Chapter 3: Neonatal
Phase and Infancy
Developmental Psychology A Study Notes
Session 3
Louw, D. A. & Louw, A. E. (2022). Child and adolescent development (3rd
ed. Ch. 3). Psychology Publications.
Chapter Overview
The "baby years" cover the first two years of life, usually divided into the neonatal phase
and infancy. Although separated for academic purposes, the two phases should be regarded
as an integrated whole, and development in this period is closely linked to development
during the prenatal period.
This chapter covers two main sections:
The neonatal phase — the neonate's adjustment to basic life processes, reflexes,
perceptual skills, sleep/dreaming, feeding, neonatal learning, and individual differences.
Infancy — the infant's physical, cognitive, personality, and social development.
Context note: less than 3% of articles published in major journals include data from low- and
middle-income countries, where 90% of the world's infants live (Tomlinson et al., 2015).
3.1 The Neonatal Phase
Neonatal phase = the period between birth and four weeks old (Hill, 2021).
Historical view: until the 1960s, neonates were seen as doing little but eating, sleeping,
breathing, and crying.
William James (1890, p. 488) described the newborn's world as "one great blooming
buzzing confusion."
Piaget (1952) described the first month of life largely in terms of reflex movements.
Current view: neonatal development is far more advanced, and far more psychologically
significant, than initially believed.
3.1.1 The Physical Appearance of a New-Born Baby
Physically, a new-born is not conventionally attractive — appearance has been compared to
a "defeated boxer": swollen purple face, broad flat nose, swollen eyelids/eyebrow ridges,
skew-looking ears. First-time parents often need reassurance that these features are normal
and temporary.
, Bodily proportions differ markedly from adults (also see UCLA Health, 2020):
Head takes up about one quarter of total body size (adult: about one eighth); neck
muscles not yet strong enough to hold the head upright.
Arms and legs appear short relative to body/head, emphasised by exceptionally small
hands and feet.
Jaundice (yellowish skin colour) is common, arising because the liver is still physiologically
immature; usually resolves within 10–14 days (Mayo Clinic, 2021).
Weight: average new-born weighs 2.5–4.5 kg (commonly around 3.5 kg); lower in
communities where malnutrition is common.
New-born girls average 120 g lighter than boys; firstborns usually weigh less than later-
borns.
Up to 10% of birth weight may be lost in the first few days (fluid loss, poor intake, poor
digestion); weight regain begins by about day 5, with birth weight regained by day 10–14.
Length: average 45–56 cm; boys tend to be slightly taller than girls; linked to parental size,
race/sex, and maternal nutrition during pregnancy.
Heart rate: can reach 170 bpm when crying, or drop to 80–90 bpm at rest; a healthy
heartbeat ranges from 120 to 150 bpm.
3.1.2 Assessment of a New-Born Baby
Apgar Scale (US Library of Medicine, 2021) — designed by Dr Virginia Apgar in 1953 for
quantitative evaluation of critical physical characteristics of new-borns.
Applied twice: 1 minute and 5 minutes after birth.
Evaluates five aspects, remembered via the mnemonic APGAR: Appearance (colour),
Pulse (heart rate), Grimace (reflex irritability), Activity (muscle tone), Respiration
(breathing).
Each aspect scored 0, 1, or 2; scores summed (maximum = 10).
~90% of babies score 7 or higher (normal/healthy); 4–6 = poor; 0–3 = dangerous.
Table 3.1 — The Apgar Scale
Sign Score 0 Score 1 Score 2
Appearance (colour) Bluish-grey or pale all over Normal colour, but Normal colour all over;
hands/feet bluish palms, soles, mouth pinkish
Pulse (heart/pulse rate) Absent Below 100 bpm Above 100 bpm
Grimace (reflex irritability) No response Grimace (facial movement Cries, pulls away, sneezes,
only with stimulation) or coughs with stimulation
Activity (muscle tone) Limp Moderate; arms/legs flexed Active, spontaneous
with little movement movement
Respiration Absent (no breathing) Slow, irregular breathing, Normal rate/effort, strong
weak cry cry
Adapted from Cronjé et al. (2016); Steegers et al. (2019)
, Low scores → need for immediate medical care (suctioning airways, supplemental oxygen,
fluids, anticonvulsants, nutrition, antibiotics).
A low score — especially at 1 minute — does not necessarily mean the baby is unhealthy:
common after prematurity, high-risk pregnancy, Caesarean section, complicated
labour/delivery (John Hopkins Children's Hospital, 2021).
Prolonged low scores (at 5- and 10-minute assessments) may be associated with greater
risk of neonatal death and neurological disabilities (Padayachee et al., 2013).
Risk factors for low Apgar scores: gestational-length abnormalities (preterm or post-term),
congenital malformations, availability/quality of health care, and parental
health/demographic/socioeconomic characteristics.
3.1.3 Adjustment to Basic Life Processes
Although the shortest of the life stages, the neonatal stage requires drastic adjustment from
an almost "parasitic" prenatal existence to independent functioning (Cook et al., 2020; Health
Encyclopedia, 2021).
Blood circulation
Prenatally, mother and foetus have separate circulatory systems/heartbeats; the mother
purifies foetal blood via the placenta.
Birth forces a critical change-over beginning with the neonate's first breath; once the cord is
cut, the heart forces blood to the lungs, now responsible for aeration (oxygen provision).
Respiration
New-borns must now obtain oxygen independently (the cord previously handled gas
exchange); breathing begins on contact with air.
Mucus/amniotic fluid may hinder breathing — usually cleared with a suction device.
Anoxia (oxygen shortage) lasting more than a few minutes could cause brain damage.
The traditional "smack" to induce crying is now considered unnecessary/obsolete; rubbing the
back/chest is used to stimulate crying if needed.
Digestion
Cord severance cuts off the food source; feeding, digestion, and elimination are taken over
gradually (less abruptly than respiration/circulation).
Sucking/swallowing reflexes are present at birth but take practice to become rhythmic; no
established hunger cycle yet; feeding intervals vary 2–4 hours with considerable individual
differences.
Waste: dark green meconium (collected prenatally) is excreted first; faeces take on typical
form/texture after about 3 days, depending on nutrition.
Urination: minimal prenatally; postnatally very frequent — about 18 times per 24 hours.
Body temperature
Uterine temperature is about 38°C vs a pleasant SA room temperature of about 22°C — the
skin must adjust to act as an insulator.
Temperature is unstable during the first week; no fat insulating layer initially, so heat is lost
, rapidly; a fat layer develops over the first few weeks.
Babies raise their activity level to help maintain body temperature when ambient
temperature drops; sweat glands begin functioning at about 1 month, aiding heat/fluid
retention.
The nervous system
Similar to older children/adults, but the brain weighs only about 25% of an adult brain
(Kuther, 2019); the cerebral cortex is not fully developed.
Reflexes play a central role in functioning/survival — they allow adaptive responses before
learning has occurred (Santrock, 2019). Table 3.2 lists the most important reflexes.
Beyond the reflexes in Table 3.2, many others exist (winking, sneezing, vomiting, yawning,
swallowing, the erection reflex in male babies); the exact number of primitive reflexes
(present at birth) is disputed — a popular estimate is about 70 (Bilbilaj et al., 2017).
Debate: is the neonatal smile a reflex or a true expression of joy/happiness (Nagy, 2018)?
Pre-mid-20th-century view: new-born behaviour seen as primarily reflexive; assumed
limited capacity to feel/express emotion or interact meaningfully with caregivers.
Newer research: new-born smiles closely resemble social smiles (Meltzoff et al., 2017);
babies often move cheeks/brows before smiling, as if focusing attention on the caregiver's
face.
Caregiver smiling depends partly on the caregiver's own state (less likely if the baby is
crying) — babies gain the ability to regulate parental behaviour; eye contact + blink +
smile →
parents smile back, making the smile rewarding (Nagy, 2018).
Table 3.2 — Important Reflexes of Neonates
Reflex Stimulus Response Age of Significance
Disappearance
Asymmetric Active/passive head Extends arm/leg on face ± 4–6 months Prohibits rolling from
tonic neck reflex rotation left or right side, flexes other back to front, bringing
arm/leg ('fencer' hands to midline, or
position) reaching for objects
Babinski reflex Stroke sole of foot Toes spread out like a ± 6–12 months Unknown; absence or
fan later occurrence may
indicate neurological
defects
Moro reflex Sudden intense Stretches out arms/legs, ± 4–6 months May help baby cling to
stimulus, e.g. loud brings arms back to caretaker; absence may
noise midline ('self- indicate neurological
embracing') dysfunction; continuation
after 9 months could
indicate mental
retardation
Rooting reflex Stroke baby's cheek Turns head toward ± 5 months Helps to find nipple
stimulus and begins
sucking
Phase and Infancy
Developmental Psychology A Study Notes
Session 3
Louw, D. A. & Louw, A. E. (2022). Child and adolescent development (3rd
ed. Ch. 3). Psychology Publications.
Chapter Overview
The "baby years" cover the first two years of life, usually divided into the neonatal phase
and infancy. Although separated for academic purposes, the two phases should be regarded
as an integrated whole, and development in this period is closely linked to development
during the prenatal period.
This chapter covers two main sections:
The neonatal phase — the neonate's adjustment to basic life processes, reflexes,
perceptual skills, sleep/dreaming, feeding, neonatal learning, and individual differences.
Infancy — the infant's physical, cognitive, personality, and social development.
Context note: less than 3% of articles published in major journals include data from low- and
middle-income countries, where 90% of the world's infants live (Tomlinson et al., 2015).
3.1 The Neonatal Phase
Neonatal phase = the period between birth and four weeks old (Hill, 2021).
Historical view: until the 1960s, neonates were seen as doing little but eating, sleeping,
breathing, and crying.
William James (1890, p. 488) described the newborn's world as "one great blooming
buzzing confusion."
Piaget (1952) described the first month of life largely in terms of reflex movements.
Current view: neonatal development is far more advanced, and far more psychologically
significant, than initially believed.
3.1.1 The Physical Appearance of a New-Born Baby
Physically, a new-born is not conventionally attractive — appearance has been compared to
a "defeated boxer": swollen purple face, broad flat nose, swollen eyelids/eyebrow ridges,
skew-looking ears. First-time parents often need reassurance that these features are normal
and temporary.
, Bodily proportions differ markedly from adults (also see UCLA Health, 2020):
Head takes up about one quarter of total body size (adult: about one eighth); neck
muscles not yet strong enough to hold the head upright.
Arms and legs appear short relative to body/head, emphasised by exceptionally small
hands and feet.
Jaundice (yellowish skin colour) is common, arising because the liver is still physiologically
immature; usually resolves within 10–14 days (Mayo Clinic, 2021).
Weight: average new-born weighs 2.5–4.5 kg (commonly around 3.5 kg); lower in
communities where malnutrition is common.
New-born girls average 120 g lighter than boys; firstborns usually weigh less than later-
borns.
Up to 10% of birth weight may be lost in the first few days (fluid loss, poor intake, poor
digestion); weight regain begins by about day 5, with birth weight regained by day 10–14.
Length: average 45–56 cm; boys tend to be slightly taller than girls; linked to parental size,
race/sex, and maternal nutrition during pregnancy.
Heart rate: can reach 170 bpm when crying, or drop to 80–90 bpm at rest; a healthy
heartbeat ranges from 120 to 150 bpm.
3.1.2 Assessment of a New-Born Baby
Apgar Scale (US Library of Medicine, 2021) — designed by Dr Virginia Apgar in 1953 for
quantitative evaluation of critical physical characteristics of new-borns.
Applied twice: 1 minute and 5 minutes after birth.
Evaluates five aspects, remembered via the mnemonic APGAR: Appearance (colour),
Pulse (heart rate), Grimace (reflex irritability), Activity (muscle tone), Respiration
(breathing).
Each aspect scored 0, 1, or 2; scores summed (maximum = 10).
~90% of babies score 7 or higher (normal/healthy); 4–6 = poor; 0–3 = dangerous.
Table 3.1 — The Apgar Scale
Sign Score 0 Score 1 Score 2
Appearance (colour) Bluish-grey or pale all over Normal colour, but Normal colour all over;
hands/feet bluish palms, soles, mouth pinkish
Pulse (heart/pulse rate) Absent Below 100 bpm Above 100 bpm
Grimace (reflex irritability) No response Grimace (facial movement Cries, pulls away, sneezes,
only with stimulation) or coughs with stimulation
Activity (muscle tone) Limp Moderate; arms/legs flexed Active, spontaneous
with little movement movement
Respiration Absent (no breathing) Slow, irregular breathing, Normal rate/effort, strong
weak cry cry
Adapted from Cronjé et al. (2016); Steegers et al. (2019)
, Low scores → need for immediate medical care (suctioning airways, supplemental oxygen,
fluids, anticonvulsants, nutrition, antibiotics).
A low score — especially at 1 minute — does not necessarily mean the baby is unhealthy:
common after prematurity, high-risk pregnancy, Caesarean section, complicated
labour/delivery (John Hopkins Children's Hospital, 2021).
Prolonged low scores (at 5- and 10-minute assessments) may be associated with greater
risk of neonatal death and neurological disabilities (Padayachee et al., 2013).
Risk factors for low Apgar scores: gestational-length abnormalities (preterm or post-term),
congenital malformations, availability/quality of health care, and parental
health/demographic/socioeconomic characteristics.
3.1.3 Adjustment to Basic Life Processes
Although the shortest of the life stages, the neonatal stage requires drastic adjustment from
an almost "parasitic" prenatal existence to independent functioning (Cook et al., 2020; Health
Encyclopedia, 2021).
Blood circulation
Prenatally, mother and foetus have separate circulatory systems/heartbeats; the mother
purifies foetal blood via the placenta.
Birth forces a critical change-over beginning with the neonate's first breath; once the cord is
cut, the heart forces blood to the lungs, now responsible for aeration (oxygen provision).
Respiration
New-borns must now obtain oxygen independently (the cord previously handled gas
exchange); breathing begins on contact with air.
Mucus/amniotic fluid may hinder breathing — usually cleared with a suction device.
Anoxia (oxygen shortage) lasting more than a few minutes could cause brain damage.
The traditional "smack" to induce crying is now considered unnecessary/obsolete; rubbing the
back/chest is used to stimulate crying if needed.
Digestion
Cord severance cuts off the food source; feeding, digestion, and elimination are taken over
gradually (less abruptly than respiration/circulation).
Sucking/swallowing reflexes are present at birth but take practice to become rhythmic; no
established hunger cycle yet; feeding intervals vary 2–4 hours with considerable individual
differences.
Waste: dark green meconium (collected prenatally) is excreted first; faeces take on typical
form/texture after about 3 days, depending on nutrition.
Urination: minimal prenatally; postnatally very frequent — about 18 times per 24 hours.
Body temperature
Uterine temperature is about 38°C vs a pleasant SA room temperature of about 22°C — the
skin must adjust to act as an insulator.
Temperature is unstable during the first week; no fat insulating layer initially, so heat is lost
, rapidly; a fat layer develops over the first few weeks.
Babies raise their activity level to help maintain body temperature when ambient
temperature drops; sweat glands begin functioning at about 1 month, aiding heat/fluid
retention.
The nervous system
Similar to older children/adults, but the brain weighs only about 25% of an adult brain
(Kuther, 2019); the cerebral cortex is not fully developed.
Reflexes play a central role in functioning/survival — they allow adaptive responses before
learning has occurred (Santrock, 2019). Table 3.2 lists the most important reflexes.
Beyond the reflexes in Table 3.2, many others exist (winking, sneezing, vomiting, yawning,
swallowing, the erection reflex in male babies); the exact number of primitive reflexes
(present at birth) is disputed — a popular estimate is about 70 (Bilbilaj et al., 2017).
Debate: is the neonatal smile a reflex or a true expression of joy/happiness (Nagy, 2018)?
Pre-mid-20th-century view: new-born behaviour seen as primarily reflexive; assumed
limited capacity to feel/express emotion or interact meaningfully with caregivers.
Newer research: new-born smiles closely resemble social smiles (Meltzoff et al., 2017);
babies often move cheeks/brows before smiling, as if focusing attention on the caregiver's
face.
Caregiver smiling depends partly on the caregiver's own state (less likely if the baby is
crying) — babies gain the ability to regulate parental behaviour; eye contact + blink +
smile →
parents smile back, making the smile rewarding (Nagy, 2018).
Table 3.2 — Important Reflexes of Neonates
Reflex Stimulus Response Age of Significance
Disappearance
Asymmetric Active/passive head Extends arm/leg on face ± 4–6 months Prohibits rolling from
tonic neck reflex rotation left or right side, flexes other back to front, bringing
arm/leg ('fencer' hands to midline, or
position) reaching for objects
Babinski reflex Stroke sole of foot Toes spread out like a ± 6–12 months Unknown; absence or
fan later occurrence may
indicate neurological
defects
Moro reflex Sudden intense Stretches out arms/legs, ± 4–6 months May help baby cling to
stimulus, e.g. loud brings arms back to caretaker; absence may
noise midline ('self- indicate neurological
embracing') dysfunction; continuation
after 9 months could
indicate mental
retardation
Rooting reflex Stroke baby's cheek Turns head toward ± 5 months Helps to find nipple
stimulus and begins
sucking
