Psy I: Winter '16: Chpt. 3 Lecture
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Transcript of Psy I: Winter '16: Chpt. 3 Lecture
mastering the world ofpsychology
CHAPTER
fifth edition
Copyright © 2014, © 2011, © 2008 by Pearson Education, Inc.All Rights Reserved
Sensation and Perception
3
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Learning Objectives
3.1 What are the absolute and difference thresholds?
3.2 How does transduction change sensory information?
3.3 How does each part of the eye function in vision?
3.4 How does visual information get from the retina to the primary visual cortex?
3.5 How does color vision work?3.6 What are the physical characteristics of
sound?
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Learning Objectives
3.7 How does each part of the ear function in hearing?
3.8 How do the kinesthetic and vestibular senses help us move and stay balanced?
3.9 How do smell sensations get from the nose to the brain?
3.10 How do we detect the primary taste sensations?
3.11 How does the skin provide pleasant and unpleasant sensations?
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Learning Objectives
3.12 What do we gain and lose when we attend to a stimulus?
3.13 How does prior knowledge influence perception?
3.14 How do we perceive social stimuli?3.15 What are the Gestalt principles of perceptual
organization?3.16 What do monocular and binocular cues
contribute to perception?
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Learning Objectives
3.17 How does the brain perceive motion? 3.18 What are three puzzling perceptions?3.19 What do studies of subliminal perception, ESP
and synesthesis show?
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Overview
• The Process of Sensation• Vision• Hearing and Balance• Smell, Taste, and Touch• Influences on Perception• Principles of Perception• Unusual Perceptual Experiences
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Process of Sensation
• Sensation– process whereby senses pick up visual,
auditory, and other sensory stimuli – transmits this stimuli to the brain– is the "raw" material
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Process of Sensation
• Perception – process whereby the brain actively
organizes and interprets sensory information
– provides the "finished" product
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Process of Sensation:Absolute and Difference Thresholds• What is the softest sound you can hear
—the dimmest light you can see—the most diluted substance you can taste?– Experiments answer these questions.– Measures of the minimal perceptible
amount for the senses are known as absolute thresholds.
LO 3.1
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
FIGURE 3.1 Absolute ThresholdsJust as the threshold of a doorway is the dividing point between being outside a room and being inside it, the absolute threshold of a sense marks the difference between not being able to perceive a stimulus and being just barely able to perceive it.
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Process of Sensation:Absolute Threshold
• Marks the difference between not being able to perceive a stimulus and being just barely able to perceive the stimulus
• Minimum amount of sensory stimulation detected 50 percent of the time
LO 3.1
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Process of Sensation:Difference Threshold
• Difference Threshold– a measure of the smallest increase or
decrease in a physical stimulus required to produce the just noticeable difference
• Just Noticeable Difference (JND) – the smallest change in sensation a
person is able to detect 50 percent of the time
LO 3.1
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Process of Sensation:Weber's Law
• JND depends on a percentage of change in a stimulus rather than on a fixed amount of change.
• Weber's Law – percent of change necessary for
detection
LO 3.1
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Process of Sensation:Weber's Law
• Examples– Weight must increase or decrease by 2
percent to allow a subject to notice the difference.
– In music, difference is noted in a tone change higher or lower in pitch by 0.33 percent.
LO 3.1
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Process of Sensation:Weber's Law
• Weber's law best applies to:– People with average sensitivities – Sensory stimuli that are neither very
strong nor very weak
LO 3.1
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Process of Sensation:Sensory Receptors and Transduction• Sensory Receptors
– highly specialized cells in the sense organs
– detect and respond to one type of sensory stimuli
– transduce (convert) stimuli into neural impulses
– provide the link between the physical sensory world and the brain
LO 3.2
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Process of Sensation:Sensory Receptors and Transduction• Transduction
– process by which sensory receptors convert sensory stimulation into neural impulses
LO 3.2
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Process of Sensation:Sensory Adaptation
• Process whereby sensory receptors grow accustomed to constant, unchanging levels of stimuli over time
• Not likely to occur in the presence of a very strong stimulus
LO 3.2
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
FIGURE 3.2 The ElectromagneticSpectrum Human eyes can perceive only a very thin band of electromagnetic waves, known as the visible spectrum.
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Vision
• Eyes respond only to visible light waves.– Waves form a small subgroup of
electromagnetic waves called the visible spectrum.
• Electromagnetic waves are measured in wavelengths.– the distance from the peak of a light
wave to the peak of the next wave
LO 3.2
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
FIGURE 3.3 The Major Parts of the Human Eye
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
VisionThe Eye: Process of Sight
• The cornea performs the first step.– bends light rays inward– directs the light rays through the pupil
• The iris contracts and dilates the pupil to regulate the amount of light entering the eye.
LO 3.3
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
VisionThe Eye: Process of Sight
• The lens focuses on viewed objects, directs images to the retina.– Accommodation: flattening and bulging
action of lens– presbyopia: age-related loss of lens'
ability to change shape• The image projected onto the retina is
upside down and reversed from left to right.
LO 3.3
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
FIGURE 3.4 From Retinal Image to Meaningful InformationBecause of the way the lens alters light rays in order to produce a clear image, images are upside down on the retina. The brain’s visual processing system takes the upside-down retinal image and flips it so it is properly orientated.
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
VisionThe Eye: Rods and Cones
• Light-sensitive receptor cells located at the back of the retina
• There are 120 million rods and 6 million cones in each retina.
LO 3.3
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
VisionThe Eye: Rods and Cones
• Rhodopsin in the rods enables adaptation to light.– two components
opsin and retinal– light adaptation
opsin and retinal break apart
LO 3.3
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
VisionThe Eye: Rods and Cones
• Rhodopsin in the rods enables adaptation to light.– dark adaptation
opsin and retinal bond, forming rhodopsin
– fovea contains only cones; involved in clear,
sharp vision
LO 3.3
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Vision:Vision and the Brain
• Light passes through 4 layers of tissue after reaching the rods and cones.
• Each layer contains specialized neurons.– include ganglion, amacrine, bipolar, and
horizontal cells
LO 3.4
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Vision:Vision and the Brain
• Axon-like extensions of ganglion cells are bundled together in a pencil-sized cable exiting the retina.– blind spot
no rods or cones present located where the ganglion cable exits
the retina
LO 3.4
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
FIGURE 3.3 The Major Parts of the Human Eye
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Vision:Vision and the Brain
• Bundled ganglion cells form the optic nerve.
• Optic Chiasm– point where some optic nerve fibers
cross to opposite side of brain– crossing over allows the image to be
projected to both hemispheres of brain
LO 3.4
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Vision:Vision and the Brain
• Nerve fibers extend from the optic chiasm to the thalamus, transmit impulses to the primary visual cortex.
LO 3.4
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Vision:Vision and the Brain
• Feature Detectors– are neurons of the primary visual cortex – respond only to specific visual patterns
(for example, to lines or angles)– coded at birth to make their unique
responses
LO 3.4
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Major Structures of the Visual System
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
FIGURE 3.2 The ElectromagneticSpectrum Human eyes can perceive only a very thin band of electromagnetic waves, known as the visible spectrum.
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Vision:Sensing Color
• Perception of Color – results from reflection of particular
wavelengths of the visual spectrum– three dimensions of light produce color
distinctions
LO 3.5
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
FIGURE 3.5 Hue, Brightness, and SaturationManipulations of hue, brightness, and saturation alter the appearance of a photo. (1) natural color; (2) altered hues; (3) altered brightness; (4) altered saturation.
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
VisionSensing Color: Dimensions of Light• Hue
– the specific color perceived• Saturation
– the purity of a color• Brightness
– the intensity of the light energy perceived as a color
LO 3.5
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Vision - Sensing Color:Theories of Color Vision
• Trichromatic Theory– There are 3 types of cones in the retina.– Each is sensitive to 1 of 3 colors.
blue, green, or red
LO 3.5
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Vision - Sensing Color:Theories of Color Vision
• Opponent-Process Theory– Cells respond by increasing or
decreasing their rate of firing when different colors are present. red/green cells: increase rate with red,
decrease with green yellow/blue cells: increase with yellow,
decrease with blue white/black cells: increase rate with
white, decrease with black
LO 3.5
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Vision - Sensing Color:Theories of Color Vision
• Opponent-Process Theory– Afterimage
visual sensation that remains after the stimulus is withdrawn
The brain will give the sensation of the opposite color.
LO 3.5
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Vision - Sensing Color:Theories of Color Vision
• Which theory is correct?– Each theory explains a different phase
of color processing. Trichromatic theory best explains cone
processing of color. opponent-process theory: cones pass on
information about wavelengths to ganglion cells
LO 3.5
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Vision:Colorblindness
• Inability to distinguish certain colors from one another
• Eight percent of males and one percent of females experience difficulty distinguishing colors.
LO 3.5
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Vision:Colorblindness
• Distinguishing red from green is the most common form of color blindness.
• Color blindness can have degrees due to:– differences related to the number of
color vision genes individual has– genetic differences in the way that
types of cones are distributed in the retina
LO 3.5
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Hearing and Balance:Sound
• Sound requires a medium, such as air or water, through which to move.
• Frequency– number of cycles completed by sound
wave in one second– determines the pitch of a sound– measured in hertz (Hz)
LO 3.6
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Hearing and Balance:Sound
• Amplitude– loudness of sound– measured in decibels (dB)
• Timbre– quality of a sound that distinguishes it
from other sounds of the same pitch and loudness
LO 3.6
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
FIGURE 3.7 Decibel Levels of Various SoundsThe loudness of a sound (its amplitude) is measured in decibels. Each increase of 10 decibels makes a sound 10 times louder. A normal conversation at 3 feet measures about 60 decibels, which is 10,000 times louder than a soft whisper of 20 decibels. Any exposure to sounds of 130 decibels or higher puts a person at immediate risk for hearing damage, but levels as low as 90 decibels can cause hearing loss if one is exposed to them over long periods of time.
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Hearing and BalanceSound: Decibels
• Amplitude is measured in decibels.• Each increase of 10 decibels makes a
sound 10 times louder.• Exposure to 130 decibels or higher
creates a risk for hearing damage.
LO 3.6
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Sound:The Ear and Hearing
• Audition – sensation and process of hearing
• Outer Ear– pinnea and auditory canal
• Middle Ear– ossicles
hammer, anvil, and stirrup• Inner Ear
cochlea and semicircular canals
LO 3.7
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
FIGURE 3.8 The Anatomy of the HumanEar Sound waves pass through the auditory canal to the eardrum, causing it to vibrate and set in motion the ossicles in the middle ear. When the stirrup pushes against the oval window, it sets up vibrations in the inner ear. This moves the fluid in the cochlea back and forth and sets in motion the hair cells, causing a message to be sent to the brain via the auditory nerve.
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Sound:How Sound Waves Are Converted• Sound waves enter the pinna, the
visible part of the outer ear.• Waves travel the auditory canal, which
causes the eardrum to vibrate. • Ossicles in the middle ear amplify
sound waves.• Amplified waves cause vibration of the
oval window.
LO 3.7
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Sound:How Sound Waves Are Converted• The oval window initiates activity in
inner ear, sets cochlea fluid in motion.• Fluid pushes and pulls the hair cells
attached to the basilar membrane.• Basilar membrane transduces
vibrations into neural impulses.• The auditory nerve carries neural
impulses to the brain.
LO 3.7
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Hearing and Balance:Sound-Hearing Theories
• Place Theory– Each pitch is determined by the location
along the basilar membrane of the cochlea that vibrates the most.
– This theory explains how we hear sounds with frequencies higher than 1000 Hz.
LO 3.7
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Hearing and Balance:Sound-Hearing Theories
• Frequency Theory– Hair cell receptors vibrate the same
number of times per second as do the sounds that reach them.
– This theory explains how low-frequency sounds are heard.
LO 3.7
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Balance and Movement:Kinesthetic Sense
• Provides information about:– The position of body parts in relation to
each other – Movement of the entire body or its parts
• Information detected by receptors in joints, ligaments, and muscles
• Other senses provide additional information about body position and movement.
LO 3.8
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
FIGURE 3.10 Sensing Balance andMovement You sense the rotation of your head in any direction because the movement sends fluid coursing through the tubelike semicircular canals in the inner ear. The moving fluid bends the hair cell receptors, which, in turn, send neural impulses to the brain.
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Balance and Movement:Vestibular Sense
• Detects movement, information about body's orientation in space
• Located in semicircular canals and vestibular sacs of the inner ear
• Semicircular canals sense rotation of head.– canals filled with fluid– moving fluid moves hair cells– hair cells send input to brain
LO 3.8
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
FIGURE 3.11 The Olfactory SystemOdor molecules travel up the nostrils to the olfactory epithelium, which contains the receptor cells for smell. Olfactory receptors are special neurons whose axons form the olfactory nerve. The olfactory nerve relays smell messages to the olfactory bulbs, which pass them on to the amygdala and olfactory cortex. From there, they go to the limbic system, the thalamus, and orbitofrontal cortex.
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Smell Taste and Touch:Smell
• Olfaction: sense of smell– aids in survival– influences emotional states– serves as a memory cue
Smell, Taste, and Touch:Smell
LO 3.9
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
FIGURE 3.11 The Olfactory SystemOdor molecules travel up the nostrils to the olfactory epithelium, which contains the receptor cells for smell. Olfactory receptors are special neurons whose axons form the olfactory nerve. The olfactory nerve relays smell messages to the olfactory bulbs, which pass them on to the amygdala and olfactory cortex. From there, they go to the limbic system, the thalamus, and orbitofrontal cortex.
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Smell: How Smell Travels from the Nose to the Brain
• Olfactory Epithelium– one-inch square patches of tissue– one at the top of each nasal cavity– contain olfactory neurons
• Olfactory Bulbs– structures above the nasal cavity – where smell sensations first register in
the brain
LO 3.9
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Smell: How Smell Travels from the Nose to the Brain
• Orbitofrontal Cortex– receives messages from olfactory bulbs
via the thalamus
LO 3.9
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Smell Taste and Touch:Taste
• Gustation: sense of taste• Five primary taste sensations have
been identified.– Sweet– Sour– Salty– Bitter
Smell, Taste, and Touch:Smell
LO 3.10
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Smell, Taste, and Touch:Taste
• Five primary taste sensations have been identified.– Umami
recent identification by researchers sensation is triggered by glutamate
LO 3.10
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
FIGURE 3.12 The Tongue’s Papillae and Taste Buds(a) A photomicrograph of the surface of the tongue shows several papillae. (b) This vertical cross-section through a papilla reveals the location of the taste buds and taste receptors.
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Taste:How Sensations Are Detected
• Papillae– small bumps on the tongue
• Taste buds lie alongside some of the papillae.– Each taste bud is composed of 60 to
100 receptor cells.– All 5 taste sensations can be detected
on all locations of tongue.
LO 3.10
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Taste:Nontasters and Supertasters
• Individuals vary widely in their capacity for experiencing taste sensations.
• Nontasters – unable to taste certain sweet and bitter
compounds• Supertasters
– taste sweet and bitter compounds with far stronger intensity than other people
LO 3.10
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Taste:Nontasters and Supertasters
• Researchers are investigating links between taste sensitivity, eating behaviors, and health.
LO 3.10
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Touch:Transmission of Touch Sensation
• Tactile (touch) information is conveyed to the brain when an object touches and depresses the skin.– One or more of several types of
receptors are stimulated.– Touch messages are sent through nerve
connections to the spinal cord.– The message is relayed next to the
somatosensory cortex of cerebrum.
LO 3.11
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Touch:Transmission of Touch Sensation
• Two-Point Threshold– measure of how far apart 2 touch points
on the skin must be before they are felt as 2 separate touches
LO 3.11
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Pain:The Gate Control Theory
• An area in the spinal cord acts as a gate and blocks or transmits pain messages to the brain.
• Pain messages are carried by small, slow-conducting nerve fibers.
• Large, fast-conducting nerve fibers carry other sensory messages.
LO 3.11
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Pain:The Gate Control Theory
• Messages from fast-conducting fibers– "tie up" gate – prevent pain message from
transmission to the brain• Rub or apply gentle pressure to injury.
– Large, fast-conducting nerve fibers are stimulated.
– Pain message is blocked.
LO 3.11
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Pain: Functions of Pain, Cross-cultural Variations, Role of Endorphins
• Pain can be a valuable warning and a protective mechanism.– Pain motivates people to tend to an
injury, to restrict activity, and to seek medical help.
LO 3.11
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Pain: Functions of Pain, Cross-cultural Variations, Role of Endorphins
• Distraction can be effective with short-term pain, but not long-term pain.
• Cross-cultural variations in chronic pain may be linked to differences in people's emotional states.
LO 3.11
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Pain: Functions of Pain, Cross-cultural Variations, Role of Endorphins
• Endorphins are natural painkillers produced by the body.– block pain and produce a feeling of well-
being– Some individuals release endorphins
when they think they are receiving pain medication.
LO 3.11
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Influences on Perception
• Perception – process through which the brain assigns
meaning to sensations– influenced by 3 factors
Attention Prior knowledge Cross-modal perception
LO 3.12
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Influences on Perception:Attention
• Process of sorting through sensations and selecting some for further processing
• When attention is focused on some sensations, others are missed altogether or misperceived.– inattentional blindness
Attention is shifted from one object to another.
LO 3.12
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Influences on Perception:Attention
• When attention is focused on some sensations, others are missed altogether or misperceived.– inattentional blindness
fail to notice changes in objects not receiving direct attention
– cocktail party phenomenon Auditory attention focuses on information
that is personally meaningful.
LO 3.12
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Principles of Perception:Information from Multiple Sources • Cross-Modal Perception
– the process by which the brain integrates information from more than one sense
– Cross-modal perception is used to process complex stimuli such as speech.
LO 3.12
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Influences on Perception:Prior Knowledge
• Bottom-Up Processing– also called data-driven processing– This strategy involves looking for
patterns in individual bits of information that can be interpreted using prior knowledge.
• Top-Down Processing– also known as concept-driven
processing
LO 3.13
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Influences on Perception:Prior Knowledge
• Top-Down Processing– Prior knowledge limits the range of
one's guesses by providing a "whole" that can serve as a context for individual bits of information.
• Perceptual Set– The expectation of what will be
perceived can affect that which is perceived.
LO 3.13
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Influences on Perception:Social Perception
• Mirror Neuron System (MNS)– A network of cells that the brain uses to
interpret and produce motor actions and emotion-related behavior.
LO 3.14
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
FIGURE 3.14 Gestalt Principles of Perceptual OrganizationGestalt psychologists proposed several principles of perceptual organization, including figure–ground, similarity, proximity, continuity, and closure.
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Principles of Perception: Gestalt Principles of Perceptual Organization• Sensory elements experience brought
together as a whole• Gestalt: a German word that refers to
the whole form, pattern, or configuration that a person perceives
• Sensory experience is organized according to basic principles of perceptual organization.
LO 3.15
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Principles of Perception:Perceptual Constancy
• Perceptual Constancy – The phenomenon that allows us to
perceive objects as maintaining stable properties, such as size, shape, and brightness, despite differences in distance, viewing angle, and lighting.
LO 3.15
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
FIGURE 3.15 Shape ConstancyThe door projects very different images on the retina when viewed from different angles. But because of shape constancy, you continue to perceive the door as rectangular.
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Principles of Perception:Depth Perception
• The ability to perceive the visual world in 3 dimensions and to judge distances accurately
LO 3.16
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Principles of Perception:Depth Perception
• How do eyes create dimensionality from a one-dimensional image on the retina?– depth cues
monocular – types include: interposition, linear
perspective, relative size, texture gradient, atmospheric perspective, shadow or shading, and motion parallax
LO 3.16
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Principles of Perception:Depth Perception
• How do eyes create dimensionality from a one-dimensional image on the retina?– depth cues
binocular– types include: convergence and binocular
(retinal) disparity
LO 3.16
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Principles of Perception:Depth Perception
• Both types of cues depend on both eyes working together– convergence
Eyes turn inward to focus on nearby objects—the closer the object, the more the objects appear to come together
– binocular (or retinal) disparity difference between retinal images
LO 3.16
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
FIGURE 3.16 Retinal Disparity and Viewing a StereogramRetinal disparity enables most of us to perceive 3-D images in stereograms. Place this picture against the tip of your nose and then very, very slowly move the book straight back from your face. Look at the image without blinking. A 3-D image will suddenly appear.
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
FIGURE 3.17 Monocular Depth Cues
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Depth Perception:Monocular Depth Cues
• Perceived by one eye alone• Seven cues• Many have been used by artists to give
the illusion of depth to their paintings.
LO 3.16
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Depth Perception:Monocular Depth Cues
• Interposition• Linear perspective• Relative size• Texture gradient• Atmospheric perspective• Shadow or shading• Motion parallax
LO 3.16
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Principles of Perception:Perception of Motion
• Brain perceives real motion by comparing the movement of images across the retina to visual reference points.
assumes points to be stable
LO 3.17
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Principles of Perception:Perception of Motion
• Autokinetic Illusion– An unmoving light in a dark room
appears to move. In reality, the eyes are moving: not the
light. In the dark, the brain has no stable
reference point to determine what is moving.
LO 3.17
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Principles of Perception:Perception of Motion
• Phi Phenomenon (Stroboscopic Motion)– The sequential flashing of stationary
lights gives the perception of the light as moving.
– Movies are an example of phi phenomena.
LO 3.17
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Unusual Perceptual Experiences
• Sensation and perception enable us to make sense of the world.
• What happens when these vital processes lead us to believe that we sense something that really isn't there?
• Is it possible to perceive without sensing?
LO 3.18
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
FIGURE 3.18 Some Puzzling Perceptions(a) Do you see random dots or something else? (b) Why couldn’t you build a replica of this three-pronged device? (c) Which horizontal line appears to be longer? (d) Which monster is larger?
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Unusual Perceptual Experiences:Puzzling Perceptions
• Ambiguous Figures– The perceptual system tries to resolve
the uncertainty by seeing the figure first one way and then another (figures [a] and [b]).
LO 3.18
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
FIGURE 3.18 Some Puzzling Perceptions(a) Do you see random dots or something else? (b) Why couldn’t you build a replica of this three-pronged device? (c) Which horizontal line appears to be longer? (d) Which monster is larger?
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Unusual Perceptual Experiences:Puzzling Perceptions
• Illusions– false perceptions or misperceptions of
an actual stimulus in the environment Figure (c) shows the Müller-Lyer illusion. Figure (d) shows the Ponzo illusion.
LO 3.18
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Unusual Perceptual Experiences: Subliminal Perception ESP and Synesthesia
• Subliminal Perception – capacity to perceive and respond to
stimuli below the level of awareness– appears ineffective at persuading
people to buy products
Unusual Perceptual Experiences: Subliminal Perception, ESP, and Synesthesia
LO 3.19
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Unusual Perceptual Experiences: Subliminal Perception, ESP, and Synesthesia
• ESP– gaining information through channels
other than known sensory ones– Researchers have been unable to
replicate experiments that support its existence.
LO 3.19
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Unusual Perceptual Experiences: Subliminal Perception, ESP, and Synesthesia
• Synesthesia – Humans may be born with the capacity.– lose it as brain becomes more
specialized during childhood
LO 3.19