Temporary Deck: Wed 4th Oct SAC Content

Question 1

What is visual perception?

The textbook does not clarify what visual perception actually is, so the card has the technical definition, and the simplified definition.

Answer 1

In technical terms, visual perception is “the registration of stimuli in phenomenal consciousness.”
However, to simplify that, visual perception is the ability to perceive the world around you through outside stimuli.

Question 2

What factors influence visual perception?

Answer 2

Biological factors
Psychological factors
Social factors

Question 3

What are depth cues?

Answer 3

Depth cues are sources of information from the environment (external cues) or from within our body (internal cues) that help us to perceive how far away objects are and therefore to perceive depth. Depth cues are often categorised into two groups — binocular or monocular.

Question 4

What is depth perception?

Answer 4

Depth perception is the ability to accurately estimate the distance of objects and therefore perceive the world in three dimensions.

Question 5

What are the types of Biological factor(s)?

Answer 5

Binocular depth cues
Monocular depth cues

Question 6

What are Binocular depth cues?

Answer 6

Binocular depth cues require the use of both eyes working together in order to provide information to the brain about depth and distance.

Question 7

What are Monocular depth cues?

Answer 7

Monocular depth cues require the use of only one eye to provide information to the brain about depth and distance, but they also operate with both eyes.

Question 8

What are the Binocular depth cues?

Answer 8

Convergence
Retinal Disparity

Question 9

What are the Monocular depth cues?

Answer 9

Accommodation
Linear perspective
Interposition
Texture gradient
Relative size
Height in the visual field

Question 10

What is convergence?

Answer 10

Convergence involves the brain detecting and interpreting depth or distance from changes in tension in the eye muscles that occur when the two eyes turn inwards to focus on objects that are close.

Question 11

What is retinal disparity?

Answer 11

Retinal disparity refers to the very slight difference (‘disparity’) in the location of the images on the retinas (due to their slightly different angles of view), which enables us to make judgments about the depth or distance of an object.

Question 12

What is accommodation?

Answer 12

Accommodation involves the automatic adjustment of the shape of the lens to focus an object in response to changes in how far away the object is.

Question 13

What is linear perspective?

Answer 13

Linear perspective is the apparent convergence of actual or imagined parallel lines as they recede (‘go back’) into the distance.

Question 14

What is interposition?

Answer 14

Interposition, also called overlap, occurs when one object partially blocks or covers another, and the partially blocked object is perceived as further away than the object that obscures it (and vice versa).

Question 15

What is texture gradient?

Answer 15

Texture gradient refers to the gradual reduction of the detail that occurs in an object or surface as it recedes into the distance, compared with an object or surface that is close and perceived in fine detail.

Question 16

What is relative size?

Answer 16

Relative size refers to the tendency to visually perceive the object that produces the largest image on the retina as being closer, and the object that produces the smallest image on the retina as being further away.

Question 17

What is height in the visual field?

Answer 17

Height in the visual field refers to the location of objects in our field of vision, whereby objects that are located closer to the horizon are perceived as being more distant than objects located further from the horizon.

Question 18

What are the types of Psychological factor(s)?

Answer 18

Gestalt principles
Perceptual set
Context
Motivation
Past experiences
Memory

Question 19

What do Gestalt’s principles refer to?

Answer 19

Gestalt principles refers to ways in which we organise the features of a visual stimulus by grouping them to perceive a whole, complete form. The ‘principles’ are like ‘rules’ that we apply to visual information to assist our perceptions.

Question 20

What is perceptual set?

Answer 20

Perceptual set is a temporary readiness to perceive something in accordance with what we expect it to be. Our expectations of what an object or event may be also make us more likely to interpret the object or event in the predetermined way.

Question 21

What is context?

Answer 21

Context refers to the setting or environment in which a perception is made. When interpreting visual information, we often take account of the setting and pay more attention to those aspects of the situation that are immediately relevant. In this way, context has a ‘focusing’ role in visual perception and usually assists us to make a quick and accurate interpretation of what we are looking at.

Question 22

What is motivation?

Answer 22

Motivation refers to processes which activate and sustain purposeful or goal directed behaviour. Motives can be influenced by psychological factors (such as interests, ambitions and desires), biological factors (such as bodily processes associated with hunger or thirst), or social factors (such as the influence of who we are with, how much money we have and our cultural background).

Question 23

What is past experience?

Answer 23

Past experience refers to our personal experiences throughout our lives. This includes everything we have learned both intentionally and unintentionally. Our visual perception relies to a very large extent on our past experience.

Question 24

What is memory?

Answer 24

Memory is the process of storing and retrieving this perceived information for use when needed.

Question 25

What are the Gestalt principles?

Answer 25

Figure-ground
Closure
Similarity
Proximity

Question 26

What is figure-ground?

Answer 26

Figure–ground organisation is generally achieved when we separate the figure from the ground using a line or boundary between the figure and ground, which may or may not exist in the scene. This line of separation between the figure and ground is known as a contour. The contour is always perceived as belonging to the figure.

Question 27

What is closure?

Answer 27

Closure is the perceptual tendency to mentally ‘close up’, fill in or ignore gaps in a visual image and to perceive incomplete objects as complete (‘whole’).

Question 28

What is similarity?

Answer 28

The principle of similarity involves the tendency to perceive parts of a visual stimulus that have similar features — such as size, shape, texture or colour — as belonging together in a unit, group or ‘whole’. For example, this principle is used when we group people wearing the same clothing and identify them as belonging to the same team, school or workplace.

Question 29

What is proximity?

Answer 29

The principle of proximity (also called nearness) is the tendency to perceive parts of a visual image which are positioned close together as belonging together in a group. We group the separate bits into a whole based on how close they are to each other.

Question 30

What are the types of Social factor(s)?

Answer 30

Culture

Question 31

What is culture (in terms of a Social factor?)

Answer 31

Culture involves influences from the external social environment in which we interact with others, and how that affects how we perceive and register stimuli.

Question 32

What is a visual illusion?

Answer 32

A visual illusion is a misperception of external visual stimuli that occurs as a result of a distortion or mistake when interpreting the stimuli. It is an experience in which there is a mismatch between our perception and what we understand as physical reality. Every time we view the same sensory information, we have the same illusory experience.

Question 33

What is the Müller-Lyer illusion?

Answer 33

The Müller-Lyer illusion is a visual illusion in which one of two lines of equal length, each of which has opposite shaped ends (feather tail and arrowhead), is incorrectly perceived as being longer than the other.

Question 34

What is the Ames room illusion?

Answer 34

The Ames room illusion involves people appearing smaller or larger, depending on where they are standing. It is based on the unusual construction of the room, particularly the shape of the back wall. The Ames room illusion involves a trapezium-shaped room that is longer and higher on one side than the other. When viewed through a peephole at the front of the room using only one eye, the room appears rectangular. The room’s unusual shape provides the basis for the illusion.

Question 35

Why does the Müller-Lyer illusion occur?

Answer 35

The Müller-Lyer illusion has been explained by psychologists from various perspectives. Some suggest it results from misinterpreting visual cues like depth and distance in 2D objects, while others attribute it to our learned perception of the physical world. The “carpentered world hypothesis” suggests our brains apply architectural context to the illusion, making one line seem closer like an outside corner and the other further like an inside corner. Critics point out that the illusion also works with horizontal lines and different shapes on the ends. Psychologist Ross Day proposed that the illusion happens because conflicting visual cues lead to conflicting information. Our brain resolves this by making a perceptual compromise, weighing contradictory cues and settling on an interpretation that makes the most sense based on available information. This explanation may apply to both the standard and variations of the Müller-Lyer illusion. In sum, psychologists have formulated and experimentally tested many hypotheses over many decades in order to understand and explain the Müller-Lyer illusion. It is generally agreed that there is not yet any single explanation of the illusion that is entirely satisfactory.

Question 36

Why does the Ames room illusion occur?

Answer 36

When we view the inside of the room through the peephole, our past experience with rectangular rooms leads us to expect that the people in the room are all the same distance away from us. However, in this situation, one person casts a smaller or larger retinal image than the other, so their sizes are perceived as different. According to apparent distance theory, when two retinal images are the same size, but one image appears to be at a greater distance, then the one that appears further away will be interpreted as bigger or larger. In the Ames room, the perceived rectangular shape of the room is consistent with the retinal image, but not consistent with the room’s real shape. The back corners on either side of the room actually produce equal-sized retinal images because the vertical length of the further left corner is double the length (but twice the distance from the observer) of the nearer right corner. Therefore, the visual angle is the same for both corners from the observer’s view. Because the observer does not have the depth cues available to ‘work out’ the real difference in distance between the two corners, the equal-sized retinal images of the corners are interpreted as equal in size. This produces an illusion of a rectangular room.

Question 37

What is synaesthesia?

Answer 37

Synaesthesia is a perceptual experience in which stimulation of one sense produces additional sensations in another. The experience associated with the additional sensations ‘adds’ to the overall perceptual experience without replacing the initial sense.

Question 38

What are three different types of synaesthesia?

Answer 38

mirror–touch synaesthesia — a person watching another individual being touched feels a tactile sensation on their own body

auditory–tactile synaesthesia — certain sounds trigger sensations in parts of the body

word–gustatory synaesthesia — experiencing tastes when hearing certain words

Question 39

What are the characteristics of synaesthesia?

Answer 39

Synaesthesia is involuntary and occurs automatically in response to the relevant sensory stimulation. It is extremely difficult to suppress. The experience is also vivid, highly memorable and consistent across time. For example, the synaesthete always associates the same colour with the same number, letter of the alphabet or sound. Blue will always be experienced with the number three, or T’s are always red to the individual synaesthete. However, these specific cross-sensory experiences vary among individual synaesthetes. For example, one synaesthete may always experience blue with the number three, whereas another may always experience yellow with the number three. Finally, synaesthesia also tends to be one-way rather than bidirectional. If a sound produces a taste, the taste will not necessarily produce the sound

Question 40

What are the causes of synaesthesia?

Answer 40

Some researchers have suggested that synaesthetes are unusually sensitive to external stimuli and may have ‘hyperexcitable’ sensory processing areas in the brain. Others have proposed that synaesthesia may result from a breakdown in sensory and perceptual processes. It has also been suggested that synaesthesia can be linked to the excess of neural connections formed during early development that are normally pruned and refined as the brain matures over time. Therefore, synaesthetes maybe people who retain rather than lose these neural connections. It is likely that the brains of synaesthetes possess unique structural and/or functional properties. Consequently, explanations often refer to the possibility of differences in the architecture of the synaesthete’s brain. For example, the brains of synaesthetes may have abnormal neural pathways or be ‘wired’ differently, so that neighbouring sensory areas in the brain cross-activate one another, thereby triggering additional sensations — the experience of seeing colour when looking at shapes might be due to cross-activation of the colour and shape recognition

Question 41

What is agnosia?

Answer 41

Agnosia is characterised by loss or impairment of the ability to recognise and identify objects, persons, sounds or other sensory stimuli using one or more of the senses despite otherwise normally functioning senses.

Question 42

What are the different senses affected by agnosia?

Answer 42

Visual agnosia (sight)
Tactile agnosia (touch)
Olfactory agnosia (smell)
Gustatory agnosia (taste)
Auditory agnosia (sound)

Question 43

What is visual agnosia?

Answer 43

Visual agnosia is loss or impairment of the ability to recognise visual stimuli. In particular, people with visual agnosia have difficulty recognising familiar objects and possibly faces. These difficulties are not related to sight, loss of memory or language.

Question 44

What are the different types of visual agnosia?

Answer 44

Apperceptive visual agnosia
Associative visual agnosia
Prosopagnosia
Simultanagnosia
Topographical agnosia
Colour agnosia
Agnosic alexia

Question 45

What is apperceptive visual agnosia?

Answer 45

An inability to accurately perceive visually presented stimuli. What is seen cannot be recognised. People with this disorder cannot perceive the individual parts of a stimulus as a meaningful, unified whole. For example, they cannot identify a dog that was shown to them, but could identify a dog by touch. They are also unlikely to be able to properly draw, copy or match a picture of a simple object with which they are familiar, even if they are told what it is. People with this disorder are sometimes described by their relatives as being blind, since they have difficulty recognising and naming even simple objects and have to rely on non-visual cues to locate objects or get around.

Question 46

What is associative visual agnosia?

Answer 46

An inability to associate a visual stimulus with stored information about objects in memory despite having otherwise normal perceptual abilities. People with this disorder can describe an object or even draw it or copy a picture of it, thereby indicating that they can correctly perceive the physical characteristics of an object. However, they do not know what they have drawn or even explain what it does or is used for. When tested with verbal or tactile information, they can recognise what an object is. But they cannot identify or assign meaning to it through vision alone.

Question 47

What is prosopagnosia?

Answer 47

An inability to recognise a familiar face, including their own when seen in a mirror or photograph. The person can, however, use other visible characteristics to recognise people, such as gender, age, the way they walk (gait), a tattoo, a characteristic hairdo or even face information such as a moustache or expression. The ability to recognise other types of visual stimuli tends to be relatively unaffected. When a person with prosopagnosia looks in the mirror they are likely to see the reflection of a stranger. However, they know they are the strange looking person since they are the only person standing in front of the mirror. If they speak, they may recognise their own voice. They may even recognise a characteristic gesture in front of the mirror, but the face is completely new to them.

Question 48

What is simultanagnosia?

Answer 48

An inability to recognise more than one object at a time in a scene that contains more than object. For example, if a banana and an orange are presented together, only one of the two is perceived. If they recognise the banana and their attention is redirected to the orange, then they will report that they see the orange but no longer see the banana. Scenes are perceived in a piecemeal manner, bit by bit. Some patients only ever see parts of objects. Many act as if they are blind because they find seeing the world one object at a time overwhelming. They typically fail to comprehend the overall meaning of the scene as they are unable to perceive the individual elements that form the whole.

Question 49

What is topographical agnosia?

Answer 49

An inability to find one’s way around familiar environments. The person typically has a good memory of the layout and specifics of the places well known to them, such as their own neighbourhood, but they are unable to navigate their way around without getting lost. In particular, they are unable to use visual cues to guide them in the right direction. For example, they are unable to recognise landmarks that would indicate the appropriate direction of travel.

Question 50

What is colour agnosia?

Answer 50

An inability to identify and distinguish between different colours, despite normal basic colour vision and colour discrimination mechanisms. People with this disorder will typically be unable to name the colour of an object when seen, provide a list of objects of a specific colour, or to sort objects into colours. For example, they could not tell you that cherries are red when shown some cherries, write a list of a objects that are red, or tell the difference between opposing teams that are wearing different coloured uniforms.

Question 51

What is agnosic alexia?

Answer 51

An inability to recognise or comprehend written or printed words. Also called word blindness and pure alexia, people with this disorder have severe reading difficulties while other language skills associated with writing, talking and listening tend to remain unaffected. For example, they remain capable of spelling and writing words and sentences but are unable to read and comprehend what was written by themselves.

Question 52

What are the causes of agnosia?

Answer 52

Agnosia is a rare disorder caused by brain damage. Less than 1% of people diagnosed with brain damage have agnosia. The disorder can occur suddenly due to a stroke or traumatic brain injury, or gradually due to a brain tumour, overexposure to an environmental toxin (e.g. carbon monoxide poisoning), a developmental disorder, dementia, or another neurological condition. Agnosia is specifically associated with damage along neural pathways that connect areas that process perceptual information. With visual agnosia, damage is likely to be found in a pathway extending from the primary visual cortex in the occipital lobe to the temporal lobe. This pathway is called the ventral stream. The ventral stream (also known as the ‘what pathway’) is involved with visual object identification and recognition. In contrast, the dorsal stream (or, ‘where pathway’) which leads from the primary visual cortex to the parietal lobe, is involved with processing an object’s spatial location. The type(s) of visual agnosia acquired by the individual and the symptoms primarily depend on the specific location of the damage, its extent and severity.

Question 53

What is the treatment for agnosia?

Answer 53

There is no direct cure for visual agnosia (or any other type of agnosia). Instead, the underlying cause is treated if found and when possible. For example, if caused by a tumour, surgery and/or radiation may be an option. Rehabilitation plays an important role in the treatment of agnosia. It is individualised, tailored to the specific problems and focuses on helping individuals cope with and adapt to their condition. In particular, compensatory strategies involving the use of other senses are taught. For example, someone with apperceptive or associative visual agnosia may be learn how to identify different types of objects by touch, whereas someone with prosopagnosia may learn how to identify and use physical features and voice characteristics to assist recognition of others.

Question 54

What is the difference between sensation and perception?

Answer 54

Sensation refers to the process of receiving signals from our senses, while perception is the brain’s response to these signals. Perception involves selecting, organising and interpreting sensations. Although perceptions are build from sensations not all sensations result in perception. Perception can vary from person to person based on learning, memory, emotions and expectations. Sensation is the initial conscious response of the brain to stimuli, while perception gives meaning to the stimuli.