PSY368 Section 1

Question 1

Sensation (definition)

Answer 1

input about the physical world obtained by our sensory receptors

Question 2

Perception (definition)

Answer 2

the process by which the brain selects, organizes, and interprets these sentations

Question 3

The first contact between the organism and environment is known as

Answer 3

sensation

Question 4

Transduction (definition)

Answer 4

the conversion of environmental energy into neural energy (energy from the environment activates receptors in our sensory systems)

Question 5

Sensory transduction energy vs. sense

Answer 5

Light - vision
vibrations in air molecules - hearing
mechanical energy - touch
chemical energy - smell, taste

Question 6

We can only perceive forms of energy that

Answer 6

can be transduced by our sensory systems

Question 7

What is the stimulus for vision?

Answer 7

electromagnetic radiation

Question 8

Wavelength (definition)

Answer 8

the distance between two consecutive peaks of a wave

Question 9

The visual spectrum

Answer 9

~ 350 - ~700 nm

Question 10

Perception is influenced by

Answer 10

memory, context, meaning, and experience

Question 11

Perception is a function of

Answer 11

the neocortex

Question 12

The neocortex can be referred to as

Answer 12

the interpretation machine

Question 13

Relationship between action and perception

Answer 13

Perception guides action and action changes perspective (the perceptual cycle)

Question 14

Psychophysical level of perception

Answer 14

the relationship between an attended stimulus and a person’s perceptual

Question 15

Neurophysiological level of perception

Answer 15

relationship between an environmental stimulus and a neuron’s firing rate

Question 16

Perceptual Neuroscience level of perception

Answer 16

relationship between brain activity and a person’s perception

Question 17

What is the difference between environmental stimulus and attended stimulus?

Answer 17

With humans you know they are attending to a stimulus when the acknowledge it

Question 18

Does neural firing measure perception?

Answer 18

No. Neural firing will happen without any perceptual information given

Question 19

Primary visual cortex

Answer 19

responsible for early visual processing (first area in the neocortex that gets information from the eye)

Question 20

The cell body

Answer 20

where the nucleus, mitochondria, etc. are located

Question 21

Dendrites

Answer 21

appendages coming off the cell body meant to connect the signals from other neurons

Question 22

Axon

Answer 22

like an electrical wire that transmits signal from point A to point B within the neuron itselfT

Question 23

Terminal branches

Answer 23

bind on the dendrites of other neurons so as to communicate the neural signal to other neurons in the neural network

Question 24

Neural transmission (definition)

Answer 24

a combination of an electrical event which travels down the axon and is followed by a chemical event (neural signal firing)

Question 25

The electron potential of a neuron

Answer 25

Neurons are often referred to as "integrate-and-fire" meaning they sum their excitatory and inhibitory inputs and if there is a big enough positive number that means the neuron can potentially reach a threshold that will start the firing process

Question 26

Action potential

Answer 26

the primary method of neural communication

Question 27

A neuron is limited in its firing rate to only

Answer 27

1000 action potentials a second (usually 400-500)

Question 28

The synapse

Answer 28

the tiny gap between two neurons, typically between the terminal branches of one and the dendrites of another

Question 29

When the action potential reaches the end of the axon, it triggers

Answer 29

release of neurotransmitters from the terminal brnaches

Question 30

Excitatory and inhibitory signals are ___ by the post-synaptic neuron

Answer 30

summed

Question 31

An excitatory NT will tend to

Answer 31

increase the firing rate of a neuron

Question 32

An inhibitory NT will tend to

Answer 32

reduce the firing rate of a neuron

Question 33

We know that firing rate is related to the amount of action potential because

Answer 33

increase in excitatory NTs means lots of action potentials are happening compared to when it is not being released

Question 34

Single-cell neurophysiology

Answer 34

the experimenter records the activity of a single neuron in response to a stimulus

Question 35

Process of Single-Cell Neurophysiology

Answer 35

- electrode is inserted into a neuron and the firing rate is recorded - experimenter notes which types of stimuli make the neuron fire the best (neurons have preferred stimuli)

Question 36

Examples of tasks to study perception

Answer 36

Recognition/Identification Visual Search Detection Discrimination Magnitude Estimation

Question 37

Recognition/Identification Task

Answer 37

there is a relationship between a physical stimulus and your perception of the object (how you categorize it in memory) higher-level perception

Question 38

Visual Search task

Answer 38

using a target goal to guide your attention and recognize when the target is found higher-level perception

Question 39

Detection task

Answer 39

asked whether or not you can detect a pattern in a field of noise lower-level perception

Question 40

Discrimination task

Answer 40

asked to judge the difference between two stimulus (e.g. which of two lines is longer) lower-level perception

Question 41

Magnitude Estimation

Answer 41

estimate how much brighter one stimulus is compared to another lower-level perception

Question 42

The Weber fraction (k)

Answer 42

measure of discriminative power - the smaller the k, the more sensitive we are to stimulus changes

Question 43

Fechner's Law:

Answer 43

S = k log I

Question 44

Psychophysical scaling

Answer 44

The relationship between physical intensity and psychological magnitutde

Question 45

Perceptual compression

Answer 45

stimulus intensity increases faster than the perceptual magnitude (i.e. you perceive the stimulus as less intense than it is)

Question 46

Perceptual expansion

Answer 46

perceptual magnitude increases faster than the stimulus intensity (i.e. you perceive the stimulus as more intense than it actually is)

Question 47

Detection task question

Answer 47

What is the minimum intensity of a stimulus needed for perception

Question 48

Absolute Threshold

Answer 48

the minimum amount of energy needed for detection by a perceptual system

Question 49

Classical Threshold Theory

Answer 49

Predicts a "step" psychometric function - subjects never report detecting the stimulus at intensities below the threshold and always report intensities above the threshold (ideally)

Question 50

Psychometric function (definition)

Answer 50

relates stimulus intensity to the subject's detection rate

Question 51

Typically, the psychomtric function is shaped like

Answer 51

An S -- probability of detection gradually increases with intensity and then levels off

Question 52

Problems with classical threshold theory

Answer 52

relatively minor changes in how the task is worded were found to affect the psychometric function absolute detection thresholds are influenced by a person's bias

Question 53

Signal Detection Theory

Answer 53

uses a mathematical analysis of errors to separate decision factors from perceptual sensitivity

Question 54

Signal (definition)

Answer 54

activity in the perceptual system related to the stimulus that you are trying to detect

Question 55

Noise (definition)

Answer 55

activity in the perceptual system that is not correlated with the stimulus/signal (i.e. all that is not the signal)

Question 56

External noise

Answer 56

originating from outside the perceptual system

Question 57

Internal noise

Answer 57

originating from inside the perceptual system

Question 58

Detection improves as you,

Answer 58

increase the signal, decrease the noise, or both

Question 59

Noise is ___ distributed

Answer 59

normally

Question 60

Four potentially outcomes of SDT

Answer 60

Hit Miss Correct Rejections False Alarms

Question 61

Liberal bias

Answer 61

minimizes the misses but generates a lot of false alarms

Question 62

Conservative bias

Answer 62

minimizes false alarms but generates lots of misses

Question 63

Bias [does/does not] affect the separation of the noise and signal+noise distributions

Answer 63

does not

Question 64

Sensitivity (definition)

Answer 64

the ability to differentiate the noise from the signal+noise distributions

Question 65

When sensitivity is high

Answer 65

the separation between signal and noise is larger and detection is easier

Question 66

Results of Clark & Clark testing

Answer 66

although both groups had a liberal bias, the Westerners were more likely to respond that stimuli were painful compared to the Nepalese - higher pain thresholds were not due to an actual difference in pain sensitivity