Perception

Question 1

what are the three physical dimensions of sound and how do these determine what we hear

Answer 1

frequency amplitude and complexity

determine pitch loudness and timbre

Question 2

what is complexity of sound

Answer 2

mix of frequencies at the same time, relative to its complexity, more frequencies we experience at once relates to an increase in complexity and a perceptual equivalent of timbre.

Question 3

can 262 hertz look different on a frequency graph

Answer 3

yes because frequencies included in 262 hertz for different musical instruments have different complexities

Question 4

what is the idea of the least common denominator (LCD)

Answer 4

with complex periodic sounds with a harmonic structure the frequencies in it are all multiples of a single number the LCD. complex sounds with all components sharing an integer LCD

Question 5

if a complex sound has all components sharing an integer LCD what is the structure

Answer 5

harmonic structure

Question 6

what is the fundamental frequency

Answer 6

it is the lowest frequency component of the sound - if it was removed from the audio recording of 250hz, with the fundamental frequency removed you can still perceive it as 250hz as all other frequencies are a multiple of that

Question 7

what is masking

Answer 7

if have a sound of particular amplitude and frequency, add a masking sound which covers up the others as we don’t detect the others anymore, it raises the absolute threshold of sound by its presence, this area is called a masking area.

Question 8

how does sound move through the ear

Answer 8

Sound changes in air pressure comes along auditory canal to ear drum, connected to bones then to the cochlea. Cochlea has connections to the auditory nerve. We are interested in the cochlea

Question 9

how does auditory transduction occur

Answer 9

inside the cochlea is the basilar membrane which has hairs on it and bends depending on frequency of the sound, the membrane base responds to high frequency sounds, the tip of the membrane responds to low frequency sounds, the middle = medium frequency. Small hairs fire diepending upon the frequency and amplitude.

Question 10

what is the purpose of the hair cells in the basilar membrane

Answer 10

they are mechanoreceptors that transduce vibrations of the basilar membrane
they send electrical signals to the brain through the auditory nerve
Mechanoreceptors are the Sensory instruments that allow us to perceive the physical properties of the sound as perceptual ones.

Question 11

how does the location of the hairs matter

Answer 11

each part of the basilar membrane vibrates to a particular frequency
frequency is highest at the base (oval window) and lowest at the tip (apex) of the cochlea
each hair cell signals the amplitude of one narrow range of frequencies in the sound

Question 12

what is loudness based on

Answer 12

the firing rate of the hair cells

amplitude has to increase ten times for us to perceive a four fold increase in loudness so its not proportional

Question 13

what is the maximum range of frequencies a person can hear

Answer 13

range of frequencies which a person can hear is approx 20 Hz – 20 kHz

Question 14

why does the maximum range of frequencies a person can hear differ

Answer 14

It changes with age when in older ages see further and further reductions in the sound range being heard, logarithmic scale used, for every ten increase in decibels the sound energy increases by 10x from 80 to 90. not perceived this way though, it is perceived as a four fold increase. The threshold shows where could lose our hearing.

Question 15

what is sound

Answer 15

waves of changing pressure travelling through a medium (air)

Question 16

how do we see a speaker make noise

Answer 16

when speaker off there is no movement of the speaker and the ambient pressure is constant. When speaker is on and playing music string moves forward and backward, moves forward = high pressure moves back = low pressure

Question 17

what does a pure tone have

Answer 17

an amplitude - the maximum air pressure in each cycle

a frequency - the number of cycles of changing air pressure per second

Question 18

what is frequency measured in

Answer 18

hertz - This has time and pressure, area of high to low returns to l=ambient pressure = one cycle. Height between high and ambient level = amplitude, frequency = how many cycles per second..

Question 19

in a pure tone what is the equivalent to frequency

Answer 19

the perceived pitch

Question 20

what do natural sounds consist of

Answer 20

natural sounds consist of pure tones of many frequencies added together

Question 21

what is the perceptual equivalent of amplitude

Answer 21

loudness

Question 22

perceptual equivalent of frequency

Answer 22

pitch

Question 23

what is visual vestibular integration

Answer 23

• Visual cues indicate we are rotating (head over heels)
• Vestibular information is contradictory (we are not falling over)
• We experience “tilting” a compromise of the two sensations.

Question 24

is what we hear always determined by sound energy reaching the ears

Answer 24

vision also located the source of the sound. visual and auditory info is usually congruent but we can artificially split them using a pseudophone

Question 25

how do we test the influence of the visual field on the location of sound

Answer 25

the pseudophone, left tube goes to right ear and vice versa, have someone drop something on the right but sound comes from the left, close eyes, drop something on right they will point to the left as sound origin, with eyes open they point to the correct side. Visual information can determine where we perceive the sound is coming from mcgurk effect is an example.

Question 26

how is perception of flavour effected by other senses

Answer 26

signals from 4 other receptor types
1) Olfactory receptors in the nose (effects of a blocked nose)
2) Light receptors in the eyes (effects of colouring food/drink with tasteless dyes)
3) Touch receptors in the mouth (crunchiness affects flavour)
4) Sound receptors in the ears (flavour of crisps changes if the sound of your own chewing is manipulated)
process of integration is unconscious – we experience

Question 27

from the cortex there are two visual streams with different functions what are htey

Answer 27

dorsal stream (to superior parietal lobe) the where system, binocular information, egocentric, unconscious

ventral stream (to inferior temporal lobe) - the what system, identify objects and events, allocentric, conscious

Question 28

what are the specialised areas of the brain for processing certain types of stimuli

Answer 28

• FFA: Fusiform Face Area. Responds to faces more than other objects
• PPA: Parahippocampal Place Area. Responds preferentially to places, such as pictures of houses
• EBA: Extrastriate Body Area. Specifically involved in the perception of body parts

these are highly responsive to specific stimuli but not others

Question 29

what was the study on recording the activity of one cell in the temporal lobe of a human patient

Answer 29

Study with ppt with epilepsy, surgical operation took place and while happened took part in the study, put small electrodes into specific cells, they found there was a cell that responded to Jennifer Anniston. Another picture of her gives another response, if shes with brad pitt less response then different person no response from the same cell. Specific cell responds to the specific stimui. Another ppt had a halle berry area. Shows there is highly specialised areas that respond to different things, study hypothesises even particular cells or neurons. People tend to dismiss this.

Question 30

how were the two visual systems of the frog demonstrated

Answer 30

Frogs visual system, the lesion in the tectum removed part of it causing some blindness in the field lateral to the lesion. After lesion it ignores prey in the blind field and ignore a large looming circle if presented in the area right to it on the picture. If it was touched on its back it will jump away in the opposite direction. When do it to the frog still jump to blind field but could also avoid obstacles and can adjust jump to avoid most efficiently. Edge of object determined where jumoed but did not respond to prey or predators, blind to some stimuli. But not others.

Question 31

how is optic ataxia evidence for the two systems

Answer 31

People with brain damage, damage along dorsal stream and specifically optic ataxia have an intact ventral stream for identifying things. Related to motor things, have diff moving towards targets. More diff pointing to things immediately. Individuals with optic ataxia have problems with reaching challenges

Question 32

what are the symptoms of optic ataxia

Answer 32

No difficulty identifying visual stimuli
Difficulty moving towards target
More difficulty in pointing without delay (‘immediate’)

Question 33

what are the symptoms of visual agnosia

Answer 33

Incapable of recognising faces, objects, shapes and sizes
Capable of drawing from memory Incapable of copying picture or
recognising own drawing

Question 34

how does visual agnosia present evidence for the two visual systems

Answer 34

Ventral stream. Struggle to copy don’t know what they are seeing but can draw same thing if they use their memory.
presented with images and shows the copy and the memory conditions.

Question 35

what could df with visual agnosia do

Answer 35

Negotiates obstacles during locomotion
Poorly estimates height of obstacles (verbal response)
Highly proficient at grasping – appropriate hand orientation and grip aperture.

Question 36

what was the example of DF abilities from the case study

Answer 36

Two conditions where df asked to do something, presented slot to put something in to not asked to post it but just indicate which orientation she would use to post it. Performance here was poor coukdnt perceive the correct orientation

But in the posting condition she could actually do it

Question 37

what is the ebbinghaus illusion

Answer 37

Two circles in middle the same exact size but consistently misinterpreted as different sizes. Ask which is bigger or are they the same size. If measure the grip aperture when go to pick it up the hand goes to the same size, the perceptual system is fooled but the online control system isn’t fooled.

Question 38

what is change blindness

Answer 38

observer fails to notice a large change to something

Question 39

how is not paying attention to everything in the visual field an evolutionary adaptation

Answer 39

Perceptual system has an evolutionary origin, doesn’t make sense to process every object in environment. Rather than storing highly detailed representation it is better to have a general grip on the scene then focus into the information we need.

Question 40

what is attention

Answer 40

We cannot process everything that falls onto the retina, mechanism to decide what is attended to and what isn’t

Question 41

what are the varieties of attention

Answer 41

external - attending stimuli in outside world
internal - attending to one line of thought over another or selecting one response over another
overt - directing a sense organ toward a stimulus like pointing your eyes or turning head
covert - attending without giving an outward sign you are doing so
divided - splitting attention between two different stimuli
sustained - continuously monitoring some stimulus

Question 42

what is visual attention

Answer 42

selection of some visual stimuli at the expense of others for further visual and cognitive analysis and often for control of behaviour

Question 43

what is the spotlight model

Answer 43

attention is like a spotlight which moves about and allows us to selectively attend to things
michael posner suggested enhanced processing occurs in this spotlight
attention directed towards space
space based model

Question 44

what is the zoom lens model

Answer 44

the attended region can grow or shrink depending on the size of the area to be processed

Question 45

what experiment did posner do

Answer 45

Ppt shown two boxes and a point in between them. Eyes fixed on the centre cross, targets may appear in the boxes, ppt have to indicate with keyboard which box the target has appeared in. Eyes don’t move from the centre cross. There is a queueing process, before the target appears one of the boxes are highlighted, this queued their spatial spotlight of attention to the highlighted box, if the highlighted box is then the one with the target they identify it faster as their attention was already queued on the highlighted box. If target appears in the non highlighted box the response is slower.

Question 46

what did posner want to know from his experiment

Answer 46

Posner and colleagues wanted to see if shifting attention improved processing of the following stimulus. Finding that processing is faster when have a valid cue or is more accurate has been found in many studies. And in different parts of the visual field. Posner was looking at covert attention as the attention was forced to be on the cross

Question 47

what are the various types of visual searching

Answer 47

feature search - target defined by presence of a single feature e.g one colour e.g red line

conjunction search - target defined by a conjunction (co-occurence) of two or more features

spatial configuration search - the target and distractors contain the same basic features

Question 48

how are visual slopes measured and what do the results mean

Answer 48

efficiency of visual search is the average increase in reaction time for each item added to the display

measured in terms of search slope or ms/item

the larger the search slope the less efficient the search

some searches are efficient and have small slopes

some searches are inefficient and have large slopes

Question 49

what is the binding problem

Answer 49

when different attributes are combined that are handled by different brain circuits we perceive a unified object but this is harder for us to find in a search as the characteristics are not combined automatically.

Question 50

what was treisman feature integration theory

Answer 50

theory of visual attention
limited set of basic features can be processed in parallel preattentively but other properties including the correct binding of features require attention

Question 51

what is the preattentive stage

Answer 51

the processing of a stimulus that occurs before selective attention is deployed to the stimulus

Question 52

what is the illusory conjunction

Answer 52

evidence that features are represented independent of each other and combined

it is an erroneous combination of two features in a visual scene e.g seeing red x when the display contains red letter and x but not red xs

Question 53

what is the problem with conjunction of features for the spotlight theory

Answer 53

attention appears to be object based not spatially based, if superimpose one object on top of another it is possible to attend to one and not the other even though they are in the same spotlight

Question 54

what does covert attention allow us to do

Answer 54

process to some extent without eyes being directly focussed onto something

Question 55

what is the bottom up model of attention

Answer 55

saliency models - = edges, colour brightness attract our attention in free view, this is a bottom up manor, seeing what captures attention from the environment.

Question 56

what are the problems with saliency models

Answer 56

Important info may not be salient, e.g stop signs in a cluttered env
Salient info may not be important e,g retinal image transients from eye/body movements
Doesn’t account for many observed fixations especially in natural behaviour

Question 57

what is the top down model for attention

Answer 57

not free view any more but have specific goals within the view. Given a goal of walking somewhere in the scene you would see a difference in where people direct their attention in the image. E.g how get to the door of the house. Changing the parameters of what is required changes their attention.

Question 58

why do we move our eyes

Answer 58

We have a limited area of high acuity on our retina. Need to place the image of the object of interest on the part with the highest acuity the fovea. Keep the image in the eye stationary despite the movement of the object or ones head.

Question 59

what was the design of the yarbus study

Answer 59

The unexpected visitor – painting used in a study by Yarbus who discovered that gaze behaviour dependent on the goal. He recorded gaze patterns of people depending on what they were told to look at. Given different tasks which resulted in a different scan path, they are dependent on each other. Supports that attention is top down driven.

Question 60

what were the results from the Yarbus experiment

Answer 60

The human eyes voluntarily fixate on those elements of a visual scene that carry essential and useful information.
The more information is contained in an element the longer the eyes stay on it
The distributions of fixations on the elements of a scene changes depending on the purpose of the observer.
People who think differently also to some extent see differently.

Question 61

describe the Land and Macleod study

Answer 61

Compared novice bats men and professional batsman. The smoother line is the path of the ball. The batsman follows the ball then shift to the bounce point then follow it more, someone throws the ball the ball is very fast, can not use smooth pursuit as its too fast, they shift their eyes using saccades. Fastest movement we can make with our body, they move to wait for the ball on the bounce point. Experts stop trying to track it sooner than novices who are usually late to the point at which it bounces. Use previous expertise on the situation to guide gaze.

Need to get through a long process from the eyes to the brain, one trip is 200 msec and the ball takes only 600msec so prediction gets around this problem

Question 62

what did brunswik think was important for a representative design

Answer 62

should be sampling from the natural environment. Organisms adapt to their natural environment it is important that experimental stimuli are sampled from the organisms natural environment.

Visual search for arbritrary objects is not very efficient, scene based guidance would help you find the object e,g search for a tap in the scene.
In real world searches the real world guides visual search, scene based guidance, information in our understanding of a scene that helps us find specific objects in scenes. For instance a mug or a bowl will typically be found on a horizontal surface and a picture on a vertical surface.

Question 63

what is cognitive ethology (kingstone et al)

Answer 63

Cog ethology advocated the study of behaviour under realistic conditions. Originally applied to animal behaviour. Maybe studying things under artificial conditions isn’t the best.

Question 64

researchers conducting lab experiments assume two things what are they

Answer 64

1) The processes that subserve cognition are invariant and regular across conditions.
2) Situational variability can be reduced or eliminated without affecting the nature of the process being measured.

Question 65

what are the restrictions of lab experiments

Answer 65

• 2d
• Limited resolution
• Size of the display
• Unnatural responses
• Constrained head movements

Question 66

what was the savelsbergh et al football study about

Answer 66

looked at gaze of goalkeepers during a simulation of a penalty kick

incorrectly assumed that behaviours observed during the simulation were invariant and therefore representative of real world behaviour

gaze at hips in the simulation

Question 67

Dicks et al tackled the issues with savelsbergh study

Answer 67

repeated but included real world condition
simulation found same thing, looked at hips
real world cond they looked at the ball the entire time