Key Terms
Sensation
What happens when sensory receptors detect a stimulus. A physical process.
Perception
How the brain organizes, interprets, and consciously experiences that input. A psychological process.
Example
Smelling cinnamon = sensation. Thinking "this smells like home" = perception.
Transduction
Conversion of sensory stimulus energy to neural impulse.
Absolute threshold
Minimum energy for detection 50% of the time. JND / difference threshold: minimum detectable difference between two stim
Subliminal messages
Stimuli presented below the threshold of conscious awareness. Research shows the brain can process them; they do not rel
Sensory adaptation
Reduced perception of a constant, unchanging stimulus over time. Inattentional blindness: failing to notice visible stim
Inattentional blindness
Failure to notice something clearly visible because attention is directed elsewhere. Classic study: Simons and Chabris (
Signal detection theory
Explains how mental state affects detection of stimuli embedded in background noise. Motivation shifts your sensitivity.
Bottom-up processing
Perception driven by environmental input. Top-down processing: perception driven by knowledge and expectation.
Top-down processing
Perception driven by knowledge, expectation, and goals. Slow, deliberate, under your control.
Amplitude
The height of a wave, measured from the center line to the peak (or trough). Determines intensity - brightness for light
Wavelength
The distance from one peak to the next. Inversely related to frequency.
Frequency
The number of waves passing a given point per second. Measured in hertz (Hz).
Visible spectrum
380 to 740 nanometers. A tiny slice of the full electromagnetic spectrum (which also includes gamma rays, x-rays, ultrav