• Reflexive grasp at birth; pre-reaching is present but ineffective. — Eliot, What's Going On in There?
• Babies remain in a flexed, fetal position with arms and legs bent toward the chest; movement at this stage is primarily reflexive rather than voluntary. — Shelhav, Child Space
• Newborns use reflexes like stepping movements when held upright — organized flex-and-extend cycles of hips, knees, and ankles, often alternating legs, not random thrashing. — Thelen & Smith, A Dynamic Systems Approach
• Newborn arm extensions toward a visually interesting sight (prereaching) are an attentional response, not an intention to grasp — they occur only when the baby is maximally alert, upright, and posturally supported. — Thelen & Smith, A Dynamic Systems Approach

• Touch is "one of a baby's most advanced abilities at birth." — Eliot, What's Going On in There?
• Smell is already functional — newborns prefer their mother's unwashed breast and can identify their own mother by smell. — Eliot, What's Going On in There?
• Taste is innate: newborns love sweet, reject sour/bitter, are indifferent to salt. — Eliot, What's Going On in There?
• Hearing is well-developed at birth — babies have about twelve weeks of prenatal listening experience, recognize their mother's voice, and prefer the higher-pitched, singsong "motherese." — Eliot, What's Going On in There?
• The vestibular system (balance/motion) is the first fiber tract in the brain to myelinate, fully sized by five months gestation — babies crave rocking and bouncing. — Eliot, What's Going On in There?
• Vision is the most immature at birth (~20/600 acuity, ~8-inch focus). — Eliot, What's Going On in There?
• Touch is the earliest-developing and most fundamental sense; the skin is a baby's "first language" of communication, and tactile stimulation speeds myelination of the brain and nervous system. — McClure, Infant Massage
• Newborns have no body clock (circadian rhythm) — they don't sleep only at night — and spend much more time in Active sleep, the infant equivalent of REM, with shorter sleep cycles than adults. — Ball, How Babies Sleep
• At birth, babies prefer to look at human faces more than any other visual pattern. — Stern, The Interpersonal World of the Infant
• Newborns prefer complex, high-contrast patterns (stripes, checkerboards, bull's-eyes) over simple low-contrast ones, and trace the outside edges of objects with their eyes. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib
• Newborns can discriminate all the sounds of all languages — they are "citizens of the world" — dividing continuous speech sounds into discrete categories. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib
• Newborns understand space as three-dimensional: they recoil from a "looming" ball that appears to rush toward them, and they have size constancy — a ball twice as far away is still the same ball. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib
• Newborns coordinate information across senses: they link the feel of a pacifier in their mouth (bumpy vs. smooth) with its visual image. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib

• Communication is through cries, facial expressions, and states of alertness. The earliest foundation of emotional intelligence begins here. — Eliot, What's Going On in There?
• Newborns imitate facial expressions from birth — stick out your tongue and a newborn sticks out theirs; the youngest tested was 42 minutes old. Imitation implies babies map their own internal body sense onto the face they see, recognizing that other people are "like me." — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib
• Infants are biologically prepared to engage with others from birth. — Stern, The Interpersonal World of the Infant
• Newborns actively seek eye contact and can fix their gaze on faces. — Beebe & Lachmann, The Origins of Attachment
• Contingency detection operates from birth — babies detect "how I affect you" and "how you affect me," generating expectancies of how interactions unfold moment to moment. — Beebe & Lachmann, The Origins of Attachment

• Parent and baby begin finding a shared rhythm, "like dancers learning through practice to coordinate their actions." Both mothers and fathers undergo hormonal brain changes fueled by oxytocin; fathers who were primary caregivers show their own hormonal brain changes from caring early. Hospitals now encourage daddy-baby skin-on-skin bonding right after birth. — Delahooke, Brain-Body Parenting
• A newborn emerges with "a powerful instinct to be close to you. Not just any adult will do" — even with blurry vision, a baby senses the parent's love and devotion. This is the person the baby intuits will be here for them. — Hoffman, Cooper & Powell, Raising a Secure Child
• Practice responsive parenting: observe the baby's cues (e.g., yawning, rubbing eyes), accurately interpret them (the baby is tired), and take action to meet the need (put the baby down for a nap). Responsive parents raise babies who sleep better, are less fearful, and experience less stress in their bodies. — Delahooke, Brain-Body Parenting
• Build attachment through caregiving routines — narrate what you're going to do, move slowly and gently. In the beginning "the hands are everything for an infant. The hands are the person, the world." (Pikler) — Gerber, Your Self-Confident Baby
• Placed skin-to-skin after birth, newborns autonomously progress through Widström's 9 stages (birth cry, rest, awakening, crawling up the mother's body, finding and suckling the breast, then sleeping) — "a built-in mission." — Ball, How Babies Sleep
• The first attachment behaviors include crying, clinging, and visual tracking of caregivers. — Beebe & Lachmann, The Origins of Attachment

• Cohen's foundational pattern is cellular breathing — the baseline of all movement, correlating to the movement of one-celled animals. — Cohen, Sensing, Feeling, and Action
• Babies are born neurologically ~3 months early — a "fourth trimester." Had delivery been delayed three more months, the baby would arrive already able to smile, coo, and flirt; newborns are "more a fetus than an infant." — Karp, The Happiest Baby on the Block
• Sleep serves rapid brain growth — babies' brains create neural pathways at a phenomenal rate through the first year, driving the rapid increase in brain size to age one. — Ball, How Babies Sleep
• Babies' attention is broad and diffuse — a "lantern" — versus adults' focused "spotlight"; babies seem aware of more, more intensely, than adults. — Gopnik, The Philosophical Baby
• The first developmental movement pattern is navel radiation — movement originates from the center (navel) and radiates outward to the periphery. — Cohen, Sensing, Feeling, and Action and — Hartley, Wisdom of the Body Moving
• The mouthing pattern precedes all other movement patterns. — Cohen, Sensing, Feeling, and Action

• Newborns have no circadian rhythm (body clock). They spend ~50% of sleep in Active sleep (the infant equivalent of REM), with short ultradian cycles of ~45–60 minutes. Sleep is distributed across the full 24-hour day. — Ball, How Babies Sleep
• Newborns sleep 16–17 hours per day in 2–4 hour stretches. — Eliot, What's Going On in There?

• Newborns feed frequently — about 8–12 times in 24 hours — because breastmilk is rapidly digested and newborn stomach capacity is tiny (cherry-sized at birth, grape-sized by day 3). — Douglas, The Discontented Little Baby Book
• Cluster feeding (frequent feeds clustered in one part of the day) is normal and supports milk supply. — Ball, How Babies Sleep
• Responsive, cued feeding — following the baby's hunger signals rather than a clock — meets both nutritional and comfort needs. — Douglas, The Discontented Little Baby Book
• Rooting and sucking reflexes are present from birth to support feeding. — Shelhav, Child Space

• Skin-to-skin / kangaroo care aids breastfeeding and weight gain. Infant massage (Tiffany Field–style) shows faster weight gain and better novelty preference. Responsive, cued feeding. Hold, carry, rock. — Eliot, What's Going On in There?
• Provide vestibular stimulation through rocking, front packs, waterbeds for premies. — Eliot, What's Going On in There?
• Practice the three steps of responsive parenting: observe the baby's cues (yawning, rubbing eyes), interpret what they mean (tired, hungry), and act to meet the need. "The best thing you can do for your baby is to lovingly observe their cues, interpret what they mean, and then take action to meet those needs." — Delahooke, Brain-Body Parenting
• Give a newborn a quiet, unstimulated transition — life itself provides enough natural stimulation. Trust that she will develop "in her own time, rhythm, and manner" rather than shaking rattles or using flashcards. — Gerber, Your Self-Confident Baby
• Soothe by imitating the womb to trigger an innate "calming reflex," via the 5 S's (Swaddle, Side/Stomach, Shush, Swing, Suck), layered together as the "Cuddle Cure." — Karp, The Happiest Baby on the Block
• Newborns need constant head and neck support — they cannot yet control these muscles. — Shelhav, Child Space
• Deep touch and containment help newborns feel secure and organized. — Delahooke, Brain-Body Parenting

• Holds head erect and steady (1–2 months). — Eliot, What's Going On in There?
• By 2 weeks, brief moments of opening from the flexed position begin to appear. — Shelhav, Child Space
• The head begins to lift briefly when on the tummy, though still wobbly. — Shelhav, Child Space
• Pre-spinal movements begin as subtle undulations through the spine. — Hartley, Wisdom of the Body Moving

• Visual acuity improves — babies begin to track moving objects smoothly. — Eliot, What's Going On in There?
• Obligatory looking behavior emerges as the visual cortex begins exerting control over brain-stem visual centers. — Eliot, What's Going On in There?

• Social smiling emerges around six weeks of age (range 4–8 weeks) — "probably the most universal of all developmental milestones." It is driven by the basal ganglia (which mature before the motor cortex), so a baby's first social smiles are genuine. — Eliot, What's Going On in There?
• Protoconversation — face-to-face, turn-taking vocal exchange — begins around six weeks and continues until three or four months. Researchers call it "prespeech." — Eliot, What's Going On in There?
• Eye contact becomes more sustained and purposeful. — Beebe & Lachmann, The Origins of Attachment
• Babies begin to show excitement through increased movement when seeing familiar faces. — Shelhav, Child Space
• By 6 weeks, infants can observe a model one day, return 24 hours later, and imitate the action — demonstrating representation of now-absent acts. — Beebe & Lachmann, The Origins of Attachment
• Random smiling during sleep begins around 4 weeks, driven by spontaneous brain-stem activity — the first smiles are not yet social. — Eliot, What's Going On in There?

• The first social smiles (~6 weeks) are the beginning of reciprocal attachment — the baby's smile hooks the parent, and the parent's smile reinforces the baby. The basal ganglia drive these smiles, so they are genuine. — Eliot, What's Going On in There?
• Protoconversation (~6 weeks) — face-to-face, turn-taking vocal exchange — is itself an attachment behavior. Researchers call it "prespeech"; it establishes the back-and-forth rhythm of human relationship. — Eliot, What's Going On in There?
• Meet the baby's needs for nutrition, safety, and security consistently, especially in the first six months. "The way to help a baby move toward self-regulation as a child is first to co-regulate with consistency." — Delahooke, Brain-Body Parenting
• Crying becomes more differentiated, with distinct cries for hunger, discomfort, and need for contact. — Delahooke, Brain-Body Parenting
• By 6 weeks, infants show a clear preference for the primary caregiver's face. — Beebe & Lachmann, The Origins of Attachment

• Self-settling isn't a skill you must teach — it matures on its own over the first year or two as a biologically normal process. Regular night-waking in the first year of life is not a problem to be fixed. — Douglas, The Discontented Little Baby Book
• Spinal patterns begin to emerge through head and tail movements. — Hartley, Wisdom of the Body Moving
• Movement becomes less reflexive and more intentional. — Cohen, Sensing, Feeling, and Action
• Coordinated newborn stepping "disappears" around 2 months not because the pattern is lost but because it is masked by biomechanical factors (leg mass and weight gain) — infants who gained weight fastest lost stepping fastest, and stepping reappears when the legs are supported in warm water. — Thelen & Smith, A Dynamic Systems Approach

• Sleep patterns remain fragmented; day and night are still blurred. Active sleep still predominates. Sleep duration is highly variable — 9 to 20 hours per day in newborns, with up to 12-hour day-to-day swings. — Douglas, The Discontented Little Baby Book
• Day-night differentiation begins to emerge around 6 weeks. — Eliot, What's Going On in There?

• Growth spurts drive increased feeding frequency. Feeding on demand continues to support supply and growth. — Douglas, The Discontented Little Baby Book
• Cued bottle-feeding — using a slow-flow teat, holding the bottle horizontally, pacing with breaks, and swapping sides — mimics the responsive rhythm of breastfeeding and lets the baby regulate intake. — Douglas, The Discontented Little Baby Book
• Feeding becomes more efficient as sucking strengthens. — Shelhav, Child Space
• Babies may begin to space feedings slightly further apart. — Shelhav, Child Space

• What changes: The baby’s senses grow rapidly — longer focus distance, more alert time, increased crying and whimpering as the baby processes more sensory input.
• Fussy phase: Lasts about 1 day to 1 week. The baby may cry more, be harder to soothe, and seem generally unsettled.
• How to support: Extra cuddling, physical contact, and responsive nursing or feeding. Provide a calm, low-stimulation environment during the fussy phase.
• Note: Leap timing is approximate and varies per baby. This is not a diagnostic schedule. — van de Rijt & Plooij, The Wonder Weeks

• Face-to-face talking, eye contact, and responsive vocal turn-taking. — Eliot, What's Going On in There?
• Tummy time — because back-sleeping (to prevent SIDS) modestly delays motor milestones, give supervised prone play. — Eliot, What's Going On in There?
• Rock, bounce, and sway to engage the vestibular system. — Eliot, What's Going On in There?
• Connect during the “quiet alert” state — when your baby’s eyes are bright and focused on you, breathing is regular, and the body is relaxed. This is when nurtured connection (eye contact, touch, interaction, back-and-forth) builds the brain’s self-regulation circuits. “You have to enter their world, be present and engaged.” — Kirshenbaum, The Nurture Revolution
• Massage stimulates the gastrointestinal system and is a tool for the "colicky" baby (colic tends to peak around six weeks). — McClure, Infant Massage
• Brief periods of quiet alertness increase, showing improved state regulation. — Delahooke, Brain-Body Parenting
• Swaddling or containment continues to support self-regulation. — Shelhav, Child Space

• Voluntary grasp emerges (~3 months); pre-reaching subsides as reaches become intentional. — Eliot, What's Going On in There?
• Rolls tummy to back (3–4 months). — Eliot, What's Going On in There?
• Lifts head and chest with arm support on tummy (2–3 months). — Eliot, What's Going On in There?
• Sits with support (2–3 months). — Eliot, What's Going On in There?
• Push-up movements begin in tummy time — the head lifts 45–90 degrees as the baby pushes up through the arms. — Hartley, Wisdom of the Body Moving
• Hands begin to open from the fisted position; batting at objects begins. — Thelen & Smith, A Dynamic Systems Approach
• Kicking becomes more vigorous and rhythmic, preparing for later locomotion. — Thelen & Smith, A Dynamic Systems Approach
• By 2.5–3 months infants can use their legs voluntarily — for example, kicking to activate a mobile. — Thelen & Smith, A Dynamic Systems Approach
• By 3–4 months infants perform well-coordinated alternating steps when supported on a slowly moving treadmill — the neuromuscular mechanism for stepping is available far earlier than independent walking. — Thelen & Smith, A Dynamic Systems Approach

• Vision improves steadily; binocular stereo depth has its sudden onset around 3.5 months. — Eliot, What's Going On in There?
• Babies can distinguish the phonemes of all world languages — an ability that narrows to the native language during the first year. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib

• Turn-taking in vocalizations begins — the foundation of conversation. — Stern, The Interpersonal World of the Infant
• Babies can predict simple sequences in social interactions. — Beebe & Lachmann, The Origins of Attachment
• Recognition of emotional expressions on faces improves. — Stern, The Interpersonal World of the Infant
• Three-month-olds engage in flirtatious interaction — cooing in response to adult coos, smiling in response to smiles, and gesturing in rhythm with the intonation of the adult's voice. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib
• Three-month-olds know their own actions can influence events — they learn to kick the foot with the ribbon to make a mobile move, and keep kicking even when the ribbon is disconnected, as if charm alone should work. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib

• In the "quiet alert" state (eyes bright and shiny, breathing regular, body relaxed), babies initiate connection through eye contact, smiling, and vocalizing — they are reaching out for attention. Connection in this state grows inhibitory neural connections from the thinking brain to the amygdala, building circuits for self-regulation and faster stress recovery. — Kirshenbaum, The Nurture Revolution
• Nurtured connection requires eye contact, touch, interaction, and participation from both parent and baby — not just proximity. "You have to enter their world, be present and engaged." Quality matters more than quantity. — Kirshenbaum, The Nurture Revolution
• You are the architect of your baby's experience. Every interaction creates memories that help the baby feel the world is "a safe and trustworthy place." You won't always read the baby accurately; the key is observing and adjusting based on the baby's feedback. — Delahooke, Brain-Body Parenting
• Attachment behaviors become more organized and directed toward specific caregivers. — Beebe & Lachmann, The Origins of Attachment
• Babies actively seek interaction through gaze, smiles, and vocalizations. — Stern, The Interpersonal World of the Infant
• Babies show distress when a familiar caregiver breaks expected interaction patterns. — Beebe & Lachmann, The Origins of Attachment

• The prevertebrate patterns — navel radiation (relating and movement of all parts of the body via the navel), mouthing, and pre-spinal movement — are the last patterns before the vertebrate sequence begins. — Cohen, Sensing, Feeling, and Action
• Development proceeds "growing down" — myelination moves top-to-bottom, so the mouth, eyes, arms, and hands come under control before the legs and feet. — Baldwin Dancy, You Are Your Child's First Teacher
• Head and tail connection strengthens through spinal movements. — Hartley, Wisdom of the Body Moving

• The circadian clock begins to organize, aided by daylight exposure and daily routines — the suprachiasmatic nucleus responds to light as a zeitgeber. Night sleep stretches may lengthen, but variability is normal. — Ball, How Babies Sleep
• Sleep consolidation begins — some babies sleep 5–6 hour stretches. — Eliot, What's Going On in There?

• Feeding rhythms become somewhat more predictable as the baby's stomach capacity grows and the parent-baby dyad finds its groove. Responsive feeding remains the evidence-backed approach regardless of feeding method. — Kirshenbaum, The Nurture Revolution
• Feeding becomes more predictable, with 3–4 hour intervals. — Shelhav, Child Space
• Hand-to-mouth movements increase — the baby self-soothes through sucking. — Shelhav, Child Space

• Offer objects within reaching distance; let the baby swat and bat. Free movement on a firm, flat surface — no propping into positions the baby cannot get into alone. — Eliot, What's Going On in There? and — Gerber, Your Self-Confident Baby
• Help your baby feel Safe, Seen, and Soothed — the first three of the Four S’s. Safe: protect from threat. Seen: known for who they are. Soothed: help them return to calm. These build the foundation for the fourth, Secure. — Siegel & Bryson, The Power of Showing Up
• Babies can maintain calm alert states for longer periods. — Delahooke, Brain-Body Parenting
• Co-regulation with the caregiver becomes more sophisticated. — Delahooke, Brain-Body Parenting

• Successful reach and grasp (4–5 months). — Eliot, What's Going On in There?
• Controlled reach and grasp (6–7 months). — Eliot, What's Going On in There?
• Rolls back to tummy (6–7 months). — Eliot, What's Going On in There?
• Sits alone (6–8 months, normal range 5–9 months). — Eliot, What's Going On in There?
• Reaching becomes more accurate — infants grasp objects placed in their hands, and their very first reaches work equally well in the dark, showing they do not need to see their hand. — Thelen & Smith, A Dynamic Systems Approach
• Hands come together at the midline; objects are transferred between hands. — Cohen, Sensing, Feeling, and Action

• Color vision is fully developed by 4 months. — Eliot, What's Going On in There?
• Babies can localize sounds by turning the head toward the source. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib
• Babies explore objects through mouthing — gathering sensory information. — Shelhav, Child Space
• Around four months there is an abrupt change in salt preference, due to the emergence of sodium-sensitive receptor proteins. — Eliot, What's Going On in There?
• By 6 months all primary visual abilities have emerged — depth perception, color vision, fine acuity, and well-controlled eye movements — and babies can use temperature information to tell apart two otherwise identical objects. — Eliot, What's Going On in There?

• Joint attention behaviors emerge — the baby follows the caregiver's gaze. — Stern, The Interpersonal World of the Infant
• Laughing appears around 4 months in response to social play. — Stern, The Interpersonal World of the Infant
• Babies can differentiate familiar from unfamiliar faces. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib
• Five-month-olds can lip-read simple vowels — matching an "ahhh" sound to a face with a wide-open mouth and an "eeee" sound to a face with pulled-back lips. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib

• The four S's of secure attachment begin here: help the child feel Safe (protect from threat), Seen (known for who they are), Soothed (help them return to calm), and Secure (the integrated result). — Siegel & Bryson, The Power of Showing Up
• The Circle of Security: a secure attachment forms when a parent can help the child feel safe when frightened, help the child feel secure enough to explore, and help the child accept and manage emotional experience. At this age the parent is both the "safe haven" (to return to) and the "secure base" (to explore from). — Hoffman, Cooper & Powell, Raising a Secure Child
• All infant stress is communication — the baby's stress systems are overwhelmed and they need to "borrow your calm, regulated brain" to come back into a safety state. You are the bridge between their threat and safety states; only the baby can walk over it. — Kirshenbaum, The Nurture Revolution
• Attachment to primary caregivers is now clear — babies show preference through differential responses. — Beebe & Lachmann, The Origins of Attachment
• At 4 months, face-to-face play — with no other goal than mutual enjoyment — can be filmed and analyzed second-by-second to predict attachment classification at 12 months. Early face-to-face communication sets the trajectory for patterns of relatedness across the lifetime. — Beebe & Lachmann, The Origins of Attachment

• The vertebrate patterns begin with spinal movement (head-to-tail, correlating to fish) and progress to homologous movement (symmetrical two-upper or two-lower limbs together, correlating to amphibians). — Cohen, Sensing, Feeling, and Action
• Yield and push patterns develop before reach-and-pull patterns — the infant must yield into the floor before pushing away from it. — Cohen, Sensing, Feeling, and Action
• Weight shifting side to side prepares for rolling. — Hartley, Wisdom of the Body Moving
• Reaching is discovered from ongoing dynamics, not prefigured by a plan in the brain or genes — each infant solves the problem in their own way (one very active baby reached at 15 weeks by taming wild movements; a quiet baby reached at 22 weeks by generating enough force). — Thelen & Smith, A Dynamic Systems Approach

• Around 3–5 months, sleep cycles mature to an adult-like structure — cycling through light, deep, and REM sleep. This reorganization often brings more frequent night-wakings. This is a normal, temporary phase of brain development, not a regression. — Ball, How Babies Sleep
• The circadian rhythm continues maturing; melatonin and cortisol rhythms are not yet fully established. — Kirshenbaum, The Nurture Revolution
• Many babies are capable of sleeping 6–8 hour stretches by this age, though night-waking remains common. — Eliot, What's Going On in There?
• Naps consolidate to 2–3 predictable times. — Eliot, What's Going On in There?

• Feeding patterns continue to stabilize. Breastmilk or formula remains the sole source of nutrition. The World Health Organization and AAP recommend exclusive milk feeding for about the first six months. — Oster, Cribsheet
• Around 6 months, readiness for solid foods emerges: the baby can sit supported and brings objects and food to the mouth with increasing accuracy. — Shelhav, Child Space

• What changes: Described as “the most troublesome leap.” The baby grasps that events have a beginning, middle, and end — anticipates routines, studies how objects interact (grasps, shakes, drops, bangs).
• Fussy phase: Intense clinginess, may last 1-5 weeks. Sleep is often disrupted.
• How to support: Repetitive cause-and-effect games (drop-and-pick-up). Maintain predictable routines. Offer extra comfort at bedtime.
• Note: Leap timing is approximate and varies per baby. This is not a diagnostic schedule. — van de Rijt & Plooij, The Wonder Weeks

• Floor time on a clean, firm surface with interesting objects just out of reach. Let the baby reach, roll, and explore physical properties (shape, weight, texture). — Eliot, What's Going On in There?
• Allow uninterrupted free play and natural gross-motor development on the child's own timeline — observe, don't intervene. — Gerber, Your Self-Confident Baby
• Be the “hands on the Circle of Security”: follow your child’s needs whenever possible, take charge whenever necessary. “We are bigger, stronger, wiser, and always kind.” You are both the safe haven (to return to for comfort) and the secure base (to explore from). — Hoffman, Cooper & Powell, Raising a Secure Child
• Self-soothing abilities increase through hand sucking and visual focus. — Delahooke, Brain-Body Parenting
• Babies can maintain longer periods of independent play while the caregiver is nearby. — Delahooke, Brain-Body Parenting

• Pulls to stand (8–9 months). — Eliot, What's Going On in There?
• Crawls (~9 months). — Eliot, What's Going On in There?
• Pincer grasp — thumb and forefinger (~9 months). — Eliot, What's Going On in There?
• Belly (commando) crawling emerges before hands-and-knees crawling. — Hartley, Wisdom of the Body Moving

• Depth perception is fully mature — babies show fear of heights on the visual cliff. — Eliot, What's Going On in There?
• Vestibular self-stimulation typically begins between six and eight months, when vestibular sensitivity reaches its peak. — Eliot, What's Going On in There?
• Babies develop preferences for certain textures through tactile exploration. — Shelhav, Child Space

• Stranger anxiety and separation anxiety emerge and peak around 8–9 months, reflecting object permanence and attachment. — Eliot, What's Going On in There?
• Within the first nine months, before babies can walk or talk or even crawl, they match a happy or sad or angry face to the matching emotional tone of voice — cross-modal emotion perception. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib
• Object permanence is developing — babies search for partially hidden objects. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib
• Before nine months, babies can tell the difference between expressions of happiness, sadness, and anger. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib

• Attachment and stranger anxiety emerge together, beginning around six months of age and growing increasingly intense until about eighteen months. This is strikingly universal across cultures — urban America, Israeli kibbutzim, Guatemalan villages, and primitive African societies all show it at the same age. The timing corresponds to the onset of independent locomotion: babies don't need to feel attached until they can crawl away. — Eliot, What's Going On in There?
• Social referencing emerges by ~9 months — the baby reads the parent's emotional expression to decide how to feel about an ambiguous situation (e.g., a stranger, a new toy). This is the attachment figure becoming "an important source of how we should feel about the world." — Eliot, What's Going On in There?
• When babies cry or cling, responding does not reinforce the behavior — it reduces it. "When we respond to crying and clinging, babies cry less and we build the infant brain to be more independent later." More responsiveness builds a resilient stress system, secure attachment, and supports social, language, and cognitive development. — Kirshenbaum, The Nurture Revolution
• Babies show a clear attachment hierarchy among caregivers. — Beebe & Lachmann, The Origins of Attachment

• Homolateral movement (same-side arm and leg, correlating to reptiles) organizes crawling; contralateral movement (diagonal opposite arm and leg, correlating to mammals) — the pattern underlying efficient crawling and walking — begins to emerge. — Cohen, Sensing, Feeling, and Action
• Spiral movements develop through reaching across the midline. — Hartley, Wisdom of the Body Moving

• The circadian clock is now well-established, with clear day-night differentiation. Night-waking continues to be biologically normal and is not associated with negative developmental outcomes. — Ball, How Babies Sleep
• Separation anxiety, which also emerges around this age, can affect settling. — Kirshenbaum, The Nurture Revolution
• Sleep patterns are more consolidated — typically 2 naps per day. — Eliot, What's Going On in There?

• Starting solids (~6 months). The old advice to introduce foods in a fixed order (rice cereal first, then purees) is not evidence-based. Two equally valid approaches: traditional purees (parent feeds with a spoon) and baby-led weaning (baby self-feeds soft finger foods). A randomized trial found baby-led weaning did not increase choking risk. — Oster, Cribsheet
• Allergens: Early and regular exposure to the eight major allergens (especially peanuts) dramatically reduces allergy risk — the LEAP trial showed early peanut exposure cut peanut allergy from 17% to 3%. — Oster, Cribsheet
• Honey must be avoided (risk of infant botulism). Whole cow's milk should not replace breastmilk or formula as a main drink before 12 months (low iron). Vitamin D drops are recommended for breastfed babies; iron-rich foods or supplementation are important after 6 months. — Oster, Cribsheet
• Repeated neutral exposure to new foods (8–15 tries) builds acceptance; pressuring or offering alternatives in response to refusal tends to backfire. — Oster, Cribsheet
• The developing pincer grasp supports self-feeding of finger foods. — Shelhav, Child Space
• Babies show food preferences and can indicate wants through gestures. — Shelhav, Child Space

• Safe spaces to roll, crawl, and pull up. Small, graspable objects to develop the pincer grasp. — Eliot, What's Going On in There?
• Respond to separation distress as a signal, not a problem to be trained out. — Eliot, What's Going On in There?
• When your baby cries or clings, respond — it does not reinforce the behavior, it reduces it. “When we respond to crying and clinging, babies cry less and we build the infant brain to be more independent later.” You are the bridge between their threat and safety states; only the baby can walk over it. — Kirshenbaum, The Nurture Revolution
• Cross-crawling matters for brain development and later learning; avoid anything that shortens crawling time (baby walkers, leg splints, or braces). — Baldwin Dancy, You Are Your Child's First Teacher
• Babies can self-regulate for brief periods through exploratory play. — Delahooke, Brain-Body Parenting

• Cruises with handholds (9–10 months). — Eliot, What's Going On in There?
• Stands alone (11–12 months). — Eliot, What's Going On in There?
• Walks alone (12–13 months, normal range for walking well is 9–15 months). — Eliot, What's Going On in There?
• Claps hands around 10 months. — Eliot, What's Going On in There?

• Visual acuity approaches adult levels. — Eliot, What's Going On in There?
• Babies can follow pointing gestures to locate objects. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib
• Babies respond differently to various musical rhythms and melodies. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib

• Around 12 months babies begin to point to share interest (proto-declarative pointing) and to look where other people point. — Stern, The Interpersonal World of the Infant
• Babies show toys to others for social sharing. — Stern, The Interpersonal World of the Infant
• Deferred imitation emerges — babies imitate novel actions after a delay, and can remember a demonstrated action a week later. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib
• Babies follow simple verbal instructions with gestures. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib
• Nine- and ten-month-olds pick up objects at random and do not yet sort them into groups; by 12 months they sort objects into categories. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib
• Ten-month-olds understand "billiard ball" causality — they look longer when two toy cars appear to influence each other without touching. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib
• By 12 months babies are surprised when a blue toy car goes behind a screen and a yellow duck emerges — they now track identity by features. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib

• The parent is now a "secure emotional base from which [the baby] can test her new assertiveness, someone to whom she can periodically return for comfort and reassurance." Attachment complements growing independence — exploration and reunion alternate. — Eliot, What's Going On in There?
• Between about 12 and 18 months, most toddlers are elated by their newfound ability to move around; returns to the parent are often brief ("no more than a touch") and the forays into the world hold the thrill. The secure base enables this exploration. — Lieberman, The Emotional Life of the Toddler
• Attachment isn't about being perfect. When you misattune, repair matters: neuroscience shows the brain is "constantly comparing new experiences with old ones, updating and changing." "Earned secure attachment" is possible at any age through consistent showing up. — Siegel & Bryson, The Power of Showing Up and — Hoffman, Cooper & Powell, Raising a Secure Child
• Attachment relationships are fully formed and specific. — Beebe & Lachmann, The Origins of Attachment
• Babies show empathy when others are distressed. — Stern, The Interpersonal World of the Infant
• The Strange Situation at 12 months reveals attachment style: secure infants are easily comforted at reunion and return to play; avoidant infants show little distress and avoid the parent; resistant infants cannot be comforted; disorganized infants show contradictory approach-and-avoidance. — Beebe & Lachmann, The Origins of Attachment
• Maternal sensitivity — alertness to the baby's signals, with appropriate and prompt responses — promotes a secure relationship. — Beebe & Lachmann, The Origins of Attachment

• The contralateral pattern (left arm with right leg, right arm with left leg) fully integrates through creeping and crawling, setting the neurological baseline for walking. Cohen's view: all babies need to move through all the patterns to be "fully rounded," even if they can walk without them. — Cohen, Sensing, Feeling, and Action
• All basic developmental movement patterns are integrated. — Cohen, Sensing, Feeling, and Action
• Babies transition smoothly between positions. — Hartley, Wisdom of the Body Moving
• At twelve months, babies begin using other people as sources of information about the world — they are already participating in culture. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib

• Sleep consolidation progresses but normal night-waking persists for many babies. Night feeding remains common. Self-settling matures gradually over the first year or two — it is not a skill that must be taught. — Douglas, The Discontented Little Baby Book
• Most babies are sleeping through the night consistently, though night-waking remains normal for many. — Eliot, What's Going On in There?
• Babies may resist naps as mobility increases. — Eliot, What's Going On in There?

• Expanding variety of solids alongside continued milk feeds. Self-feeding practice with graspable foods; cup introduction. The transition toward family foods continues. — Oster, Cribsheet
• Breastmilk or formula remains the primary source of nutrition through the first year. — Oster, Cribsheet
• Babies drink from a cup with assistance. — Shelhav, Child Space
• Babies feed themselves with fingers and attempt the spoon. — Shelhav, Child Space

• What changes: The baby discovers sequences — things must happen in order. For the first time, the baby tries to put things together rather than taking them apart.
• Fussy phase: 3-7 weeks of the three Cs. Frustration at not being able to execute sequences perfectly. Sleep may be disrupted.
• How to support: Simple step-by-step activities (stacking, putting in and taking out). Narrate sequences. Allow repeated practice.
• Note: Leap timing is approximate and varies per baby. This is not a diagnostic schedule. — van de Rijt & Plooij, The Wonder Weeks
• Research parallel: a major cognitive leap at 12 months brings understanding of sequences and categories, and the beginnings of symbolic thought — babies use objects functionally in play. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib and — Stern, The Interpersonal World of the Infant

• Low, stable furniture to cruise along. Open floor space. — Eliot, What's Going On in There?
• Trust the process — "from the moment of birth to wriggling to crawling to sitting to creeping to standing, the infant approaches this goal" of walking, "the triumphant accomplishment of a year or so of dauntless preparation." — Cohen, Sensing, Feeling, and Action
• Repair, repair, repair. “There’s no such thing as perfect parenting.” When you misattune or a rupture happens, reconnect as soon as you can — repair is what builds secure attachment, not flawlessness. — Siegel & Bryson, The Power of Showing Up
• Babies can tolerate brief separations with a transition object. — Delahooke, Brain-Body Parenting
• Babies self-soothe through movement and exploration. — Delahooke, Brain-Body Parenting

• Walks well (normal range 9-15 months for walking well). — Eliot, What's Going On in There?
• Squats to pick up objects, may climb stairs with help, carries objects while walking. — Eliot, What's Going On in There?
• Babies can squat and return to standing. — Hartley, Wisdom of the Body Moving
• Babies throw objects with improving aim. — Shelhav, Child Space
• Babies climb stairs on hands and knees. — Cohen, Sensing, Feeling, and Action
• Objects are released crudely around 12–14 months, progressing to controlled release. — Eliot, What's Going On in There?

• Babies integrate sensory information for complex exploration. — Eliot, What's Going On in There?
• Babies show preference for familiar foods by sight and smell. — Shelhav, Child Space
• Babies enjoy sensory play with various textures. — Shelhav, Child Space

• Points to body parts, follows simple commands, uses 1–5 words, experiments with cause and effect (dropping, banging). Social referencing is well-established — the toddler reads the parent's face to evaluate ambiguous situations. — Eliot, What's Going On in There?
• First words emerge around 12 months — "Mama," "Dada," "juice," "ball," but also "gone," "there," "uh-oh," "more," "what's that." — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib
• Simple pretend play begins. — Stern, The Interpersonal World of the Infant
• Babies show understanding of object permanence in A-not-B tasks. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib
• Fourteen-month-olds assume everyone wants what they want — they hand over crackers even to someone who showed disgust for crackers and delight for broccoli. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib
• Between twelve and eighteen months, babbling becomes language-specific: Chinese babies sound Chinese, Swedish babies sound Swedish. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib
• Toddlers cooperate with dressing by extending limbs. — Shelhav, Child Space

• “Elated by newfound mobility” — exploration/return cycles continue; returns to the parent are often brief, “no more than a touch.” — Lieberman, The Emotional Life of the Toddler
• Repair after ruptures is key — misattunements are normal and reconnection builds security. — Siegel & Bryson, The Power of Showing Up
• Babies seek comfort from the attachment figure when distressed. — Beebe & Lachmann, The Origins of Attachment
• Babies show jealousy when the caregiver attends to others. — Stern, The Interpersonal World of the Infant
• Babies bring objects to share with the caregiver. — Beebe & Lachmann, The Origins of Attachment

• The contralateral pattern fully integrates through walking; yield-and-push reflexes mature into controlled locomotion. — Cohen, Sensing, Feeling, and Action
• Babies can combine movement patterns fluidly for complex actions. — Hartley, Wisdom of the Body Moving
• The A-not-B error (searching at the old hiding place after watching the object hidden elsewhere) is not a simple object-permanence failure — it is variable and context-dependent, appearing at 3–5 second delays and vanishing when containers are visually distinctive. — Thelen & Smith, A Dynamic Systems Approach

• The one-nap transition typically occurs somewhere in this window (range: 10–18 months). Night-waking continues to be normal and variable. Sleep needs remain highly individual. — Ball, How Babies Sleep
• Bedtime routines become important for settling. — Eliot, What's Going On in There?

• Transition to family foods accelerates. Whole cow's milk can be introduced as a drink. Self-feeding with utensils begins. Appetite varies day to day — this is normal and not a cause for concern. — Oster, Cribsheet
• Toddlers use a spoon with spilling and drink from an open cup. — Shelhav, Child Space
• Clear food preferences are established. — Shelhav, Child Space

• Low, stable furniture; open floor space; narrate actions. Offer limited choices (“the red cup or the blue cup?”). Follow, don’t lead. — Eliot, What's Going On in There? and — Gerber, Your Self-Confident Baby
• Toddlers need consistent routines for security. — Delahooke, Brain-Body Parenting
• Toddlers can play independently for 10–15 minutes near the caregiver. — Delahooke, Brain-Body Parenting

• Runs stiffly, walks up stairs with hand held, throws a ball, scribbles. — Eliot, What's Going On in There?
• Babies walk backwards and sideways. — Hartley, Wisdom of the Body Moving
• Babies kick a ball forward. — Cohen, Sensing, Feeling, and Action
• Controlled release of objects develops around 18 months. — Eliot, What's Going On in There?

• Babies match objects by touch without seeing. — Eliot, What's Going On in There?
• Babies discriminate small differences in sounds and sights. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib
• Babies enjoy music and attempt to dance. — Shelhav, Child Space

• Points to body parts, follows simple commands, uses 5-20 words, uses objects as tools. — Eliot, What's Going On in There? and — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib
• The naming explosion begins at ~18 months — babies go into a frenzy of pointing and naming, learning multiple new words daily. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib
• Toddlers follow two-step commands. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib
• Parallel play begins near other children. — Stern, The Interpersonal World of the Infant
• Eighteen-month-olds understand that other people may have different desires — they hand the experimenter broccoli (which the experimenter liked) even though they themselves prefer crackers. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib
• Eighteen-month-olds can remember a novel event for up to four months and systematically sort objects into separate groups. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib
• Tool use emerges — babies use a rake to pull an out-of-reach toy toward them, with a visible "aha" moment. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib

• Separation anxiety peaks around 18 months; the child is caught between autonomy and need for security. — Lieberman, The Emotional Life of the Toddler
• Repair after ruptures is key — misattunements are normal and reconnection builds security. — Siegel & Bryson, The Power of Showing Up
• Toddlers test limits while checking for the caregiver's response. — Beebe & Lachmann, The Origins of Attachment
• Toddlers show affection spontaneously. — Stern, The Interpersonal World of the Infant

• The contralateral pattern continues to refine through complex locomotion — running, climbing, dancing. — Cohen, Sensing, Feeling, and Action
• Toddlers can plan and execute complex movement sequences. — Hartley, Wisdom of the Body Moving

• Sleep continues maturing; normal variability in night-waking and nap needs persists. Most toddlers still benefit from one daytime nap. — Ball, How Babies Sleep
• Sleep needs are about 11–14 hours per day including the nap. — Eliot, What's Going On in There?
• Toddlers may resist bedtime as autonomy increases. — Eliot, What's Going On in There?

• Independent eating progresses with growing motor skills. Food neophobia (rejection of new foods) and picky eating are normal developmental phases, not behavioral problems. Repeated neutral exposure without pressure remains the most evidence-backed strategy. — Oster, Cribsheet
• Toddlers use a spoon and fork with increasing skill. — Shelhav, Child Space
• Toddlers want to feed themselves independently. — Shelhav, Child Space

• What changes: The toddler discovers that principles are connected into systems. They begin to understand social systems (family roles, turn-taking) and show empathy in rudimentary form.
• Fussy phase: May be bossy, demand things “just so,” melt down when systems don’t work as expected.
• How to support: Explain systems simply (“first shoes, then outside”). Maintain predictable family routines. Model flexibility when systems break.
• Note: Leap timing is approximate and varies per baby. This is not a diagnostic schedule. — van de Rijt & Plooij, The Wonder Weeks
• Research parallel: a major leap in symbolic thinking and language occurs in this window, with a beginning understanding of categories and concepts. — Gopnik, Meltzoff & Kuhl, The Scientist in the Crib and — Stern, The Interpersonal World of the Infant

• Name objects and feelings; offer limited choices (“the red cup or the blue cup?”); allow safe exploration; acknowledge frustrations before redirecting. — Eliot, What's Going On in There?, — Gerber, Your Self-Confident Baby, and — Faber & King, How to Talk So Little Kids Will Listen
• Emotional co-regulation is still primary, but self-regulation is emerging. — Delahooke, Brain-Body Parenting
• Toddlers benefit from a predictable daily rhythm. — Delahooke, Brain-Body Parenting