Download Review Unit 4 Sen_ Perception 2014-2015

Myers’ Psychology for AP*
David G. Myers
PowerPoint Presentation Slides
Altered by Loretta Merlino
Worth Publishers, © 2010
*AP is a trademark registered and/or owned by the College Board, which was not involved in the production of, and does not endorse, this product.
Introduction
Sensation activation of our senses, the raw data=
Bottom Up Processing
Perceptual set- our experience creates schemata/mental
representations and influences how we see perceive our
world
Perception brains interpretation of sensory messages
depending on our experience=Top Down Processing
Because of top down processing, even when pieces of
information are missing, I can still perceive it (EX: letters
from words missing-I can still read it)
Sensation and Perception are one continuous process
Selective Attention
Selective Attention the focusing of conscious awareness
on a particular stimulus-Dichotic Listening Experiments
Cocktail party effect=in crowded Room, I am able to drown out
other Conversations, but I can hear my name
Called (also true in dichotic listening experiement)
Sensory Habitation or Adaptation=sensitivity declines as result of
constant stimulation. Ex: scent in a room or sound of fan
Inattentional blindness failing to see visible objects when our
attention is directed elsewhere.
Change blindness failing to notice changes
in the environment
Change deafness-same as above
Pop-out=powerful stimuli grab our attention without us choosing to
attend
Thresholds
Absolute threshold the minimum
stimulation necessary to detect a
particular stimulus 50% of the time.
Difference threshold (aka just noticeable
difference) minimum change needed in a
stimulus before we detect a change.
Just noticeable difference (jnd) is computed
by :
Weber’s Law =to be perceived as
different, two stimuli must differ by a
constant percentage. Describes different
thresholds for different senses.
The more intense a stimulus the more it
needs to change before we notice a
difference ( or sense it)
Intensity of stimulus impacts
us sensing it!
Thresholds
Signal Detection
• Signal-detection theory -theory predicting how and when we detect
the presence of a faint stimulus (signal) amid background
stimulation (noise). Assumes there is no absolute threshold but our
detection depends partly on our experiences, expectations,
motivations, and alertness.
Thresholds
Subliminal Stimulation
• Subliminal Message(below threshold) below one’s
absolute threshold for conscious awareness.
• Priming= the activation, of certain
associations, predisposing one’s
perception, memory, or response.
I tell you you will notice red objects so
you do
Vision
Energy Senses =vision, hearing, touch
Chemical Senses: taste and smell
The Stimulus Input: Light Energy
Transduction (transform) conversion of stimuli, such as sights, sounds,
and smells into neural impulses our brains can interpret.
In Sound and Vision:
1. Wavelength (aka Frequency) = length of
wave=color (or Hue)
2. Amplitude=wave’s height=brightness
The Physical Property of Waves
The Eye
Cornea transparent protective covering
Pupil adjustable opening in center of eye where light enters.
Iris a ring of muscle tissue that forms the colored portion of eye around
pupil; controls size of the pupil opening.
Lens bends light rays into retina; help focus images on retina
-accommodation =eye’s lens changes shape to focus near or far
objects on retina.
Retina light-sensitive inner surface of eye, processing of visual
information-transduction starts here(transforming of one form of
energy to another the brain can interpret)contains receptor rods
and cones -retinal focus in the eye determines visual acuity
(Visual Acuity is best in the fovea)
The Structure of the Eye
*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.
The Eye
The Retina
• *Rods retina receptors that detect black, white, and gray; needed
for peripheral and twilight vision
• *Cones function in daylight /well-lit conditions. The cones detect
detail, give rise to color sensations.
Cones
Rods
The Retina’s Reaction to Light or neural pathway=Photochemical reaction in rods & cones, Bipolar cells,
ganglion cells, to optic nerve to visual cortex in brain
The Structure of the Eye-TheRetina
Optic Nerve = carries neural impulses from the eye to the brain.
Fovea = the central focal point in retina, around which the eye’s cones
cluster. When light is focused on retina, you have visual clarity
Blind Spot = part of retina without rods/cones at the point at which optic
nerve leaves eye, creating “blind” spot b/c no receptor cells located there.
Brain accommodates so we don’t notice blind spot
Visual Information Processing
• Feature detectors nerve cells in brain that
respond to specific features of the stimulus
(shape, angle, or movement, lines, curves,
etc….discovered by Hubel & Weisel) –cortical
cells in OCCIPITAL cortex respond to certain
features
• Parallel processing = processing many
aspects of a problem simultaneously (such as
color, Motion, form, depth)
• If reverse blindness there from birth, may have
difficulty interpreting information in Visual
Cortex in Occipital lobe, possibly due to critical
period in brain development
Color Vision
• Young-Helmholtz trichromatic (three color) theory the theory that the
retina contains three different cone color receptors – one most
sensitive to red, one to green, one to blue – which, when
stimulated in combination can produce the perception of any color.
Red – Green – Blue
Colorblindness:
Monochromatic =see only shades of
grey
Dichromatic=cannot see red-green or
Blue-yellow
This helps to support the next theory:
*Color Vision-most view the combo. Of trichromactic theory and
Opponent-process as responsible for color vision
• ******Opponent-process theory stated that sensory
receptors in retina come in pairs; enable color
vision. If one sensor is stimulated, its
pair is inhibited from firing-explains
Afterimage. Stare at red-switch
Gaze to blank page, will see green
afterimage
– Three sets of colors
• Red-green
• Blue-yellow
• Black-white
After image
Hearing
The Stimulus Input: *Sound Waves
Audition (= the sense or act of hearing)
• ******Sound Waves=vibrations travel through air and collected by:
ear
1. Amplitude=height =Loudness
2. Frequency =length =pitch-(high and low pitch)
The structure of the ear
outer(auditory canal and eardrum), middle (******Bones
middle ear = the hammer, anvil, stirrup- vibrate with the eardrum.
inner.
The sound waves travel down the auditory canal to the eardrum.
The structure of the ear
Eardrum = tight membrane that vibrates when struck by sound
waves.
The structure of the ear
Bones of the middle ear = the hammer, anvil, stirrup which
vibrate with the eardrum.
Oval window = where the stirrup connects to the cochlea.
The structure of the ear
****Cochlea = a coiled, snail shaped, bony, fluid-filled tube in the
inner ear through which sound waves trigger nerve impulses.
Neural messages sent to auditory cortex in temporal lobe
The Ear
• Inner ear
– Oval window
–Cochlea
• Basilar membrane
Damage=nerve
Deafness (caused by
loud sounds)
– Auditory nerve then to Auditory cortex
The structure of the ear
Inner Ear: aud. Nerve, cochlea, oval window
Auditory nerve = nerve which sends the auditory message to the
brain via the thalamus.
The structure of the ear
Auditory nerve
Neural impulse to the brain
The Ear
Perceiving Pitch (high/low)-Two Theories
• Basilar membrane’s hair cells
• Place theory=hair cells in cochlea’s basilar membrane respond
to dif. sound frequencies based on where they are located on
membrane
• Frequency theory=entire cochlea
vibrates at particular frequency of a tone sending signals to brain
The Ear
How do we Locate Sounds?
• Placement of two ears allows
Stereophonic hearing
• Localization of sounds
=if sound to right (horn),
right ear hears it
sooner and more
intense than left
Hearing Loss and Deaf Culture
• Hearing loss/Nerve Deafness:
Nerve deafness=when hair cells in Basilar Membrane
have been damaged, usually by loud noise; difficult to
treat since no way to regenerate hair cells
Conduction hearing loss=something goes wrong with other
ear parts and getting sound to cochlea (with ear
canal, eardrum,
hammer/anvil/stirrup or
oval window)
Touch
Kinesthesis the system for sensing the position and
movement of individual body parts. Receptors in
muscles & joints, and Vision send brain messages
Vestibular sense sense of Balance and how body is
oriented in space-located in Semicircular
Canals in inner ear-fluid moves in canals as position of
head moves, then signal brain
Semicircular Canals
Pain
Understanding Pain
Biological Influences:
Nociceptors =sensory receptors that detect hurtful
temperature, pressures or chemicals
Gate-control theory:
theory that spinal cord contains a neurological “gate” that blocks
pain signals or allows them to pass on to the brain. Competing
signals (such as rubbing) can temporarily reduce pain. Some
pain messages have a higher priority than others
Endorphins, ”opiate like” or pain killing chemicals
(nuerotransmitter) in body, also swing gate shut.
If I move my hand from a hot surface: Initiated in the spinal
cord, not motor cortex
Taste(or *gustation)
taste and smell are chemical senses –respond to chemicals rather than energy
-Humans sense 5 types: Sweet, sour, salty, bitter,
Umami (protein)-bitter and sour taste protect us from
harm-born with this repulsion
-Taste buds on tongue, cheeks, roof of mouth
Age and taste=taste smell decreases with age
Sensory interaction one sense influences another (smell
and taste; sight and hearing, etc..)
Smell
• Smell aka Olfaction
– Chemical sense
– Odor molecules
– Nerve fibers from
Olfactory bulb
connect to brain at
amygdala and
then to hippocampus
(both connect to emotional
Impulses/memory) –may be
why smell is powerful
memory trigger
– Olfactory nerve
The Thalamus
• Thalamus
–Sensory
–switchboard
for all the senses
EXCEPT smell
Smell (olfaction)
Perceptual Organization
• Gestalt (form or whole) an organized whole. Gestalt psychologists
emphasized our tendency to integrate pieces of information into
meaningful wholes or groups-this is innate and inevitable. The
whole is different from the sum of its parts
• Figure-ground tendency to view certain figures of a scene as figures
and the rest as a background
• Grouping stimuli together:
• Proximity-things near each other are related
• Similarity-things that Resemble each other are related
• Continuity-things that form a flowing line are viewed as continuous
ratherthen broken up
• Connectedness perceive things as single units
• Closure –we fill in gaps to create a complete an object
Form Perception
gestalt rules:Figure and Ground
• Figure-ground tendency to view certain figures of a scene as figures
and the rest as a background
Form Perception
Grouping – Proximity-see 3 sets of two lines rather than 6
Form Perception
Grouping – Similarity-see as vertical columns of similar shapes, not as
horizontal rows of dissimilar shapes
Form Perception
Grouping – Continuity: we see 1 wavy and 2 straight lines, not
semicircles
the visual tendency to create continuous figures
Form Perception
Grouping – Connectedness-do not see these as 2 circles and 1 line
perceive uniform or attached items as a single unit.
Form Perception
Grouping – Closure=fill in gaps to create a
complete object
More on Perception
• Muller-Lyer Illusion, two lines appear to be of
different lengths even though they are the
same. <-----------> >-----------<
Depth Perception
• 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; believed to
be innate and starts at crawling
– Visual-cliff
a laboratory
device for testing
depth perception
in infants and
young animals
Depth Perception
Binocular Cues
• Binocular cues depth cues, such as retinal disparity, that
depend on the use of two eyes.
– Retinal disparity a binocular –NEED TWO EYES-cue
for perceiving depth. By comparing images from the
retinas in the two eyes, the brain computes distance –
the greater the disparity (difference) between the two
images, the closer the object.
Depth Perception
Depth cues are either Mononocular or
binocular Cues
Monocular cues
– Relative height-things higher seem taller
– Relative size-closer items appear bigger
– Interposition-something that blocks another item is
perceived as closer –a tree blocking a horse
– Linear perspective-parallel lines seem to converge
with distance
– Relative motion-objects that are stable appear to
move as we move (in a car)
– Light and shadow
Perceptual Constancy
• Perceptual Constancy perceiving objects as unchanging (having
consistent shapes, size, lightness, and color) even as illumination
and retinal images change. Size, shape and brightness are types of
constancy
Motion Perception
Stroboscopic movement = brain perceives
continuous movement in rapid series of slightly
varying images EX: draw slightly different pics on of
notes pad, than fan through them quickly
Phi phenomenon =an illusion of movement
created when two or more adjacent lights blink
on and off in quick succession. Ex: neon,
blinking arrow sign
Motion Parallax=Nearby objects seem to be
moving/passing faster than further objects
(ex: plane in sky seems to move slowly)
Perceptual Set
Perceptual set (experiences, assumptions, expectations,
motivation and emotion)a mental disposition to perceive
one thing and not another. What establishes our
perceptual sets?:
-Mental predisposition-schema (with below pic, it
depends on which pic I looked at first
– Schemas-try to fit things into existing ones
Perceptual Set
Context Effects
Context effects (our brain
interprets info, say words, in the context in which they are
heard or seen: die v dye, mourning v morning)
Similar to what we learned in Memory
Even perception can be seen from a
biopsychosocial approach (as in the case with pain)