Child Temperament and Development

Temperament and Its Continuity

• Emotionally reactive newborns often remain reactive into later childhood and adulthood, suggesting stability in temperament (Wilson & Matheny, 1986; Worobey & Blajda, 1989; Larsen & Diener, 1987).
• A New Zealand study assessed 3-year-olds, linking traits like frustration tolerance and impulsivity to welfare reliance, parenting behaviors, and criminality by age 38 (Caspi et al., 2016).
• Temperament reflects a person's emotional reactivity and intensity, with physiological indicators, such as heart rate variability, seen in anxious infants (Kagan & Snidman, 2004; Roque et al., 2012).

Heritability of Traits

• Heritability estimates the influence of genetics on individual traits within a group, indicating that about 40% of personality trait variation is genetic, while major depressive disorder is approximately 30% genetic (Haworth et al., 2010; Pettersson et al., 2019).
• Intelligence heritability ranges from 50-80%, meaning genetics account for a significant portion of observed variations among individuals, not a direct proportion of intelligence itself (Madison et al., 2016; Plomin et al., 2016; Plomin & von Stumm, 2018).
• Individual differences in personality do not imply similar group differences, highlighting the complexity of genetic influence amid diverse environmental contexts.

Gene-Environment Interaction

• Human adaptability is influenced by both genetics and environment, where some traits manifest in specific environments (e.g., toughened feet from going barefoot).
• Gene-environment interactions are a prominent area of research, studying how stress and abuse impact individuals differently based on genetic predispositions (Byrd et al., 2019; Manuck & McCaffery, 2014).
• The National Institutes of Health is conducting extensive studies on how genes interact with environmental factors to influence health outcomes (NIH, 2019).

Molecular Behavior Genetics

• Behavior geneticists use molecular genetics to explore how gene interactions influence behaviors and traits, moving beyond mere questions about genetic influence.
• Complex traits cannot be attributed to single genes but arise from multiple genetic factors that contribute collectively to behaviors like obesity and impulsivity.

Epigenetics

• Epigenetics examines how environmental factors can turn genes on or off, illustrating genetic adaptability rather than deterministic blueprints.
• Examples include environmental influences that lead to different traits in animals, such as domesticated foxes developing behaviors due to controlled breeding practices.

Evolution and Similarities

• While human differences are prominent, shared genetic traits indicate a common genetic legacy with minimal genetic diversity among populations.
• Fundamental human behaviors and emotions remain consistent across cultures, highlighting deep-seated similarities despite outward differences.

Individualism vs. Collectivism

• Individualist cultures emphasize personal achievement and independence, while collectivist cultures stress social responsibilities and group harmony.
• Trends in naming practices reflect individualism, with a decrease in the use of common names in the U.S. compared to Japan, where name choices are more communal.
• Cultural differences also manifest in how achievements, such as Olympic medals, are attributed, with individualist cultures attributing success primarily to personal effort.

Explore the fascinating connection between early temperament and later emotional responses. This quiz delves into research findings about how newborn characteristics can predict behavior in preschoolers and beyond. Discover the significance of emotional reactivity through various stages of life.