trait.

Shared Environment (C)

Aspects of environment that make siblings similar, such as family socioeconomic status or parenting style.

Unique Environment (E)

Experiences not shared by siblings that contribute to their differences, including measurement error.

False Dichotomy (Black-and-White) Fallacy

Logical error of framing complex issues as having only two opposing options when more possibilities exist.

Natural-Kinds Appeal

The mistaken claim that social categories (e.g., ‘male brain,’ ‘race’) are fixed, biologically distinct groups.

Essentialist Bias

Cognitive tendency to assume groups or individuals possess an unchangeable ‘essence’ explaining their characteristics.

Gene-Environment Interaction

Situation in which the effect of genes on a trait depends on specific environmental conditions.

Gene-Environment Correlation

Process by which genetic propensities influence the environments individuals experience or select.

Differential Susceptibility

Theory that some individuals are more biologically sensitive to environmental influences—thriving in supportive settings but suffering in adverse ones.

Epigenetics

Biochemical processes (e.g., DNA methylation) through which the environment modifies gene expression without changing the DNA sequence.

Arched-Back Nursing

High-nurturance maternal posture in rats that increases offspring’s access to milk and reduces later stress reactivity.

Licking and Grooming (LG)

Maternal rat behavior providing tactile stimulation that epigenetically programs pups’ stress-response systems.

Polygenic Trait

Characteristic influenced by many genes, each contributing a small effect, rather than by a single ‘gene for’ the trait.

‘Genes Load the Gun, Environment Pulls the Trigger’

Metaphor emphasizing that genetic potential requires environmental conditions to influence behavioral outcomes.

Turkheimer’s First Law

All human behavioral traits are heritable to some degree.

Turkheimer’s Second Law

The effect of being raised in the same family is smaller than the effect of genes when explaining individual differences.

Turkheimer’s Third Law

A substantial portion of behavioral variation is not accounted for by genes or family environment.

Turkheimer’s Fourth Law

Human behavioral traits are polygenic—affected by numerous genes of small effect.

Reading Acquisition

A culturally transmitted skill with no dedicated ‘reading gene,’ illustrating the necessity of environmental instruction.

Social Cognition (Theory of Mind)

Ability to understand others’ thoughts and feelings; twin studies show strong environmental, especially conversational, influences.

Internalizing Disorders

Psychopathology involving inward-focused symptoms (e.g., anxiety, depression) where both genetics and shared environment play roles.

Externalizing Disorders

Outward-directed behavior problems (e.g., conduct disorder, ADHD) influenced by genes, shared, and non-shared environments.

Sensitive Period

Developmental window (e.g., early childhood) during which the brain is especially responsive to particular environmental inputs.

Toxic Stress

Chronic, severe stress in childhood that disrupts brain architecture and leads to long-term health and behavioral problems.

Genome-Wide Association Study (GWAS)

Research method scanning the genome to find common genetic variants (SNPs) associated with complex traits.