© Prentice Hall, 1999.  Sensation – An early stage of perception in which neurons in a receptor create an internal pattern of nerve impulses that represent.

 Sensation – An early stage of perception in which neurons in a receptor create an internal pattern of nerve impulses that represent the conditions that stimulated it – either inside or outside the body  Perception – A process that makes sensory patterns meaningful and more elaborate Copyright © Allyn and Bacon 2006

The brain senses the world indirectly because the sense organs convert stimulation into the language of the nervous system: neural impulses

 Absolute threshold – Amount of stimulation necessary for a stimulus to be detected  Difference threshold – Smallest amount by which a stimulus can be changed and the difference be detected (also called just noticeable difference – JND) Copyright © Allyn and Bacon 2006

 The principle that the jnd for any given sense is a constant fraction or proportion of the stimulation being judged. © Prentice Hall, 1999

 Weber’s law – The JND is always large when the stimulus intensity is high, and small when the stimulus intensity is low  Fechner’s law – S = k log R S = sensation R = stimulus k = constant that differs for each sensory modality Copyright © Allyn and Bacon 2006

 Vision: a candle flame seen from 30 miles on a clear, dark night  Hearing: the tick of a watch from 20 feet in very quiet conditions  Smell: 1 drop of perfume diffused throughout a three-room apartment © Prentice Hall, 1999

 Taste:.0356 ounce of table salt in 529 quarts of water  Touch: a bee wing falling on your cheek from a height of 1 centimeter © Prentice Hall, 1999

 Transduction – Transformation of one form of energy into another – especially the transformation of stimulus information into nerve impulses  Receptors – Specialized neurons that are activated by stimulation and transduce (convert) it into a nerve impulse Copyright © Allyn and Bacon 2006

 definition: below threshold  We can process some information from stimuli too weak to recognize.  effect of subliminal stimulation: a subtle, fleeting effect on thinking © Prentice Hall, 1999

 No. The goal of using subliminal advertising is to increase the likelihood that you will buy a particular product.  Research has repeatedly demonstrated that subliminal advertising cannot change an individual’s behavior. © Prentice Hall, 1999

 Signal detection theory – Perceptual judgment as combination of sensation and decision-making processes Copyright © Allyn and Bacon 2006 Stimulus event Neural activity Comparison with personal standard Action (or no action)

wavelength amplitude

Rods C Rods C Receptors: rods and cones 120 million120 million peripheryperiphery sensitivitysensitivity night visionnight vision 8 million8 million centralcentral clarityclarity color visioncolor vision onesonesonesones

light photoreceptors bipolar cells ganglion cells LGN visual cortex

 dark adaptation: increased sensitivity of rods and cones in darkness e.g., entering a darkened room  light adaptation: decreased sensitivity of rods and cones in bright light e.g., waking up at night and turning on a bright light © Prentice Hall, 1999

 hue: subjective experience of “color”  saturation (purity): vividness or richness of a hue  brightness: intensity of the light © Prentice Hall, 1999

 additive color mixing: mixing lights of differing wavelengths  subtractive color mixing: mixing pigments © Prentice Hall, 1999

 Trichromatic theory  Opponent-process theory © Prentice Hall, 1999

 There are three types of cones: red, green, and blue.  The colors we see are the result of a combination of the differing amount of light absorbed by the three types of cones. © Prentice Hall, 1999

 This theory only explains the way the cones transduct color.  The trichromatic theory provides an explanation for some types of colorblindness. © Prentice Hall, 1999

 monochromats: people who are totally colorblind  dichromats: people who are blind to either red-green or yellow-blue © Prentice Hall, 1999

black  color-sensitive ganglion cells are arranged in opposing cells: red-green, yellow- blue, black-white (brightness) © Prentice Hall, 1999

 The activation of one cone (at retinal level) inhibits another cone.  This theory explains color vision at the level of the ganglion cells. © Prentice Hall, 1999

 Opponent-process theory may explain color afterimages:  continual viewing of red weakens the ability to inhibit green;  remove red and you see green © Prentice Hall, 1999

 frequency: the number of cycles per second in a wave — primary determinant of pitch  amplitude: the magnitude (height) of a wave — primary determinant of loudness © Prentice Hall, 1999

 pitch: the frequency of sound vibrations, resulting in a higher/lower tone  overtones: tones that result from sound waves that are multiples of the basic tone  timbre: the “texture” of sound © Prentice Hall, 1999

 hertz (Hz): cycles per second; used to measure pitch  decibel: unit of measurement for the loudness of sounds © Prentice Hall, 1999

eardrum middle ear oval window cochlear organ of Corti

 place theory  frequency theory © Prentice Hall, 1999

 vibration of the basilar membrane (B.M.) at different places results in different pitches/frequencies  near the oval window (where B.M. is thinner)--higher frequencies; lower frequencies occur farther from oval window © Prentice Hall, 1999

 The speed of vibration determines pitch:  The faster the vibration, the higher the pitch. © Prentice Hall, 1999

 auditory neurons fire in sequence: first one, then another, then perhaps a third, and finally the first one is able to fire again © Prentice Hall, 1999

 conductive hearing loss: vibrations are not transmitted effectively from the eardrum to the oval window due to a stiffening of the connections between the middle ear bones  tinnitus: constantly hearing a steady, high-pitched hum © Prentice Hall, 1999

 Odorant binding protein (OBP) makes the detection of odors possible.  A nasal gland coats airborne molecules with OBP to facilitate detection by the receptors in the olfactory epithelium. © Prentice Hall, 1999

receptor cells olfactory bulb amygdala thalamus hypo- thalamus temporal lobe

 Women have a better sense of smell than men.  The ability to smell diminishes with age. Smell acuity is greatest during early adulthood (ages 20-40). © Prentice Hall, 1999

 Pheromones are chemicals produced by an animal that affects the behavior of another animal through scent.  Receptors in the vomeronasal organ detect pheromones. © Prentice Hall, 1999

 Yes, humans can detect pheromones, but detection typically does not alter behavior.  Menstrual synchronicity may be the one exception. © Prentice Hall, 1999

 Taste buds are the structures on the tongue that contain taste receptor cells.  An adult has about 10,000 taste buds.  Taste receptors die and are replaced every 7 days.  The number of taste buds decrease with age. © Prentice Hall, 1999

taste buds medulla thalamus primary somatosensory cortex anterior- insular cortex

 provides specific information about muscle movement, changes in posture, and strain on muscles and joints  receptors: stretch receptors and Golgi tendon organs (provide information about stretching and contraction of individual muscles) © Prentice Hall, 1999

 The sense of equilibrium and awareness of body position in space.  2 types of vestibular senses: — body rotation — gravitation and movement © Prentice Hall, 1999

 relays messages about the speed and direction of body rotation  stimulus: movement of the head  receptors: hair cells in the semicircular canals © Prentice Hall, 1999

 provides information about gravitation and movement forward and backward, up and down  stimulus: movement of body and/or gravity  receptors: hair cells in the vestibular sacs © Prentice Hall, 1999

 A chemical sense in which certain chemicals are released when injury (tissue damage) occurs.  These chemicals activate pain receptors. © Prentice Hall, 1999

 A “gate” in the spinal cord either opens to permit pain signals traveling up small nerve fibers to reach the brain or closes to prevent their passage. © Prentice Hall, 1999

Copyright © Allyn and Bacon 2006 Fovea – Area of sharpest vision in the retina Retina – Light-sensitive layer at the back of the eyeball Photoreceptors – Light-sensitive cells in the retina that convert light energy to neural impulses Rods – Sensitive to dim light but not colors Cones – Sensitive to colors but not dim light

 Optic nerve – Bundle of neurons that carries visual information from the retina to the brain Copyright © Allyn and Bacon 2006 Blind spot – Point where the optic nerve exits the eye and where there are no photoreceptors

 Visual cortex – Part of the brain – the occipital cortex – where visual sensations are processed Copyright © Allyn and Bacon 2006 Color – Psychological sensation derived from the wavelength of visible light – color, itself, is not a property of the external world

 Electromagnetic spectrum – Entire range of electromagnetic energy, including radio waves, X-rays, microwaves, and visible light  Visible spectrum – Tiny part of the electromagnetic spectrum to which our eyes are sensitive Copyright © Allyn and Bacon 2006

 Pitch – Sensory characteristic of sound produced by the frequency of the sound wave  Loudness – Sensory characteristic of sound produced by the amplitude (intensity) of the sound wave  Timbre – Quality of a sound wave that derives from the wave’s complexity Copyright © Allyn and Bacon 2006

 Conduction deafness – An inability to hear resulting from damage to structures of the middle or inner ear  Nerve deafness – An inability to hear, linked to a deficit in the body’s ability to transmit impulses from the cochlea to the brain, usually involving the auditory nerve or higher auditory processing centers Copyright © Allyn and Bacon 2006

 Olfaction – Sense of smell  Olfactory bulbs – Brain sites of olfactory processing  Pheromones – Chemical signals released by organisms to communicate with other members of the species Copyright © Allyn and Bacon 2006

Perception brings meaning to sensation, so perception produces an interpretation of the external world, not a perfect representation of it

 Feature detectors – Cells in the cortex that specialize in extracting certain features of a stimulus  Binding problem – A major unsolved mystery in cognitive psychology, concerning the physical processes used by the brain to combine many aspects of sensation to a single percept Copyright © Allyn and Bacon 2006

 Bottom-up processing – Analysis that emphasizes characteristics of the stimulus, rather than internal concepts  Top-down processing – Emphasizes perceiver's expectations, memories, and other cognitive factors Copyright © Allyn and Bacon 2006

 Illusions – Demonstrably incorrect experience of a stimulus pattern, shared by others in the same perceptual environment  Ambiguous figures – Images that are capable of more than one interpretation Copyright © Allyn and Bacon 2006

Do you see or ?

The Herman Grid Do you see small gray squares between the black squares?

 Learning-based inference – View that perception is primarily shaped by learning, rather than innate factors  Perceptual set – Readiness to detect a particular stimulus in a given context Copyright © Allyn and Bacon 2006

B A Which box is bigger, A or B?

 Gestalt psychology – View that much of perception is shaped by innate factors built into the brain  Figure – Part of a pattern that commands attention  Ground – Part of a pattern that does not command attention; the background Copyright © Allyn and Bacon 2006

 Subjective contours – Boundaries that are perceived but do not appear in the stimulus pattern Copyright © Allyn and Bacon 2006 Closure – Tendency to fill in gaps in figures and see incomplete figures as complete

© Prentice Hall, 1999.  Sensation – An early stage of perception in which neurons in a receptor create an internal pattern of nerve impulses that represent.

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© Prentice Hall, 1999.  Sensation – An early stage of perception in which neurons in a receptor create an internal pattern of nerve impulses that represent.

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