Sensation & Perception

Question 1

Sensation

Answer 1

the processing of basic information from the external world by the sensory receptors
-> bottom-up processing

Question 2

Perception

Answer 2

The process of organizing and interpreting sensory information
-> top-down processing

Question 3

How to study infant’s sensory & perception?

Answer 3

1. Preferential-looking: show 2 stimuli at the same time to see what infants prefer to look at
2. Habituation: repeatedly show a stimulus until response declines
3. Operant conditioning: reward infant with stimulus to see which stimulus they prefer

Question 4

How to know if the infant can distinguish/sense?

Answer 4

If the infant’s response increases when a novel stimulus is presented, the researcher infers that the baby can discriminate between the old and new stimuli

Question 5

Vision Acuity in infants

Answer 5

sharpness of visual discrimination

development:
- 8 months: similar to adults
- 6 years: full adult acuity

how to test: comparing the duration baby (reaction to new stimulus) looks at black-white striped square vs. gray square of same size and brightness

Question 6

Contrast sensitivity in infants

Answer 6

The ability to detect differences in light & dark area

birth -> 2 months: prefer images with high visual contrast

reason for poor contrast sensitivity:
- underdeveloped fovea
- cone cells (light-receptors) differ from adults’ in size, shape and spacing

Question 7

Colour vision in infants

Answer 7

2-3 months: similar to adult colour vision (colour discrimination)
Infants can discriminate between two bright, vivid colors better than between two faint, pastel colors

Question 8

Scanning & tracking development in infants?

Answer 8

Scanning:
- 1 month: scan perimeter of shapes
- 2 months: perimeters and interiors of shapes

Tracking: although start tracking since birth but can’t follow object motion until 2-3 months of age

Question 9

Face recognition in infants?

Answer 9

From birth, infants are drawn to faces because of a general bias toward configurations with more elements in the upper half than in the lower half

Question 10

What is surprising about facial recognition in 6-month-old infants?

Answer 10

6-month-old infants are better at distinguishing between monkey faces than 9-month-olds and adults

-> less used to seeing only human faces

Question 11

Facial preferences in infants?

Answer 11

1. Prefer caregiver’s face
2. Understand significant of facial expressions
3. Beauty bias: look longer at (more) attractive adults -> attractiveness affect behaviours: infants interact more positively with people with attractive faces

Question 12

Pattern perception in infants?

Answer 12

Two-month-old infants can analyze and integrate separate elements of a visual display into a coherent pattern

-> study: invisible square by arranging 4 circles with 90-degree angles

Question 13

What are 3 characteristics of objects perception?

Answer 13

1. Perceptual constancy: perception of objects being constant in size (despite contradictory images)
2. Object segregation: can perceive if overlapping image is made of 2 or more objects or not based on physical cues (e.g. gravity)
3. Depth perception: ability to register a visual image of an object is 3D (using optical expansion, stereopsis and monocular cues)

Question 14

Key developments of depth perception in infants?

Answer 14

1 month: optical expansion

4 months: stereopsis

6-7 months: sensitive to monocular/pictorial cues

19 months: pictorial representation - stop treating images of 3D objects as real objects

Question 15

Optical expansion?

Answer 15

First appear in 1-month-old infants
A depth cue in which the object image increases, indicating that they are getting close

Question 16

Stereopsis?

Answer 16

First appear in 4-month-olds

Visual ability to perceive the world in 3D by combining visual signals from binocular disparity (difference in what is seen from left & right eyes)

Question 17

Monocular/pictorial cues

Answer 17

The perceptual cues of depth that can be achieved by one eye alone.

Including:
1. Relative size (larger is closer)
2. Interposition (overlapping)
3. Linear perspective (convergence of parallel lines).

Question 18

Auditory perception in infants?

Answer 18

Takes 5-6 years for infants to reach the same level in adults.

Good at recognizing subtle differences in human speech

Auditory localisation: newborns will turn toward sound, especially with repeated sound

Question 19

Perception of sounds? (phonemes)

Answer 19

2-month-olds can recognise between 2 difference phonemes by measuring baseline sucking rate as responses to auditory stimulus
Measure by using habituation

Question 20

Perception of music?

Answer 20

Evidence suggests a biological foundation for music perception

Evidences:
1. 31-week-olds heart rates calm down when listen to Brahms lullaby
2. Singing keep 7-10 months old infants calm twice as long as speech
3. Strong preferences for pleasing music sound similar to adults
4. Infants respond to rhythm and temporal organization in music
5. Sensitive to melody (even withs pitch-change)

Question 21

Tastes & Smell in infants?

Answer 21

• Preference for sweetness
• Newborns prefer their own amniotic fluid and their mothers’ breast milk
• Newborns facial expression after tasting various substances are similar to adults’ (innate abilities)

Question 22

Touch sensory in infants?

Answer 22

• birth -> 4th month: oral exploration - infants will put everything into their mouth
• 4 months: increase in hand movements

Question 23

Intermodal perception

Answer 23

Very young infants can link sight and sound, oral and visual experience, and visual and tactile experience

Question 24

Evidence for intermodal perception in infants?

Answer 24

• 2-months old prefer video that correspond to the sounds they are hearing when 2 videos are played
• 5-months old infants can link facial expressions with emotion in voice
• Infants can recognize shape of ring by connecting visual to touch