Nature, Nurture, and Human Diversity in Psychology

Nature

The genetic, biological, and inherited factors that influence an individual's traits, behaviors, and development.

Nurture

The environmental, social, and experiential factors that influence an individual's traits, behaviors, and development.

Behavior genetics

The study of the relative power and limits of genetic and environmental influences on behavior.

Heredity

The genetic transfer of characteristics from parents to offspring.

Environment

Every nongenetic influence, from prenatal nutrition to the people and things around us.

Chromosomes

Threadlike structures made of DNA molecules that contain the genes.

DNA (deoxyribonucleic acid)

Complex molecule containing the genetic information that makes up the chromosomes.

Genome

The complete instructions for making an organism, consisting of all the genetic material in that organism's chromosomes.

Allele

One of two or more versions of a gene at a specific location (locus) on a chromosome.

Dominant traits

A trait is considered dominant when it is expressed in the phenotype (observable characteristics) of an organism even if only one copy of the allele is present.

Recessive traits

A trait is considered recessive when it is only expressed in the phenotype if two copies of the recessive allele are present.

Human genome

The shared genetic profile that distinguishes humans from other species, consisting of all the genetic material in an organism's chromosomes.

Chromosome count

The human genome includes 46 chromosomes in 23 matched sets; each chromosome has the same gene locations.

X and Y chromosomes

The X and Y chromosomes are not a matched set in males, who are missing some genes on the Y chromosome.

Chromosome donation

Each biological parent donates half of their set of chromosomes to their offspring.

DNA sharing in siblings

Siblings (on average) share about 50% of their DNA.

Genetic recombination

During reproduction, genetic recombination and random chromosome selection create unique combinations of parental DNA for each child.

Random DNA selection

Each parent passes on a random 50% of their DNA to each child.

Cell differentiation

The process by which genes that get expressed in each cell are different, despite every cell having the same DNA (except gametes).

Phenotype

The observable characteristics of an organism.

Locus

A specific location on a chromosome where a gene is found.

Siblings DNA sharing

Siblings don't necessarily receive the same 50% from each parent.

Unique combinations of DNA

Resulting in siblings sharing about 50% of their DNA on average.

Polygenetic traits

Traits that depend on the combination of many genes, each with its own small effects.

Identical twins

Twins that develop from a single fertilized egg and share nearly 100% of their DNA.

Fraternal twins

Twins that develop from two separate fertilized eggs and are genetically no more similar than ordinary siblings.

Similarity in Identical Twins

~100% genetic similarity, ~100% prenatal environmental similarity.

Similarity in Fraternal Twins

~50% genetic similarity, ~100% prenatal environmental similarity.

Separated twins

Twins that are raised apart; genes matter, but so does the environment.

Three Identical Strangers

A story of triplets separated at birth and adopted into different families.

Adoption

Creates two groups: genetic relatives (biological parents and siblings) and environmental relatives (adoptive parents and siblings).

Impact of shared family environment

Unless an environment is extreme, shared family environment has little discernible impact on children's personality.

Temperament

A person's characteristic emotional reactivity and intensity, apparent from the first weeks of life and generally persists into adulthood.

Heritability

The proportion of variation among individuals that can be attributed to genes.

Novelty-seeking behavior

Variants in the DRD2 and DRD4 genes are linked to a desire for new experiences.

Caution and self-discipline

KATNAL2 gene variants are associated with carefulness and self-control.

Sociability

PCDH15 and WSCD2 gene variants are connected to social behavior tendencies.

Emotional reactivity

Several genes, including AGBL2, BAIAP2, and CELF4, contribute to traits like anxiety and depression.

Heritability

A population-level statistic that measures the proportion of trait variation due to genetic differences in a specific population.

Genetic Determinism

The belief that genes determine all aspects of human behavior and characteristics.

Environmental Factors

External influences that can significantly affect gene expression and individual development.

Epigenetics

The study of environmental influences on gene expression that occur without a DNA change.

Epigenetic Marks

Organic methyl molecules laid down by life experiences that can influence gene expression.

Molecular Behavior Genetics

The study of how the structure and function of genes interact with our environment to influence behavior.

Evolutionary Psychology

The study of the evolution of behavior and the mind using principles of natural selection.

Natural Selection

The principle that inherited traits that better enable an organism to survive and reproduce in a particular environment are most likely to be passed on to succeeding generations.

Adaptive Flexibility

The ability to respond to different environments, contributing to survival and reproduction.

Sexual Mating Preferences

Men tend to prefer women with signs of future fertility, while women prefer men with loyal behavior and resources.

Social Learning Theory

A psychological theory proposed by Albert Bandura in 1977 that explains how people learn new behaviors through observation, imitation, and modeling.

Nature vs. Nurture

Nature creates possibilities, while nurture selects from those possibilities.

Genetic Potential

The inherent capabilities provided by genes that can be activated by environmental factors.

Dynamic Development

The concept that individual development is responsive and can be shaped by choices and experiences.

Genetic Predispositions

Inherent tendencies or vulnerabilities that individuals may have due to their genetic makeup.

Twin Studies

Research that examines the similarities and differences between twins to understand the influence of genetics and environment.

Adoption Studies

Research that investigates the effects of environment and genetics by studying individuals who were adopted.

Gene Expression

The process by which information from a gene is used to synthesize functional gene products, often influenced by environmental factors.

Genome

The complete set of genes or genetic material present in a cell or organism.

Mutations

Changes in the DNA sequence that can lead to variations in traits.

Gene Combinations

New arrangements of genes that occur at conception, contributing to genetic diversity.

Human Sexuality

The study of how evolutionary principles explain mating preferences and behaviors.

Critiques of Evolutionary Psychology

Arguments against evolutionary psychology that suggest more immediate explanations for behaviors are often rooted in social learning rather than ancestral decisions.

Influence of Life Experiences

The impact of personal experiences on the development and expression of traits and behaviors.