Perceptual Development

Question 1

Why is it important to study perceptual development?

Answer 1

• understand how infants/children experience the world
• individual differences
• comparison

Question 2

What are the 3 trajectories of Aslin’s perceptual develpment diagram? What is an example of each trajectory?

Answer 2

Undeveloped trajectory
* No development in a system until the onset of experience
* Onset of experience can either have no effect or can induce development of a system
* Example: William James environmental/learning = induction as nothing from nature that predetermines ability (all nurture)

Partially developed trajectory
* Leans towards nature argument
* Genetic driver leading the system to be set up
* Onset of experience leads to 3 options in system:
1. Attunement or facilitation: for exposure to environmental experience and how system is operating
1. Maintenance: continues as is
1. Loss: possess ability but aren’t exposed to environment that enables ability/needs ability
* example: Ethological Gibsonian theories - nature and nurture

Fully developed trajectory
* Maintenance
* Loss: something lacking in environment preventing maintenance of skill
* example: face processing - all nature

Question 3

What are the details of William James’ Environmental/learning theory of perceptual development? What are the critiques of this theory?

Answer 3

Stimuli originally meaningless sensory input meaning learnt through interactions and building associations

Critiques of theory
* Large amount of time/effort required to learn this way – lacks efficiency
* Fails to note how we view before meaning is applied ie why are we interacting with it if it has no meaning to us?

Question 4

What are the 2 types of ethological/Gibsonian theories of perceptual development? Explain each and how they are related to Aslin’s model of perceptual development.

Answer 4

Overall: Perceptual system pre-set to learn about most important things in environment

Experience-expectant learning
* Biologically biased to attend to critical aspects of environment e.g. faces, danger signals
* Neural circuitry is rapidly tailored to environmental input during critical or sensitive periods
* Neural pruning – removal of non critical information

Experience dependent learning
* Ongoing neural and behavioural plasticity in response to environmental input
* Occurs outside sensitive periods
* May be more gradual or subtle
* Occurs via synaptic connections (rather than neural pruning)
* e.g. learning language as a child vs as an adult

Question 5

What is perceptual narrowing and why is it thought to happen? What evidence is there for this process?

Answer 5

Neural architecture is initially untuned and then tuned by environmental input
* No need to keep unused abilities
* Critical or sensitive periods
* done for efficiency of cognitive processing
* e.g. kitten studies w/ sensory deprivation for vision

Question 6

What is neural pruning and how does it impact neural development?

Answer 6

Neural pruning = removal of non-critical information

Impact on development
* Prior to pruning (0-2YO) chaotic and inefficient neural connections which results in a more global experience of input
* Pruning thought to occur from 1-13YO
* results in mature connections being organised and precise leading to improved efficiency in neural connectivity

Question 7

What are the challenges of measuring perception in infants?

Answer 7

• no language
• must rely on other measures (behaviour, neural, psychophysiological e.g. HR)
• meaning inferred as indirect measures of perceptual processing

Question 8

What are 3 examples of behavioural measures of infant perception?

Answer 8

• Natural looking (infants vs adults) (e.g. how face is scanned)
• Exploratory behaviour (e.g. how objects held)
• Reaching or other gestures
• Facial expressions (e.g. positive or negative)
• Vocalisations (not words but other noises)
• Habituation-Dishabituation
• Preferential looking

Question 9

What did Walle & Campos’ (2014) study on infant responses to normal vs exaggerated fear expressions demonstrate about measuring infant perception?

Answer 9

Multiple ways to measure infant perception
* focused on facial expression interpretation as to whether real/fake

Question 10

Explain the habituation-dishabituation paradigm. What is this paradigm used to infer?

Answer 10

Measuring looking times at novel vs habituated stimlus

Thought to measure whether infant can tell the difference between 2 stimuli

Question 11

What is the preferential looking paradigm and what is it thought to infer?

Answer 11

• Technique for studying infant vision
• Measuring preference for 1 stimuli over the other
• inferring meaning that they must be able to tell the difference in order to show a preference

Question 12

What are 2 common neurological measures of infant perception?

Answer 12

• EEG (most common)
• fMRI (starting to be used)

Question 13

How is vision thought to develop in infants?

Answer 13

• Last sense to develop
• Eye-movement in utero but minimal visual stimulation
• Rely heavily on visual info in 1st few weeks of life = rapid development in ability

Question 14

What is newborn scanning?

Answer 14

• Non-random scanning of world
• Preference for figure over background and high contrast features

Question 15

How does colour preferance in infants compare to adults? How is this preference measured?

Answer 15

• Prefer blue/purple - matches adult preferences worldwide
• Preferential looking paradigm
• Unable to tell reasoning behind preference

Question 16

How is object perception in regards to size constancy measured in infants?

Answer 16

• Peekaboo experiment – measuring size constancy abilities
• Trained to look at object same as retinal size

Question 17

What preference to infants show for illusory contours of objects?

Answer 17

show preference for ‘correct’ samples

Question 18

How does depth perception develop in infants?

Answer 18

Kinetic cues 1-3 months
* Motion parallax -> closer objects appear to move faster

Binocular depth cues 4-6 months
* Relies on sensitivity to differences between images seen by left and right eyes

Pictorial cues 7months

Question 19

What is a practical example of visual development in infants? How is our knowledge of infant/child depth perception used in the real world?

Answer 19

Practical example: looming
* Objects get larger as they travel closer
* Even older children (up to 11YO) have trouble detecting looming at >50km/h
* Especially if the child is moving or not looking directly at the car
* See applications in road rules and teaching to kids

Question 20

What is the visual cliff experiment and what does it show about infant perception?

Answer 20

• Babies refusing to go to mothers when perceive visual cliff
• Infants can’t determine that cliff is an illusion and perceive as an actual drop
• Demonstrates role of non-verbal communication to determine child’s behaviour in uncertain contexts

Question 21

What is the evidence showing humans have a preference for faces from birth? What measures are used in these studies and what are the limitations of them?

Answer 21

Evidence:
* Track upright faces more so than scrambled or inverted faces 9 mins after birth
* Can tell mother from other females by 4 days (remove scent and other senses)
* Can discriminate novel faces by 3MO - also some evidence we can discriminate by 3 days (front views)

Measure
* Preferential looking used

Limitations
* might not be preference for faces might be for characteristics key to faces e.g. upright, symmetrical
* Can’t tell us whether infants can tell between different identity faces

Question 22

How is habituation-dishabituation used to measure whether infants can recognise identity faces?

Answer 22

Logic: same identity shown at different angle, if no response shows know same person

Measure:
Different ID shown at different angle = increased looking time as recognition of new person/novel stimuli

Question 23

What is the evidence that faces are special for adults?

Answer 23

holistic processing
* disproportionate inversion effect
* part/whole effect (face parts better recognised in original context)
* composite effect (gold standard) - 2 halves of face perceptually integrated giving illusion of new person - more time spent looking at misaligned faces showing holistic processing

Fusiform facial area (FFA)
* thought to be region specifically for face processing

N170
* thought to be ERP that measures face processing

Question 24

Is it thought that infants show special face processing abilities? What evidence supports this?

Answer 24

Yes:
* Discrimination of novel faces at 3 days for upright faces only
* Preference for attractive faces at 1 weeks for upright faces only
* Thatcher illusion at 6MO - When faces inverted we have trouble determining whether differences between them
* 6-8MO treat a face where features have been combined from 2 previously seen faces as new only if shown upright

Question 25

What is the neurological evidence for infant face processing in human vs monkey?

Answer 25

Monkeys * Single-cell recordings * Selective for faces @2MO (earlier age tested) * Monkey development faster than humans Humans * N290 ERP selective for faces in infants (not N170 as neural acitivity becomes more efficient as we age) * Selective for human faces @3months relative to faces of other species * But shows reverse inversion effect * Other ERP components show adult-like inversion effects @3MO * 5-8MO show stronger responses for upright compared to inverted faces in right hemisphere

Question 26

What do behavioural measures of face perception show for 4YO-Adults?

Answer 26

* young children show inversion effect, part/whole effect and composite effect * also show range of other behavioural effects that adults show for faces * qualitatively adult-like from an early age * unclear whether quantitatively adult-like as confounded w/ other cognitive processes

Question 27

What do neurological measures of face perception show for 4YO-adults?

Answer 27

FFA in 5-8YO and 7-11YO * FFA increases in size w/ development * RFFA size correlated with face recognition memory in children and adolescents ERP components gradually become more adult-like * e.g. N170 decreases in latency

Question 28

How does perceptual narrowing alter cross-specie face processing in human vs monkey infants?

Answer 28

Humans * 6MO can discriminate monkey and sheep faces * ability lost by 9MO through perceptual narrowing Monkeys * vice versa for monkeys as can delay sensitive period

Question 29

How does perceptual narrowing alter within-species preferences for face processing?

Answer 29

Gender preference * Female faces (unless primary care-giver is male) Race preference * Own-race faces * 3MO looking preference unless raised in multi-cultural environment but not clear if other race effect (ORE) for individuation * Show ORE for individuation by 9MO Age preference * Adult faces - unless have younger sibling (3YO)

Question 30

How does evidence explain the potential face preferences in infants?

Answer 30

Exposure to faces * 1 and 3MOs * 25% of time spent looking at faces * exposed to mostly female, own race and adult faces which could explain preference due to familiarity

Question 31

What does evidence show about a potentially critical period for holistic face processing?

Answer 31

Congenital cataract patient study * Normal input from 2-28 months (cataracts removed) * Adults reported no day to day difficulties in recognising individual faces * but showed deficits in holistic processing (no composite effect) * Suggests critical period for holistic processing, which may be important for cross-view recognition

Question 32

How does exposure in infancy mediate potential losses in face processing ability? (4)

Answer 32

* Training effects: infants around 9MO to individuate between other species faces able to regain ability * Adoption studies: ORE can be eliminated or reversed when adoptive family of another race * Childhood contact: other race contact in school settings * Adulthood: teachers and maternity nurses have better skills to differentiate between children when socially relevant

Question 33

How is neural plasticity thought to develop for language and face processing?

Answer 33

Parallel courses of development plasticity for faces and language * measured ORE and contact with own/other race people during primary school, high school and adulthood * found more contact during primary school = reduced other race effect but effect reduces with age (thought due to plasticity reduction)

Question 34

Where does facial perception sit on Aslin's perceptual development trajectory?

Answer 34

mostly with fully or partially developed trajectories i.e. either nature or interactionist view

Question 35

How does hearing develop? What evidence supports this theory of development?

Answer 35

* appears @24 weeks gestation * continuous improvements in hearing for both high and low frequencies until 20YO Evidence * Newborns prefer speech heard in utero over matched non-speech sounds * Preference for music heard in utero over other music * Cortical activation to speech vs backward speech * Infants sensitive to elements relevant to speech e.g. prefer pauses where they are supposed to be

Question 36

Describe a study demonstrating auditory perceptual narrowing

Answer 36

* 6MOs compared w/ adults * Western vs Javanese scales * Habituation-dishabituation paradigm * Adults performed better for Western scales * 6MOs performed equivalently for both scales Equal performance for 6MO but not adults shows ability is narrowed to culturally relevant stimuli by adulthood

Question 37

How does smell develop? What are some findings of smell perception development? Why is smell important?

Answer 37

Newborns show discrimination between smells * study relying on infant facial expressions in response to different food smells Preference for mother's scent about 2 weeks old (preferential orientation) * Only case for breastfed infants Early memory for smells Smell fully developed by 6YO Plays important role in emotional regulation

Question 38

When does taste develop and what evidence supports this?

Answer 38

When * present in utero * primitive - even babies w/o cortexes have taste Evidence * newborns show discrimination between tastes * early preferences for sweetness then switch to salty around 4MO

Question 39

When does touch develop and what evidence supports this?

Answer 39

When * Present from 8weeks gestation (pressure) * Pain in 3rd trimester Evidence: newborns * Turn in direction of puff of air on cheek or stimulus that touches near mouth * Different responses to invasive vs noninvasive procedures * Standard facial expressions for invasive procedures suggest newborns experience pain

Question 40

What is the neonatal facial coding system (NFCS) and what is it used for?

Answer 40

system to measure/determine pain in newborns

Question 41

What is the evidence used to support Ethological/Gibsonian theories of perceptual development?

Answer 41

studies showing that very young infants can tell when a speaker's lip movements are not synched with the speech they are hearing even though they had no prior experience with such asynchronies

Question 42

What is intermodal perception?

Answer 42

the way that information from different senses combines to form perception of a unitary object or event

Question 43

What is intermodal exploration?

Answer 43

how information about an object received through one sense leads to exploration of the object using another sense * Appears that transfer of information across modalities is present from birth

Question 44

Describe preferential looking. What types of questions can be answered with this technique?

Answer 44

* Used to measure infant perception as doesn't require language * do they prefer 1 over another - inferring meaning that they must be able to tell the difference in order to show a preference Questions answered * face processing in infants * gender preference (female face preference unless primary care giver male) * race preference (own-race preference unless raised in multi-cultural environment, other race effect by 9MO) * age preference (preference for adults unless have younger siblings)

Question 45

Describe habituation-dishabituation. How can we use this technique to answer different questions than we can with preferential looking?

Answer 45

present novel and habituated (familiar) stimuli - seeing if infant has encoded familiar stimuli and whether they can tell the difference between 2 stimuli Questions different to preferential looking * can infants tell identity of face at different angles (same identity shown at different angle where no response shows they know its the same person and different ID shown at different angle = increased looking time as recognition of new person/novel stimuli)

Question 46

Define and explain the process of perceptual narrowing.

Answer 46

Neural architecture is initially untuned and then tuned by environmental input

Question 47

Describe the evidence for perceptual narrowing in face perception.

Answer 47

Evidence * cross-species: humans @6MO can discriminate between different monkey and sheep faces - ability lost by 9MO (narrowing/pruning due to unnecessary process) * within-species preferences: female faces (unless primary care-giver is male), own-race faces (unless multi-cultural environment), adult faces (unless have younger sibling)

Question 48

# [](http://) Describe the sequence of perceptual development across and within modalities.

Answer 48

Taste * amniotic fluid contains flavours w/ foetal preference for sweet flavours * even babies w/o cortex (anencephalic) have taste * newborn discrimination * early preference for sweet but switches to salty ~4MO Smell * amniotic fluid takes on odours from mum's food w/ smells coming into contact w/ olfactory sense via breathing * newborns show discrimination between smells * early memory for smells (preference for mother's scent by 2WO for breastfed infants only) * smell fully developed by 6YO * play important role in emotional regulation Touch * tactile experience in utero due to own movement * full term infants respond to mother's movement (vestibular system and spatial orientation) * present from 8 weeks gestation (pressure) * pain in 3rd trimester * newborns respond to touch stimuli e.g. puff of air on cheek or stimuli touches near mouth * tactile exploration important developmental process to learn about environment Hearing * react to noises from 6 months gestation (habituation to repetitive sounds study, preference to mother's HR) * final trimester: external noise = physiological responses * full term can distinguish between sounds * episodic memory of salient stimuli (cat and the hat study w/ sucking paradigm post birth) * perceptual narrowing @6MO to culturally relevant sounds (Javanese vs Western scales study) * preference for familiar speech and music heard in utero Sight/Vision * minimal visual experience in utero (dark) * last sense to develop * rapid development after birth w/ high reliance on visual information in first few weeks of life * depth perception (kinetic cues 1-3MO, binocular depth cues 4-6MO, pictorial cues 7MO) * visual cliff experiment