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Perceptual development (Y1) - Coggle Diagram
Perceptual development (Y1)
Difficult to obtain data from children due to their limited communication, ethics and a lack of control over innate variables, such as disorders we are not aware of
Sensory perception - touch, taste, smell, audition, balance, vision, proprioception and intermodal integration (how senses integrate for perception)
Methods for studying infant perception
sensation - sensory receptor neurons detect information and transmit it to the brain - this is a passive process; purely about sensing information, but not necessarily understand the information
Perception - the interpretation of sensory information; active process in which sensory information is transformed
Sensation occurs and is followed by perception
Integration of multiple senses improves memory - multiple encoding processes are helpful
To help perception, the brain has also adapted to integrate senses despite it coming in at different speeds or volumes
1950s - babies are born with some kind of sensory knowledge; tabula rasa belief diminished, and children can actually perceive information in the womb
Why study infant perception - motor and perceptual development fo together, as when we can perceive and understand the world, we can interact with it more
Implications for later development in areas of language, social and cognitive (learn where arm is in relation to mouth, we learn about distance and we learn spatial awareness, leading to better understanding in maths - learning where we are helps us learn where everything else is) development
Inform interventions for children with atypical perceptual development
Vision development is also important for learning perception
Methods of studying it - to assess infant perception, we must observe a behaviour that an infant can control and use that to infer perception
Methods used - preferential looking, habituation-dishabituation, high amplitude sucking and EEGs
First sign of learning and reflect their understanding of patterns and relationships
Preferential looking paradigm - Fantz (1958, 1961) - presented babies with visual stimuli, using live experimenter observations (baby in perspex box and with a chequerboard block that could be replaced with other stimuli)
Found that if babies spend more time gazing at one pattern, it is assumed they can remember an earlier stimulus, are interested in it and can discriminate between stimuli - found chequerboard more interesting
Assumption babies could remember and discriminate from previous board
Issues - human eye error, looking at eyes is not as accurate as eye tracking technology, experimenter bias as he did the tests himself
Fantz and Miranda - (1975) - newborn infants less than 7 days old
looking at eye movement, and recorded the looking times at curved or straight edged stimuli shown in pairs
Infants showed a preference for curved stimuli, looking at them more than 60% of the time
infants can discriminate different forms, with some appearing more interesting for infants than others
Also indicates that there is cognitive development as they moved their eyes to choose to spend longer looking at the other
Fantz - infants showed a preference for a drawing of a face over a bull's eye or a newsprint, but preferred these to coloured discs
At 2-3 months old, there was a higher percent of total fixation time for the face stimulus
at 4-6 months old, the fixation / interest time was more spread out between the 6 stimuli (more interested in plain colours) but they still mostly fixated on the face, which could be due to increased curiosity and cognition
Visual fixations of facial patterns - Haith et al (1977) - used infrared light detection to see where children were looking
1 month old infants - look longer at external features of the face, such as the chin and outer hairline
2 month old infants look longer at internal features - eyes and mouth
Talking produced an intensification of scanning in the eye area of the older group
3 months - infants can tell the difference between a mother and a stranger's face
This is likely due to higher cognitive and visual development levels at 2 months; we can normally only see contrasts in light at 1 month, but 2 month old babies have worked out that information mainly comes from the inner features for sensory information, and so their cognitive and visual focus changes
Face preference - newborns only a few minutes old were shown some patterns of faces that were all the same shape but had the features in different arrangements
A - correct face, B - upside down face, C - sideways features, D - blank face
If they looked just at image D, it would be a shape indication they were focused on
If they spent equal time on A,B and C, they are looking for contrast
If they spend the most time looking at A, there is a face mechanism, and we are genetically designed to want to look at faces
Follow up studies with babies older than a few days found that recognizing the mother was learned, but when she wore a headscarf it was harder for her to recognize
issues with this method - a visual preference may not equate to a cognitive discrimination - not always interest, could be fatigue, could have only just learned how to use eyes
The absence of a visual preference does not mean infants cannot discriminate; system may not have matured enough
Some infants may show a familiarity preference
Experimenter bias
General method - two stimuli presented to an infant, and researcher measures how long the infant spends looking at each one - if equal time is spent, then they are not differentiating between them
if they focus on one stimuli more than the other, it can be inferred this is the preferred image - suggests infants can distinguish between the two pictures and that the infant also finds the image more stimulating than the other one, giving an indication of what aspects of the environment are contributing to development
Easy to do if accurate measures of infant looking can be made
Contemporary research tends to film face for objective scoring and inter-observer reliability (eye fixations are also recorded to determine where they are focusing an what part of the stimuli most interests them)
Indicates stimulating aspects of the environment, indicating where learning is coming from
Pascalis et al (2002) - study in which adults and children were shown 4 faces, two monkey and two human, and were shown one of each first then the second one - adults were able to distinguish the novel stimuli of faces but not the monkeys, and the same happened in the 9 month old children
6 month old babies were however able to distinguish the novel face in both, suggesting a perceptual window for face processing which narrows in the first year - young children can distinguish faces of other species, with this being lost as you age
Face perception is specialized for own species in older children and this loss of ability for facial recognition may parallel the loss of ability that young children experience in speech perception
Habituation-Dishabituation - habituation refers to the decrease in response to a stimulus as a result of its repeated presentation
Infants can habituate to a visual stimulus - the longer infants are exposed to it, the shorter time they spend looking at it
Dishabituation - the recovery or increase in infant's response when a familiar stimulus is replaced by a novel one
Technique - infants are shown a stimulus repeatedly until they respond less to it - habituation
New stimulus presented, causing dishabituation
1-3 day old infants can habituate / dishabituate to visual stimuli (Friedman 1972)
If infant does not start looking at the second stimulus, it is assumed that they cannot differentiate between the two, but if they do it is assumed they are able to discriminate between stimuli
This is useful for detecting just how large or small a difference there needs to be between two stimuli for an infant to detect the difference between them
Constant encouragement to explore new things due to interest
Conditioning / high amplitude sucking: infants are provided with a special pacifier containing electrical circuitry -
DeCasper and Spence (1986) - pregnant women read one of three passages aloud 2x per day
Also used the father's voice and a stranger's voice to test if it was the mother specifically
Shortly after birth, headphones were placed on infants, and infants would alter their sucking rates for familiar passages
Infants carry out reinforced behaviours - if an experimenter conditions a baby to turn their head by reward, they can use this to test perception (have to wait for natural turn of head to reward)
If infants increase their sucking above a normal rate, they can be rewarded with a stimulus presentation - as long as this stimulus remains interesting, the infant will increase their sucking rate to hear it
However, their interest rate will naturally decreases at some point and sucking decreases, leading to a new stimuli being introduced
If sucking does not increase, a lack of discrimination between stimuli can be assumed
Measure of how well infants discriminate between different stimuli and allows infant to control environment
Electrocencephalography - EEG's; another way of determining what infants can sense is to present them with a stimulus and record their brain waves -
EEG is taken from the name of the overall method and is the general term for measuring electrical activity
increased activity = perception
Considerations of this technique with infants - informed parental consent, infant distress, levels of cooperation in infants when applying ERP cap / electrodes and reduced attention span on infants
Have to take a lot more data than you actually need to solve attrition rates etc
Sensory perception
Touch - earliest sense to develop in all species - 5 week embryos sense touch to the lips and nose
by 12 weeks, chin, eyes, arms and the rest of the body
True awareness (non-reflexive)- end of 2nd trimester
Infants have a sense of touch when born, demonstrated through the routing reflex (hands to mouth)
Steri et al (2000) - newborns can distinguish between two objects placed in their hands
Tactile stimulation - very important to infants, with preterm infants who receive massage gaining more weight, spending more time awake, and display more advanced cognitive and motor skills than do non-massaged pre term babies (Schanber and Field, 1987)
Infants are sensitive to pain, important for motor development and learning
Taste - most infants have a 'sweet tooth' - amniotic fluid / milk are sweet tasting
At birth, babies can distinguish between several tastes (Steiner et al 2001) - cannot recognize salty tastes at birth
At 4 months, infants prefer salty tastes to plain water, in preparation for solid food
Evolutionary purpose for sweet preference - less likely to be poisonous, and easier to digest
Smell - odour preferences at birth; Macfarlane 1975 - six day olds prefer the scent of their mother's breast pads over those of a stranger
Steiner, 1979 - smell of bananas / vanilla = relaxed pleasant facial expression, smell of rotten eggs, = infant frowns
Prefer sweet again to prevent accidental consumption of rotten or harmful food
Only sense to bypass thalamus (sensory pathways) - olfactory bulbs near amygdala and hippocampus explains why smell is associated with memory and emotions
Moving away from the smell means some cognition is growing
Audition - foetuses begin to hear in the third trimester of pregnancy (DeCasper and Spence, 1986)
Auditory perception is well developed in newborns
1-3 day old infants alter sucking rates to hear tape recording of mother's voice rather than a stranger (DeCasper and Fifer, 1980)
3 day old infants turn their heads in the general direction of a sound
Precise location of a sound improves over the first 6 months
Infants hear sounds best that have high pitches in the range of human speech (Jusczyk, 1995)
Newborns can make distinctions on many speech sounds; will listen to human speech longer than structurally similar non-speech, differentiate vowels from consonants, at 4 months old know own name
Infants have an auditory threshold about 4 times louder than the adult threshold
Hearing develops substantially in the first year - adult life, approx 10 years
Bilingual children taught language before first year of life complete will have no accent but after this point they form accents
Balance - the vestibular system located in the inner ear comprising of the semicircular canals (rotational acceleration) and the otilith organs (linear acceleration)
Both structures are filled with endolymph and contain sensory hair cells activated by the movement of the head
The vestibular sense - one of the first to develop in the foetus, by 5 months in utero this system is well developed and fully developed structurally before birth
Vestibular processing is subject to developmental change (Assainte and Amblard, 1995, 1993)
Proprioception - used to identify the position of body segments in relation to each other
4 sensory receptors providing information - muscle, tendon, joint and cutaneous receptors
Main development 3-5 months before birth - proprioceptive information improves dramatically between 5-8 years (Sigmundson et al 2000, von Hofsten and Rosblad, 1988)
Visual perception - infants are born with a complete visual system although it is not fully developed:
This is the least developed sense at birth, taking the longest to develop and requiring the most stimulation
But, it is the sense we depend upon the most for active exploration of the environment
Visual acuity - defined as motor or sensory responses to a threshold stimulus of known size at a known distance - optimal viewing about 30 cm, last to develop
Newborn visual acuity is 20/400 to 20/800 - 20/200 or worse is defined as legal blindness in adults; by 6 months, visual acuity is 20/25, and by 1 year it is normally at adult levels of 20/20
At 1 month, can only see contrasts, but as time continues they can see further away and in more detail
Contrast sensitivity - at birth, infants are sensitive to fine, high spatial frequency gratings, like their acuity are very poor but improve with age
Clarity of infant vision - infants prefer to look at patterned stimuli rather than plain stimuli
Colour perception - at birth, infants have the greatest sensitivity to intermediate wavelengths (yellow/green) and less to short (blue/violet) or long (red/orange)
Newborns can perceive few colours, but by 3-4 months newborns are able to see a full range of colours (Kellman, 1998)
At 1 week, infant can discrimiate desaturated red from grey
At 2 months, the infant can discrimnate the desturated blue from grey
By 3-4 months, the infants have colour perception similar to adults (Adams, 1995)
Practical and theoretical applications
Depth perception
infants have to develop this, they are not born with it - the images on the back of our eyes are flat and 2 dimensional - in order to create a 3D world, the brain combines information from the separate images of two eyes, known as retinal disparity
Parietal lobe - processing of somatosensory events and spatial awareness
Sensitivity to depth cues - kinetic (image moving or not relative to the eyes)
Binocular - one or two eyes
Pictorial - lines, textures, overlaps
Visual experience along with development in the brain lead to emergence of binocular depth perception around 3-5 months of age
Gibson and Walk's visual cliff experiment (1960) - early spatial knowledge:
Infants aged between 6-14 months were placed on the shallow side of a table and encouraged to crawl over visual cliff to caregivers
27/36 infants did not cross the visual cliff, suggesting that when infants are healthy and able to crawl, they can perceive depth
Newborn goats and chicks will not cross either
Intermodal perception
Campos et al (1981) - importance of experience - infants with 11 days crawling experience tesyed in a visual cliff task, about half crossed the deep side
Compared to infants with 41 days of crawling experience, of whom only 1/4 crossed to the deep side
The more crawling experience = more depth perception
Gibson and Walk's experiment demonstrated depth perception in the ages they studied:
Schwartz et al (1973) - placed 5-9 month olds on the shallow and deep sides of the visual cliff and measured their heart rates
Infant hear rates icnrease when they are frightened or scared / surprised, and slows during periods of increased attention
9 month old's heart rate increased when over deep side, but 5 month's old one decreased
The fact that their heart rates changed showed they noticed a difference in the sides at 5 months, but as it did not increase, there is no evidence that they recognise the drop
Experience is deemed more important in developing the depth perception needed to recognise the drop on the deep side of the visual cliff
Campos et al (1992) - heart rate of infants who could crawl increased when placed on deep side of the cliff, but the heart rate of similarly aged infants who could not had a HR decrease
In a similar study, infants who could not crawl on their own were given a wheeled walker and several hours of experience in moving it, and were then placed on visual cliff
HR increase in infants on deep side - this suggests that learning not to move to the deep side of the cliff is the result of experience that infants have gained from crawling
Lee and Aronson (1974) - moving room paradigm - tested infants sensitivity to balance and movement
Manipulated perceptual information
If the walls move forwards or backwards, toddlers aged 12-18 months will fall over, suggesting that vision dominates over vestibular system and proprioceptive information
Infants show correct sway responses even before they can sit unassisted
Active experience helps to tune the system - adults sway but do not fall over
Imitation of facial expressions - Meltzoff and Moore (1977) - suggested that newborns are capable of imitating facial gestures without ever having seen their own faces
Infants capable of imitating both tongue protustions and mouth opening, despite having seen no faces before - innate
Sensory integration for movement - to take in and make sense of their surroundings, infants must be able to balance the body and adjust their movements to remain steady
Intermodal perception - perception through multiple senses
Three sensory inputs or orientation - visual, vestibular (balance), and proprioceptive (receptors in skin, muscles, tendons and joints)
All three systems integrate to form a complete mental picture
Developmental coordination disorder - DCD / Dyspraxia: an idiopathic movement disorder affecting the development of fine and gross motor coordination skills
Affects 5-6% of children, continuing into adulthood, with problems manifesting in areas such as riding a bike, walking and riding
Wann et al (1998) - used the moving room paradigm to look at perceptual abilities of children with DCD
Children with DCD - postural responses to the swinging environment compared to TD controls
Indicates a greater reliance on visual information for individuals with DCD
Possibly to assist with poor intermodal sensory integration
Theoretical considerations
Differentiation theory - E.J Gibson (2000,2003) - the environment supplies most of the information required for perception - perceptual leaning (how to effectively use information from the environment in bottom up processing)
Two components to this - distinctive features and discrimination; infants search for invariant features in the environment - face perception
Over time, infants detect finer and finer invariant features such as depth perception
Perception is guided by affordances - the action possibilities that a situation offers an organism with certain motor abilities
Acting on the environment is vital for perceptual development
Constructivist theory - Gregory - the environment supplies inadequate sensory information
Perceptual learning uses models, ideas and scehmas to augment information from limited sensory inout (top-down procesisng)
Perception involves making inferences about what we see and trying to interpret this in a meaningful way
Sensory receptors receive information from the environment, which is then combined with previously stored information about the world that has been built up through experience
Muller-Lyer illusion - three lines all of one length, but arrow junctions and fork junctions change perception of line length - idea that environment transmits inadequate information, and we have to use what we know to interpret it correctly
We add to sensory stimulation by drawing on stored knowledge in order to perceive a meaningful world
Face perception
infants have frequent experience of faces from immediately after birth
Fantz (1961) - showed infants aged 1-15 weeks three stimuli based on a face
Three flat objects - one was a stylised face on a pink background, one with same features but scrambled, and one with a solid black area equivalent to the feature space taken up in the first two stimuli
Infants prefer to look at real faces rather than scrambled, and prefer real over the solid pattern
Infants prefer complex patterns - not looking because it is a face but rather because it is complex and more interesting
No understanding of the cause of their preference
Maurer and Barrera (1981) - overcame issue of this complexity by using the stimuli with 1-2 month old children
One was a normal face, one a symmetrical scrambled face and one an asymmetrical scrambled face
All had same features and were equal in complexity
No difference in how long each infant aged at 1 month old looked at each stimulus, and so any preference for natural faces at 2 months of age was more than just a preference for complex stimuli
Goren et al - newborns can recognise faces - showed a schematic face, a symmetrical schematic face or a blank face
Moved stimulus in an arc over their face and measured the infant's head and eye movements to assess how long she tracked each stimulus - infants track the schematic face more than the other two, suggesting they can detect face like stimuli from birth
Johnson et al (1991) - confirmed Goren's findings and also found that 3 month old infants no longer spent more time tracking the schematic face
Johnson and Morton (1991) - if children are shown moving faces, they a face preference at birth but not after 3 months
If children are shown static faces, they do not show face preference until about 2 months
Proposed early face recognition is based on two different processing systems - early system which operates during the first few weeks of life to draw the infant's attention to moving faces as they are the most important stimuli in the infant's environment
Such processing would be advantageous in helping infants select what is relevant in the world around them and by attending to moving faces, infants can learn about the different faces and then at 2 months a second processing system takes over
This contributes to the ability to distinguish between human faces and other stimuli and at this time, static faces can be distinguished
Much evidence has shown that very young infants have good face recognition skills and learn faces rapidly
Walton et al (1992) - showed 1-4 day old infants a video of their mother and a similar looking unfamiliar female, and all adults had a neutral expression
Video = no olfactory cues
Shown one face, if sucking happened then face remained, if they did not, other face appeared
If they did not suck at the second, first reappeared - infant controlled face they looked at
Measured number of sucks for mother's face and how often they sucked to keep the stranger's face in view
All but one of the infants in the study sucked to see their mother's face, and this showed that they can distinguish a specific familiar face, such as their mother's, at a very early age
Pascalis et al (1995) - confirmed Walton's findings and did a further study with the same method, but had the women wear headscarves
Found that the infants could not distinguish based on internal features alone, and so early recognition is based on external contours
Younger infants do respond to internal features when those features move - Meltzoff andMoore
Newborns can also recognize the eye gaze in pictures of faces
Farroni et al (2002) - tested infants who were 1-5 days old with pairs of pictures of the same adult female face
Females with eyes averted and female shown looking directly out of the picture
Infants spent more time looking at latter image
Field et al (1982) - showed newborn infants one of either happy, sad and surprised expressions until infants stopped looking at her and then the adult would change expression - when expression changed, they looked again
Can discriminate facial expressions
Slater et al (2000)
infants between 1 day and 1 week old presented with female faces - faces pre rated by adults, with half rated attractive and half rated unattractive
Infants shown one attractive and one unattractive face - infants spent longer looking at the attractive face, discriminating the same way adults did
Quinn et al (2008) - 3-4 month olds preferred attractive faces when they were looking at faces from other species, and so there is an early and general ability to recognise attractive faces (better survival? better genes?)
Kimura et al (2010) - Canonical colour recognition in infants: explored the ability of infants to recognise colours of everyday objects, including two colour-specific objects (human face and fruit) and a non-colour specific object (flower) using a preferential looking tehcnique
58 infants aged 5-8 months were tested with a stimulus composed of two colour pictures of an object placed side by side
Correctly coloured picture e.g. red strawberry and an inappropriately coloured one e.g. blue or green strawberry
6-8 month olds showed preference for the correctly coloured picture for colour specific objects, but showed no preference for non-colour specific objects
5 month olds showed no significant preference for the correctly coloured pictures for all object conditions, and these findings suggest that the recognition of canonical colour for objects emerges at 6 months of age
Clifford et al 2014 - memory and colour - these findings contrast the findings of Kimura et al
Showed stimuli of typically and atypically coloured faces
Infants at 5 months and 8 months looked equally at a presentation of natural and atypical coloured faces and the pattern of looking across hues was the same for face and phase-scrambled stimuli
These findings suggest that infants do not have memory colour at 5 months or at 8 months of age, contrary to previous findings which suggest that infants are able to use colour to recognise objects by 6 months of age
Infant knowledge of the world is constructed slowly from their exploration of objects, and indicate that the process of binding colour to objects is a complex computation that does not emerge until after 8 months of age
Memory colour for objects still needs to be explored