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Sensation & Perception PowerPoint  Lecture Notes Presentation. CHAPTER 4. Lecture Overview. Understanding Sensation How We See & Hear Our Other Senses Understanding Perception. Introduction to Sensation & Perception.

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CHAPTER 4

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Sensation & Perception

PowerPoint  Lecture Notes Presentation

CHAPTER 4

©John Wiley & Sons, Inc. 2010


Lecture Overview

  • Understanding Sensation

  • How We See & Hear

  • Our Other Senses

  • Understanding Perception

©John Wiley & Sons, Inc. 2010


Introduction to Sensation & Perception

  • Sensation:process of detecting, converting, & transmitting raw sensory information from the external & internal environments to the brain

  • Perception:process of selecting, organizing, & interpreting sensory information into meaningful patterns

©John Wiley & Sons, Inc. 2010


What is the top, bottom, or back of this cube?

Is this a young woman looking over her right shoulder, or an older woman looking downward?

When viewing these figures, your visual sensory system receives an assortment of light waves = sensation. Interpreting the lines as a cube or an old/young woman = perception.

Sensation Vs. Perception

©John Wiley & Sons, Inc. 2010


Sensation Vs. Perception

©John Wiley & Sons, Inc. 2010


Processing:Ourfive senses (vision, audition, etc.) have special receptors (e.g., eye’s rods & cones), which detect & transmit sensory information

Understanding Sensation: Processing

©John Wiley & Sons, Inc. 2010


Understanding Sensation: Processing

  • Bottom-Up Processing: information processing beginning “at the bottom” with raw sensory data” sent “up” to the brain for higher-level analysis

  • Top-Down Processing: information processing starting “at the top” with higher-level processes and then working down

©John Wiley & Sons, Inc. 2010


Understanding Sensation: Processing

Four Forms of Processing:

  • Sensory detection:eyes, ears, other sense organs contain receptor cells that detect & process sensory information

  • Transduction:converts receptor’s energy into neural impulses that are sent on to the brain

  • Coding: converting sensory inputs into different sensations

  • Sensory Reduction: filtering and analyzing incoming sensations before sending neural messages on to the cortex

©John Wiley & Sons, Inc. 2010


Neural impulses from sensory receptors in our eyes, ears, skin, & other sensory organs create neural messages sent to various areas of our brain.

Understanding Sensation: Processing (Continued)

©John Wiley & Sons, Inc. 2010


Understanding Sensation: Thresholds

  • Psychophysics:studies the link between physical characteristics of stimuli and our sensory experience

  • Absolute Threshold: smallest amount of a stimulus we can reliably detect

  • Difference Threshold: minimal difference needed to detect a stimulus change; also called the “just noticeable difference” (JND)

©John Wiley & Sons, Inc. 2010


Understanding Sensation: Thresholds

©John Wiley & Sons, Inc. 2010


Pause & Reflect: Psychology at Work

  • Subliminalperceptionmay occur, but there is little or no evidence ofsubliminal persuasion.

©John Wiley & Sons, Inc. 2010


Sensory Adaptation: decreased sensitivity due to repeated or constant stimulation

Understanding Sensation

©John Wiley & Sons, Inc. 2010


Pause & Reflect: Assessment

  • Smokers generally fail to notice that their hair & clothing often smell like smoke. This may be because of _____.

©John Wiley & Sons, Inc. 2010


How We See: Vision

  • Light is a form of electromagnetic energy that moves in waves.

  • Various types of electromagnetic waves form the electromagnetic spectrum.

©John Wiley & Sons, Inc. 2010


How We See: Light Waves

©John Wiley & Sons, Inc. 2010


How We See:Light Waves

  • Wavelength: distance between the crests (or peaks)

  • Frequency: how often a light or sound wave cycles

  • Amplitude: height of a light or sound wave

©John Wiley & Sons, Inc. 2010


How We See: Electromagnetic Spectrum

©John Wiley & Sons, Inc. 2010


The flower on the left is what we normally see. The one on the right, photographed under ultraviolet light, is what we think most animals & insects see.

How We See:Electromagnetic Spectrum

©John Wiley & Sons, Inc. 2010


How We See:Anatomy of the Eye

  • The function of the eye is to capture light waves & focus them on receptors at the back of the eyeball.

©John Wiley & Sons, Inc. 2010


How We See:Structures of the Retina

  • Receptors for vision are the rods& coneslocated in the retina.

©John Wiley & Sons, Inc. 2010


©John Wiley & Sons, Inc. 2010


©John Wiley & Sons, Inc. 2010


Do You Have a Blind Spot?

  • (Everyone does! Close your right eye & stare at the X with your left eye, & then slowly move your head toward the screen. The worm will disappear!)

©John Wiley & Sons, Inc. 2010


Pause & Reflect: Assessment

  • Enter the correct label on each line, & then compare your answers with Process Diagram 4.1 p. 137.

©John Wiley & Sons, Inc. 2010


Pause & Reflect: Psychology at Work

  • Vision research helps explain how the shape of your eyeball creates two common visual problems--nearsightedness& farsightedness.

©John Wiley & Sons, Inc. 2010


Color visionis a combination of two theories

Trichromatic Theory:color perception results from three types of cones in the retina, each most sensitive to either red, green, or blue

How We See:Theories ofColor Vision

©John Wiley & Sons, Inc. 2010


How We See:Theories ofColor Vision (Continued)

  • Opponent-Process Theory:color perception results from three systems of color opposites (blue-yellow, red-green, & black-white)

©John Wiley & Sons, Inc. 2010


Pause & Reflect: Assessment

  • Stare at the dot in the middle of the flag for 60 seconds. Then look at a white surface. You’ll see a regular red, white, & blue U.S. flag, known as a negative afterimage. Can you explain how this is related to the opponent-process theory?

©John Wiley & Sons, Inc. 2010


Pause & Reflect: Assessment

  • Click on the photo of the spiral to the right and follow the directions on the website. How does the opponent-process theory help explain the effects of this aptly named “spiral illusion”?

©John Wiley & Sons, Inc. 2010


Are you “color blind”? People who have red-green color deficiency have trouble perceiving the green colored number in the center of this circle.

How We See:Color-Deficient Vision

©John Wiley & Sons, Inc. 2010


How We Hear: Audition

  • Soundresults from movement of air molecules in a particular wave pattern.

  • Sound waves vary in:

    • wavelength, which determines pitch (highness or lowness).

    • amplitude, which determines loudness (intensity of the sound).

©John Wiley & Sons, Inc. 2010


How We Hear: EarAnatomy

  • Outer Ear (gold color) = pinna, auditory canal, & eardrum

  • Middle Ear (blue color) = hammer, anvil, & stirrup

  • Inner Ear (pinkish color) cochlea, semicircular canals, & vestibular sacs

    • Cochlea contains key receptors for hearing

©John Wiley & Sons, Inc. 2010


©John Wiley & Sons, Inc. 2010


How We Hear:Theories of Pitch Perception

  • Place Theory: pitch perception is linked to the particular spot on the cochlea’s basilar membrane that is most stimulated

  • Frequency Theory: pitch perception occurs when nerve impulses sent to the brain match the frequency of the sound wave

©John Wiley & Sons, Inc. 2010


How We Hear: Audition

  • The loudness of a sound is measured in decibels. Constant noise above 90 decibels can cause permanent nerve damage & irreversible hearing loss.

©John Wiley & Sons, Inc. 2010


Pause & Reflect: Assessment

  • Enter the correct label on each line & then compare your answers with Process Diagram 4.2 p. 142

©John Wiley & Sons, Inc. 2010


Our Other Senses

  • Olfaction: sense of smell

  • Receptors for smell are embedded in the nasal membrane (the olfactory epithelium).

©John Wiley & Sons, Inc. 2010


Pause & Reflect: Assessment

  • Enter the correct labels & then compare your answers with Process Diagram 4.3 p. 147.

©John Wiley & Sons, Inc. 2010


Our Other Senses:Gustation (Sense of Taste)

  • Receptors for taste (or gustation) are taste buds, located in papillae on the surface of the tongue.

©John Wiley & Sons, Inc. 2010


Skin sensesinvolvethree skin sensations-- touch(or pressure),temperature,& pain.

Receptors for these sensations occur in various concentrations & depths in the skin.

Our Other Senses:Three Body Senses

©John Wiley & Sons, Inc. 2010


Vestibular sense (or sense of balance) involves the vestibular sacs & semicircular canals located within the inner ear.

Three Body Senses (Continued)

©John Wiley & Sons, Inc. 2010


Three Body Senses (Continued)

  • Kinesthesia provides our brains with information about posture, orientation, & movement.

  • Kinesthetic receptors are located in muscles, joints, & tendons.

©John Wiley & Sons, Inc. 2010


Understanding Perception

  • Illusion:false or misleading perception that helps scientists study the processes of perception

  • The horizontal-vertical illusion Which line is longer?

©John Wiley & Sons, Inc. 2010


The Muller-Lyer Illusion Which vertical line is longer?

©John Wiley & Sons, Inc. 2010


Understanding Perception

Do you see the cow?

©John Wiley & Sons, Inc. 2010


Understanding Perception

Now can you see the cow?

©John Wiley & Sons, Inc. 2010


Understanding Perception

  • Perception’s three basic processes:

  • Selection

  • Organization

  • Interpretation

©John Wiley & Sons, Inc. 2010


Understanding Perception: Selection

  • Selection (choosing where to direct attention) involves:

    • Selective Attention(filtering out & attending only to important sensory messages)

    • Feature Detectors(specialized neurons that respond only to certain sensory information)

    • Habituation(brain’s tendency to ignore environmental factors that remain constant)

©John Wiley & Sons, Inc. 2010


Kittens reared in an environment having only vertical lines are later unable to detect horizontal lines. Can you explain why?

Pause & Reflect: Critical Thinking

©John Wiley & Sons, Inc. 2010


Understanding Perception: Organization

  • Organization:assemblinginformation into patterns that help us understand the world

  • We organize sensory information in terms of:

    • Form

    • Constancy

    • Depth

©John Wiley & Sons, Inc. 2010


Organization(Form)

©John Wiley & Sons, Inc. 2010


Pause & Reflect: Psychology at Work

  • Perception research helps explain these so-called “impossible figures.”

©John Wiley & Sons, Inc. 2010


Organization (Constancies)

  • Perceptual Constancy: perceiving the environment as remaining the same even with changes in sensory input

  • Four best-known constancies:

    • Size

    • Shape

    • Color

    • Brightness

©John Wiley & Sons, Inc. 2010


Organization(Size & Shape Constancy)AmesRoom Illusion

©John Wiley & Sons, Inc. 2010


Pause & Reflect: Assessment

Can you label these examples of size, shape, color,& brightness constancies?

©John Wiley & Sons, Inc. 2010


Depth Perception:ability to perceive three dimensional space & accurately judge distance

Organization (Depth Perception)

©John Wiley & Sons, Inc. 2010


Depth Perception (Continued)

Visual cliff—infants hesitate to crawl over the glass, demonstrating some depth perception

©John Wiley & Sons, Inc. 2010


Depth Perception (Continued)

  • Depth perception involves both binocular(two eyes) & monocular (one eye) cues.

  • Two binocular depth cues:

    • Retinal Disparity(separation of the eyes causes different images to fall on each retina)

    • Convergence(the closer the object the more the eyes converge, or turn inward)

©John Wiley & Sons, Inc. 2010


Binocular Cues:Retinal disparity (left) & Convergence (right)

©John Wiley & Sons, Inc. 2010


Pause & Reflect: Assessment

  • Can you label these 7 monocular depth cues?

  • Linear perspective

  • Interposition

  • Relative size

  • Texture gradient

  • Aerial perspective

  • Light & shadow

  • Relative height

©John Wiley & Sons, Inc. 2010


Interpretation(how the brain explains sensations) involves three major factors:

Perceptual Adaptation:brain adapts to changed environments

Perceptual Set:readiness to perceive in a particular manner, based on expectations

Frame of Reference:based on the context of the situation

Understanding Perception: Interpretation

©John Wiley & Sons, Inc. 2010


Do you notice anything wrong with these photos of actress Julia Roberts?

Pause & Reflect: Assessment

©John Wiley & Sons, Inc. 2010


Now that the photos are inverted, can you explain how this is an example of perceptual set?

Pause & Reflect: Assessment

©John Wiley & Sons, Inc. 2010


Science & ESP

  • Extrasensory Perception (ESP): supposed “psychic” abilities that go beyond the known senses (e.g., telepathy or clairvoyance)

  • ESP research is criticized for its lack of experimental control & replicability.

©John Wiley & Sons, Inc. 2010


Pause & Reflect: Assessment

  • How the brain explains sensations is known as _____.

  • Briefly discuss how perceptual adaptation differs from perceptual set.

©John Wiley & Sons, Inc. 2010


Sensation & Perception

PowerPoint  Lecture Notes Presentation

End of CHAPTER 4

©John Wiley & Sons, Inc. 2010


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