1. As the intensity of the brightness of a light is increa - PowerPoint Presentation

Slide1

1. As the intensity of the brightness of a light is increased, the sizes of the action potentials of the neurons involved:a. increaseb. decreasec. stay the samed. first increase, then decrease

3. A blind experimental design should be sufficient to eliminate:a. placebo effectsb. experimenter effectsc. self-selectiond. non-random selection

13. Which

area of the brain acts as a relay station, directing most incoming sensory information to a proper region of the cerebral cortex?

a. sensory cortex

b. medulla

c. cerebellum

d. thalamusSlide2

14. Which of the following is NOT an example of genetic drift:a. A species of bird must change its location once a new predator arrives. The climate of the new location is warmer than the previous, and in several generations, the species sheds its formerly thick layer of feathers.b. Evolutionary bottleneckc. The group of individuals that colonized an area near the Arctic circle just happened to have higher rates of schizophrenia. Therefore, the current population has a higher rate of schizophrenia.

d. All of these are examples of genetic drift.21. A study in a scientific journal has revealed that there is a significant difference between the IQs of males and females. Which of the following statements about the p-value must be true?

a. The p-value should be very high in order to obtain significance.

b. The p-value should be very low in order to obtain significance.

c. The p-value must be exactly 5% in order to obtain significance.d. The p-value can be anything; it doesn’t have anything to do with significance.

28. Which

of the following brain areas, when damaged, would most likely lead to the cessation of breathing?

a. parietal lobe

b. primary motor cortex

c. thalamus

d. brainstemSlide3

7. Sheldon uses positive reinforcement to make Penny behave in a favorable way. He gives her a piece of chocolate following a desired behavior. If, instead, he chose to use negative reinforcement, which of the following actions would he take?a. Relieve her of her daily chores when she behaves well.b. Spray her with a bottle of water every time she misbehaves.c. Take away her Wi-Fi privileges every time she misbehaves.

d. Buy her a gift card to her favorite store when she behaves well.Slide4

Reinforcement and Punishment

INCREASES TARGET BEHAVIOR

DECREASES TARGET BEHAVIOR

Positive Reinforcement

(Lever Press

 Food pellet)

+ Add something good

Positive Punishment

(Lever Press  Shock)+ Add something badNegative Reinforcement(Lever Press  Shock off)- Take away something badNegative Punishment(Lever Press  removes food)- Take away something good

Goal

Manipulation

Negative (Removing something)

Positive

(Introducing

something)Slide5

7. Sheldon uses positive reinforcement to make Penny behave in a favorable way. He gives her a piece of chocolate following a desired behavior. If, instead, he chose to use negative reinforcement, which of the following actions would he take?a. Relieve her of her daily chores when she behaves well.b. Spray her with a bottle of water every time she misbehaves.c. Take away her Wi-Fi privileges every time she misbehaves.

d. Buy her a gift card to her favorite store when she behaves well.19. Which of the following is NOT true about the theory of evolution?a. Humans and monkeys share common ancestry.

b. Evolution describes the origin and development of life.

c. Natural selection ensures that one living species is never more evolved than another.

d. Evolution is not a moral force.Slide6

Psychophysics & The Psychology of VisionChapter 8Slide7

Psychophysical ThresholdsAbsolute Threshold

PSYCHOPHYSICS: Relationship between physical characteristics of stimuli and the sensory experience that the stimuli produce

ABSOLUTE THRESHOLD: the faintest stimulus of a given sensation that an individual can detect

Difference Threshold

DIFFERENCE THRESHOLD: the minimal difference that must exist between two otherwise similar stimuli for an individual to detect them as different (

jnd

)Slide8

Psychophysics

Psychophysical function

– measuring sensation.

Ratio scale

: Absolute Threshold (A.L.) represents sensory zero.

Difference

Threshold (

Δ

I) represents sensory step (just-noticeable-difference –

j.n.d

.).

I

T

I

T

+ I

B

I

BSlide9

Psychophysics: Classical Methods

Adjustment. Limits (ascending; descending). Constant Stimuli.

Constant Stimuli:

Fixed set of stimuli (6 – 10), above & below expected threshold; presented in random order. Set repeated several times to obtain

“

% Yes

”

for each stimulus. Threshold derived by interpolation.Slide10

Psychophysics: Variability

Stimulus

Neural Response

Sensation

Behavior Yes, No

Noise

(Apparatus)

Noise

(Spontaneous firing rates. Genetic variation)

Noise

(Criterion. Response bias.)Slide11

Psychophysics: Psychophysical

“

Laws

”

“

Typical

”

Weber experiment:

I

B

I

B

+I

T

Δ

I

Δ

I/I k

11

1 1/10 = 0.1

20 22 2 2/20 = 0.1

50 55 5 5/50 = 0.1

Ernst Weber

1795-1878

Weber Constants:

Brightness ~ 1/80 = 1.25%

Loudness ~ 1/80 = 1.25%

Saltiness ~ 1/5 = 20%

Weber’s Law

jnd

=

kISlide12

Psychophysics: Fechner

’

s

“

Law

”

(logarithmic law of sensory magnitude)

Gustav Fechner

1801-1887Slide13

Psychophysics: Stevens

’

“

Law

”

(power law of sensory magnitude)

Stevens’ Power Law

S = c M

p

S

is the magnitude of the sensory experience,

c

is a proportionality constant,

M

is the magnitude of the physical stimulus and

p

is the constant powerSlide14

Psychophysics: Infants

Forced-choice Preferential Looking

Habituation/DishabituationSlide15

Functional Organization of the EyeSlide16

Transduction Occurs in the RetinaSensory ReceptorsCONES: permit sharply focused color vision

Fovea~6 millionRODS: permit vision in dim lightEverywhere else~120 million

Transduction

RHODOPSIN: the photochemical in rods that undergo structural changes in response to light

Rod opsin and retinal

The breakdown of rhodopsin creates an electrical charge that initiates an action potential on the neurons of the OPTIC NERVESlide17

Differences Between Cone and Rod VisionCone vision = PHOTOPIC visionColor perception and high acuity

Rod vision = SCOTOPIC visionSensitivity (or ability to see in dim light)DARK ADAPTATION: the increased visual sensitivity that occurs when the eyes are exposed for a period of time to dimmer light than was present before the adaptation periodLIGHT ADAPTATION: the decreased visual sensitivity that occurs when the eyes are exposed for a period of time to brighter light than was present before the adaptation periodSlide18
Slide19

The Electromagnetic SpectrumSlide20

Types of Color MixingSUBTRACTIVE-COLOR MIXING: the mixing of pigments whereby each pigment absorbs a different set of wavelengths of light that would otherwise be reflected to the eyeADDITIVE-COLOR MIXING: the mixing of colored lights by superimposing them to reflect off the same surface

Three-primaries lawSlide21

Two Classic Theories of Color VisionThe Trichromatic Theory

Theory proposed by Young and Helmholtz to explain the three-primaries law of color vision; it holds that the human ability to perceive color is mediated by three different types of receptors, each of which is most sensitive to a different range of wavelengths

3 cone types: red, green and blue

Differences in Cone WavelengthsSlide22

Two Classic Theories of Color Vision

The Opponent-Process Theory

Theory proposed by

Hering

to explain the law of complementarity; it holds that units (neurons) that mediate the perception of color are excited by one range of wavelengths and inhibited by another (complementary) range of wavelengths

540nm

640nm

+G – R cell

Encodes the presence of green (the absence of red).Slide23
Slide24
Slide25
Slide26
Slide27
Slide28
Slide29

Color Blindness

ProtanopiaDeuteranopia

TritanopiaSlide30

Enhancement of ContoursCONTOURS: sudden changes in brightness or color that separate objects from their backgroundSlide31

Treisman’s Two-Stage Feature-Integration Theory of Perception

1. Detection of FeaturesPARALLEL PROCESSING: the early steps in the analysis of sensory information that act simultaneously on all of the stimulus elements that are available at any given moment2. Integration of Features

SERIAL PROCESSING: steps in the process of sensory information that operate sequentially on the available sensory information

✖

∨Slide32

Support for Treisman’s Theory

OSlide33

Gestalt Principles of Perceptual GroupingSlide34

Gestalt Principles of Perceptual GroupingSlide35

Figure and GroundFIGURE: that which calls your attentionGROUND: the background

REVERSIBLE FIGURE: a visual stimulus in which any given part is seen sometimes as the figure and other times as the groundSlide36

The Whole Can Affect the Perception of the PartsIllusory Contours

Illusory Lightness Differences

Slide37

Biederman’s Recognition-by-Components TheoryOur visual system organizes the stimulus information into a set of basic, three-dimensional components (GEONS), and then uses the arrangement of those components to recognize the object

Slide38

The Man Who Mistook His Wife For A HatVISUAL AGNOSIA: condition caused by damage to specific portions of the occipital and temporal lobes of the cortex, in which people cannot make sense of what they see

VISUAL FORM AGNOSIA: a type of agnosia in which people can identify some elements of what they see but cannot perceive an object’s shapeVISUAL OBJECT AGNOSIA: a type of

agnosia

in which people can identify and draw the shapes of objects but cannot identify the objectsSlide39

Two Pathways of Visual Processing in the BrainThe “what” pathwayOccipital lobe  temporal lobe

Disrupts recognition of objectCan manipulate the objectThe “where and how” pathwayOccipital lobe  parietal lobeCan recognize the object but interaction with the object is disruptedSlide40

Cues for Depth PerceptionBINOCULAR DISPARITY: cue for depth perception that stems from the separate views the eyes have of any given object or visual sceneThe farther away the object is, the more similar are the two views of it

The degree of disparity between the two eyes’ views can serve as a cue to judge an object’s distance from the eyesSlide41

Monocular Cues for DepthMOTION PARALLAX: cue for depth perception that stems from the changed view one has of a scene or object when one’s head moves sideways to the scene or object

OcclusionRelative image size for familiar objectsSlide42

Monocular Cues for Depth

3. Linear Perspective4. Texture Gradient

5. Position Relative to the Horizon

6. Differential Lighting of SurfacesSlide43

The Role of Depth Cues in Size PerceptionSize Constancy

The Ames RoomSlide44
Slide45

Unconscious Depth Processing as a Basis for Size IllusionsThe Ponzo Illusion

The Müller-Lyer Illusion