AP Psychology Key Terms 1.1-1.2

Psychology – The scientific study of behavior and mental processes.

Nature-Nurture Issue – The debate over how much behavior is influenced by genetics (nature) versus environment (nurture).

Natural Selection – The evolutionary principle that traits aiding survival and reproduction are more likely to be passed on.

Evolutionary Psychology – The study of how evolution shapes behavior and mental processes.

Behavior Genetics – The study of how genetics and environment influence differences in behavior.

Mutation – A random genetic error that leads to a change in a gene.

Environment – Every external influence, from prenatal nutrition to social and cultural surroundings.

Heredity – The genetic transfer of traits from parents to offspring.

Genes – Units of heredity that make up chromosomes and code for proteins.

Genome – The complete set of genetic instructions for an organism.

Identical (monozygotic) twins – Twins that develop from a single fertilized egg and share nearly 100% of their genes.

Fraternal (dizygotic) twins – Twins that develop from two separate fertilized eggs and are genetically no more similar than siblings.

Interaction – The way that genes and environment work together to influence traits.

Epigenetics – The study of how environmental factors can switch genes on or off without changing DNA.

Nervous System – The body’s electrochemical communication network consisting of all nerve cells.

CNS (Central Nervous System) – The brain and spinal cord, the main control center of the body.

PNS (Peripheral Nervous System) – The sensory and motor neurons that connect the CNS to the rest of the body.

Nerves – Bundled axons that form cables connecting the CNS with muscles, glands, and sense organs.

Sensory (afferent) Neurons – Neurons that carry information from sensory receptors to the CNS.

Motor (efferent) Neurons – Neurons that carry instructions from the CNS to muscles and glands.

Interneurons – Neurons within the CNS that process information between sensory input and motor output.

Somatic Nervous System – The division of the PNS that controls voluntary movements of skeletal muscles.

Autonomic Nervous System – The division of the PNS that controls involuntary functions of glands and internal organs.

Sympathetic Nervous System – The part of the autonomic system that activates the body’s “fight-or-flight” response.

Parasympathetic Nervous System – The part of the autonomic system that calms the body and conserves energy.

Reflex – An automatic, involuntary response to a stimulus, often mediated by the spinal cord.