Module 4 - Lesson 1

Question 1

Prosopagnosia

Answer 1

Face blindness; inability to recognize faces.

Question 2

Sensation

Answer 2

Our sensory receptors and nervous system transfer information from stimuli to the brain

Question 3

Perception

Answer 3

Our conscious understanding of the world around us based on stimuli; organization of input

Question 4

Bottom-Up Processing

Answer 4

Analysis begins with sensory receptors and works up to the brain (analysis starts at entry-level)

Question 5

Top-Down Processing

Answer 5

Perception drawn from both stimuli and our prior experience and expectations (information guided by higher-level mental processes)

Question 6

Psychophysics

Answer 6

The study of relationships between the physical characteristics of stimuli (eg. intensity) and our psychological experience of them.

Question 7

Absolute Threshold

Answer 7

The minimum stimulation needed to detect a particular stimulus 50% of the time.

Question 8

Explain signal detection theory.

Answer 8

Signal detection theory predicts how and when we detect the presence of a faint stimulus amongst background stimulation. This theory assumes that there is no single absolute threshold and that someone’s ability to detect a certain stimulus depends on a person’s experience, expectations, motivation, and level of fatigue. Measured as our ratio of “hits” to “false alarms.”

Question 9

Subliminal

Answer 9

Below someone’s absolute threshold for conscious awareness

Question 10

Priming

Answer 10

Predisposing someone’s perception, memory, or response by exposure to a stimulus; often unconsciously done.

Question 11

Is most of our information processing conscious or unconscious?

Answer 11

Unconscious; most processing occurs automatically outside of our consciousness.

Question 12

Does subliminal persuasion work? Why or why not? In what situations does subliminal persuasion work?

Answer 12

Subliminal persuasion has been proven to be ineffective. However, subliminal persuasion has been proven to have an effect on those who believe it works (“believing is perceiving”).

Question 13

Difference Threshold

Answer 13

The minimum difference between two stimuli required for detection 50% of the time. Experienced as a “just noticeable difference” (JND)

Question 14

Weber’s Law

Answer 14

Principle. To be perceived as different, two stimuli must differ by a certain percentage, not a constant amount (eg. change volume by 6% instead of 6 dB).

Question 15

Sensory Adaptation

Answer 15

Diminished sensitivity with prolonged exposure to stimuli.

Question 16

Why do we undergo sensory adaptation?

Answer 16

After constant exposure to a stimulus, our nerve cells fire less frequently.

Question 17

Transduction

Answer 17

The conversion of one type of energy to another; in sensation, stimulus energies are converted to neural impulses that our brains can understand and interpret

Question 18

What is the electromagnetic spectrum? Which frequencies are perceived as visible light by humans?

Answer 18

It is a spectrum comprised of all frequencies of electromagnetic radiation. Different wavelengths constitute different energies, and range from radio waves (longer wavelength) to gamma rays (shorter wavelength). Wavelengths between 400 and 700 nanometers are perceived as visible light by humans.

Question 19

What colors are represented by shorter wavelengths (higher frequencies)?

Answer 19

Bluish colors

Question 20

What colors are represented by longer wavelengths (lower frequencies)?

Answer 20

Reddish colors

Question 21

Amplitude

Answer 21

A wave’s height

Question 22

The amplitude of wavelengths affect a color’s _________; those with greater amplitude are brighter colors, and those with small amplitude are duller.

Answer 22

Intensity

Question 23

Hue

Answer 23

The color we experience, such as blue or green; a dimension of color determined by the wavelength of light

Question 24

Intensity

Answer 24

The amount of energy in a light or sound wave, which we perceive as brightness or loudness

Question 25

Pupil

Answer 25

A small adjustable opening through which light enters the eye

Question 26

Iris

Answer 26

Colored muscle surrounding the pupil that constricts and dilates to permit different amounts of light to enter through the pupil. May be responsive to emotions as well

Question 27

Lens

Answer 27

A transparent structure behind the pupil that changes shape in order to help focus images on the retina

Question 28

Retina

Answer 28

The light-sensitive inner surface of the eye which contains receptor rods and cones in addition to layers of neurons that begin the processing of visual information.

Question 29

Accomodation

Answer 29

The process by which the eye's lens changes shape to focus near or far objects on the retina.

Question 30

What do receptor rods do?

Answer 30

Detect black, white, and gray. Particularly useful for peripheral and twilight vision, where cones do not respond as well.

Question 31

What do receptor cones do? Why are they less helpful in our peripheral vision?

Answer 31

Cones detect color and function in well-lit conditions. They are concentrated in the fovea and so there is less effective color vision in our peripheral eyesight.

Question 32

Optic Nerve

Answer 32

The nerve that carries neural impulses from the eye to the brain; made up of the axons of ganglion cells and transmits messages to the visual cortex (via the thalamus) in the brain.

Question 33

Blind Spot

Answer 33

Area where the optic nerve leaves the eye, leaving an empty area in our vision that is filled in by the brain; there are no receptor cells here.

Question 34

Fovea

Answer 34

Central focal point in the retina, around which the eye's cones cluster.

Question 35

What forms the optic nerve?

Answer 35

Ganglion cells in the eye converge to form a cord: the optic nerve.

Question 36

Bipolar Cells

Answer 36

Are triggered by rods and cones, and trigger the neighboring ganglion cells.

Question 37

Compare rods and cones.

Answer 37

Cones: 6 million, located in the center of the retina, low sensitivity in dim light, high color sensitivity, and high detail sensitivity. Rods: 120 million, located in periphery of retina, high sensitivity in dim light, low color sensitivity, and low detail sensitivity.

Question 38

Feature Detector

Answer 38

Nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle, or movement.

Question 39

Parallel Processing

Answer 39

Processing many aspects of a problem simultaneously. Parallel processing is the brain's natural mode for information processing for many functions, including vision. Contrasts with step-by-step (serial) processing used in conscious problem solving.

Question 40

How does parallel processing work in reference to vision?

Answer 40

The brain breaks a visual scene into subcategories, such as movement, color, form, and depth, and interprets them simultaneously before reassembling them.

Question 41

Young-Helmholtz Trichromatic Theory

Answer 41

Theory that the retina contains three different color receptors (red, green, and blue) that can produce the perception of any color when combined.

Question 42

Opponent-Process Theory

Answer 42

Theory that opposing retinal processes (red-green, blue-yellow, black-white) enables color vision. Eg. some cells are stimulated by green and inhibited by red and vice versa.

Question 43

Compare the Young-Helmholtz and Opponent-Process theories: how do they compare? Which better explains afterimages and why?

Answer 43

Trichromatic color theory better explains afterimages because it shows that one component of a receptor pair can tire. Eg. if you were to look at a green dot for too long, the corresponding color, red, would appear when you look away.