1.6a - Sensation: Basic Concepts

sensation

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

sensory receptors

sensory nerve endings that respond to stimuli

perception

brain organizes/interprets sensory information, enabling us to recognize objects/events as meaningful

bottom-up processing

information processing that begins with the sensory receptors and works up to the brain’s integration of sensory information

top-down processing

information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectations

transduction

conversion of one form of energy into another (receive sensory stimulation, transform into neural impulses that brain can interpret, deliver info to brain)

psychophysics

the study of relationships between the physical characteristics of stimuli, such as their intensity, and our psychological experience of them
*absolute threshold, Jnd and Weber’s law

absolute threshold

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

signal detection theory

predicts how/when we detect the presence of a faint stimulus amid background stimulation; assumes there is no single absolute threshold and that detection depends partly on a person’s experience, expectations, motivation, and alertness

_{^{-explains how we make decisions abt stimuli in uncertain/ambiguous situations}}

_{^{-Hit: signal present + reponse}}

_{^{-Miss: signal present + no response}}

_{^{-False alarm: No signal + response}}

_{^{-Correct rejection: No signal + no response}}

subliminal

below one’s absolute threshold for conscious awareness (still detect, but not conscious of it)

priming

the activation, often unconsciously, of certain associations, thus predisposing one’s perception, memory, or response (ex: flash cute cat, rate face more favorable)

difference threshold

the minimum difference between 2 stimuli required for detection 50% of the time (to distinguish between the 2) *just noticeable difference (jnd)

Weber’s law

the principle that, to be perceived as different, 2 stimuli must differ by a constant minimum percentage (rather than a constant amount)

sensory adaptation

diminished sensitivity as a consequence of constant stimulation (ex: don’t notice fan until turned off since has been on for so long, get used to it)