Lecture 5&6: Sensation And Perception

Question 0

What is perception?

Answer 0

An active process where the brain selects, organises and interprets sensory inputs/information

Question 1

What is sensation?

Answer 1

The stimulation of sense organs: eyes, nose, ears, tounge, skin

Process by which body gathers info about the environment and transmits the info to the brain for initial processing

Question 2

What are a baby’s hearing capacities at birth?

Answer 2

Babies can hear BEFORE birth
Prefer complex sounds
Able to discriminate sounds

Question 3

What are human hearing capacities at 2-3 months?

Answer 3

Babies can distinguish phonemas (e.g. Between ba and pa)

Likes mothers voice

Question 4

What are human hearing capacities later in life?

Answer 4

Hearing loss occurs with age (presbycusis)
Decrements are greatest at high frequencies
Can’t detect soft sounds at particular frequencies
Responsiveness to startling noises lessens

Question 5

What are the effects of hearing loss?

Answer 5

Impacts self care (although visual impairment has a larger impact)
Affects safety and enjoyment of life - decline in spec perception is the greatest impact on life satisfaction

Question 6

What are vision capabilities of a new born?

Answer 6

Pattern and face perception
sensitivity to contrast
Preference to contour contrast and movement
Preference of complex over simple patterns

Question 7

What are our visual capabilities as we age?

Answer 7

Becomes harder to focus on nearby objects, see in dim light, perceive colour
Cornea is more translucent and scatters light (doesn’t focus on the retina, blurry image)
Lean continues to yellow

Question 8

What occurs to our vision from middle to older age?

Answer 8

Cataracts increase as a result of:
Reduction in light reaching retina
Acquity worsens, there is a sharp drop after 70
Macular degeneration - loss of vision in central visual field (retina)

Question 9

What are the impacts of visual difficulties?

Answer 9

Older people’s self confidence

Extensive vision loss may affect leisure pursuits and be isolating (can’t drive)

Question 10

What are the face perception capabilities of babies at 1,2 and 3 months of age?

Answer 10

Face perception is not innate, it is learned.
At 1 month- baby scans separate parts of face
2 months- integrate characteristics
3 months- can discriminate between photos of different strangers and recognise mother

Question 11

What does perception of human face support?

Answer 11

An infants earliest social relationship

Question 12

What are our taste and smell capabilities after 60?

Answer 12

Reduced sensitivity to tastes

Decreased smell receptors, leading to declines in sensitivity to odours (floral, musky, fruit or sweet)

Question 13

What are our touch capabilities as we age?

Answer 13

Touch is crucial for blind people
There is a sharp decline of sensitivity in hands
All adults are affected after 70

Question 14

What is the role of attention in perception?

Answer 14

Actively search environment to make sense of it
Can only process a finite amount of info
What we attend to determines what we perceive

Question 15

What is perception influenced by?

Answer 15

Motives e.g. When hungry, hunger is the motive, we are more likely to notice the smell of food.

Expectations:

1) context e.g. In a bakery, more food, or at work, less food
2) schemas I.e. an enduring knowledge of structures

Question 16

What are some specific medical applications of perception?

Answer 16

Symptom perception

Question 17

What is symptom perception.

Answer 17

Internal and external stimuli compete for our attention
If the environment is boring we are more likely to pay more attention to our body and notice mor symptoms
Distraction can reduce symptoms (e.g. Thinking of something else to distract from pain)

Question 18

What is a schema?

Answer 18

A cognitive framework that helps organize and interpret information in the world around us.

Question 19

What is a schema in symptom perception?

Answer 19

Can drive searches for symptoms and influence interpretation e.g. Medical student disease (mass psychogenic illness)

Question 20

What is the gate control theory of pain?

Answer 20

A theory about pain modulation that proposes that certain cells n the spinal cord acts as gates to interrupt and block some pain signals while sending other ones to the brain

Question 21

What happens when the gate is closed? (Gate control theory)

Answer 21

Pain perception is inhibited by activity in a-β fibres, relaxation, distraction, positive emotion

Question 22

What happens when the gate is open? (Gate control theory)

Answer 22

Pain perception is facilitated by anxiety, depression, attention

Question 23

What causes pain stimulus in the gate control theory?

Answer 23

Activity in A-δ and C fibres

Question 24

What is perceptual organisation?

Answer 24

The organisation of a continuous array of sensations into meaningful units.

Question 25

What are the four aspects of perceptual organisation?

Answer 25

Form perception
Depth or distance perception
Motion perception
Perceptual constancy

Question 26

What is form perception?

Answer 26

Perception which organises sensory info into meaningful shapes and patterns e.g. Gestalt view, where the whole is more than the sum of the parts

Question 27

What are the 5 gestalt principles?

Answer 27

The law of proximity- people to to group together the nearest elements
The law of similarity- people tend to group together the most similar elements
The law of good continuation- people experience lines as continuous even when they are interrupted
The law of closure- people tend to fill in small gaps to experience objects as wholes
The law of common fate- people tend to group together objects that appear to be moving in the same direction

Question 28

What is depth or distance perception?

Answer 28

The organisation of perception in three dimensons

Question 29

What are the two kinds of visual info that provides important information about depth and distance?

Answer 29

Binocular cues: visual input integrated from the 2 eyes

Monocular cues: visual input from 1 eye

Question 30

What are some monocular depth perception cues?

Answer 30

Interposition
Linear perspective 
Texture gradient
Shading
Aerial perspective
Familiar size, 
Relative size

Question 31

What is interposition?

Answer 31

When an object blocks out part of another object

Gives depth info indicating that the blocked out object is further away

Question 32

What is linear perspective?

Answer 32

A depth cue that depends on the size/distance relation.
E.g. When parallel lines recede into the distance, they converge towards a point on the horizon in your retinal image
Your visual interpretation will give the Ponzo illusion where the image looks long and like its going into the distance as the parallel lines converge

Question 33

What is texture gradient?

Answer 33

Depth cues due to the density of a texture becomes greater as a surface recedes in depth,

The units that make up the texture become smaller as they recede into the distance. Your visual system interprets this diminishing texture as greater distance in 3dimensional space

Question 34

What is shading?

Answer 34

Concluding surfaces block out lights creating shadows that can be used as an additional source of depth info.

Question 35

What is aerial perspective?

Answer 35

the effect the atmosphere has on the appearance of an object as it is viewed from a distance. As the distance between an object and a viewer increases, the contrast between the object and its background decreases, and the contrast of any markings or details within the object also decreases.

Question 36

What is familiar size?

Answer 36

A perceptual cue in which the known (familiar) size of an object is used to judge its distance from the observer.

Question 37

What is relative size?

Answer 37

Involves the basic rule of light projection in which objects of the same size at different distances project images of different sizes on th retina,
The closest object projects the largest image and the furtherest object, the smallest image.

This is called the size/distance relation

Question 38

What are the 2 sources of binocular depth perception?

Answer 38

Retinal disparity: each eye gets a different picture of the world. The greater the difference between the pictures, the closer the object

Convergence: eyes point inwards when looking toward close objects and move out wards when looking at distant objects