Sensation and perception

Question 1

what is attention?

Answer 1

attention is the ability to preferentially process some parts of stimulus at the expense of other parts of stimulus.giving more of your “attention” to one object over another means that you will percieve that object greater to others.

Question 2

What are the 2 types of attention?

Answer 2

Overt attention:involves directly looking at an object

Covert attention: Involves looking at one object but attending to another, often through your peripheral vision.

Question 3

what is attention needed?

Answer 3

-Perception system has limited capacity, not everything can be processed at once.
-attention can avoid us becoming overwhelmed.

Question 4

how is where someone’s attention is determined?

Answer 4

-Often determined through an individual’s eye movements. When an individual has their attention on something they are said to “fixate” on it. Fixations are determined by foals and expectations.
-between fixations, individuals often experienced rapid eye movements these are known as “saccades”

Question 5

What directs an individual’s attention?

Answer 5

Attention is dictated by 2 different processes.An involuntary and voluntary process.

-Initial process is involuntary, guided by attentional capture which is the saliency of an image (saliency=quality of being noticeable i.e. bright colors)
-However, the subsequent process is involuntary guided by your expectations and goals. (what you find interesting/appealing)

The “saliency” of an object is often determined by
-Contratst/luminance
-size/texture
-orientation
-motion

Question 6

What are the effects of attention?

Answer 6

-Attention speeds up the response to stimuli
-It can influence opinion (i.e effect the contrast of an image)
-Can change the appearance of an object, making perception more vivid.
-Can influence psychological responses.

Question 7

What is the binding problem?

Answer 7

-The idea that different aspects of stimulus are processed independently in different parts of the brain
-Meaning that this causes an issue of how objects individual features are combined to create a bound/coherent perception. Consequentially known as the binding problem.

Question 8

What does the feature integration theory determine about the binding problem

Answer 8

-Suggests that the binding problem can be solved, by just focusing on one object at a time.
-This therefore means that only features associated with only one location are processed and only those features can bind together, avoiding the binding of different features of different objects.

Question 9

what are illusory conjunctions, what do they aim to do?

Answer 9

Aims to prove the feature integration theory, suggesting that if attention is inhibited then features of different objects will be incorrectly bound together.
-Illusory conjunctions occur when an individual is unable to focus on just a single object often caused by damage to the parietal lobe.

Question 10

how does visual search work in relation to the binding problem?

Answer 10

Conjunction searches, which are a form of visual search that require the binding problem to be solved are often slow.Conjunction searches, the target shares a feature with the distractor making it more complicated.

whilst…….

Feature searches that dont require the binding problem to be solved are often fast.Feature searches contain a feature that the distractors do not contain.

Question 11

What is change blindness?

Answer 11

-the idea that only few things in a scene can be remembered at one time (typically 4), if something were to change and it was not an object of attention, we would not recognize this change.
-for change blindness to occur, the change needs to be missed when attention is not drawn, but must be recognised when attention is drawn.

Question 12

what are motion transients and how do they relate to change blindness?

Answer 12

-Can be challenging for change blindness to occur because, changes typically draw attention to the location of the change even if the exact change is not known. However this drawing of attention does make it easier to notice.

Question 13

Who showed evidence for illusory conjunctions, what did the findings suggest?

Answer 13

-Triesman and schmidt, presented character strings masked by noise briefly.Primary tasks of O’s (Observers) were asked to report the coloured letters. Observers associated the wrong letters with the wrong numbers indicating illusory conjunctions.

Question 14

What are the problems associated with object scene and perception?

Answer 14

Perception is complex, computers are unable to replicate human perception as of yet. This is because;

-Stimulus on retina is ambigious (same 1d and 2d image is ambigious, since multiple stimuli can produce same image)
-objects can be hidden/blurred
-objects look different from different angles,viewpoints and poses.

Question 15

what are the 2 solutions to the difficulties associated with the complexities of perception?

Answer 15

-2 solutions are known as structuralism and gestalism

Question 16

what does structuralism suggest about perception?

Answer 16

Structuralism suggests that conscious awareness is the sum of sum of sensation and awareness (elementary sensation) because of this it suggests that these perceptions contain nothing that wasn’t already present within the elementary sensations. Structuralism states that sensations combine to form perception.

Question 17

What are sensations and what are perceptions?

Answer 17

Sensations: Elementary processes that occur in response to stimulation

Perception: Conscious awareness of objects and scenes.

Question 18

what is gestaltism?

Answer 18

Gestaltism suggests that conscious awareness can have characteristics not present within initial elementary sensation (sensation and awareness).

Question 19

what evidence is there for gestaltism?

Answer 19

Apparent motion: Motion perceived even when an object is not moving.

Illusory contours: Contours can be seen for images that don’t have contours.

Therefore these phenomena support gestaltism by highlighting how these characteristics can be perceived although not actually physically present within the image.

Question 20

What are the competing solutions for perceptual organization? Name their definitions.

Answer 20

Grouping: Process by which images are bounded together to form a perceptual whole. (i.e. the perception of 1 object)

Segregation: Process of which parts of a scene are perpetually separated to form wholes. (i.e. the perception of 2 separate objects)

Question 21

what are Gestalts 5 key principles of grouping? (GPSPC)

Answer 21

(note: the more that apply the more likely a scene is to be perceptually organised)

-good continuation
-Prägnanz
-Similarity
-Proximity
-Common fate

Question 22

what do the elements of GPSPC mean?

Answer 22

Good continuation: aligned objects or objects that appear to share the same contour are grouped together, therefore its important for good continuation and clear contours to be present.

Prägnanz: “Good figure” groupings should occur to make an image as simple looking as possible

Similarity: More similar objects are, more likely they are to be grouped together.

Proximity:Closer objects are, more likely they are to be grouped together.

Common fate:Objects moving in the same direction are likely to be grouped together.

Question 23

what are the 2 additional elements of gestalts grouping?

Answer 23

-Common region: Elements in the same region of space are likely to be grouped together.

-Uniform Connectedness: Connected regions with the same visual features (i.e colours) will be grouped together.

Question 24

What are the principles of segregation? (also known as figural cues) FBCR

Answer 24

(note: objects need to be segregated from background and each other), being able to establish an image from its background occurs because of its figural properties these include;

-front of image
-Bottom of image
-Convex
-Recognisable due to experinece.

Question 25

What is gist perception? how does it aid perception?

Answer 25

-Observers can rapidly percieve an objects "gist" -minimum exposure time to perceive gist was 27ms, however longer periods of time allowed for greater perception's very accurate perception was established after 250ms.

Question 26

What is the function of motion perception?

Answer 26

-Help break camouflage -Help attract attention -Help segregate objects from the background. -Help us interpret events -Help us determine the structure and shape of objects -Help us determine what actions individuals are performing.

Question 27

What is life without motion perception called?

Answer 27

-Condition known as akinetopsia. -individuals who have experienced trauma or disease to certain parts of brain are unable to detect motion perception.

Question 28

When do we perceive motion?

Answer 28

-Real motion (when somethings moving) -Illusory motion (when something appears to moving but its not) -motion aftereffects -induced motion, when a nearby object usually large effects the perceived motion of another smaller object.

Question 29

What are examples of illusory motion?

Answer 29

-Static images: such as the rotating snake's illusion, perception of motion is created by contrasting colors. -Apparent motion: series of stationary images that when presented in succession appear to be moving. For apparent motion to occur, as separation increases alternation rate needs to decrease.

Question 30

What is motion induced blindness and motion induced change blindness?

Answer 30

-Whilst motion can make things more visible by breaking camouflage, it can also cause things to disappear. -Motion can also make it harder to notice changes.

Question 31

How does motion induced blindness and motion induced change blindness occur?

Answer 31

-Color changes typically attract attention because of the transient signals associated with change. -when objects are moving however, there are a plethora of transient signals associated with all objects, not just colour changes. -Consequentially, attention is no longer drawn to the changing objects, so the changes are not noticed.

Question 32

What are motion illusions?

Answer 32

-Motion illusions can inform us of the processes underlying motion perception. i.e -Footsteps illusion indicates color contrast effects motion perception. Higher contrast moves faster whilst lower contrast moves slower. -Aperture problem: Movement of a line is ambiguous if the ends of a line are covered. If the "terminators" covering the line move horizontally, the line appears to move horizontally as well. If it moves vertically, line appears to move vertically as well. -Barber pole illusion: Lines in a barber pole curve around a cylinder creating visual terminators that move horizontally, as a result the lines appear to move vertically.

Question 33

What is the function of colour perception?

Answer 33

-allow humans to search for things. (i.e to forge for berries) -colour perception can help people make judgements. (i.e is a banana ripe to eat) -It can be used for mating (peacocks)

Question 34

What are the physics of color?

Answer 34

-Color, is visible light. It's an electromagnetic radiation with wave lengths varying from 400nm to about 700nm. -White light is a mixture of all of these wavelengths (all lights together)

Question 35

how can color be thought of in relation to opaque objects?

Answer 35

-Opaque, means that light can pass through, cant see thru it. -Colour of an opaque object= light that it reflects.

Question 36

How can color be thought of in relation to translucent objects.

Answer 36

-Translucent, you can see through object. -Colour is determined by the light it transmits

Question 37

What is the Munsell color system?

Answer 37

Colours are categorized according to 3 categories: -Value (lightness) -Hue (colour) -Chroma (Saturation)

Question 38

What are cones and rods, when are they used?

Answer 38

Dark light=rods are used Normal light=cones are used -Retina has photoreceptors called "cones" and "rods" -Rods can't distinguish between colors, only active when dark. -Cones are therefore used during normal light conditions, distinguishing between colors.

Question 39

what is the trichromatic theory of color vision? (i.e. name the cones and their respective wavelengths and colors) note: that the names respond to short, medium and long cones

Answer 39

there are 3 types of cones: each type responds differently to different wavelengths of light. - S cones:419 nm (blue) - M cones:531 nm (green) - L cones:558 nm (red) whichever cone is most active, will correspond with what color light will most prevalent.

Question 40

How does colour matching work, using the trichromatic theory of colour to explain?

Answer 40

- if for example you have pure green light, of 500nm it would strongly activate the M and L cones. Therefore, to colour match, we can match the cone activations.

Question 41

what are the 2 types of colour deficiency?

Answer 41

Monochromatism: -Rare type of colourblind, can only see black and white, sees world in shades of grey -Occurs because they have no functioning cones, Dichromatism: -Individual who is lacking 1 of the 3 types of cones.

Question 42

what are the 3 types of cones?, what cone letter is absent?, and what color is affected?.

Answer 42

protanopia: L cone absent. Cant distinguish, red and green. Deuteranopia: M cone absent. Cant distinguish, red and green either. Tritanopia: S cone absent. Cant distinguish between blue and green. protanopes and deuteranopes see the world in shades of blue and yellow-ish green. Whilst tritanopes see the world in shades of blue and red.

Question 43

Describe what the Opponent-process theory of color vision means

Answer 43

-colour isint only determined by the cones in our retina but also the signals from these cones processed by the retina. -Signals are broken up into 3 colour-oponnent channels: red and green blue and yellow white and black

Question 44

what evidence is provided for the opponent color theory?

Answer 44

evidence of 3 channels includes; -Afterimages -impossible colors After images: overtime the original cones habituate and become less sensitive, eventually when a white stimulus is shown, the opposite cones will respond stronger. Impossible images: Some color combinations are impossible, bluish yellow and reddish green can't be perceived blue and yellow light are added together, would just create white light. Blueish yellow is impossible because they are opponent colors.

Question 45

what is color constancy:

Answer 45

-Color of object is not only determined by its reflectance but also by how light shines on it. -The light reflected by an object is determined by the product of its reflectance and illumination. (Reflectance x illumniation = reflected light)

Question 46

what are the 2 ways in which colour constancy occurs?

Answer 46

Can occur through habbituation or through "discounting the illuminate" -Habituation, refers to the process of which an individual habituates(becomes less sensitive) to colour. -Discounting the illuminate

Question 47

what are the 3 ways we perceive depth?

Answer 47

-Oculometer cues -Monocular cues -Binocular cues

Question 48

what are the 3 ways we perceive size?

Answer 48

-Size constancy -size illusions -Holway and Boring (1941)

Question 49

What are oculumeter cues?

Answer 49

Oculumeter cues are cues based on our ability to sense the position and state of our eyes. there are 2 types of oculumeter cues -Binocular convergence (knowing if eyes are looking inwards or straight) -Accomodation (knowing how thick the lens is to determine how far away we are, having an understanding of depth)

Question 50

What are monoculer cues?

Answer 50

Monoculer cues: Cues based on visual information avaliable within the eye. There are 3 types of monoculer cues: -Accomodation (Knowing how thick the eye lens is to understand how far away an object is) -Pictorial cues (go into detail in later on flashcard) -Movement based cues (Motion parallax, where objects closer to an observer appear to move faster than those further away, providing crucial depth perception cues and deletion and accretion, Deletion is the gradual occlusion of a moving object as it passes behind another object. Accretion is the gradual reappearance of a moving object as it emerges from behind another object)

Question 51

what are the 7 main pictorial cues?

Answer 51

- Occlusion - Relative height - Familiar and relative size - Perspective convergence - Atmospheric perspective:things far away obscured by atmosphere - Texture gradient - Shadows

Question 52

What are binocular cues?

Answer 52

Cues that depend on visual information within both eyes.The eyes see different angles, left and right eye retinal images are different. it should be noted that relative and absolute disparity affect binoculer cues. Relative disparity: -the disparity of binoculer cues is not dependent on where the person is looking,therefore the fixation does not alter relative disparity. Absolute disparity: -Point of fixation does affect disparity, whichever object is fixated has zero absolute disparity.Right and left images of the object fall on the corresponding parts of the retina.

Question 53

What is the correspondance problem?

Answer 53

-Retinal objects are ambiguous due to binocular cues, When there are multiple identical objects in a scene makes it hard to distinguish what objects in left retinal should be associated with the right retinal to make a full image. To solve this issue, things like colour often make it easier.

Question 54

How is the perception of depth related to the perception of size?

Answer 54

The perceived depth and angular size of an object impacts its perceived size as, the closer an object is to a person (It's perceived angular size/ its perceived distance), the larger it appears.

Question 55

What does size perception involve?

Answer 55

-Size constancy -Size illusions -Holway and Boring (1941)

Question 56

What is size constancy?

Answer 56

Size constancy is the phenomenon where an objects apparent size does not depend on its physical distance. -For size constancy to occur observer must manage both size of retinal image and the distance of an object. This is why size and distance are connected, if an individual misinterprets the distance this will cause them to misinterpret the size.

Question 57

Why do size illusions occur, in relation to distance

Answer 57

Most illusions of size occur because people mistake the distance of an object, causing the object to appear smaller than it is (if further away), or larger (if it is closer).

Question 58

What was the Holway and Boing experiment (1941):

Answer 58

-Holway and boring investigated how observers accurately estimate the size of objects. Mainly investigating how depth cues impact size perception. -observers sat between an intersection of 2 doors, were challenged to make 2 different circles, which were of different distances, the same size. Group 1: Had Binocular disparity, motion parrallex, shadows to determine distance Group 2:Had motion parrallex and shadows Group 3:only had shadows Results found: the less depth cues harder it was to determine the relative size. Suggesting that the perception of size does heavily depend on the depth cues present and the ability to accurately to determine distance.

Question 59

What are the 5 aspects to auditory perception?

Answer 59

-Physical aspects of sound -Perceptual aspects of sound -Auditory localization -Hearing inside rooms -Auditory organization

Question 60

What is the definition of sound, if considering its physical perception?

Answer 60

Sound is pressure changes in the air or in other mediums (Air waves floating through air). When sound occurs air molecules move back and forth whilst pressure waves continue to move in one direction.

Question 61

What is a pure tone?

Answer 61

Pure tones occur when the changes in air pressure (which makes sense) creates a pattern which can be mathematically described through a sine wave.

Question 62

What are 4 factors of the physical aspect of sound?

Answer 62

-Pure tone -Frequency -amplitude -Complex tones

Question 63

What is frequency and how does it impact sound?

Answer 63

-Higher frequency=higher sound - Humans can hear tones ranging from about 20 Hz to about 20,000 Hz

Question 64

What is amplitude and how does it affect sound?

Answer 64

-greater amplitude=louder sound seems - Amplitude is measured in decibels (db)  dB = 20 x logarithm(p/po)  Where p is the pressure (i.e. amplitude) of the sound (measured in micropascals) For context some items amplitudes are: -Conversation:316 -Hairdryer:3,162 -Subway train: 100,000

Question 65

What are complex tones and how do they affect sound?

Answer 65

if you add more tones, becomes more complex.the other tones become multiples of the first frequency (fundamental frequency) it should be noted that if a tone has 4 frequencies, 200 Hz, 400 Hz, 600 Hz and 800 Hz, since the fundamental frequency is 200 Hz as all the frequencies are multiples of 200 Hz - Thus, the tone will repeat at 200 Hz. -Complex tone will complete fundamental frequency when its absent because all the other components of the tone are multiples of the fundamental Frequency

Question 66

what do the perceptual aspects of tone refer to? and how are they decided?

Answer 66

-Perceptual aspect of sound refers to it as an experience of which we hear, our perception of sound is normally determined by its physical aspects.

Question 67

What are 3 considerations of the perceptual aspects of sound?

Answer 67

-"Loudness": How loud a sound is, is determined by frequency as we are all more sensitive to certain frequencies, however "loudness" is often also associated with amplitude, greater amplitude=greater sound. -Pitch: pure tone=determined by frequency complex tone=determined by fundamental frequency -pitch can be talked about considering chroma (the cyclic in the neighbouring letters of same type, c1 and c2) or height (tone increasing from left to right on a key board) timbre:when harmonics arent removed but pitch doesnt change, the tone will still sound different. This is evident when 2 instruments can be heard playing the same note,they still wont sound the same since they have different timbre.You can have periodic and aperiodic waveforms of timbre,musical sounds which can be repeated are periodic, however sounds that are spontaneous and cant be repeated such as a door slamming shut are aperodic.

Question 68

What is auditory localisation?

Answer 68

Auditory localisation is used to determine where a sound is coming from.Auditory localisation is based on both binaural and monaural cues.

Question 69

What are binaural and monaural cues?

Answer 69

Binaural cues: -interaul time difference, our ears here different sounds at slightly different times. -Interaul frequency differences, high frequency sounds can be large intearaural differences between 2 ears caused by shadows in head, low frequency sounds, not as much. Monaural cues:A sound coming from a different elevation. -Sounds coming from different elevations bounce of different parts of the pinna before entering the ear cannal.Consequently sound has different frequencies depending on its elevation.

Question 70

How does hearing inside of rooms occur?

Answer 70

-Sound travels to observer both directly and indirectly within a room,. Some factors of hearing inside rooms include: -the precedence affect which dictates whether an echo occurs. If the same sound is heard twice within a temporal separation of 5-20m, a second sound will not be registered. However, if the temporal seperation between the 2 sounds is more than a tenth of a second, an echo will occur. -The Architectual acoustics of a concert hall will affect the percieved quality of the sound.4 factors affecting the architectual acoustics include (reverbation time, intimacy time, bass ratio and spaciousness factor)

Question 71

What is Auditory organisation?what are the 5 factors impacting the ability of auditory organisation?

Answer 71

auditory organization is the seperation of sound sources. The five factors affecting an individuals ability to organise sound includes. -Location (use of interaural time differences and interaural level differences.) -Onset time (2 different times would indicate 2 different sources, making auditory organisation alot easier) -Timbre and Pitch (easy to segregate different instruments as they have different timbre) -Auditory continuity (Tones separated by silence are thought to be distinct from one another) -Experience (Knowledge of the different sounds)