Sensation is where it all begins: your sense organs respond to physical energy from the environment. Psychophysics studies how those physical stimuli turn into psychological experiences, and ideas like sensory thresholds and adaptation explain how your nervous system picks out what matters in a noisy world.
Watch for the classic contrast between absolute threshold (detecting that a stimulus is there at all) and difference threshold (detecting that a stimulus has changed). Students often trip over Weber’s law; remember it is about a constant proportion of change, not a constant absolute amount. Also keep sensation and perception separate in your mind: sensation is the physical activation of sense organs, while perception is the brain’s interpretation.
Part of Basic Psychology, module “Sensation & Perception”. Sign in (free) to read the full notes, flashcards and the lesson quiz.