Dev Psych_Module 1, 2 & 3

• Heredity


  The epigenetic framework
• Nature


  Heredity plays the most important role in bringing about a feature
• Nurture


  Environment is most significant in shaping the way we are
• There is a constant interplay between nature and nurture
• We cannot isolate the root of any single behavior as a result solely of nature or nurture
• Polygenic


  A result of many genes
• Multifactorial


  A result of many factors, both genetic and environmental
• Genetic makeup sets up a range of possibilities
• Genes may or may not be realized depending upon one's environmental experiences
• Environment affects the expression of genes just as genetic predispositions can impact a person's potentials
• Environmental circumstances can trigger symptoms of a genetic disorder
• Heritability


  A statistic that represents proportion of phenotypic variance that is due to genetic differences
• Estimates of heritability of intelligence range from 50% to 80%
• Environment plays a significant role in a person's mental ability
• The Human Genome Project


  An internationally funded effort to map the locations of human genes and understand the role these genes play in development, health, and illness
• Genes


  Segments of chromosomes that vary in length, contained in the nucleus of each human cell
• Understanding the role of genes in health and illness can bring about both harm and good
• Monozygotic twins


  Occur when a single zygote or fertilized egg splits apart in the first two weeks of development
• Dizygotic twins


  Two eggs or ova are released and fertilized by two separate sperm
• Genotype


  The genetic complement, coded in DNA inherited from our parents
• Phenotype


  The expression of those genes in behavioral traits that we can measure
• Dominant genes


  Express themselves in the phenotype even when paired with a different version of the gene
• Recessive genes


  Express themselves only when paired with a similar version gene
• Incomplete dominance


  When a dominant gene does not entirely suppress the recessive gene
• Most characteristics are polygenic, not the result of a single gene but of several genes
• Chromosomal abnormality


  Occurs when a child inherits too many or too few chromosomes
• Sex-linked chromosomal abnormality


  When the abnormality is on pair #23
• Most of the known genetic disorders are dominant gene-linked, and the vast majority are not severe disorders
• Autosomal dominant disorders


  • Heterozygous
• Recessive disorders


  • Homozygous
• Behavioral genetics


  The scientific study of the interplay between the genetic and environmental contributions to behavior
• Genotype-environment correlations


  Processes by which genetic factors contribute to variations in the environment
• Types of genotype-environment correlation

  • Active
  • Passive
  • Evocative
• Genotype-environment interactions


  Involve genetic susceptibility to the environment
• Germinal period


  Starts at conception, zygote contains combined genetic information from both parents
• Embryonic period


  Begins once the multi-cellular organism is implanted in the uterine wall, placenta provides nourishment and oxygen
• Fetal period


  Organism develops hair, nails, teeth, excretory and digestive systems, all body parts including external genitalia
• During the 4-6th months of the fetal period, eyes become more sensitive to light, hearing develops, respiratory system continues to develop, reflexes such as sucking, swallowing, and hiccupping appear, and cycles of sleep and wakefulness are present
• During the 7th-9th months of the fetal period, the fetus primarily prepares for birth by exercising its muscles, lungs begin to expand and contract, and it develops fat layers under the skin for insulation and temperature regulation
• Teratology


  The study of factors that contribute to congenital disabilities