3 - Sensation and Perception

Question 1

Sensation

Answer 1

The result of neural responses that occur after physical energy stimulates a receptor cell - BEFORE the stimulus is organized and interpreted by the brain

Question 2

Perception

Answer 2

The result of neural processes that organize (eg, specifiying shape) and interpret (indentifying the object) information conveyed by sensory signals

Question 3

Visual Perception (2 things)

Answer 3

1. Organization into coherent units (size and location)

2. Identifying WHAT and WHERE

Question 4

Psychophysics

Answer 4

Studies the relation between physical events and the corresponding experience of those events

Question 5

Threshold

Answer 5

The point at which stimuli activate receptor cells strongly enough to be sensed

Question 6

Absolute threshold

Answer 6

The magnitude of the stimulus needed, on average, for an observer to detect it half the time it is present

Question 7

Just-noticeable difference (JND)

Answer 7

the size of the difference in a stimulus characteristic needed for a person to detect a difference between to stimuli (or a change in one stimulus)

Question 8

Weber’s Law

Answer 8

The rule that the same percentage of a magnitude must be present in order to detect a difference between two stimuli
eg gaining 5lbs when you weigh 100lbs vs 500lbs –> one is noticeable, one isn’t, even though it’s the same change

Question 9

Signal detection theory

Answer 9

Theory of how people detect signals, which distinguishes between sensitivity and bias. Signals are always embedded in noise, the challenge is distinguishing the signals from the noise

Question 10

Signal noise

Answer 10

Arises from other stimuli in the environment

and from random firing of neurons

Question 11

Sensitivity

Answer 11

The amount of information needed to detect a signal (greater sensitivity, less information required)

Question 12

Bias

Answer 12

Willingness to decide you have detected a target stimulus

Question 13

Transduction

Answer 13

The conversion of physical energy into neural signals by a sernsory receptor cell

Question 14

Accomodation

Answer 14

The automatic adjustment of the eye for seeing at particular distances, which occurs when the muscles adjust the shape of the lens so that it focuses incoming light towards the back of the eye

Question 15

Retina

Answer 15

The part of the eye that contains receptor cells - a sheet of cells as thick as a piece of paper at the back of the eye

Question 16

Fovea

Answer 16

The small central region of the retina with the highest density of cones and the highest resolution

Question 17

Rods

Answer 17

retinal receptor cells that are very sensitive to light but only register shades of grey. Each eye has ~100-120 million rods

Question 18

Cones

Answer 18

Retinal receptor cells that respond most strongly to one of three wavelengths of light. Combined signals from cones produce color vision ~5-6 million cones

Question 19

Optic nerve

Answer 19

The large bundle of axons carrying neural signals from the retina to the brain (about as thick as your little finger)

Question 20

Dark adaptation

Answer 20

The process that leads to increased sensitivity to light after being in the dark. (opening of pupils, rods release rhodopsin)

Question 21

Trichromatic theory of color vision

Answer 21

The theory that color vision arises from the combinations of signals from three different kinds of sensors, each of which responds to a different wavelength

Question 22

Opponent process theory of color vision

Answer 22

The theory that for some pairs of colors, if one is present, it causes cells to inhibit sensing the complementary color (such as red vs green)

Question 23

Colorblindness

Answer 23

Common cause: the filtering substance is the same for both red and green cones

Question 24

Perceptual constancy

Answer 24

The perception that the characteristics of objects remains the same even when the sensory information striking the eyes changes.

Question 25

Top-down processing

Answer 25

Guided by knowledge, expectation, or belief

Question 26

Bottom-up processing

Answer 26

Triggered by physical energy striking receptor cells

Question 27

Attention

Answer 27

The act of focusing on particular information, which allows it to be processed more fully than what is not attended to

Question 28

Selective attention

Answer 28

Picking out and maintaining focus on a particular quality, object, or event, and ignoring other stimuli or characteristics of the stimuli

Question 29

Perceptual set

Answer 29

The sum of assumptions and beliefs that lead a person to expect to perceive certain objects or characteristics in certain contexts

Question 30

Blindsight

Answer 30

The neural pathway that bypasses the primary visual cortex and leads directly to the parietal lobe—subconscious vision

Question 31

Attentional blink

Answer 31

A rebound period in which a person cannot pay attention to a second stimulus after having just paid attention to another one (not necessary the same stimulus)

Question 32

Cocktail party phenomenon

Answer 32

The effect of not being aware of other people’s conversation until your name is mentioned and then suddenly hearing it

Question 33

Balint’s Syndrome

Answer 33

1. inability to perceive the visual field as a whole (simultanagnosia),
2. difficulty in fixating the eyes (oculomotor apraxia),
3. inability to move the hand to a specific object by using vision (optic ataxia).

Question 34

Associative agnosia

Answer 34

Conscious percept stripped of meaning
Left hemisphere
Can’t say what they draw

Question 35

Apperceptive Agnosia

Answer 35

Failure to construct a percept from sense data
Right hemisphere
Can’t draw what they see

Question 36

Retinotopy

Answer 36

Mapping of sensory neurons to occipital lobe

Question 37

Gestalt Laws of Organization

Answer 37

Proximity, Continuity, similarity, closure, and good form

Question 38

Dichotic listening

Answer 38

When different messages are provided to each of the two ears and the person is asked to listen to only one. Even so some of the information from the ignored year is processed

Question 39

Chemical senses

Answer 39

Smell and taste. Rely on sensing the presence of specific chemicals

Question 40

Pheromones

Answer 40

Chemical substances that serve as a means of communication. Like hormones-modulate functions of various organs. Released outside the body

Question 41

Somasthetic senses

Answer 41

Senses that produce the perception of the body and its position in space.
Kinesthetic
Vestibular
Touch
Temperature sensitivity
Pain
Magnetic sense

Question 42

Kinesthetic sense

Answer 42

The sense that registers the movement and position of the limbs

Question 43

Vestibular sense

Answer 43

The sense of balance or information about the body’s orientation relative to gravity

Question 44

Double pain

Answer 44

The sensation that occurs when an injury first causes a sharp pain and later a dull pain. Arises from two different neural pathways sending the messages at different speeds

Question 45

Gate control

Answer 45

The mechanism that allows top down processing to inhibit interneurons that send pain signals to the brain