Lecture 4

Question 1

what was Stanley Smith Stevens’ question

1906 - 1973

Answer 1

In proportion, how much more/less intense are two stimuli of different intensites perceived?
(with regard to fechner)

Question 2

what did stevens test

Answer 2

he wanted to test magnitudes

so fechner’s y axis was very broad/arbituary and stevens wanted to know actual numbers of stimuli

Question 3

what is the name of the equation stevens came up with

Answer 3

Stevens’ power law:

Question 4

what is Stevens’ power law:

Answer 4

R = aSb

Question 5

explain each of the parts inn R = aSb

Answer 5

R: Response
S: Stimulus magnitude
b: controls the curvature of the function
a: corrects for the scaling of measurement units used for S

Question 6

what is another variation of stevens power law

Answer 6

R = aψ ψ=Sb

Question 7

what is ψ:

Answer 7

Perceived intensity

Question 8

what was the problem with Stevens expierments

Answer 8

the modules

why do you choose the intensity and why do you tell participants it is that number of intensity?

Question 9

how did this issue that steven had become eliminated

Answer 9

absolute magnitude ratings

Question 10

what re absolute magnitude ratings

Answer 10

Absolute magnitude ratings: How intense is a percept in relation with two «absolute» boundaries?

0= no pain
100 = worst pain imaginable

Question 11

what is an issue the absolute magnitude ratings

Answer 11

it is difficult to imagine extreme pain

Question 12

what is the problem and solution to absolute magnitude ratings

Answer 12

Problem: is my «10/100» equal to your «10/100»

Solution: cross-modality matching

Question 13

what is cross-modality matching

Answer 13

use another sensory modality to rate a sensory perception

for example, match sweetness of coke to auditory sound
‘super sweet tasters’ right rate a coke slower in sweetness than normal people so then this was identified and they could do further research

Question 14

what are the nervous systems

Answer 14

Central Nervous System (CNS)

Peripheral Nervous System (PNS)
Nerves in the body

Question 15

what is included in Central Nervous System (CNS)

Answer 15

brain + spinal cord

Question 16

what is included in Peripheral Nervous System (PNS)

Answer 16

Nerves in the body

Question 17

what are the The Four steps of sensation and perception

Answer 17

Physical stimulus

1. transduction –> 2. transmission –> 3. perception

Question 18

what is transduction

Answer 18

The physical stimulus interacts with a specific receptor located on a peripheral sensory neuron and causes the neuron to fire, i.e. the stimulus is transduced into a electrical signal

Question 19

what is the Doctrine of specific nerve energies

Answer 19

A doctrine formulated by Johannes Müller (1801–1858) stating that the nature of a sensation depends on which sensory fibers are stimulated, not on how the fibers are stimulated.

Question 20

give an example of how the nature of a sensation depends on which sensory fibers are stimulated, not on how the fibers are stimulated.

Answer 20

when you eat something minty (methane) it feels cold but it actually not the sensory fibres for cold are just stimulated which makes you think it is cold

same with heating a hot pepper

Question 21

who came up with the Doctrine of specific nerve energies

Answer 21

Johannes Müller

Question 22

what is important to understand about action potentions

Answer 22

they are an all or non phenomenon

Question 23

what are the different types of actions potentials

Answer 23

no stimulus, weak stimulus, strong stimulus

Question 24

what happens to the neurones in no stimulus

Answer 24

there is a baseline firing that happens in our nervous system, so it fires occasionally but nothing out of the ordinary

Question 25

what is the Second step in physical stimulus -

Answer 25

transmission

Question 26

what is transmission

Answer 26

The signal is transmitted to the brain

Question 27

what is the only stimulus to have sensors in the spinal cord

Answer 27

pain

all others transmit directly to their respective locations

Question 28

what are the types of nerves that go to the brain

Answer 28

sensory and motor

Question 29

what nerves do we have to focus on in this class

Answer 29

sensory

Question 30

what are the sensory nerves

Answer 30

optic (vision)
olfactory (smell)
trigeminal (face, touch and pain sensation in face)
Facial (tongue, soft palette)
Vestulochoclear (spatial orientation, balance, hearing)
glossopharyngeal (posterior tongue, tonsils, pharynx, pharyngeal muscles)
vagus (internal organs and orgasms; heart, lungs, gastrointestinal tract, bronchi, trachea, larynx)

Question 31

what is the third step in sensation and perception–perception

Answer 31

The signal reaches the cortex and produces a counscious perceptual experience.

Question 32

what is the fourth step in sensation and perception

Answer 32

modulation

Question 33

what is included in modulation

Answer 33

Cognitive factors, like expectations, attention, etc. will influence how sensations are perceived.

e. g. Top-down vs bottom-up processing
e. g. Bayesian prediction process

Question 34

give an example of a bottom up process

Answer 34

you see a light and then the nerves fire and go to your brain and you perceive a light

Question 35

give an example of a bottom down process

Answer 35

you take a placebo, you think it is real and it impacts your brain to believe something is happening

Question 36

what is the Bayesian prediction process equation

Answer 36

P(A | B) = P(B | A) P(A) / P(B)

Question 37

explain the parts to the Bayesian prediction process equation

Answer 37

P(A|B) = Probability of A (e.g. having cancer) given B (e.g. test is positive)
P(B | A) = Probability of B (e.g. test is positive) given A ( e.g. having cancer)
P(A) = Probability of A (e.g. having cancer)
P(B) = Probability of B (e.g. test is positive)