AP Psychology · Summary

Unit 1 summary

1. Only an experiment with random assignment can show cause and effect. A correlation shows only an association.
2. An operational definition says exactly how a variable is measured, with its unit or scale.
3. Heritability describes variation within a group, never the share of one person's trait that comes from genes.
4. The sympathetic branch arouses the body and the parasympathetic branch calms it. Both are part of the autonomic nervous system.
5. A neuron fires all or none. Agonists mimic or boost a neurotransmitter, and antagonists block it.
6. The deepest sleep is NREM stage 3. REM pairs an active brain with a still body and grows longer through the night.
7. Sensation starts with transduction, and Weber's law says the smallest noticeable change is a constant proportion of the stimulus.