Week 2 Flashcards
sensation
information about environment picked up by sensory receptors and sent to the brain
Perception
brain’s interpretation of sensory input
Preference technique
Baby looks at new shapes in a room
Habituation: should dishabituate and look longer. Shows can distinguish between pictures
Conditioning
Reward when turn head to side (e.g. peekaboo)
Link with noise until habituated
Change noise
Event related potentials ERPs
Most commonly used brain imaging technique with infants
Measuring evoked potentials
Auditory perception
22-24 weeks foetus respond to sound (Hepper & Shahidullah, 1994)
Measured by heart rate & movements
Low frequency range (250-500 Hz)
Expands as foetus matures (Hepper, 2005)
Sound reaching foetus is distorted
Skin, muscle, amniotic fluid
Noisy environment
Non-nutritive sucking technique
Rubber teat placed in infant’s mouth
Filled with fluid and connected to a pressure-sensitive device.
Sound is played
Babied learn quickly that each time they suck they hear a sound
After a while the infant habituates to the sound and sucks less often
When new sound is place the baby sucks more again
Prenatal Learning Revisited DeCasper & Spence (1986)
33 pregnant women read a target story to their unborn babies twice a day during the last 6 weeks of pregnancy
Non-nutritive sucking technique used with newborn infants
Infants preferred the story they had heard in utero to a control story
Sucked faster to hear target story
Control group (infants matched for sex, age, ethnicity) showed no difference in responses to stories
Auditory perception: after birth
Auditory acuity at birth better than visual
Newborns turn head towards sound
Preference for mums voice (DeCasper & Fifer, 1980)
3 day olds suck more to hear mum than stranger
Learnt mums voice prenatally or v. rapidly since birth?
No preference between dad and stranger…. Mum’s voice learnt prenatally.
Prefer mum’s voice as heard in womb rather than after birth (Moon & Fifer, 1990)
Speech pereception
(Mehler et al., 1988)
40 4-day-old French babies from monolingual families
Speech stimuli (French-Russian speaker talking about events from her life)
4 conditions: F-F R-R F-R R-F
Non-nutritive sucking technique
Infants could discriminate between familiar & unfamiliar language… and preferred the familiar language.
No effect observed when experiment was repeated with infants where French was not the home language.
Accents (Kitamura et al., 2013)
Explore the abilities of 6- and 9-month-olds to discriminate between accented speech in their own native language (AusE, AmE and SAE).
Infant fixation-controlled serial preference procedure (apart from study 3 and 6).
Study 1: 6-month-olds looked longer at AusE than SAE.
Study 2: 9-month-olds no significant difference in fixation time for AusE and SAE.
Study 3: 9-month-olds played accented speech (AusE v SAE) until there was a 50% reduction in fixation (becoming bored) then half played same accented speech and half played the other accented speech. No significant difference.
Study 4: 6-month-olds no significant difference between AusE and AmE fixation times.
Study 5: 3-month-olds fixated significantly longer on AusE than AmE
Study 6: 6-month-olds discriminate between AusE and SAE but not AusE and AmE
Accent findings
6-month-olds show accent preference; but only when unfamiliar accent utilised.
9-month-olds able to ignore differences in accents regardless of exposure.
Antecedent to ability to recognise words despite highly variant pronunciations.
Occurs outside of language exposure (e.g. SAE)
When exposed to different accents earlier on this developmental pattern shifts e.g. 6-month-olds ignore differences between AusE and AmE, high exposure due to tv, films, music in the home.
Later on in development accents become important for social reasons; by 5 years preference for native accent versus foreign accent (Kinzler, Dupoux, & Spelke, 2007)
Visual perception
Newborns have poor visual acuity
Limited ability to detect colour in newborn
Can’t track a a moving object smoothly at 2 months
Visual scanning
To perceive objects it is necessary to scan the object
1 month olds start by focusing on single feature then tend to scan the outer the outer edges of an object
2 months olds move in to scan the internal features. A shift from where things are to what things are
Pattern Perception (Fantz & Fagan, 1975)
As the visual system develops, a preference for complex stimuli increases
1 month prefer less complex. 2 month prefer complex
Face perception
3 stimuli based on faces
1 to 15 week old infants
Slight preference for natural face over others
Strong preference for face like over non-faces
Male and female faces
From 3-4 months visual preference for female faces (Johnson et al., 2021, Quinn et al., 2002)
Evidence from parental reports and observations indicates infants spend more time with females (Sugden et al., 2014)
Infants have been found to process female faces as individual stimuli whereas male faces are processed at summary category level (Quinn et al., 2002) not consistently found (Johnson et al., 2021), variance in stimuli utilised.
Face perception
Infants show a preference for ‘attractive faces’ (judged by adults) by 2 months (Slater et al., 1998), evident regardless of sex, age or race.
Attractive faces
Facial symmetry, facial averageness and sexually dimorphic traits affect adult ratings of faces.
Previous research mixed and methodological issues.
64 infants 12-24 months
Stimuli: male and female faces manipulated for 3 traits
Presented in pairs and fixation measured via eye-tracking
Face recognition (Pascalis et al., 1995)
Can infants recognise their mother using only visual information?
Study 1: 34 infants (72 to 120 hours old)
Live presentation of two female faces
Faces matched for complexion, hair colour and style
Olfactory cues blocked
Infants looked at mothers significantly longer than at stranger
Study 2: repeated with females wearing pink headscarf
Infants no longer looked longer at the mother’s face
Babies use external face contours not internal features.
Impact of masks
Adults and children impaired at learning and recognising faces that are masked (Stajduhar et al., 2022)
Utilised visual paired comparison task with 6- to 9-month old infants
2 (familiarisation stimuli masked v unmasked) x 2 (test stimuli masked v unmasked) design
Familiarisation phase (two identical images masked or not)
Test phase presentation of familiar face with a novel face (masked or not)
Infants showed preference for novel faces only when faces during test phase not masked
But relatively unaffected by faces being masked during familiarisation phase
Infants also looked at the upper part of face more when masks were present
Holistic face processing evident
Recognise a whole face when initial encoding is only part of face but unable to recognise part of face (e.g. masked) when initial input was whole face.
Species-specific face discrimination (Pascalis et al., 2002)
Adults are poor at discriminating non-human faces (Pascalis & Bechevalier, 1998)
6- & 9-month-old infants & adults
Habituation/ novelty-preference paradigm
6-month-olds distinguish between human faces and monkey faces
9-month-olds and adults only discriminate human faces
Own Race Effect? ( Timeo, et al. 2019)
Other race faces remembered less well than own race faces (Meissner & Brigham, 2001).
5- and 9-month-old Caucasian infants brain activity measured using FNIRS.
Shown male and female Caucasian and African faces for a maximum of 4 minutes & parents completed a scale measuring experience with other races
African faces resulted in greater brain activity than Caucasian
9-month-olds activation occurred in the right hemisphere
Greater activation overall for 9-month-olds
Brain specialization occurring between 5- and 9-months
Other studies have reported older children and adult’s greater activation for own race (Zhou et al., 2016), in infants’ greater activation may be due to novelty .
Size Constancy (Bower, 1965)
6- to 8-week-old infants
Conditioned to turn head and receive peekaboo as reward
Conditioned to turn head only when 30cm cube present and receive peekaboo as reward3 times more likely to turn head to 30cm cube 3m away than 90cm cube 3 m away
Object separation (Kellmen & Spelke, 1983)
When moving in unison, adults presume one object.
From 3months (2months in later studies) infants looks more at broken rod, suggesting they thought rod complete.
Newborns look more at completed rod, suggesting they treated it as two separate parts (Slater et al., 1990).
Depth perception (Gibson & Walk, 1960)
Infants aged 6-14 months (from crawling age)
Infant placed in the centre of the platform and encouraged to climb over deep side
If the infant does not have depth perception: expect to crawl across ‘deep’ side to get to mother
If the infant has depth perception: expect to refuse to crawl over deep sides
Depth perception is evident in 6-month-old infants
Is depth perception therefore innate?
Has it been learned over the first 6 months?
Depth PerceptionSchwartz et al. (1973)
5- and 9-month-old infants
Placed over deep and shallow side of platform
DV = heart rate
5-month-old infants heart rate decreased
Noticed a difference, but not fearful
9-month-old infants heart rate increased
Noticed a difference and fearful or excited?
Because of greater experience with the environment?
Olfactory Perception
Newborns turn head away from noxious substances e.g. ammonia (Rieser, Yonas, & Wilkner, 1976)
Prefer chocolate, bananas, honey over rotten eggs (Steiner, 1979)
But learning still takes place over development.
Many pre-schoolers do not find smells unpleasant that adults do.
We can continue to learn to discriminate smells into adulthood, e.g. wine.
When does learning start?
Cross-modal Perception(Meltzoff & Borton, 1979)
1-month-old infants given 2 dummies to suck
Different textures – smooth vs nobbled
Infants could not see dummies when placed in mouth
In the second phase of the experiment, infants shown enlarged pictures of the two dummies
Most babies preferred to look at the dummy they had just been sucking
i.e. had ability to match perceptual information across modalities
