924 n n What do you see in

9/24 n n What do you see in the first image? What do you see in the 2 nd image?

9/25 n n How does sensation and perception relate to this photo? We will be watching a Psychology 101 video relating sensation & perception to sports. Write down her brief explanation of why people can interpret plays differently.

9/26 Have homework out (Auditory half sheet) n Think about…. If you had to lose a major sense (vision, hearing, taste, touch, smell), what would it be and why? n © 2008 The Mc. Graw-Hill Companies, Inc.

9/27 1. A) B) C) D) Frequency is to pitch as ______ is to ______. Wavelength; loudness Amplitude; loudness Wavelength; intensity Amplitude; intensity 2. A decrease in sensory responsiveness accompanying an unchanging stimulus is called: A) Sensory fatigue B) Accommodation C) Sensory Adaptation D) Sensory Interaction © 2008 The Mc. Graw-Hill Companies, Inc.

Sensation and Perception Consciousness

Windows on the World n n How we understand our world Two basic processes: n n Sensation: Gathering information Perception: Interpreting information

Basic Principles n Sensation n n Transduction n n The process of receiving stimulus energies from the external environment The process of transforming physical energy into electrochemical energy (action potential) Perception n The process of organizing and interpreting sensory information

Sensation and Perception n Can you identify anything meaningful in these patterned shapes? Sensation is detecting the different shapes However, organizing it into something is the process of perception.

Perceptual Processing n Bottom-up Processing n Processing of sensory info as it enters the receptors and travels to the brain n n Face-value interpretation Initiated by sensory input Sensation Perception Top-Down Processing n n n Uses existing information (learning history) to interpret sensory information Initiated by cognitive processing Perception Sensation

Sensation and Perception n Look at the three boxes below. Write down what color you think each box represents.

Sensation and Perception n n The boxes are colored in lime, turquoise and rose. If each student is receiving the same sensation of color from each of the boxes, then why do some students have different perceptions of the colors?

Sensation n Sensory Receptors n Specialized cells that detect and transmit sensory information to the brain n These cells respond selectively to stimulation n Cells send signals via distinct neural pathways

Sensation (senses) n Photoreception (Vision) n n Mechanoreception (Touch and Hearing) n n Detection of light Detection of pressure, vibration, and movement Chemoreception (Smell and Taste) Detection of chemical stimuli Psychophysics: The study of how this physical energy relates to our psychological experience. n

Nature’s sensory gifts suit each recipient’s needs…. n n n A frog has eyes with receptor cells that only fire in response to small, dark, moving objects. A male silkworm moth has receptors so sensitive to the female odor that a single female need to release only a billionth of an ounce per second to attract every male silkworm moth within a mile. Human ears are most sensitive to sound frequencies that include human voice consonants and a baby’s cry.

Absolute Thresholds n Absolute threshold: n n the lowest level of a stimulus detected half the time n n Example: Why do dogs go crazy when you blow into a dog whistle? Can you image if our auditory absolute threshold was lower than it is?

Absolute Thresholds n Absolute thresholds can vary across individuals n Limitations and variances n n Age Abilities Experiences Fatigue: Life and death implications © 2008 The Mc. Graw-Hill Companies, Inc.

Difference Thresholds n Detection of change or discrimination between stimuli n JND: n n n smallest difference between two stimuli detected half the time JNDs vary from person to person and by sense

Difference Thresholds n n Weber’s Law: For a person to notice change: Difference threshold is not a constant amount, but some constant proportion of the stimulus. Example: May notice that a 2 liter of Coke is on sale for $1 less, but would notice if a car was on sale for $1 less. n

Sensory Adaptation n n responsiveness to stimuli diminishes with repeated exposure Smell adapts quickly n n n Ex) Being on a farm or an ethnic restaurant. Ex) Jumping into a cold pool Ex) Ring or watch Vision prevents adaptation Our eyes are constantly quivering! n

Signal Detection Theory n n Predicts when and how we will detect the presence of a faint signal with background noise. There is no single absolute threshold n Depends on participants experience, expectations, motivation, and level of fatigue. © 2008 The Mc. Graw-Hill Companies, Inc.

Signal Detection Theory

Factors Affecting Perception n Attention n n Stroop Effect n n n Selective attention Cocktail party effect Novelty, size, color, movement Reading is highly practiced, automatic activity Bottom-up processing (stimulus-driven) Sensory Adaptation

9/28 In addition to trying the activity below, have your homework out

Subliminal Stimulation n n We can unconsciously sense subliminal (literally “below threshold”) stimuli. Ex. 1956 report of NJ movie audiences being influenced by subliminal messages.

Unwittingly influenced? !? n n Only has a subtle, fleeting effect Anthony Greenwald experiment (tapes with self esteem or memory) 16 double blind experiments and all proved to be ineffective Priming=predisposing one’s perception, memory, or response by a previous association.

Vision n n Transduction: conversion of one form of energy to another in sensation, transforming of stimulus energies into neural impulses (ex: light energy into neural messages) © 2008 The Mc. Graw-Hill Companies, Inc.

Sensation Chart Sense Stimulus Receptors Vision Electromagnetic energy Rods and cones in retina Hearing Sound waves Hair cells of the inner ear Smell Chemical Substances in air Receptor cells in the nose Taste Chemical Substances in saliva Taste buds Touch Pressure on skin Nerve Endings Threshold

Vision n What strikes our eyes is not color, but pulses of electromagnet ic energy that are visual system perceives as color. © 2008 The Mc. Graw-Hill Companies, Inc.

Vision § 2 Physical Characteristics that help determine our sensory experience. § § Wavelength= distance from wave peak to the next. Determines the Hue=or color we experience. Amplitude=Height of wave Determines the intensity=the amount of energy in light waves.

Wavelength and Amplitude © 2008 The Mc. Graw-Hill Companies, Inc.

Processing Light n n n Color is produced/created by the nervous system in response to wavelengths Color is determined by an absorption certain wavelengths Wavelengths n n n Short violet Midlength green, blue, yellow Long red Average person can discriminate about two million different colors Photoreceptors n n Rods—black, white, gray Cones—colors © 2008 The Mc. Graw-Hill Companies, Inc.

Differing Eyes n Bee detects reflected ultraviolet wavelengths

Getting the Light into the Eye

Mirror image is inverted……we don’t see image as a whole, but receptor cells convert light energy into neural pulses. Impulses are sent to the brain to be perceived and processed.

Acuity=sharpness in vision can be affected by small distortions in the eye’s shape. Nearsighted Farsighted

Converting Light into Images n n From here conversion is continued by photoreceptors in the retina. Two main types of photoreceptors: Rods and cones. 36

Rods and Cones n n They contain photopigments – chemicals that respond to light. Light triggers action potentials in photoreceptors (rods and cones) by breaking down photopigments. 37

Rods and Cones n Rods unable to discriminate color. n n n But more sensitive to light than cones. Three forms of pigments in cones provide the basis for color vision. Rods and cones differ in their distribution in the eye. Cone = Color 38

Distribution of rods and cones • Cones are concentrated in the fovea or center of the retina • We have greatest visual acuity in the center of our field of vision because we have the most cones there. • There are no rods in the human fovea. • The number of rods increases as we move away from the fovea to the outer parts of the retina. * This is why our pupils dilate • Rods are more sensitive to light than cones, so you can see dim light better just outside of 39 your central field of vision.

Figure 4. 10: Cells in the Retina 40

Cells in the retina – that help rods and cones send signals to the brain n Light energy striking the rods and cones produces chemical changes that generate neural signals. These signals activate neighboring bipolar cells which activate Ganglion Cells – they sum up the signals from the rods and cones and send action potentials through the optic nerve and to the brain. The axons from the network of Ganglion Cells converge like the strands of a rope to form an Optic Nerve= passage way to the visual cortex through the thalamus 41

Figure 4. 14: Pathways from the Ganglion Cells into the Brain 42

Visual Information processing n n n Info. From the retina’s nearly 130 million receptor rods & cones is received and transmitted by the million or so ganglion cells, whose axons make up the optic nerve, which shoots info. To the brain. Any given retinal area relays its info. to a corresponding location in the occipital lobe. This sensitivity can also lead to misfires, however. Try this: Turn your eyes to the left, close them, and then gently rub the right side of your right eyelid with your fingertip. Note the patch of light to the left, moving as your finger moves. This is because your retinal cells are so sensitive that even pressure triggers them to relay information. © 2008 The Mc. Graw-Hill Companies, Inc.

Blind Spot? Where the optic nerve leaves the eye (there are no receptor cells)

Figure 4. 16: The Color Circle 45

Trichromatic or Young. Helmholtz Theory of Color Vision n n Any color can be produced by mixing pure lights of blue, green, and red. There are three types of cones, each most sensitive to particular wavelengths. 46

Figure 4. 18: Relative Responses of Three Cone Types to Different Wavelengths of Light 47

Problem with the Trichromatic Theory n n n Cannot explain some aspects of color vision, such as afterimage. Color blind can often see yellow when mixing red and green (no red cones) Example: Stare at the dot on the next slide for thirty seconds. 48

Opponent-Process Theory of Color Vision n Visual elements sensitive to color are grouped into three pairs. n n n Members of each pair oppose, or inhibit, each other. Three pairs are a red-green element, a blueyellow element, and a black-white element. Explains color afterimages and the phenomenon of complimentary colors. 49

Figure 4. 20: Color Coding and Ganglion Cells 52

Present Solution to Color Vison Mystery n 1. 2. Two stages: Retina’s red, blue, and green cones respond in varying degrees to different color stimuli (young-helmholtz trichromatic theory). Signals are then processed by the nervous system’s opponent-process cells on the way to the visual cortex. © 2008 The Mc. Graw-Hill Companies, Inc.

Colorblindness n n n If you only have 2 photopigments in your cones you will be color blind (usually lack red or green cones). Do you see a number in the image on the right? Some women have 4 photopigments… super color vision. 54

Hearing-Auditory Processing © 2008 The Mc. Graw-Hill Companies, Inc.

Audition- The Ear § Middle Ear § § Inner Ear § § chamber between eardrum and cochlea containing three tiny bones (hammer, anvil, stirrup) that concentrate the vibrations of the eardrum on the cochlea’s oval window innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs Cochlea § coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses

Perceiving Pitch § § Place Theory – best explains how we sense high pitches § theory that links the pitch we hear with the place where the cochlea’s basilar membrane is stimulated Frequency Theory – best explains how we sense low pitches § theory that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch. *Problem with high pitched sounds (neurons can not fire faster than 1000 times per second. Volley Principle

How We Locate Sounds n n n Sound waves will strike one ear sooner and more intensely than the other allowing us to locate sound This is why we tilt our head to one side when trying to pinpoint a sound. Sound travels at 750 miles per hour and our ears our ~6 inches apart, so the difference is small, but our brain can pick up on this.

Hearing Loss § Conduction Hearing Loss § hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea § § Ex: eardrum punctured, damage to the tiny bones that vibrate Sensorineural Hearing Loss – more common § hearing loss caused by damage to the cochlea’s receptor cells or to the auditory nerve § § Also called nerve deafness Can be due to a disease, but more commonly from heredity, aging, and prolonged exposure

Deafness Sensorineural Deafness Conduction Deafness n n Something goes wrong with the sound and vibration on the way to n n the cochlea. You can get a hearing aid n to help. n The hair cells in the cochlea get damaged. Can be caused by loud noises NO WAY to replace the hairs. Cochlea implant is possible.

Perceptual Constancy n n Perceptual Constancy: The tendency to perceive objects as relatively stable despite continually changing sensory information. Examples: n Shape, size, color, brightness n Varying distances, lighting conditions, angles © 2008 The Mc. Graw-Hill Companies, Inc.

Hearing Loss § Amplitude required for perception relative to 20 -29 year-old group Older people tend to hear low frequencie well but suffer hearing loss for high frequencies High frequency Results from nerve Degeneration near The beginning of The basilar Membrane. This Supports the Place Theory! 1 time 10 times 1000 times 32 64 128 256 512 1024 2048 4096 8192 16384 Frequency of tone in waves per second

Cochlear Implants n n A way to restore hearing for people with nerve deafness. Translates sound into electrical signals that, wired into the cochlea’s nerves, convey some information about the sound to the brain. © 2008 The Mc. Graw-Hill Companies, Inc.

Cochlear Implants and Deaf Culture n n Many parents want their children to experience the world of sound and talk. Do not wait for child’s consent because it would not make the implant as effective Deaf culture advocates object to using cochlear implants before they can speak because they do not view deafness as a disability. They do not believe that signing shows a linguistic disability. © 2008 The Mc. Graw-Hill Companies, Inc.

Touch n n Energy detected is physical pressure on tissue. Many nerve endings in the skin act as touch receptors. Touch is both an active and passive sense. Changes in touch provide most important sensory information. 66

Coding of Touch Information n Intensity of the stimulus is coded by: n n n Firing rate of individual neurons and The number of neurons stimulated. Location is coded by the location of the neurons responding to the touch. 67

Pain n n Pain provides information about impact of world on body. Information-carrying aspect of pain very similar to that of touch and temperature. Two types of nerve fibers carry pain signals from skin to the spinal chord. Pain pathways Cerebral cortex plays role in the experience of pain. 68

Figure 4. 25: Pain Pathways 69

Modulating Pain n n Gate Control Theory – There is a “gate” like function in the spinal cord that can let pain signals through to the brain or not. – Spinal cord contains small nerve fibers that conduct most pain signals and large nerve fibers that conduct most other sensory signals Rubbing the skin around a wound cancel out some pain signals (stimulate large nerve fibers and block some of the pain messages) Pain gate can be closed by information from the brain (you can be distracted from pain). 70

The Chemical Senses n Olfaction detects airborne chemicals (Olfactory System) n n Our sense of smell Gustation detects chemicals in solution that come into contact with receptors inside the mouth (Gustatory System) n Our sense of taste 71

Smell, Taste, and Flavor n n Smell and taste act together to form system known as flavor. Tastes and odors can prompt strong emotional responses. Nutritional state can affect taste and flavor of food and motivation to eat particular foods. Flavor includes other characteristics of food. 72

Gustation n Taste receptors are in the taste buds… they are groups of cells called papillae (pores that catch food chemicals) Different papillae code more strongly for sweet, sour, bitter and salty. They respond to two or three, but code most strongly for one. Two additional taste sensations, umami enhances other tastes (MSG/meaty) and astringent which is a “dry” sort of taste found in red wine and some teas. 73

There are several types of papillae 74

Are you a super taster? n n Lets find out…. Draw a simple blank map of the tongue From http: //www. thetech. org/genetics/supertaster. php Swab the blue food coloring on the front of the tongue (cover the tip and about 1/2 inch back). Have the subject move the tongue around in the mouth and swallow. This distributes the dye. Swallowing the dye is not hazardous. You will see pink circles emerge from the blue background. The pink circles are the fungiform papillae. The fungiform papillae appear pink because they do not stain. Now use the hole-punched cards to take 4 or 5 samples from your partner’s tongue. Count how many papillae you find in the circle. Map these areas on your tongue drawing. What is the average number of papillae per sample? 75

Are you a supertaster? >30 papillae 8 papillae 76

A few facts…. n n n Taste receptors replace themselves every week or two (smoking and alcohol will accelerate the decline in taste buds!) Our emotional responses to taste our hardwired. People without tongues can still taste…through receptors in the back and on the roof of the mouth. If you lose taste sensation on one side of your tongue, you wouldn’t notice because the other side will become supersensitive and compensate. We can not taste or smell nutrients (fat, protein, starch…. sugar, however…. of course we can sniff that one out!) © 2008 The Mc. Graw-Hill Companies, Inc.

© 2008 The Mc. Graw-Hill Companies, Inc.

Sensory Interaction n n Principle that one sense may influence another. Smell plus texture plus taste equals flavor (love apple pie a la mode for this reason) © 2008 The Mc. Graw-Hill Companies, Inc.

Figure 4. 23: The Olfactory System 80

Olfactory System n n Employs about 1, 000 different types of receptors tied straight to Olfactory Bulbs. Only sense that does not send its messages through the thalamus. Processing in several brain regions including frontal lobe, hypothalamus and amygdala. Strong relationship between olfaction and emotional memory 81

Pheromones n Chemicals released by one animal, and when detected by another, can shape the second animal’s behavior or physiology. n n n Ants, termites use for navigation Often involved in mating behavior Role of pheromones in humans not clear. n n n Vomeronasal organ detects pheromones May or may not be very active in humans Seems to detect some hormones 82

Kinesthesia n Sense that indicates where the parts of the body are with respect to one another. n n n Necessary guide for movement. Kinesthetic information comes primarily from the joints as well as muscles. Close your eyes and wave your arms around a bit… now touch your right and left index fingers together. 83

Vestibular Sense n n Organs: n Vestibular sacs n Otoliths- crystals that stimulate nerves in vestibular sacs. n Semicircular canals Neural connections to: n The cerebellum n The autonomic nervous system (digestive…) n The eye muscles – turn your head… 84

Gestalt Psychology n n n n Gestalt: A German word meaning “form” or “whole”. . Example with Necker Cube (seeing a “whole” or “form”) Looks at how we GROUP objects together. Proximity-group objects that are close together Similarity-group objects similar in appearance Continuity-group objects that create a continuous form Closure-we fill gaps to complete an object (like top-down processing) I _ant ch_co_ate ic_ cr_am.

Figure-Ground The ability to distinguish an object from its background Ex. As you read, the words are the figure and the white paper is the ground.

Depth Cues • Visual Cliff Experiment • Babies refused to go over the cliff • We see depth by using two cues that researchers have put in two categories: • Monocular Cues • Binocular Cues

Binocular Cues • We need both of our eyes to use these cues. • Retinal Disparity-Our eyes receive slightly different images because they are 2 ½ inches apart. The brain compares these two images. Disparity becomes less as distance increases. Ex. The floating finger sausage. • Convergence-A neuromuscular cue caused by the eyes’ greater inward turn when they view a near object. The greater the inward strain, the closer the object.

Monocular Cues • You really only need one eye to use these (used in art classes to show depth). • Linear Perspective • Interposition • Relative size • Texture gradient • Shadowing

The Mueller-Lyer Illusions n Depending on the direction of the arrow n n n Inward or outward Two equal length lines One appears longer © 2008 The Mc. Graw-Hill Companies, Inc.

The Visual Cliff n n Experiment to test depth perception in infants Found that infants early on could perceive depth n n Older infants would not crawl on “deep” side Younger infants showed physiological changes © 2008 The Mc. Graw-Hill Companies, Inc.

Form Perception n The process by which sensations are organized into meaningful shapes and patterns. n The figure-and-ground principle n brain organizes sensory input into: n n n a figure (the center of attention) ground (the background) Rubin’s characteristics n “Thinglike” n In front of ground n Dominates, more memorable © 2008 The Mc. Graw-Hill Companies, Inc.

Laws of Grouping n Similarity- Group together stimuli that are similar n Proximity-Group together stimuli that are together n n Continuity-Perception of contours or straight lines as continuous Closure- Tendency to close figures gaps in a figure and perceive it as whole. © 2008 The Mc. Graw-Hill Companies, Inc.

Laws of Grouping: Demos © 2008 The Mc. Graw-Hill Companies, Inc.

Operational Definition? n also called functional definition, defines something (e. g. a variable, term, or object) in terms of the specific process or set of validation tests used to determine its presence and quantity. EXAMPLES: An operational definition describes exactly what the variables are and how they are measured within the context of your study. For example, if you were doing a study on the impact of sleep deprivation on driving performance, you would need to operationally define what you mean by sleep deprivation and driving performance. In this example you might define sleep deprivation as getting less than seven hours of sleep at night and define driving performance as how well a participant does on a driving test. © 2008 The Mc. Graw-Hill Companies, Inc.