Sensation : stimulus detection process by which our sense organs respond to and translate environmental stimuli into nerve impulses that are sent to the brain. Perception : making sense of what our senses tell us, is the active process of organizing this stimulus input and giving it meaning. 5 senses: vision, audition(hearing), touch, gustation(taste), olfaction(smell) psychophysics: study the relations between the physical characteristics of stimuli and sensory capabilities. Dark adaptation: progressive improvement in brightness sensitivity that occurs over time under conditions of low illumination. The trichromatic theory: additive color mixture: blue green red red (young helmholtz theory) after image: an image in a different colour appears after a colour stimulus have been viewed steadily then withdrawn. Opponent-process theory: (hering)3 cones types responds to 2 diff wavelengths: red/green, yellow/blue, black/ white [short(blue), medium(green), long(red)] dual-process theory:(young) combines the trichromatic and opponent-process theories to account for the colour transduction process.