1. Chapter Three
Tools for Exploring the World:
Physical, Perceptual, and Motor
Development

2. 3.1 The Newborn:
Learning Objectives
• How do reflexes help newborns interact with
the world?
• How do we determine whether a baby is
healthy and adjusting to life outside the
uterus?
• What behavioral states are common among
newborns?
• What are the different features of
temperament? Do they change as children
grow?

3. The Newborn’s Reflexes
• Reflexes: the newborn is born with unlearned
responses triggered by specific stimuli
– Certain reflexes have survival value
• rooting, sucking, eye blinks
– Other reflexes are developmental precursors
to later voluntary motor behaviors
• stepping a precursor to walking
• Reflexes reflect the health of the child’s
nervous system

4. Assessing the Newborn
• The five Apgar scores
1. Heart rate 2. Respiration
3. Muscle tone 4. Reflexes
5. Skin tone
• Each scored from 0 to 2; then summed
– Good physical condition: total of 7+
– Needs special attention: total of 4-6
– Life-threatening: total of 3 or less

5. Assessing the Newborn (cont’d)
• Neonatal Behavioral Assessment Scale
(NBAS)
– Includes 28 behavioral and 18 reflex items
– Assesses four systems
1. Autonomic: body regulation (e.g.,
breathing)
2. Motor: activity level and control of body
3. State: maintaining states (e.g., alertness)
4. Social: interacting with people

6. The Newborn’s States
• Alert inactivity: calm, eyes open and attentive;
deliberately inspecting environment
• Waking activity: open but unfocused eyes;
uncoordinated motions
• Crying: cries vigorously; motion is agitated and
uncoordinated
• Sleeping: eyes closed; degree of activity and
quality of breathing alternate

7. Crying
• Basic cry
– Starts softly and builds in volume and
intensity
– Often seen when the child is hungry
• Mad cry
– More intense and louder
• Pain cry
– Starts with a loud wail, followed by a long
pause, then gasping

8. Sleeping
• Newborns sleep an average of 16-18 hours/day
• Sleep cycles
– Newborns: 4-hour cycle; 3 hours sleep and 1
hour awake
– By 3 to 4 months: 5-to-6-hour cycle
– By 6 months: sleep 10 to 12 hours at night
• REM sleep
– 50% of newborn sleep
– 25% by 12 months

9. Co-sleeping
• The practice of sleeping in the same room or
bed with the child
• Much more common in cultures valuing
interdependence than independence
• Research shows no evidence of increased
dependence
• Co-sleeping has the advantage of avoiding
elaborate sleep-time rituals

10. Sudden Infant Death Syndrome (SIDS)
• SIDS: sudden, inexplicable death of a healthy
baby
• Risk factors
– Premature birth and low birth weight
– Parental smoking
– Child overheating and sleeping on stomach
– African-American infants (often sleep on
stomach)
• Reducing risk? Sleeping on back or sides

11. VIDEO: Preventing SIDS

12. Dimensions of Temperament
• Temperament: consistent styles or patterns of
infant behavior
• Number of temperament dimensions still
debated (ranging from 2 to 9)
• Rothbart’s (2007) three dimensions indicate
how much a child
– is generally happy, active, vocal, and seeks
stimulation (surgency/extroversion)
– is angry, fearful, frustrated, shy, and not easily
soothed (negative affect)
– focuses attention, is not easily distracted, and can
inhibit impulses (effortful control)

13. Rothbart’s Dimensions of
Temperament
• Three dimensions are not independent
– High effortful control predicts high
surgency/extroversion, but low negative
affect
• Scores during infancy predict personality in
adolescents and adults

14. Hereditary and Environmental
Contributions to Temperament
• Heredity and twin studies
– Identical twins are more similar in
temperament than are fraternal twins
– Heredity influences negative affect more
than other temperament dimensions
• Heredity contributes more to temperament in
childhood than during infancy

15. Hereditary and Environmental
Contributions to Temperament (cont’d)
Environment
• Asian babies are less emotional, whereas
Russian babies show more fear and negative
affect compared to Euro-American babies
• Parental characteristics influence
temperament
– Parental responsiveness reduces infant
emotionality
– Depressed mothers have more fearful infants

16. Hereditary and Environmental
Contributions to Temperament (cont’d)
Heredity and environment interact
• Temperament influences environment’s effect
on children
– Fearful children cheated more if disciplined
with power assertion, but less if parents
were nurturing and supportive
• Temperament influences how others treat the
child and his or her experiences

17. Stability of Temperament
• Studies suggest that temperament tends to
be somewhat stable from infancy through
adulthood
• Temperament predisposes, but does not
always guarantee, later personality
characteristics
• Parents can nurture children to behave in
ways somewhat different from their
temperament

18. 3.2 Physical Development:
Learning Objectives
• How do height and weight change from birth to
two years of age?
• What nutrients do young children need? How
are they best provided?
• What are the consequences of malnutrition?
How can it be treated?
• What are nerve cells, and how are they
organized in the brain?
• How does the brain develop? When does it
begin to function?

19. Growth of the Body
• Growth is more rapid in infancy than during
any other period after birth
• Infants double their weight by three months
• Infants triple their weight by one year
• Average is not the same as normal
– Children of the same age can vary greatly
in their heights and weights
• Height depends largely on heredity

21. Nutrition and Growth
• Rapid growth requires young babies to
consume large amounts of calories relative to
body weight
• Breast-feeding is the best way to ensure
proper nourishment
• Bottle-feeding has advantages and
disadvantages
– All family members can enjoy intimacy with bottle
– Formulas can promote proneness to allergies and
reduced immunity

22. Nutrition and Feeding
• New foods should be introduced one at a
time
• Growth slows at two years and children
become finicky eaters
– Finicky eating may have survival value
• Toddlers do not know which foods are safe and
stick with familiar foods
– Virtually all finicky eaters receive adequate
nutrition
– New foods still introduced one at a time

23. Malnutrition
• World-wide about 1 in 4 children under age
five are malnourished (UNICEF, 2006)
• Malnourished children develop more slowly
• Malnutrition is most damaging during infancy
due to rapid growth rate
• Giving malnourished children adequate diets
is challenging because they are listless, quiet,
and inactive
– These characteristics call less urgent
attention to the children’s needs

24. The Emerging Nervous System
• The brain and the rest of the nervous system
consist of cells known as neurons
• Neurons consist of a soma, dendrites, the
axon, and terminal buttons
• Terminal buttons release chemicals called
neurotransmitters

26. The Brain
• The brain has 50 to 100 billion neurons
• Cerebral cortex: the wrinkled surface of the
brain
• Hemispheres: the two halves of the brain
• Corpus callosum: the thick band of fibers
connecting the two hemispheres

27. The Making of the Working Brain
• The brain weighs about three-quarters of a
pound at birth – about 25% of an adult brain
• At around three years of age, the child’s brain
is about 80% of an adult’s brain weight

28. Emerging Brain Structures
• At 3 weeks after conception, the neural plate, a
flat structure of cells, forms
• By 28 weeks after conception, the brain has all
the neurons it will ever have
• In the 4th month of prenatal development,
axons begin to form the fatty sheath, myelin
– Helps speed neural transmission
– Improves coordination and reaction times
• Number of synapses peaks at 12 months
– Synaptic pruning: certain unnecessary synapses soon begin
to disappear

29. Growth of a Specialized Brain:
Brain-Mapping Methods
Methods to study origins and time course of
brain specialization
• Studying children with brain damage
• Measuring the brain’s electrical activity
through electrodes place on scalp (EEG or
electroencephalogram)
• Using magnetic fields to track brain blood
flow (fMRI, functional magnetic resonance
imaging)

30. Five General Principles of
Brain Specialization
1. Specialization is early in development
Ex.: newborns’ left hemisphere generates
higher electricity in response to speech
1. Specialization takes two specific forms
A. Specialized areas become more
focused and less diffuse
B. Stimuli triggering brain activity
become more specific than general

31. Five General Principles of
Brain Specialization (cont’d)
3. Different brain systems specialize at different
rates
Ex.: systems for sensory and perceptual
processes specialize before those for
higher-order processes
4. Environmental stimulation is necessary for
successful specialization
A. experience-expectant growth
B. experience-dependent growth

32. Five General Principles of
Brain Specialization (cont’d)
5. Plasticity is a benefit of the immature brain’s
lack of specialization
• Atypical experiences may disrupt normal
course of development (e.g., brain
damage disrupting speech)
• Plasticity: brain is very flexible, allowing
recovery of function, especially in young
children

33. Brain Specialization Principle:
Experience-Expectant vs.
Dependent-Growth
Experience-expectant growth
• All human brains require exposure to
experiences common to all individuals (e.g.,
exposure to faces) to fine-tune their circuits and
to have different regions specialize
Experience-dependent growth
• Brain circuits and regions also are fine-tuned
according to each person’s unique experiences
(e.g., learning to play the violin vs. learning to
play soccer)

34. VIDEO: Visual-Spatial Processing

35. 3.3 Early Motor Skills:
Learning Objectives
• What are the component skills involved in
learning to walk? At what age do infants
master them?
• How do infants learn to coordinate the use of
their hands?

37. Locomotion
• By 7 months, infants can sit alone
• Toddling: at around 14 months, toddlers may
stand alone briefly and walk without
assistance
• Dynamic systems theory
– Instead of simple maturation, motor
development involves many distinct skills
that are organized and reorganized over
time to meet specific task demands

38. Posture and Balance
• Infants are “top-heavy” and easily lose their
balance
• Within a few months, infants use inner ear
and visual cues to adjust posture
• Infants must relearn balance each time they
achieve new postures

39. Stepping
• Many infants move their legs alternately in a
stepping-like motion as early as 6-7 months
• Infants use environmental cues to judge
whether a surface is suited to walking (e.g.,
flat vs. bumpy)

40. Coordinating Skills
• Walking skills must be learned separately and
then integrated with others
• Differentiation: mastery of component skills
• Integration: combining components into the
sequence needed to accomplish the task
• Unsupported, independent walking occurs at
about 12 to 15 months, once children have
mastered and coordinated its component
skills

41. Cultural Impact on Motor Development
• Some cultural practices encourage certain
skills early and others discourage them
– Ex.: parents in Africa carry children
piggyback style, which promotes walking at
earlier ages than in the U.S.
– Ex.: in Paraguay, mothers constantly carry
toddlers, delaying motor skills
• Despite cultural differences in average age of
skill development, children acquire skills
within a normal range

42. Fine Motor Skills
• Fine motor skills are associated with
grasping, holding, and manipulating objects
• At 4 months, infants clumsily reach for
objects
• By 5 months, they coordinate movement of
the two hands
• By 2-3 years, children can use zippers but not
buttons
• Tying shoes is a skill that develops around
age 6 years

43. Handedness
• About 90% of children prefer to use their right
hand
• Most children grasp with their right hand by
age 12 months, with a clear preference seen
by preschool age
• Preference is affected by heredity, but
environmental factors also influences it
• Left-handedness has increased since U.S.
teachers stopped urging right-handedness

44. 3.4 Perception:
Learning Objectives
• Are infants able to smell, to taste, and to
experience pain?
• Can infants hear? How do they use sound to
locate objects?
• How well can infants see? Can they see color
and depth?
• How do infants coordinate information
between different sensory modalities, such as
between vision and hearing?

45. Coming to Know the World:
Smell and Taste Perception
• Perception: brain processes receiving, selecting,
modifying, and organizing sensory inputs
• Newborns have keen senses of smell and taste
– Odors: they distinguish pleasant from unpleasant,
or familiar from unfamiliar (e.g., mother’s breast or
perfume)
– Taste: they differentiate among salty, sour, bitter,
sweet, and changes in mother’s breast milk
– Facial reactions (e.g., lip licking) show they have a
“sweet tooth”

46. Coming to Know the World:
Touch and Pain
• Babies react to touch with reflexes and other
movements
• In reaction to painful stimuli, babies manifest
the pain cry – a sudden, high-pitched wail –
and they are not easily soothed

47. Coming to Know the World: Hearing
• Startle reactions suggest that infants are
sensitive to sound
• Infants hear less well than adults
• They best hear pitches in the range of human
speech (neither high nor low pitches) and
differentiate consonants from vowels
• They prefer pleasant more than unpleasant
melodies and can remember songs
• By 4 months, they recognize their own names

48. Coming to Know the World: Seeing
• Newborns respond to light and track moving
objects with their eyes
• Visual acuity (clarity of vision) is the smallest
pattern that can be distinguished dependably
• Infants at 1 month see at 20 feet what adults
see at 200-400 feet
• By 1 year, infants’ visual acuity is the same
as adults

49. Coming to Know the World: Color
• Cones: sets of neurons located along the
retina at the back of the eye, each specialized
to one of the three light wavelengths
• Newborns perceive few colors
• 3- to 4-month-old infants can perceive colors
similarly to adults

50. Coming to Know the World: Depth
Perception
• Visual cliff research
– 6-week-olds react with interest to
differences in depth (heart rate
deceleration)
– By 7 months, they show more fear than
interest to the cliff’s deep end (heart rate
acceleration and refusal to cross the deep
side)
– Fear of depth seems to develop around the
time babies can crawl

51. Coming to Know the World: Depth
Perception (cont’d)
Seven cues adults use to infer depth
Cues Closer compared to distant objects...
1. Kinetic cues … appear larger while moving
2. Visual expansion … fill more of the retina
3. Motion parallax … move faster
4. Retinal disparity … yield greater disparity
5. Sound … sound louder
Pictorial cues
6. Linear perspective … have wider parallel lines
7. Texture gradient … are coarser and distinctly textured

52. Coming to Know the World: Depth
Perception (cont’d)
• Few-week old babies use kinetic, visual
expansion, and motion parallax weeks after
birth to see depth
• Infants use sound to accurately gauge depth
• 4- to 6-month-old babies use retinal disparity
• 7-month-old babies use linear perspective
and texture gradient to see depth

53. Coming to Know the World:
Perceiving Objects
• Perceiving objects involves interpreting
patterns of lines, textures, and colors
• Object perception is limited in newborns, but
develops rapidly in the first few months
• By 4 months, infants use several cues to
discern that a stimulus is an object
– elements that move together
– similar colors and textures
– aligned edges

54. Perceiving Faces
• Newborns prefer to look at moving faces,
suggesting an innate attraction to them
• By 4 weeks, infants track all moving stimuli,
including faces and nonfaces
• Before 6 months, infants have a prototype of a face
that includes both human and nonhuman faces
• Between 6 to 12 months, the prototype is fine-tuned
to reflect familiar faces, which they prefer viewing
• By 7 to 8 months, infants process faces similarly to
adults, as a unique arrangement of features

55. Integrating Sensory Information
• Infants visually recognize objects they only
touched previously
• Infants soon begin to perceive the link
between visual images and sounds
• Intersensory redundancy: simultaneously
available multimodal sensory information
(e.g., sight, sound, touch)
– Infants perceive best when sensory information is
redundant
– Why? Brain regions specialized for a specific
sense are not yet developed

56. 3.5 Becoming Self-Aware:
Learning Objectives
• When do children begin to realize that they
exist?
• What are toddlers’ and preschoolers’ self-concepts
like?
• When do preschool children begin to acquire
a theory of mind?

57. Origins of Self-Concept
Self-awareness
• Mirror test: red rouge surreptitiously rubbed
on child’s nose; child placed in front of mirror
and behavior is observed
– 9-month-old infants smile at the image in
the mirror but do not seem to recognize it
as themselves
– By 15-24 months, infants see the image in
the mirror and touch their own nose,
suggesting they know the image is theirs

58. Origins of Self-Concept (cont’d)
•Toddlers look more at photographs of themselves
than other children
•Toddlers refer to themselves by name and use
personal pronouns “I” or “me”
• They use “I” in the present and in the past, showing awareness of
the self’s continuity over time
• Toddlers understand ownership, indicated by use of “mine” in
reference to possessions
•Preschoolers describe the self in terms of
possessions, physical characteristics,
preferences, and competencies

59. Theory of Mind (TOM)
• Theory of mind: naïve understanding of the
relationship between mind and behavior
• Develops in three phases (Wellman, 1993, 2002)
– Phase 1: by 2 years, aware of desires; speak of
wants and likes
• Understand that people have desires and that desires cause
behavior (e.g., “Ew peas; I not eat.”)
– Phase 2: by 3 years, distinguish the mental from
physical world
• Use mental verbs (“think”, “believe”, “forget”), but still emphasize
desires as main causes of behavior

60. Theory of Mind (TOM) (cont’d)
Phase 3: by 4 years, know that behavior can be
based on beliefs about events, even if belief is false
• False belief tasks
– Child hears story about Sally, who puts ball in the basket and leaves
– Child told the ball is moved from the basket to the box, which Sally does
not know
– Child is asked, “When Sally comes back, where will Sally look for the
ball ”
• 3 &1/2-year-olds: Sally will look in the box (wrong)
• 4-year-olds: Sally will look in the basket (correct)

61. Theory of Mind (TOM) (cont’d)
How does TOM develop?
• Could reflect expanding mental state language and
grammatical skills
• Might be due to interactions with others, who provide
insights into people with different mental states,
perspectives, feelings, intentions, moods
TOM and autism
• Autism spectrum disorder (ASD)
– Echoic speech and later language acquisition
– Obsessive and compulsive interest in objects
– Disinterest in other people

62. Theory of Mind (TOM) (cont’d)
• Autism spectrum disorder (ASD) (cont’d)
– Awkward social interactions with other people
– Do not follow rules governing social interactions
– Symptoms emerge around 18 to 24 months
– Diagnosed in 1 out of 200-300 U.S. children
– 80% of diagnoses are in boys
– Is heritable
– Atypical brain functioning; perhaps abnormal neurotransmitter
levels
– Cannot be cured, but medications and a supportive environment
help a lot

63. Theory of Mind (TOM) (cont’d)
• ASD and TOM
– Very slowly grasp false belief
– Some argue they may not have a TOM
» mindblindness is a defining feature of ASD
– Some attribute mindblindedness to other deficits
» cannot inhibit irrelevant actions
» have problems shifting smoothly between actions
– Some attribute to a “focused” processing style
» too much emphasis on perceptual details instead of the
bigger coherent picture