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Growth and Development Across Childhood and Adolescence

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Overview: Principles of Child Development

1. Gross motor - large muscle control, posture, locomotion
2. Fine motor/adaptive - hand-eye coordination, problem-solving
3. Language - receptive and expressive communication
4. Personal-social - self-care, interaction with others

• Delay - below average in one or more streams
• Deviancy - milestones occurring out of sequence
• Dissociation - major difference in rate between streams (e.g., motor delay with normal cognition in cerebral palsy)

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1. INFANTS (Birth to 12 Months)

Physical Growth

• Birth weight: Average ~3.4 kg
• Weight gain: ~30 g/day in first 3 months; birth weight doubles by 5 months, triples by 12 months
• Length: Increases ~50% by end of year 1 (birth length ~50 cm → ~75 cm at 12 months)
• Head circumference: Grows ~2 cm/month for first 3 months, then ~1 cm/month until 6 months; birth HC ~34 cm → ~46 cm at 12 months
• Fontanelles: Posterior closes by 6-8 weeks; anterior closes by 9-18 months
• Teeth: First tooth (lower central incisor) typically at 6-8 months

Primitive Reflexes (Neonatal Period)

Postural Reactions (Prerequisites for Motor Skills)

Developmental Milestones - Infancy

• Gross motor: Raises chin off surface in prone; strong head lag when pulled to sit
• Fine motor: Grasp reflex present
• Language: Alerts to sound, cries
• Social: Fixes and follows face briefly

• Gross motor: Raises chest off surface in prone
• Fine motor: Hands predominantly open
• Language: Social smile; cooing, vowel sounds ("ooh", "aah")
• Social: Recognizes parent's face; regards face

• Gross motor: No head lag; rolls from prone to supine; bears weight on forearms in prone
• Fine motor: Reaches for objects; hands come together at midline
• Language: Laughs aloud; squeals; turns to sound
• Social: Smiles spontaneously and frequently; enjoys social interaction

• Gross motor: Rolls both ways; sits with tripod support; bounces when standing with support
• Fine motor: Transfers objects hand to hand; raking grasp; reaches with one hand
• Language: Babbles (consonant-vowel chains: "bababa", "mamama")
• Social: Recognizes familiar faces vs. strangers; mirrors own image

• Gross motor: Sits independently; pulls to stand; crawls or commando-crawls
• Fine motor: Pincer grasp emerging (thumb-finger opposition); bangs objects
• Language: "Mama"/"dada" non-specifically; responds to own name; waves bye-bye
• Social: Stranger anxiety begins; object permanence developing; peek-a-boo

• Gross motor: Walks with one-hand support; stands alone momentarily; cruises along furniture
• Fine motor: Mature pincer grasp well established; releases objects voluntarily; turns pages (several at once)
• Language: 1-2 meaningful words besides "mama"/"dada"; follows simple commands with gesture
• Social: Imitates actions; comes when called; plays pat-a-cake

Cognitive Development (Piaget: Sensorimotor Stage)

• Infant learns entirely through senses and motor actions
• Object permanence (understanding that objects exist when out of sight) develops around 8-9 months - this is why stranger and separation anxiety begin here
• By 12 months: understands cause-and-effect, intentional problem-solving

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2. TODDLERS (12 Months to 3 Years)

Physical Growth

• Weight: Gains ~2-3 kg/year (slowing from infancy); birth weight quadruples by ~2.5 years
• Height: Gains ~12 cm in the 2nd year, then ~6-8 cm/year through preschool
• Head circumference: Growth slows significantly; adult HC (~55 cm) approached by 5-6 years
• Body proportions: Protruding abdomen, lordotic posture, wide-based gait are all normal in toddlers
• Teeth: Primary (deciduous) dentition complete by ~2.5 years (20 teeth total)

Developmental Milestones - Toddler

• Gross motor: Walks independently (wide-based gait); creeps up stairs; stoops and recovers
• Fine motor: Builds tower of 2 blocks; marks with crayon; uses spoon (messily); turns book pages several at a time
• Language: 4-6 meaningful words; may use jargon
• Social: Indicates wants by pointing; drinks from cup; brings objects to show caregiver

• Gross motor: Runs (stiffly); throws ball overhand; climbs furniture; walks up stairs with one hand held
• Fine motor: Tower of 3-4 blocks; scribbles spontaneously; removes shoes/socks; uses spoon/fork
• Language: 10-25 words; points to body parts; echoes words; follows 2-step commands
• Social: Parallel play begins; temper tantrums emerge; stranger anxiety may persist; shows affection

• Gross motor: Runs well; walks up and down stairs with 2 feet per step; kicks ball; jumps in place
• Fine motor: Tower of 6-7 blocks; imitates vertical and circular strokes; turns pages one at a time; uses a fork
• Language: 50+ words; 2-word phrases ("more juice", "daddy go"); 50% of speech intelligible to strangers; uses pronouns (I, me)
• Social: Parallel play; begins symbolic play (feeding doll); toilet training readiness begins; very egocentric

• Language: 3-word sentences; 75% intelligible; names body parts; uses plural words
• Fine motor: Differentiates horizontal and vertical strokes; tower of 8 blocks
• Social: May start cooperative play; beginning of "mine" concept; increased autonomy-seeking

• Gross motor: Rides tricycle; walks up stairs alternating feet; stands on one foot briefly (2-3 seconds); broad jumps
• Fine motor: Tower of 9-10 blocks; copies circle; uses scissors (with help); begins dressing/undressing
• Language: 3-word sentences; 75% intelligible to strangers; uses past tense; knows full name and age; 200+ word vocabulary
• Social: Group play begins; shows gender-role awareness; toileting mostly independent by day; magical thinking begins

Cognitive Development (Piaget: Pre-Operational Stage begins ~2 years)

• Language begins to represent objects (symbolic thought)
• Egocentric thinking dominates - cannot take another's perspective
• Animism - attributes life to inanimate objects
• Magical thinking - believes wishes can cause events

Key Behavioral Themes in Toddlerhood

• Autonomy vs. shame/doubt (Erikson) - this is the core developmental conflict; children assert independence, leading to the "terrible twos"
• Temper tantrums peak at 18 months-2 years; normal response to frustration and limited language
• Separation anxiety normally peaks at 9-18 months; school-readiness requires its resolution
• Toilet training: Most children have physiologic and developmental readiness between 18-36 months

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3. PRESCHOOLERS (3 to 5 Years)

Physical Growth

• Height: ~6-7 cm/year gain; legs elongate and body proportions become more adult-like
• Weight: ~2 kg/year; body fat decreases, muscle mass increases
• Brain development: By age 5, brain is ~90% of adult weight; massive myelination and synaptic pruning ongoing
• Vision: Visual acuity matures to 20/20 by age 5-6

Developmental Milestones - Preschool

• Gross motor: Hops on one foot (4+ times); skips (one-sided); throws overhand; catches a bounced ball; walks down stairs alternating feet; pumps on a swing
• Fine motor: Copies cross (+); cuts with scissors; uses fork/spoon and sometimes knife; draws a person with 3 parts; buttons large buttons
• Language: 4-5 word sentences; fully intelligible to strangers; counts to 4; tells stories; uses past/future tense; asks "why" constantly; 1,500-word vocabulary
• Social: Associative/cooperative play; has friends; dramatic play and role play; follows 3-4-step commands; knows gender; distinguishes fantasy from reality begins

• Gross motor: Skips alternating feet; jumps rope; catches ball with hands (not arms); balances on one foot 10 seconds; rides bicycle with training wheels
• Fine motor: Copies square and triangle; draws person with 6 parts; prints some letters; ties shoelaces (some); uses knife for spreading
• Language: Fully intelligible; complex sentences; 2,000+ word vocabulary; counts to 10; defines words by use; knows address and phone number; uses all parts of speech
• Social: Cooperative play; understands rules; shares and takes turns; best friends; prefers same-sex play partners; school-readiness

Cognitive Development (Piaget: Pre-Operational continued)

• Symbolic play flourishes - elaborate pretend scenarios
• Centration - can focus on only one aspect of a situation at a time (pre-logic)
• Conservation not yet mastered (the classic water/clay problem)
• Egocentrism persists but slowly declines; beginning of empathy
• Preoperational substages: Symbolic function (2-4 yrs) → Intuitive thought (4-7 yrs)

Key Behavioral Themes in Preschool

• Initiative vs. guilt (Erikson) - child initiates activities and play; guilt arises from perceived misbehavior
• Oedipal/Electra complex (Freudian theory) - gender identity and identification with same-sex parent
• Fears - of the dark, monsters, "bad" things; nightmares and sleep disruptions common
• Discipline: Consistent, positive reinforcement strategies most effective; time-out appropriate at this age
• School readiness by age 5 requires: self-care, ability to separate, basic self-regulation, understanding simple instructions

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4. SCHOOL-AGE CHILDREN (6 to 12 Years)

Physical Growth

• Height: ~5-6 cm/year in girls; ~5-7 cm/year in boys
• Weight: ~2-3 kg/year
• Body composition: Girls begin to accumulate fat; boys increase muscle mass slightly
• Teeth: Primary teeth shed starting ~6 years; permanent teeth replace them; all 28 permanent teeth (excluding wisdom teeth) erupt by ~12 years
• Brain: Continued pruning and myelination, especially prefrontal cortex (executive function)
• Pre-pubertal growth spurt: Begins earlier in girls (~10-11 years) than boys (~12-13 years)

Developmental Milestones - School Age

• Gross motor: Rides bicycle without training wheels; skips, hops, jumps well; team games
• Fine motor: Copies diamond shape; writes legibly; draws with perspective; uses all utensils
• Language: Reads simple sentences; 10,000+ word vocabulary; understands sarcasm and jokes; uses complex grammar
• Cognitive: Concrete operations begin (Piaget) - conservation of number, then mass, then volume; logical thinking about concrete objects
• Social: Rule-bound games; strong group identity; "chums" (Sullivan) - same-sex best friendships become key to mental health

• Cognitive: Masters conservation; can seriate and classify objects; reversibility of thought; understands time concepts
• Social: Peer group takes on huge importance; school performance is central to self-concept; "industry vs. inferiority" (Erikson)
• Emotional: Internalization of moral standards (right vs. wrong); conscience development; pride and shame tied to achievement

• Cognitive: Early formal operational thinking in some children - abstract reasoning begins
• Social: Peer pressure intensifies; cliques form; increasing time with peers and less with family
• Physical: Girls typically enter puberty (see below); boys may begin early pubertal changes

Cognitive Development (Piaget: Concrete Operational Stage, ~7-12 years)

• Conservation: Understands that quantity is unchanged despite change in appearance
• Seriation: Can arrange objects in sequence (size, weight)
• Classification: Can group objects by multiple attributes
• Reversibility: Can mentally undo an operation
• Decentration: Can consider multiple aspects of a problem simultaneously
• Still limited to concrete objects - abstract, hypothetical reasoning not yet consistent

Key Behavioral Themes in School Age

• Industry vs. inferiority (Erikson) - competence and mastery in skills; failure leads to feelings of inadequacy
• Moral development (Kohlberg: Conventional level begins) - rules are sacred; fairness is key; authority is respected
• Peer relationships: Friendships become deeper and more selective; peer acceptance is crucial for self-esteem
• Academic skills: Reading fluency by grade 2-3; multiplication and division by grade 3-4; abstract reading comprehension by grade 5-6
• Sleep: 9-11 hours/night recommended for school-age children
• Screen time: AAP recommends consistent limits; quality of content matters more than quantity at this age

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5. ADOLESCENTS (12 to 18+ Years)

Physical Growth and Puberty

Female Puberty (Tanner Stages)

• Thelarche (breast development) is typically the first sign in girls, average age 10-11 years
• Menarche occurs about 2-2.5 years after thelarche; average age 12.5 years in the USA (range 10-16)
• Peak height velocity in girls: ~5-8 cm/year, occurring at Tanner stage II-III
• Girls gain ~25 cm total height during pubertal growth

Male Puberty (Tanner Stages)

• First sign in males is testicular enlargement (>4 mL by orchidometer), average age 11-12 years
• Spermarche (first ejaculation): average age 13-14 years
• Peak height velocity in boys: ~7-12 cm/year, occurring at Tanner stage III-IV (later than girls)
• Boys gain ~28-30 cm total height during pubertal growth; PHV occurs ~2 years later than in girls

Other Pubertal Changes (Both Sexes)

• Adrenarche: Adrenal androgen production begins at ~8-10 years (before gonadal puberty); causes pubic/axillary hair and body odor
• Acne: Due to sebaceous gland stimulation by androgens
• Body composition: Boys - major increase in lean muscle mass; Girls - increase in fat mass, especially hips/breasts
• Voice change: Males - testosterone causes laryngeal growth (voice drops ~1 octave)
• Bone density: Peak bone mass is accrued during adolescence; calcium and Vitamin D needs are highest

Cognitive Development (Piaget: Formal Operational Stage, ~12+ years)

• Abstract reasoning: Can think about hypotheticals ("what if...")
• Deductive logic: Can reason from general principles to specific conclusions
• Metacognition: Thinking about one's own thinking; introspection
• Idealistic thinking: Can imagine ideal worlds, leading to idealism and disillusionment
• Personal fable: Belief that one is unique and invincible ("this can't happen to me") - contributes to risk-taking
• Imaginary audience: Feels constantly observed and judged by others - explains extreme self-consciousness

Psychosocial Development in Adolescence (Erikson: Identity vs. Role Confusion)

• Concrete thinking still dominant
• Focus on body image and peer acceptance
• Ambivalence about separation from parents
• Strong identification with same-sex peer group
• Moodiness, emotional lability common

• Abstract thinking developing; risk-taking peaks
• Peer relationships dominate; romantic/sexual interests emerge
• Greater independence from parents; conflict may increase
• Identity exploration (career, values, beliefs)
• "Personal fable" and "imaginary audience" thinking at peak

• Identity consolidation; future-oriented thinking
• More stable relationships; intimacy capacity develops (Erikson's next stage)
• Autonomy from parents with maintained relationship
• Career/educational planning; delayed gratification
• Lower impulsivity; emotional regulation improves

Moral Development (Kohlberg: Post-Conventional Level in late adolescence)

• Conventional morality (early-mid adolescence): Rules followed because society/authority requires it
• Post-conventional morality (late adolescence/adulthood): Principles transcend specific rules; social contract; universal ethical principles

Health Risks in Adolescence

• Leading causes of death: Unintentional injuries (especially motor vehicle accidents), suicide, homicide
• Mental health: Anxiety and depression are common; median onset of mental disorders is 14 years
• Substance use: Experimentation with alcohol, tobacco, cannabis peaks in mid-adolescence
• Sexual health: Contraception, STI prevention; HPV vaccination recommended at 11-12 years
• Eating disorders: Anorexia and bulimia most common in females aged 14-18 years
• HEADSSS assessment (Home, Education, Activities, Drugs, Sexuality, Suicide/Depression, Safety) is the standard adolescent psychosocial screening tool

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Summary Table: Key Milestones at a Glance

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Red Flags Requiring Evaluation

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Growth and Development: Preschoolers and School-Age Children

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PART 1 - PRESCHOOLERS (3 to 5 Years)

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GROSS MOTOR DEVELOPMENT

• Jumps with both feet off the ground
• Climbs up and down playground equipment with supervision
• Runs with better control than at 24 months
• Walks on tiptoes a few steps

• Walks up stairs alternating feet (without holding rail)
• Pedals and steers a tricycle
• Jumps from a low step with both feet
• Stands briefly on one foot (1-2 seconds)
• Runs smoothly and changes direction
• Broad jumps (standing long jump)
• Kicks a ball forward while walking

• Catches a large ball most of the time (uses hands, not arms)
• Hops on one foot (4+ consecutive hops)
• Skips on one side (gallop-skip)
• Walks down stairs alternating feet without support
• Pumps self on a swing
• Throws overhand with accuracy
• Climbs ladders and playground structures independently

• Hops on one foot 10+ times; hops on alternating feet
• Skips alternating feet smoothly
• Balances on one foot for 10 seconds or more
• Jumps rope
• Rides bicycle with training wheels (some without)
• Catches a small ball with hands only
• Throws with mature, controlled overhand pattern
• Walks heel-to-toe in a straight line

• Proximal-to-distal and cephalocaudal progression continues
• Balance and coordination improve dramatically between 3-5 years
• Running, jumping, throwing, and catching all refine into controlled, adult-like patterns
• By age 5, a child should be fully mobile on playground equipment

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FINE MOTOR / ADAPTIVE DEVELOPMENT

• Tower of 8 blocks
• Strings large beads
• Turns single pages of a book
• Holds crayon/pencil in fingers (not fist) - mature grip beginning
• Imitates horizontal and vertical strokes (not yet spontaneous)
• Puts on some clothing (loose pants, jacket)
• Uses a spoon with little spilling; attempts a fork

• Tower of 9-10 blocks
• Copies a circle (key milestone - when shown how)
• Strings items like large macaroni
• Uses a fork consistently
• Begins to use safety scissors (with help)
• Puts on some clothes by himself (loose pants, jacket)
• Turns single pages; holds book correctly

• Copies a cross (+) consistently
• Holds crayon or pencil between fingers and thumb (not a fist) - well established
• Draws a person with 3 or more body parts (head, body, legs, arms, face features)
• Unbuttons some buttons; attempts to button
• Serves herself food or pours water with adult supervision
• Uses scissors with some control to cut along a line
• Builds elaborate block structures beyond simple towers

• Copies a square and triangle (key milestones)
• Draws a person with 6 parts (head, body, 2 arms, 2 legs, plus facial features)
• Buttons some buttons independently
• Writes some letters in her name
• Names some letters when pointed to
• Uses a knife for spreading
• Ties shoelaces (some children)
• Colors within lines with reasonable control
• Cuts along a straight line with scissors independently

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LANGUAGE / COMMUNICATION DEVELOPMENT

• Vocabulary of ~450-500 words
• Uses 2-3 word sentences regularly
• Says first name when asked
• Uses some pronouns correctly (I, me, mine, you)
• Points to items in a book when asked ("Where is the dog?")
• 75% of speech intelligible to strangers
• Asks "what" and "where" questions

• Talks in conversation using at least 2 back-and-forth exchanges
• Asks "who," "what," "where," and "why" questions actively
• Describes what is happening in a picture ("running," "eating")
• Says first name when asked
• Fully intelligible to strangers most of the time
• 3-4 word sentences; uses plurals, past tense (imperfect)
• 500-900 word vocabulary
• Names body parts
• Follows 3-step instructions

• Sentences of 4 or more words consistently
• Recites some words from songs, rhymes, or stories
• Tells about at least one thing that happened during the day ("I played soccer")
• Answers simple questions about function - "What is a coat for?"
• Uses conjunctions (and, because, so)
• 1,500+ word vocabulary
• Uses all pronouns correctly
• Counts to 4 with one-to-one correspondence
• Can tell you her full name
• Speech fully intelligible to all listeners

• Tells a story with at least two events in sequence ("The cat was stuck in a tree and a firefighter saved it")
• Answers questions about a book or story after it is read to him
• Keeps a conversation going with 3+ back-and-forth exchanges
• Uses and recognizes simple rhymes (bat-cat, ball-tall)
• 2,000-2,500 word vocabulary; uses all parts of speech
• Counts to 10; names some numbers 1-5 when pointed to
• Uses time words correctly ("yesterday," "tomorrow," "morning," "night")
• Writes some letters in her name
• Names some letters when pointed to
• Tells full name, age, and address
• Understands and uses comparative words (bigger, heaviest)
• Speech fully normal; all consonant sounds present (some minor articulation errors still acceptable)

• By 3 years: p, b, m, n, h, w, y sounds clear
• By 4 years: t, d, k, g, f, v sounds clear
• By 5 years: l, sh, ch, j sounds clear
• By 6-7 years: s, z, r, th fully mastered

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SOCIAL / EMOTIONAL DEVELOPMENT

• Plays alongside other children (parallel play still dominant)
• Notices when others are hurt or upset; pauses or looks sad
• Looks at parent's face to see how to react in a new situation ("social referencing" continues)
• Increasing desire to help - puts away toys when asked
• Insists on own way - "No!" and "Mine!" are common
• Beginning symbolic play (pretend feeding, "going to sleep")
• Shows increasing independence

• Calms down within 10 minutes after parent leaves (e.g., childcare drop-off) - separation anxiety significantly reduced
• Notices other children and joins them to play - transition to associative play
• Shows empathy: comforts others when hurt or sad
• Avoids hot objects when warned - beginning abstract safety understanding
• Plays "dress-up" and role-play games
• Gender identity solidifying (knows own gender)
• Can share with prompting; takes turns with support
• Understands "mine" vs. "yours" vs. "his/hers"
• Engages in magical thinking (monsters, imaginary friends)
• Erickson's stage: Initiative vs. Guilt - initiating play and activities; guilt from perceived misbehavior

• Pretends to be someone else during play (teacher, superhero, doctor) - rich symbolic/dramatic play
• Asks to go play with children if none around ("Can I play with Alex?") - actively seeks peers
• Comforts others who are hurt or sad (hugs a crying friend)
• Avoids danger (does not jump from tall heights)
• Enjoys being a "helper" to adults
• Changes behavior based on where he is (quieter in library, louder on playground) - context awareness
• Cooperative play well established; understands and follows rules of simple games
• Strong awareness of fairness ("That's not fair!")
• Beginning theory of mind (understanding others have different thoughts/feelings)
• Best friendships forming (usually same sex)
• Can separate from parents easily; comfortable in school/childcare
• Tattling on peers is normal and common

• Follows rules and takes turns in group games consistently
• Sings, dances, or acts for others - enjoys performing and showing off skills
• Does simple chores at home (matching socks, clearing table) - sense of responsibility
• Pays attention for 5-10 minutes during structured activities (story time, arts and crafts)
• Counts to 10 reliably; understands number concepts
• Strong cooperative play; plans and negotiates in group games
• Consistent, stable friendships with 1-3 "best friends"
• Clear gender-role identification; prefers same-sex play partners
• Can distinguish fantasy from reality most of the time
• School-readiness behaviours present: self-care, follows multi-step directions, controls impulses
• Understands the concept of rules and that breaking them has consequences
• Writes some letters in name; names some letters when shown

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PART 2 - SCHOOL-AGE CHILDREN (6 to 12 Years)

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GROSS MOTOR DEVELOPMENT

• Rides a bicycle without training wheels (typically achieved at 5-6 years)
• Skips confidently on alternating feet
• Hops on either foot repeatedly with balance
• Catches a small ball reliably with hands
• Throws with full overhand technique, accurate and with force
• Walks a balance beam without falling
• Jumps rope alone
• Swims or learns to swim (most children by age 7-8)
• Participates in organized simple team games (tag, relay races)
• Engages in gymnastics-type movements: cartwheels, somersaults

• Agility, speed, and endurance all increasing significantly
• Coordinates movements in complex team sports (soccer, basketball, baseball)
• Accuracy of throwing and catching markedly improved
• Fine balance and coordination reaching near-adult levels
• Eye-hand coordination good enough for racquet sports
• Rides bicycle with speed and control; begins tricks
• Enjoys competitive sports; understands strategy

• Near-adult gross motor skill in most children
• Strength and endurance increase rapidly, especially in boys approaching puberty
• Coordinated in complex sports; can master specific athletic techniques
• Girls: PHV (peak height velocity) begins; movement patterns may briefly become more clumsy during the growth spurt
• Boys: pre-pubertal increase in muscle coordination; full PHV arrives ~2 years later
• Fine sports skills (batting, dribbling, gymnastics, swimming strokes) are practiced and specialized
• Reaction time, proprioception, and dynamic balance all near adult levels

• Movement becomes smoother, faster, and more efficient each year
• Preschool's jerky, exaggerated movements are replaced by economical, fluid motion
• Speed, strength, agility, and endurance all increase linearly until puberty, then more rapidly with hormonal changes
• Boys and girls are nearly equal in motor performance until ~10-11 years, when boys begin to show advantage in strength and speed

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FINE MOTOR / ADAPTIVE DEVELOPMENT

• Writes all letters of the alphabet (upper and lower case) legibly
• Writes own name and simple words independently
• Copies complex shapes: diamond and overlapping figures
• Draws a house with perspective (chimney, windows, door)
• Draws a detailed person: clothing, hair, features, proportions
• Ties shoelaces independently and reliably
• Uses knife and fork together for cutting food
• Handles buttons, zippers, shoelaces without help
• Cuts accurately along curved lines with scissors
• Holds pencil with mature tripod grip; good writing pressure

• Writing becomes faster and more legible
• Printing transitions to cursive writing (begins in most school curricula)
• Draws with perspective and spatial proportion
• Uses tools (ruler, compass, protractor) for academic tasks
• Builds complex models; assembles detailed kits (LEGO, crafts)
• Piano/instrument fingering, typing, craft skills developing
• Dominant hand clearly established and highly skilled
• Sewing, knitting, simple carpentry become possible

• Writing speed and legibility near adult levels
• Fine motor precision sufficient for detailed artwork and crafts
• Keyboarding/typing becomes faster
• Complex hand tool use (microscope, soldering, instruments) possible
• Specialized fine motor skills develop for chosen activities (music, sport, art)
• Precision, control, and endurance of fine motor tasks approach adult capability

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LANGUAGE / COMMUNICATION DEVELOPMENT

• Vocabulary of 10,000-14,000 words (massive expansion from 5-year-old's 2,500)
• Reads simple sentences and short books independently (decoding at grade level)
• Understands and uses complex sentence structures (subordinate clauses, conditionals)
• Understands and uses figurative language (some idioms: "it's raining cats and dogs")
• Produces and enjoys jokes and riddles (understanding ambiguity)
• Understands sarcasm in context
• Narrates stories with beginning, middle, and end
• Follows multi-step verbal instructions
• Uses metalinguistic awareness - can talk about language itself

• Vocabulary ~20,000 words
• Reads chapter books; reading comprehension deepens
• Writes multi-sentence paragraphs with topic and supporting sentences
• Uses and understands analogies
• Understands multiple meanings of words (homonyms, puns)
• Expressive written language developing
• Uses language to argue a point and persuade
• Understands passive voice; uses complex syntax consistently

• Vocabulary of 40,000+ words by age 12
• Reads and writes with near-adult fluency
• Understands abstract language, symbolism, metaphor
• Uses language for persuasion, debate, humour, social bonding
• Slang and peer-group language becomes prominent
• Reading comprehension includes inferential and evaluative levels
• Language is a major tool for social negotiation with peers

• 6-7 years: Begins to narrate and explain rather than just label
• 8-9 years: Conversation becomes truly reciprocal; can debate and argue logically
• 10-12 years: Peer discourse dominates; language identity strongly tied to social group

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SOCIAL / EMOTIONAL DEVELOPMENT

• Industry vs. Inferiority (Erikson) - competence and mastery become central; takes pride in achievements; failure creates shame
• Peer relationships become central to identity; friendships are selective and meaningful
• Same-sex friendships dominant and intense
• Sullivan's concept of the "chum" - a same-sex best friend during latency who validates and mirrors the child; this friendship is a critical marker of healthy social development
• Understands and respects rules of games; calls out peers who break rules
• School performance becomes linked to self-esteem
• Can sustain attention for 15-30 minutes on structured tasks
• Empathy deepens; can take another person's perspective (theory of mind fully developed ~6-7 years)
• Conscience and internalized moral standards active

• Peer group identity intensifies; cliques begin to form
• Comparative thinking: "Am I as good as him/her?" - competition emerges
• Best friendships become reciprocal and exclusive ("you're my best friend")
• Gender separation in play intensifies (boys vs. girls groups)
• Interests become more specialized (sports, hobbies, music, gaming)
• Greater emotional regulation; fewer outbursts than preschool
• Kohlberg's Conventional Morality - rules are rules because authority says so; "good boy/good girl" orientation
• Can sustain attention for 30-45 minutes on academic tasks
• Beginning of self-concept independent of parents

• Peer relationships reach peak importance; more time with peers than family
• Loyalty and trust become central friendship values
• Exclusion and rejection by peers become profoundly painful
• Same-sex peer groups very strong; cross-gender interaction may decrease temporarily before increasing in early adolescence
• Beginning of puberty in most girls (~10-11 years): body image concerns emerge
• Self-consciousness increases
• Growing capacity for abstract moral reasoning: "rules exist for good reasons" (Kohlberg Stage 3-4)
• Can plan and organize multi-day projects
• Increasing independence: manages own school supplies, homework, some self-care

• Identity exploration begins
• Greater conflict with parents over autonomy
• Peer norms have enormous influence on behavior and self-image
• Abstract thinking emerging (formal operations beginning)
• Puberty arrival (in boys and late-developing girls): bodily self-consciousness, moodiness
• Planning for future begins (career interests, skill development)
• Moral reasoning transitions from "rules" to "values"

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Domain Summary: Preschoolers vs School-Age

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Red Flags in These Age Groups

• Age 3: Not using 3-word sentences; speech not intelligible to strangers; no cooperative play; still walking on tiptoes persistently
• Age 4: Not hopping; not drawing any recognizable shapes; not using 4-word sentences; still drooling excessively
• Age 5: Cannot hop on one foot; no letter recognition; speech remains unclear; cannot follow 3-step commands; does not play cooperatively

• Persistent reading difficulty after age 7 (screen for dyslexia)
• Cannot copy diamond by age 7
• Extreme social isolation or inability to make/keep friendships
• Regression of previously acquired skills at any age (always warrants urgent evaluation)
• Persistent inattention, impulsivity, and hyperactivity interfering with school (screen for ADHD)

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