1.6a - Sensation: Basic Concepts

Prosopagnosia

facial blindness

Sensation

the process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment

Sensory Receptors

sensory nerve endings that respond to stimuli

Perception

the process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events

Transduction

conversion of one form of energy into another. In sensation, the transforming of stimulus energies, such as sights, sounds, and smells, into neural impulses our brains can interpret.

Psychophysics

the study of relationships between the physical characteristics of stimuli, such as their intensity, and our psychological experience of them

Absolute Threshold

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

Bottom-Up Processing

analysis 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

Signal Detection Theory

a theory predicting how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise). Assumes there is no single absolute threshold and that detection depends partly on a person's experience, expectations, motivation, and alertness.

Subliminal

below one's absolute threshold for conscious awareness

Priming

the activation, often unconsciously, of certain associations, thus predisposing one's perception, memory, or response

Difference Threshold

the minimum difference between two stimuli required for detection 50 percent of the time. We experience the difference threshold as a just noticeable difference (or JND)

Weber's Law

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

Sensory Adaptation

diminished sensitivity as a consequence of constant stimulation