Psychology Chapter 4Sensation and Perception

Most amazing introduction ever!! Turn to page 77 and prepare to be amazed!

Chapter 4 Section 1 EQ:Distinguish between sensation and perception, and explain how they contribute to an understanding of our environment.

-Sensation is the stimulation of sensory receptors (eyes, ears, etc.) and the transmission of sensory information to the central nervous system (spinal cord and brain)

The Basics

-The stimulation of the senses is automatic and results from sources of energy, sound, or from the presence of chemicals.

Basics

-Absolute threshold is the weakest amount of a stimulus that can be sensed. Remember this test? What is your threshold?

Basics

-Difference threshold is the minimum amount of difference that can be detected between two stimuli.

Basics

-The Signal-Detection theory suggests that perception of sensory stimuli is influenced by factors such as setting and expectations.

Basics/Selective Attention

-Because of sensory adaptation, we become less sensitive to unchanging stimuli.

Selective Attention Video

Perceptual Constancies

-Size, Shape, Location, and Color-Visual Illusion: Brain is attempting to perceive image. Good for researchand studying how people image differently.

Chapter 4 Section 1 Review

-Define absolute threshold. -Give two examples of sensory adaptation. -Section 1ERT

Chapter 4 Section 2 EQ: Explain how the eye works to enable vision.

-No other sense allows us to gather so much information from nearby and distant sources. -To understand vision it is important to know how light works and how our eyes function.

Vision

-Light is electromagnetic energy. It is described as wavelengths.-Not all light is visible to humans.

Vision

-Vision is the most studied of all the senses, reflecting the high importance we place our sense of sight. How does vision occur?

Natural Hallucinogen (DubStep)

Vision “How it works”

1) Light enters the eye through the pupil and reaches the lens that focuses light on the retina2)The retina contains light-sensitive receptor cells (rods and cones) that change the light into neuronal impulses which travel over the optic nerve to the brain.

-Cones = Daylight Rods= Night Vision

Eye Explanation Video

Vision

-The place where the optic nerve leaves the eye is called the blind spot because it is the only spot on the retina where there are no receptors. -Adaptation to low light continues to improve up to 45 minutes, while adaptation to bright light happens in a few minutes. Special Forces, Flashbangs, Darkness, Night Vision

Vision

-Visual acuity is the sharpness of vision (Snellen Chart)

Vision and Color

-People with normal color vision see any color in the spectrum of visual light. -Cones enable us to perceive color. Some cones are sensitive to blue, red, and green. When more than one cone is stimulated we perceive other colors.

Vision and Color (Page 84 Test)

-The color circle is the spectrum of light bent into a circle. -The afterimage of a color is its complementary color. -You perceive an afterimage when you have viewed a color for a whileand then the color is removed.

Vision and Color

-Color deficiency affects about 8% of American men and less than 1% of American women. It results from a hereditary defect in the cones.-The defect is carried in the genes of women whose vision is usually normal. -People can be partly or totally color blind.

-Test time! Color blind test, I mean.

Chapter 4 Section 2 Review

-What is visible light?-What is the retina, and what is its function?-Explain how we are able to see color.

Chapter 4 Section 3 EQ:Describe the process of hearing.

-Hearing depends on vibrations of air, called sound waves.-Sound waves from the air pass through various bones and fluids until they reach the inner ear, which contains tiny hairlike cells that move back and forth.

Hearing 101 Video

Hearing-These hair cells change vibrations into neuronal signals that travel via the auditory nerve to the brain.

Hearing (Pitch)

-Pitch (low/high) depends on the frequency or cycles per second of the sound.-The human ear can hear sound waves from 20 to 20,000 cycles per second. -The loudness of a sound is determined by the height or amplitude of sound waves. -Loudness is measured in decibels.

Hearing-Ear is shaped to capture sound waves, to vibrate them, and to transmit sound to the brain-The ear is divided into the outer ear, middle ear, and the inner ear. -Sound vibrates the eardrum which transmits sound waves to the three bones in the middle ear (hammer, anvil, and stirrup) which transmits sound to the inner ear.

Hearing

-The cochlea contains fluids as well as neurons that vibrate and send neural impulses to the auditory nerve and then on to the brain. -Sounds are located by determining which ear strikesmost loudly.

Hearing Issues

-People with conductive deafness cannot hear soft sounds. (ME)-People with sensorineural deafness cannot hear the sound of certain frequencies. (IE)-About 2 million Americans are deaf, usually caused by heredity, disease, injury, or old age. -Deafness has its own culture in America.

Chapter 4 Section 3 Review

-What determines the loudness of a sound? How is loudness measured?-Define eardrum and explain its function.

Chapter 4 Section 4 EQ:Identify the chemical, skin, and body senses, and explain how they work.

-Smell and taste are known as the chemical senses because their receptors are sensitive to chemical molecules rather than light energy or sound waves.

Smell and Taste (Cont.)

-These molecules enter the nose in vapors, which a membrane in the upper part of the nasal passages on which the smell receptors are located. -These receptors send messages about smells via the olfactory nerve to the brain.

Smell and Taste (Cont.)

-For you to taste something, chemicals must stimulate receptors in the taste buds on your tongue.

Absolute Threshold Taste Time! Can you find the sugar water?

Smell and Taste (Cont.)

-Taste information is relayed to the brain along with data about the texture and temperature of the substance you have put in your mouth. -Much of what is referred to as taste is actually produced by the sense of smell

Touch

-Receptors in the skin are responsible for providing the brain with at least three kinds of information about the environment:1)Pressure2)Temperature3)Pain

Touch (Cont.)

-Sensitivity to pressure varies from place to place on the skin. -Some skin receptors are particularly sensitive to hot and cold stimuli.-Many kinds of stimuli can produce pain. Take Down Time Video!

Touch (Cont.)

-Pain acts as a warning system for your body, it does not easily adapt to stimulation - you rarely get “used to” pain.

Found our boy again! Pain! Video Link

Balance

-The body’s sense of balance is regulated by the vestibular system inside the inner ear. -Kinesthesis is the sense of movement and body position. -It cooperates with the vestibular and visual senses to maintain proper posture and balance.

When your systems can not communicate you have major problems!

Balance (Cont.)

-The sensation of kinesthesis comes from receptors in and near the muscles, tendons, and joints.-When any movement occurs, these receptors immediately send messages to the brain.

Balance (Cont.)

-Without kinesthetic sensations, movements would be jerky and uncoordinated.-Walking would be difficult if not impossible and complex physical activity would be impossible.

Chapter 4 Section 4 Review

-How does the sense of smellwork?-What is the vestibular sense?

Chapter 4 Section 5 EQ:Summarize the laws of sensory perception.

-Perception is the process of assembling sensations into usable mental representation of the world - something done so automatically we are rarely aware of it.

Perception

The Rules of Perceptual Organization (Gestalt)1)Closure- the tendency to complete a figure so that is has a consistent form2) Figure Ground- the ability to discriminate properly between figure and ground 3) Proximity- stimuli that are near each other tend to be grouped together

1 2 3

Perception (Cont.)

4)Similarity- stimuli that are similar in size, shape, color, or form tend to be grouped together. 5)Continuity- perceptions tend toward simplicity not disruption.6)Common fate- we perceive things as belonging together, to continue together

4 5 6

Perception (Cont.)

-Perception of movement is accomplished by seeing an object change its positive relative to other objects. -Stroboscopic motion is an illusion made by a rapid progression of still images.

Stroboscopic Motion Illusion/Example Video

Perception (Cont.)

-Depth perception is the ability to see three-dimensional space and to accurately estimate distances.-A number of depth cues combine to produce the experience of three-dimensional space.

Perception (Cont.)

-Some will work with just one eye (monocular cues), while others require two eyes (binocular cues).-monocular cues: perspective, clearness, overlapping, shadow, texture gradient-binocular cues: retinal disparity, convergence

Perception (Cont.)

- Size, color, brightness, and shape constancies are created through experience.-Principles of perception sometimes trick us, as in visual illusions.

Amazing Animated Optical IllusionsCan you trust your eyes?The Hollow Face Illusion

Brain Tricks

Chapter 4 Section 5 Review

-List and explain three rules of perceptual organization. -Explain the cues people use to perceive motion and depth.-Describe four perceptual consistencies.

Chapter 4 Sensation and Perception

Review and Summarization Activities -Chapter 4 G.O.-Chapter 4 Review Worksheet-Chapter 4 page (Practice Test) -Exam is Tuesday!

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