Psych Unit 3: Sensation and Perception

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

sensation

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

perception

sensory nerve endings that respond to stimuli

sensory receptors

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

transduction

how stimuli excite different neuronal pathways gives the perception of our senses

doctrine of specific nerve energies

"joined perception" sensory disorder

synesthesia

vision, hearing (audition), touch (cutaneous)

energy senses

smell (olfaction) and taste (gustation)

chemical senses

vestibular senses and kinesthetic senses

body position senses

visual, auditory, taste, smell

known or outside of us

touch/tactile, vestibular, and kinesthetic

hidden/not aware

which process starts with sensory input to build complete perception (what am I seeing?)

bottom-up processing

which process is guided by experience, we see what we expect to see (Is that something I've seen before?)

top-down processing

tendency to focus on a particular stimulus among the many that we receive

selective attention

Example of this effect: focus attention on a conversation with friends and you hear your name from across the room

Cocktail party effect

at the level of conscious awareness, we are in only one place at a time and so we miss salient objects that are available to be sensed

selective inattention

failing to see visible objects when our attention is directed elsewhere

inattentional blindness

when people fail to detect changes to the visual details of a scene; a form of inattentional blindness

change blindness

the study of the relationship between the physical characteristics of stimuli and our psychological experience of them

psychophysics

minimum stimulation needed to detect 50% of the time (the min stimulation necessary to detect a particular light, sound, pressure, taste, or odor 50% of the time)

absolute threshold

minimum difference between two stimuli detected 50% of the time. Just noticeable difference (JND)

difference threshold

Vision: candle flame from 30 miles on a clear night (absolute or difference threshold)

absolute threshold

smell: one drop of perfume in a small house (absolute or difference threshold)

absolute threshold

the principle that to be perceived as different, two stimuli must differ by a constant minimum percentage (ex: two lights must differ in intensity by 8%, two objects must differ in weight by 2%, and two tones must differ in frequency by 0.3%)

Weber's Law

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

signal detection theory

the phone rings, you hear it, you answer, shows (signal? perception?)

signal and perception

the phone rings but you dont hear it shows (signal? perception?)

signal no perception

no phone rings but you hear it shows (signal? perception?)

no signal and perception

no phone rings and hears nothing shows (signal? perception?)

no signal no perception

sensory Habituation-focus on stimuli, sensory adaptation-constant, sensory deprivation, and sensory overload are

sensory thresholds

our perception of sensations is partially due to how focused we are on them

sensory habituation

a decrease in sensitivity to a constant level of stimulation

sensory adaptation

the absence of normal levels of sensory stimulation

sensory deprivation

condition resulting from excessive sensory input to which the brain is unable to meaningfully respond

sensory overload

notions we may respond to stimuli that are below our level of awareness; only in highly controlled laboratory studies

subliminal perception

outside lab is not significant data in what perception?

subliminal

the activation (often unconscious) of certain associates influencing one's perception memory or responses

priming

mental predisposition to perceive one thing and not another

perceptual set

what is based on schemas

Perceptual set

beliefs/expectations based on our past experiences

schemas

top-down processing, context, motivation, emotion influences

perceptual set

Parapsychology, clairvoyance, telepathy, precognition, psychokinesis are examples of

extrasensory perception (ESP)

the controversial claim that perception can occur apart from sensory input; includes telepathy, clairvoyance, and precognition. research is unable to conclusively demonstrate its existence

extrasensory perception (ESP)

Perceptual set influences how we interpret stimuli. but our immediate _____________, and the ____________ and _________ we bring to a situation, also affect our interpretations

context motivation emotion

the distance from the peak of one light or sound wave to the peak of the next

wavelength

the dimension of color that is determined by the wavelength of lights; what we know as the color names blue, green, etc.

hue

amplitude of light energy

brightness

1. light bounces off object passes through the ___________

cornea

the eye's clear, protective outer layer, covering the pupil and iris

cornea

2. light passes through the _________. it's size is controlled by the __________

Pupil Iris

a ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening

iris

3. the light is focused by the _____ by the process of _____________________

lens accommodation

the transparent structure behind the pupil that changes shape to help focus images on the retina

lens

4. then it travels on to the ________ (center of visual field Fovea)

Retina

the light-sensitive inner surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the processing of visual information

retina

area without receptor cells

blind spot

the process by which the eye's lens changes shape to focus near or far objects on the retina

accommodation

how many rods are in an eye

120 million

where are rods located

outside the fovea

retinal receptors that detect black, white, and gray; necessary for peripheral and twilight vision, when cones don't respond

rods

how many cones are in an eye

8 million

where are cones located?

(mainly in the) fovea

retinal receptor cells that are concentrated near the center of the retina and that function in daylight or in well-lit conditions. The cones detect fine detail and give rise to COLOR sensations.

cones

the central focal point in the retina, around which the eye's cones cluster

fovea

1 per cone; rods share

bipolar cells

axons form optic nerve

ganglion cells

from eye to brain

receptor cells, optic nerve, optic chiasm, thalamus and occipital lobe

Formation of colors by superimposing lights, putting more light in the mixture than exists in any one light by itself (lights and RGB)

additive color mixing

Formation of colors by removing some wavelengths of light, leaving less light than was originally there (mixing pigments and RYB)

subtractive color mixing

the theory that the retina contains three different types of color receptors (red, green, and blue)

accounts for some types of colorblindess

helmholtz's trichromatic theory

the theory that opposing retinal processes (yellow-blue, red-green, black-white) enable color vision and explains color afterimages

hering's opponent-process theory

adaptation that is a quick process within a minute

light adaptation

adaptation that is a slower process and takes 30 minutes

dark adaptation

sense experience after image removed, see previous image in opposite color

negative afterimage

effects about 10% of men and 1% of women

colorblindness

People who cannot perceive any color, usually because their retinas lack cones.

monochromats

People who can distinguish only two of the three basic colors.

dichromats

what is the most common form of color blindness

red-green cone deficiency

discovered by David Hubel and Torsten Wiesel, groups of neurons in visual cortex respond to different types of visual images (edges, lines, angles, curves, motion)

feature detectors

caused by severe damage to the brain, healthy retinas and optic nerves, behaves as if they can see forms, colors, and motion

cortical blindness (blind sight)

the brain delegates the work of processing motion, form, depth, and color to different areas. after taking a scene apart, the brain integrates these subdimensions into the perceived image

parallel processing

gestalt principles

figure-ground, proximity, similarity, closure, continuity

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

figure-ground

the perceptual tendency to organize stimuli into coherent groups

grouping

ex: we group nearby figures together. we see not six separate lines, but three sets of two lines

proximity

ex: we perceive smooth, continuous patterns rather than discontinuous ones

continuity

ex: we fill in gaps to create a complete, whole group

closure

the _______ cube is an excellent vehicle for understanding the distinction between sensation and perception

Necker

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

depth perception

the ____________ ________ experiment determined whether crawling infants and newborn animals can perceive depth

visual cliff

a depth cue, such as interposition or linear perspective, available to either eye alone

monocular cues

relative height/elevation, relative size, interposition/superposition, aerial perspective, texture gradient, linear perspective, shadowing, and relative motion/motions parallax are examples of __________________ _______

molecular cues

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

binocular cues

stereoscopic vision, retinal disparity, and convergence are examples of _______________ ______

binocular cues

a binocular cue for perceiving depth

retinal disparity

apparent movement, autokinetic illusion, stroboscopic motion, and phi phenomenon are examples of _________________ ____ __________________________

perception of movement

the perception that a stationary object is moving

apparent movement

the perception that a stationary object is actually moving; perceived motion of a single object

autokinetic illusion

The illusion of movement is produced by showing the rapid progression of images or objects that are not moving at all (created by a rapid series of still pictures)

stroboscopic motion