Sensations and Perceptions

prosopagnosia

face blindness; can’t remember faces

sensation

process where our sensory receptors and nervous system receive and represent stimulus energies from our environment

sensory receptors

sensory nerve endings that respond to stimuli

perception

process where our brain organizes and interprets sensory info, enabling us to recognize objects and events as meaningful

bottom-up processing

begins with sensory receptors and works up to the brain’s integration of sensory information (forms images)

top-down processing

guided by higher-level mental processes, perceptions drawing on our experiences and expectations, senses detect

transduction

conversion of one form of energy into another, transforming of physical energy into neural impulses that the brain can interpret.

psychophysics

study of relationships between the physical characteristics of stimuli, such as intensity, and how we experience them

absolute threshold

minimum stimulus energy needed to detect a particular stimulus 50 percent of the time

signal detection theory

a theory predicting how and when we detect the presence of a faint stimulus amid background noise. There is no absolute threshold and it depends on person’s experiences, expectations, motivation, alertness

subliminal

below one’s absolute threshold for conscious awareness

difference threshold

difference between two stimuli required for detection

Weber’s law

perceive a difference, two stimuli must differ by a constant minimum percentage

sensory adaptation

diminished sensitivity as a consequence of a constant stimulation