Sensation and Perception How you develop your view

Sensation vs. Perception l Sensation The experience of sensory stimulation. l Initial electrical activity

The Nature of Sensation Psychology: An Introduction Charles A. Morris & Albert A. Maisto

The Basic Process l Receptor cells…. Specialized cells that respond to a particular type

Sensory Thresholds l Absolute threshold l The minimum amount of energy that can be

Absolute Threshold Examples: l l l Taste: 1 gram (. 0356 ounce) of table

Sensory Thresholds l Sensory adaptation l l An adjustment of the senses to the

Sensory Thresholds l Weber’s Law States that the difference threshold is a constant proportion

Subliminal Perception The notion that we may respond to stimuli that are below our

Extrasensory Perception l Refers to extraordinary perception such as Clairvoyance – awareness of an

Example of ESP l http: //www. youtube. com/watch? v=Ewu. H 0 7 q. IAUk&feature=related

Back to the Senses This may take awhile…. . l Quick test: What color

Vision Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice

The Visual System l Cornea l l Pupil l l Transparent protective coating over

The Visual System l Lens l l Retina l l Focuses light onto the

Receptor Cells in the retina that are sensitive to light l Visual receptors are

Receptor Cells l Rods l l l About 120 million rods Respond to light

Receptor Cells l Bipolar cells l l Ganglion cells l l Receive input from

Adaptation l Dark adaptation l l Light adaptation l l Increased sensitivity of rods

Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

From Eye to Brain l Optic nerve l l l Made up of axons

Color Vision l Properties of color Hue – refers to colors such as red

Theories of Color Vision l Trichromatic theory l Three different types of cones l

Forms of Colorblindness l l l Approximately 10% of men and 1% of women

Theories of Color Vision l Trichromatic theory cannot explain all aspects of color vision

Theories of Color Vision l Opponent-process theory l Three pairs of color receptors l

Color Vision in Other Species Other species see colors differently than humans l Most

The Vision Test Psychology: An Introduction Charles A. Morris & Albert A. Maisto ©

Hearing Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice

Sound l Sound waves l l Changes in pressure caused by molecules of air

Sound l Amplitude l l l Overtones l l Magnitude (height) of sound wave

The Ear l l Eardrum Middle ear l l Contains three small bones; the

The Ear l Oval window l l Membrane between middle ear and inner ear

The Ear l Basilar membrane l l Membrane in the cochlea which contains receptor

Theories of Hearing l Place theory l l Frequency theory l l Pitch is

Hearing Disorders About 28 million people have some form of hearing damage in the

The Other Senses Psychology: An Introduction Charles A. Morris & Albert A. Maisto ©

Smell l Detecting common odors l l l Odorant binding protein is released and

Smell Women have a better sense of smell than men l Anosmia l l

Smell l Pheromones l l l Used by animals as a form of communication

Taste l Four basic tastes Sweet l Salty l Sour l Bitter l l

Taste l l l Receptor cells are located in taste buds Taste buds are

Kinesthetic Senses l Kinesthetic senses provide information about speed and direction of movement Stretch

Vestibular Senses Vestibular senses provide information about equilibrium and body position l Fluid moves

The Skin Senses Skin is the largest sense organ l There are receptors for

Pain Serves as a warning about injury or other problem l Large individual differences

Pain l Biopsychosocial theory l l Holds that pain involves not just physical stimulus,

Pain l Alternative approaches Hypnosis l Self-hypnosis l Accupuncture l Psychology: An Introduction Charles

Perception Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice

Perceptual Organization l Figure-ground l l We perceive a foreground object (figure) against a

Perceptual Organization l Other principles of organization l l Proximity Similarity Closure Continuity Psychology:

Perceptual Organization l Perceptual Constancy l l l Our tendency to perceive objects as

Perception of Distance and Depth l Monocular cues – those that require only one

Perception of Distance and Depth l Binocular cues – those that require both eyes

Localizing Sounds l l We use both monaural and binaural cues Loudness l l

Perception of Movement l Apparent movement l l Autokinetic illusion l l Perceived motion

Visual Illusions l l Occur because of misleading cues in the stimulus Gives rise

Individual Differences and Culture in Perception l Motivation l Our desires or needs shape

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Sensation vs. Perception l Sensation The experience of sensory stimulation. l Initial electrical activity created by colors, forms, sounds, smells, tastes…. Ya know, all the stuff that bombards you everyday! l l Perception The process of creating/organizing sensory data into meaningful patterns/stimuli l How you understand what you see, hear, feel, taste…. It goes on l Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

The Basic Process l Receptor cells…. Specialized cells that respond to a particular type of energy l This is why we learned about the body first… now you know what's up! How these cells work: applying pressure with your finger to your eye results in a visual experience l These receptor cells will communicate with the neurons to let your brain know what's what l There is a receptor cell for each sense… l Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Absolute Threshold Examples: l l l Taste: 1 gram (. 0356 ounce) of table salt in 500 liters (529 quarts) of water Smell: 1 drop of perfume diffused throughout a three-room apartment Touch: the wing of a bee falling on your cheek from a height of 1 cm (. 39 inch) Hearing: the tick of a watch from 6 meters (20 feet) in very quiet conditions Vision: a candle flame seen from 50 km (30 miles) on a clear, dark night Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Sensory Thresholds l Sensory adaptation l l An adjustment of the senses to the level of stimulation they are receiving Difference threshold The smallest change in stimulation that can be detected 50% of the time l Also called the just noticeable difference l Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Sensory Thresholds l Weber’s Law States that the difference threshold is a constant proportion of the specific stimulus l Senses vary in their sensitivity to changes in stimulation l Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Subliminal Perception The notion that we may respond to stimuli that are below our level of awareness l Research shows that the effect only occurs in controlled laboratory studies l Research outside the laboratory shows no significant effect of subliminal information l Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Extrasensory Perception l Refers to extraordinary perception such as Clairvoyance – awareness of an unknown object or event l Telepathy – knowledge of someone else’s thoughts or feelings l Precognition – foreknowledge of future events l Research has been unable to conclusively demonstrate the existence of ESP l So there is no evidance that Ghost Hunters is real or fake…. l Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Back to the Senses This may take awhile…. . l Quick test: What color is my hair!!!! l What color is my Shirt, and isnt it cute too? l So how do you know that those color are right? l Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

The Visual System l Cornea l l Pupil l l Transparent protective coating over the front of the eye Small opening in the iris through which light enters the eye Iris l Colored part of the eye Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

The Visual System l Lens l l Retina l l Focuses light onto the retina Lining of the eye containing receptor cells that are sensitive to light Fovea l Center of the visual field Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Receptor Cells l Rods l l l About 120 million rods Respond to light and dark Very sensitive to light Provide our night vision Cones l l About 8 million cones Respond to color as well as light and dark Work best in bright light Found mainly in the fovea Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Receptor Cells l Bipolar cells l l Ganglion cells l l Receive input from receptor cells Receive input from bipolar cells Blind spot l Area where axons of ganglion cells leave the eye Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Adaptation l Dark adaptation l l Light adaptation l l Increased sensitivity of rods and cones in darkness Decreased sensitivity of rods and cones in bright light Afterimage l Sense experience that occurs after a visual stimulus has been removed Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

From Eye to Brain l Optic nerve l l l Made up of axons of ganglion cells carries neural messages from each eye to brain Optic chiasm l Point where part of each optic nerve crosses to the other side of the brain Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Color Vision l Properties of color Hue – refers to colors such as red and green l Saturation – refers to the vividness of a hue l Brightness – the nearness of a color to white l Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Theories of Color Vision l Trichromatic theory l Three different types of cones l Red l Green l Blue-violet Experience of color is the result of mixing of the signals from these receptors l Can account for some types of colorblindness l Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Forms of Colorblindness l l l Approximately 10% of men and 1% of women have some form of colorblindness Hereditary defect in your cones Women pass the gene onto their sons, (sorry guys) Dichromats l People who are blind to either red-green or blue-yellow Monochromats l People who see no color at all, only shades of light and dark Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Theories of Color Vision l Trichromatic theory cannot explain all aspects of color vision People with normal vision cannot see “reddish -green” or “yellowish-blue” l Color afterimages l Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Theories of Color Vision l Opponent-process theory l Three pairs of color receptors l Yellow-blue l Red-green l Black-white Members of each pair work in opposition l Can explain color afterimages l l Both theories of color vision are valid Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Color Vision in Other Species Other species see colors differently than humans l Most other mammals are dichromats l Rodents tend to be monochromats, as are owls who have only rods l Bees can see ultraviolet light l Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Sound l Sound waves l l Changes in pressure caused by molecules of air moving Frequency l l Number of cycles per second in a wave, measured in Hertz (Hz) Frequency determines pitch Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Sound l Amplitude l l l Overtones l l Magnitude (height) of sound wave Determines loudness, measured in decibels (d. B) Multiples of the basic tone Timbre l Quality of texture of sound Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

The Ear l l Eardrum Middle ear l l Contains three small bones; the hammer, anvil, and stirrup These bones relay and amplify the incoming sound waves Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

The Ear l Oval window l l Membrane between middle ear and inner ear Cochlea l l Part of inner ear containing fluid that vibrates This causes the basilar membrane to vibrate Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

The Ear l Basilar membrane l l Membrane in the cochlea which contains receptor cells, called hair cells Auditory nerve l l Connection from ear to brain Provides information to both sides of brain Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Theories of Hearing l Place theory l l Frequency theory l l Pitch is determined by location of vibration along the basilar membrane Pitch is determined by frequency hair cells produce action potentials Volley Principle l Pattern of sequential firing determines pitch Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Hearing Disorders About 28 million people have some form of hearing damage in the U. S. l Can be caused by l Injury l Infections l Explosions l Long-term exposure to loud noises l Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Smell l Detecting common odors l l l Odorant binding protein is released and attached to incoming molecules These molecules then activate receptors in the olfactory epithelium Axons from those receptors project directly to the olfactory bulb Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Smell l Pheromones l l l Used by animals as a form of communication Provides information about identity Also provides information about sexual receptivity Pheromones stimulate the vomeronasal organ (VNO) Information from the VNO is sent to a special part of the olfactory bulb used for pheromonal communication Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Taste l l l Receptor cells are located in taste buds Taste buds are located in papillae on the tongue Chemicals dissolve in saliva and activate receptors Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Kinesthetic Senses l Kinesthetic senses provide information about speed and direction of movement Stretch receptors sense muscle stretch and contraction l Golgi tendon organs sense movement of tendons l Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Vestibular Senses Vestibular senses provide information about equilibrium and body position l Fluid moves in two vestibular sacs l Vestibular organs are also responsible for motion sickness l Motion sickness may be caused by discrepancies between visual information and vestibular sensation l Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

The Skin Senses Skin is the largest sense organ l There are receptors for pressure, temperature, and pain l Touch appears to be important not just as a source of information, but as a way to bond with others l Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Pain Serves as a warning about injury or other problem l Large individual differences in pain perception l Gate control theory l l Neurological “gate” in spinal cord which controls transmission of pain to brain Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Pain l Biopsychosocial theory l l Holds that pain involves not just physical stimulus, but psychological and social factors as well Placebo effect l l Shows that when a person believes a medication reduces pain, their pain is often reduced even though no medication was given Pain relief is likely the result of endorphin release Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Perceptual Organization l Figure-ground l l We perceive a foreground object (figure) against a background (ground) Animals may look like the background they inhabit as a way of destroying figureground distinction Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Perceptual Organization l Perceptual Constancy l l l Our tendency to perceive objects as stable and unchanging despite changing sensory information Size constancy Shape constancy Brightness constancy Color constancy Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Perception of Distance and Depth l Monocular cues – those that require only one eye l l l Aerial perspective Texture gradient Linear perspective Motion parallax Superposition Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Localizing Sounds l l We use both monaural and binaural cues Loudness l l Louder sounds are perceived as being closer Time of arrival l l Sounds will arrive at one ear sooner than the other This helps determine direction of the sound Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Perception of Movement l Apparent movement l l Autokinetic illusion l l Perceived motion of a single object Stroboscopic motion l l Illusion that still objects are moving Created by a rapid series of still pictures Phi phenomenon l Apparent motion created by lights flashing in sequence Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall

Individual Differences and Culture in Perception l Motivation l Our desires or needs shape our current perceptions Values l Expectations l Cognitive Style l Experience and Culture l Personality l Psychology: An Introduction Charles A. Morris & Albert A. Maisto © 2005 Prentice Hall