Notes for Units 2-8 PYSC228 - Athabasca University

Unit 2 – Infancy
Lesson 3: Physical and Cognitive Development in Infancy: the First Two Years
Learning Objectives
1. Differentiate the two primary growth patterns.
- When you’re born you weigh 3.4Kg and are 48cm long. By age 2 you’re 3x your
weight and 2x your height
- There are 2 major growth processes that begin prenatally
1. Cephalocaudal pattern of growth: Growth from the head downwards (head
develops first followed by what is more down)
2. Proximodistal pattern of growth: growth from the inside of the body towards the
outside (trunk of the body develops faster than the arms or the legs)
2. Discuss infant brain development, including the concepts of synaptic pruning and
plasticity.
- Given the cephalocaudal pattern of growth, the brain develops very quickly in the 1 st
2 years of life
- The brain goes form 2500 synapses @ birth  10 000 @ age 2
- Myelination also happens to increase impulse travel rates
- Synaptic connections that are constantly activated get strengthened. Those that don’t
are discarded by synaptic pruning
- The potential for systematic change w/i a person to fit their environment is called
plasticity. The human brain is extremely plastic during infancy
3. Describe the importance of experience and sleep in brain development.
- 2 processes related to early experience and brain development
1. Experience-expectant processes: brain development that occurs based on
environmental experiences that all members of the species typically encounter.
(e.g. for normal visual and auditory development one must see light and hear
sound)
2. Experience-dependent processes: brain development that occurs based on unique
environmental stimuli shared by only individuals in particular environmental
circumstances (e.g. repeated exposure to the sounds of a language helps the child
create those sounds)
- Most brain development occurs during sleep. Where infants sleep 10 – 19 hours. But
they wake up frequently most notably due to immature brain development
- Infant sleep-wake cycles are controlled by the brain-stem which needs to be trained
- Rapid eye movement (REM) sleep: sleep that aids in learning and memory
consolidation. Newborns spend 50% of sleep on REM sleep. By age 2 it’s 20-25%
- The other category of sleep is non-REM sleep (NREM).
4. Describe the newborn reflexes and development of gross and fine motor skills.
- A reflex is a quick and simple neural pathway that involves few neurons of the PNS
- Some reflexes are for survival while others disappear over time. They include
1) Planter grasp: flexing of the toes when applied pressure. Appears 28 wks
gestation and is integrated @ 9 mo
2) Babinski (planter response): Fanning out of toes when outside of the foot is
stimulated. Appears birth to 12-18 mo and is integrated after walking

, 3) Moro: shoulders pull back and fingers, elbows and wrists extend after head
and neck drop to the other hand. Appears 28 wks gestation and integrated at 5-
6 mo
4) Palmar grasp: Infants flex around the finger. Appears 10 wks gestation and
integrated 4-6 mos
5) Rooting and sucking: infant turns head with mouth open twds finger and
attempts to suck on finger. Appears 28 wks gestation, integrated 3 mos
6) Stepping or walking: alternating, rhythmical, coordinated steps. Appears 37
wks gestation, integrated 2 mos
7) Crawling: infant pulls legs underneath abdomen and pushes forward. Appears
at birth, integrated 3-4.
8) Tonic neck: infant adopts fencer position when on the back. Appears at birth,
integrated 6-7 months.
- Gross motor skills: skills that use the large muscle groups such as those in the legs or
arms
- Fine motor skills: skills that use smaller muscle groups such as those of the fingers
and eyes
- Most newborn movements are involuntary responses to sensory stimulation. By the
end of infancy they have developed many gross and fine motor skills due to
integration of the muscular and nervous system
5. Discuss Piaget’s sensorimotor stage and associated sub-stages.
- Sensorimotor stage: Piaget’s first stage of cognitive development, in which infants
develop from reflex-driven organisms to more complex and symbolic thinkers
- From one stage to another requires assimilation and accommodation and requires
schemes (mental structures that help us organize and process information)
- Object permanence: infants develop a concept of objects that goes beyond immediate
sensory contact (remembering a hidden toy)
- Sub-stages
1. Reflexes (birth – 1 mo)
2. Habits and repetition (1 – 4 mo) doing reflexive habits without stimulation
3. Actions with objects (4 – 8 mo) doing things with objects (e.g. Grasping)
4. Coordination of schemes and intentional behaviour (8 – 12 mo)
5. Using objects in novel ways (12 – 18 mo)
6. Symbolic thought (18 – 24 mo) e.g. think about a toy even if it’s not present.
If an infant can’t do it’s A not B error
6. Describe the development of memory and the methods used to measure memory.
- It is very difficult to measure memory in infants
- There are 2 kinds of memory
1. Implicit memory: repetition of a behaviour, such as leg movement to make an
object move, that occurs automatically and without apparent conscious effort
2. Explicit memory: repetition of a behaviour that shows a clear, observable,
conscious effort to recall an event such as when an infant imitates at a later time a
behaviour seen earlier
- Imitation requires infants to internalize a behaviour and then repeat it. They need to
learn deferred imitation which occurs at 6-7 months which is the ability to imitate
when there is a delay in imitation

, - Infants must concentrate to remember objects
- A way to measure LTM in infants is Carolyn Rovee-Collier’s crib mobile test
1) Infants can form LTM but it’s very specific. E.g. if they learn to kick a mobile
in one room they won’t remember to do it in another room
7. Discuss language development in terms of expressive and receptive features.
- Receptive language: language that an infant understands but may not be able to
produce (comprehension)
- Expressive language: language that an infant can produce (production)
- Expression is the most complex because it requires understanding another person’s
perspective, the motor control to produce sounds and cognitive awareness of the
meaning of those sounds
- Noam Chomsky proposed that humans have an inborn language acquisition device
(LAD) which is a theoretical structure possessed by all humans that prewires us to
learn language and grammar rules, two areas are involved: Wernicke’s and Broca’s
area
- The interactionist approach is a view of language learning that stresses the role of
socialization. The more language parents use with their children increase language
acquisition
8. Describe the key features of sensory development in terms of vision, hearing, taste, and
smell.
- Sensation is the physical reception of stimulation
- Vision: Newborns have 20/120 + 20/240 vision. Therefore very poor visual acuity.
During the 1st moth their focal length is able see their mothers face. By 1 year of age
infants can see like adults. By 2 wks infants can discriminate btw colours and by 4
mos they have fully developed colour perception b/c cones are still developing until
this point
- Hearing: Starts 3-4 months before birth when the ear is fully formed and functional.
Infants respond reflexively to soft stimuli and simple auditory signals. They prefer
sounds like those they heard in the womb. Their hearing improves btw 4-7 mos where
they move their eyes in the direction of the sound
- Taste and Smell : Infants are adapted to their mothers bodies so it’s her familiar taste
and smell that hep newborns feel secure. At 1 wk they turn away from smells they
don’t like. They have well-developed taste abilities at birth
9. Discuss the perception of depth and pain.
- Depth perception: visual cliff method. Younger infants are more likely to “fall over
the cliff” compared to older cliffs
- Pain perception: newborns feel pain contrary to popular belief. Breastfeeding is a
potent painkiller in newborns
10. Discuss the issues around infant immunization and the benefits of breastfeeding.
- Lately immunization has become an issue. There was an incorrect article about the
relationship btw autism and vaccination that caused a development of anti-vaxxers
- Breastmilk gives the child all the nutrients it needs and also contains many factors
that protect from infection, and aid in digestion and nutrient absorption. It also
prevents childhood obesity. It is also associated with cognitive benefits. It is also
good for the mother because it delays back to fertility by 6 months which is
associated with increased health benefits

, - Vaccine hesitancy: delay or refusal to get vaccines b/c of concerns about it
- Approximately 14 immunizations by age 2
- Younger, less eduacated mothers are more likely to breastfeed
11. Describe the issues associated with breast milk substitutes and malnutrition.
- Less nutrition and immunity benefits. People back in the 1920s thought it would lead
to diseases. But it may be influenced by SES as well, where low-SES women may not
have the access to areas where they can breastfeed
- Malnutrition is the deficiency of nourishment (not food) to the body. The most
common cause is protein-energy malnutrition (PEM) which occurs when there is a
lack of food or a dietary imbalance
- Highest rate of malnutrition is in South Asia
- In developing countries, infants who are not breastfed are 10x more likely to die
12. Discuss the issues of infant sleep.
- The dominant Western medical model of infant care says that infants should sleep
separately from their mothers that night wakings should be treated with behavioural
interventions like gradual extinction or “controlled crying.” A mother may suffocate
her child by accident in her sleep
- Our evolutionary past shows the normality and necessity of mother-infant co-
sleeping. It was especially important for breastfeeding
- But evolutionary conditions may be different to modern conditions of life so this may
not be applicable anymore
- Research shows that modern parenting strategies are associated with negative
outcomes like gastrointestinal infection, dehydration, failure to thrive, attachment
issues
- SIDS: occurs once every 3000 births
1) Risk factors include: sleeping on stomach, maternal smoking, hot rooms

- Performance underestimates competence

Study Questions
1. Describe the role of experience in brain development and the two types of processes:
experience-expectant and experience-dependent. Provide original examples of the two
types of processes.
2. Describe the difference between gross and fine motor skills. What has the cross-cultural
study of early motor development revealed?

3. Describe Piaget’s sensorimotor stage. What is object permanence and why is it
significant? What is the A-not-B error, and how is it related to object permanence?
4. Describe language development in terms of expressive and receptive abilities. Describe
the explanation for language development that involves the language acquisition device
(LAD). What is the interactionist approach to language development?
5. Summarize the development of vision in terms of acuity, focal length, and colour vision.
Describe the major milestones in hearing from birth to the first year.