modules 20, 21, 23

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/interpreting sensory information, enabling us to recognize meaningful objects and events

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 based on experience and expectations

selective attention

the focusing of conscious awareness on a particular stimulus

inattentional blindness

failing to see visible objects when our attention is directed elsewhere

change blindness

failing to notice changes in the environment; a form of inattentional blindness

transduction

conversion of one form of energy into another; transformation of stimulus energies (sights, sounds, smells —> interpreted neural impulses)

psychophisics

study of relationships between the physical characteristics of stimuli (intensity) and the experience of them

absolute threshold

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

signal detection theory

theory predicting how and when we detect the presence of a faint stimulus amid background stimulation

subliminal

below one’s absolute threshold for conscious awareness

priming

the activation of certain associations , predisposing one’s perception/memory/response

weber’s law

to be perceived as different, two stimuli must differ by a constant minimum percentage

sensory adaptation

diminished sensitivity as a consequence of constant stimulation

perceptual set

a mental predisposition to perceive one thing and not another; to see what you expect to see (top-down processing)

extrasensory perception (ESP)

controversial claim that perception can occur apart from sensory input

• telepathy (mind to mind communication)

• clairvoyance (perceiving remote events; house on fire in another state)

• precognition (perceiving future events; unexpected death in the next month)

parapsychology

study of paranormal phenomena; includes ESP and psychokinesis (moving matter with the mind)

gestalt

an organized whole; psychologists emphasized the tendency to integrate pieces of information into meaningful wholes

figure-ground

the organization of the visual field into objects (figures) that stand out from their surroundings (ground)

• illusion

• faces/vase

grouping

the perceptual tendency to organize stimuli into coherent groups

• proximity

• continuity

• closure

• similarity

• connectedness

proximity

grouping objects together when they are near each other

continuity

perceiving smooth,continuous patterns rather than discontinuous ones

closure

filling in gaps to create a complete, whole object

connectedness

assuming connected objects are related

depth perception

the ability to see objects in three dimensions although the images that strike the retina are two-dimensional; allows us to judge distance

visual cliff

a laboratory device for testing depth perception in infants and young animals

binocular cue

a depth cue, such as retinal disparity, that depends on the use of both eyes

retinal display

a binocular cue for perceiving depth; by comparing both retinal images from both eyes, the brain can perceive distance

the two slightly different images produced in both eyes are blended into one view when both eyes are open

monocular cue

a depth cue such as interposition or linear perspective that only one eye is needed for

phi phenomenon

an illusion of movement created when two or more adjacent lights blink on and off in quick succession (

perceptual constancy

perceiving objects as unchanging (having consistent color, brightness, shape, size) even as illumination and retinal images change

• still knowing what an object is in different lighting/perspectives

perceptual adaptation

the ability to adjust to changed sensory input, including an artificially displaced or even inverted visual field

convergence

in order to perceive depth properly, your eyes must move slightly inward or converge; allowing you to determine if objects are close or far away (the more inward, the closer the object is)

relative motion

objects closer to a fixation point move faster and in opposing direction to those objects that are farther away from a fixation point, moving slower and in the same direction

relative height

perceiving things that are shorter to be closer and taller to be farther away