Cornell Notes Chapters 1, 3, 4&6, 5 PDF

Chapter 1 lecture notes Cues Notes Definition of Infancy - Latin origin "INFANS" = unable to speak. - Period from birth to 2 years. - Before speech develops, so cognition does not include a linguistic component. Why s...

Chapter 1 lecture notes Cues Notes Definition of Infancy - Latin origin "INFANS" = unable to speak. - Period from birth to 2 years. - Before speech develops, so cognition does not include a linguistic component. Why study infancy? - Identify inborn vs. learned abilities (Nature vs. Nurture). - Track rapid vs. gradual developmental changes (Qualitative vs. Quantitative). - Establish foundation for adult behavior & capacities. - Ensure a safe, stimulating environment for learning. Theories of Infancy - Nativism vs. Empiricism: Are abilities preformed (fixed) or predetermined (develop over time)? - Piaget’s Constructivist Theory: Infants are born with perception & memory but must construct knowledge. - Gibson’s Ecological Theory: Infants actively seek information in their environment. Function of Infant - Energy Budget: Initial function is to maximize energy intake for growth. Development - Limitations: Infants cannot obtain fuel independently or regulate bodily functions. - Cognitive & social development occurs once these limitations are overcome. Types of Research - Correlational: Examines relationships but does not establish causation. - Experimental: Manipulates independent variable (IV) to measure effect on dependent variable (DV) (cause-and-effect). - Quasi-Experiment: Uses natural groups but does not allow causal conclusions. Developmental Research - Longitudinal: Studies same children across time (Issues: subject loss, testing Designs effects). - Cross-Sectional: Compares different children examined at each age (Issue: Cohort effects). - Cross-Sequential (Hybrid): Groups of children are examined multiple times at overlapping ages. Controls for cohort effects, examines stability. - Microgenetic: Some children are examined multiple times at short intervals usually at a time of developmental transition. Focuses on short developmental phases (e.g., perception studies). -Cross cultural: Compares species or human cultural differences. Example: African vs. Asian parenting affects motor development (e.g., walking milestones). Infant Research Methods - Looking Paradigms: Measures visual attention. - Preferential Looking: Measures spontaneous visual preference for one stimulus. - Habituation: Infants lose interest in repeated stimuli; renewed attention to new ones = learning. - Reaching Studies: Measures depth perception. - Visual Evoked Potentials (VEP): Uses electrodes to measure brain responses to visual stimuli. - Extra Writing: Infants look longer at novel stimuli when they recognize a difference. Summary Infancy (birth to 2 years) is a critical period where cognition exists without language. Research helps differentiate innate vs. learned abilities through longitudinal, cross-sectional, and experimental designs. Scientists study infant perception and cognition using looking paradigms, habituation, and brain activity measures. Culture and environmental interactions also shape development. Chapter 1 reading notes Cues Notes Qualitative vs. - Qualitative Change = Sudden, fundamental shifts (e.g., crawling → walking). Quantitative Change - Quantitative Change = Gradual, continuous (e.g., height, weight, vocabulary growth). - Example: Charlie’s eye color changing from dark to light = qualitative change, while gaining weight over time = quantitative. Nature vs. Nurture - Nature: Genetic & biological influences on development. - Nurture: Environmental & experiential influences. - Example: Newborns prefer human faces (innate), but social experience shapes preference further. - Extra Writing: No ability is purely genetic—environment always plays a role in shaping expression. Additive Effects & - Additive Effect: Both genes & environment independently contribute to development. GXE Interactions - GXE Interaction: Genes & environment interact, meaning the environment can enhance or suppress genetic traits. - Example: A child genetically predisposed to high intelligence needs enriched learning environments to reach full potential. Specific time window when development is most vulnerable and susceptible to variations in Critical Periods experiences and conditions. This is when the brain is being built. - Parents & Caregivers: Provide the first social and learning environments. Policymakers & - Institutions: Policies on education, healthcare, and childcare impact infant outcomes. Development’ - Public Policies: Government programs shape early childhood growth (e.g., maternity leave, child welfare). Benefits and - Correlational: B=Examines relationships between variables that can't be manipulated. Limitations of L=Cannot draw cause and effect conclusions. Research Designs - Experimental: L=Can assess the effect of one variable on another. B= Some variables cannot be manipulated. - Quasi-Experiment: L=Uses non-manipulated variables as groups. B= Correlational designs that do not allow causal conclusions. Benefits and Limitations of - Longitudinal: B=Evaluates child development and individual differences. L=Time consuming developmental requires family commitment; repeated testing may affect results. designs - Cross-sectional: B= Quick and requires less family commitment. L=Age differences may be confounded with group differences. - Cross-sequential: B=Explorers long-term development in less time with minimal family commitment. L=Cohort differences may affect results beyond age. - Microgenetic: B= Observes real time development. L= Requires multiple sessions and family commitment. Measurement of - Behavioral Measures: Observing actions, interactions, responses. infant development - Looking Time: Measures visual attention (e.g., Habituation, Preferential Looking). - Physiological Measures: EEG/ECG (brain waves, heart rate) track responses to stimuli. - Visual Cliff Experiment: Used to study depth perception in infants. Psychological - Concepts that researchers measure but cannot directly observe (e.g., memory, Constructs perception). - Example: Infant preference for faces suggests an early form of social cognition. - Development is holistic—cognitive, motor, emotional, and social growth interact. The Whole Child - Example: Motor development (e.g., learning to walk) impacts social interactions and language acquisition. - Development emerges from the interaction of multiple systems (body, brain, Dynamic Systems environment). Theory - Example: Walking depends on muscle strength, balance, and motivation. - Early experiences shape later outcomes. Developmental - Example: Poor nutrition → Delayed brain development → Learning difficulties. Cascades  - Bronfenbrenner: Development is shaped by multiple environments. Ecological Systems - Microsystem (family, caregivers) → Mesosystem (schools, neighborhoods) → Exosystem Theory (indirect environment) → Macrosystem (culture, policies). - Example: A child raised in a stimulating environment develops stronger cognitive and social skills. Piaget’s Theory - Constructivist Approach: Infants actively build knowledge through experiences. - Stages of Cognitive Development: Sensorimotor → Preoperational → Concrete → Formal. - Example: Object permanence (understanding that objects exist even when out of sight) develops during the sensorimotor stage. Summary Infant development is studied to answer fundamental questions about growth, learning, and change. Researchers examine nature vs. nurture, qualitative vs. quantitative change, and gene-environment interactions. Research designs include longitudinal, cross-sectional, and experimental studies. Measurements such as behavioral observation, looking time, and physiological recordings (EEG, ECG) help assess infant abilities. Theories like Piaget’s, Dynamic Systems, and Ecological Systems Theory explain how development unfolds in complex environments. Early experiences, policies, and social environments shape infant growth. Chapter 3 lecture notes Cues Notes Conception & - Gametes (egg & sperm) carry 23 chromosomes each, combine to form a zygote (46 Chromosomes chromosomes, 23 pairs). - Neuroplasticity: The brain adapts and changes due to experience. Stages of Stage 1: Zygote (0-2 weeks) Prenatal - Cells divide (mitosis) and form a hollow ball. Development - Implants in the uterus, cells differentiate (embryo vs. support structures (placenta and amniotic sac)). Stage 2: Embryo (3-8 weeks) - Formation of major organs & structures. - Three layers: Endoderm (internal organs), Mesoderm (muscles, bones, heart), Ectoderm (nervous system, skin, eyes, ears). - Brain development begins (week 5). Stage 3: Fetus (9-38 weeks) - Body growth & differentiation (e.g., nails, facial features, hair). - Brain areas specialized by 3 months (visual, auditory, cognitive). - By 5 months, the fetus responds to sound (kicking, turning). - 8 months: Immune system starts developing with help from mother. Teratology - Study of teratogens (non-genetic agents causing birth defects). - Most affect the fetus after 3 weeks via placenta. How Teratogens - Genetic Sensitivity (species-specific impact). Act - Temporal Sensitivity (timing matters). - Effect Specificity (e.g., Thalidomide → limb defects, Rubella → sensory/internal organ issues). - Severity & Dosage Effects (higher exposure = worse effects). Types of - Rubella: Low birth weight, heart defects, cataracts, microcephaly. Teratogens - Herpes: CNS damage. - HIV: Facial deformities, poor soothing ability. - Zika: Severe birth defects, microcephaly. - COVID-19: Twice the risk of neurodevelopmental issues, respiratory distress. - Syphilis & Gonorrhea: Prematurity, eye infections, spontaneous abortion. - Malnutrition: Prematurity, growth restrictions. - Parental Age: Older parents → increased risk of Down’s syndrome. - Drugs (Street drugs, Caffeine, Nicotine, Alcohol): Developmental defects. Fetal Alcohol - Caused by prenatal alcohol exposure. Syndrome (FAS) - Results in facial deformities, cognitive impairments, growth issues. Labor & Birth Stage 1: Contractions dilate cervix, baby moves down birth canal. Process Stage 2: Delivery of baby (vaginal or C-section). Stage 3: Placenta delivered. Prenatal Learning - Newborns prefer their mother’s voice over strangers (DeCasper & Fifer, 1980). - Infants remember rhythms of speech (e.g., those whose moms read Cat in the Hat in the womb preferred hearing it after birth) (DeCasper & Spence, 1986). - Mozart effect is a myth—fetal brains are not developed enough for math or intelligence gains. Birth Process & Brain - Labor contractions may influence neurotransmitter release & brain wiring. Development - Passing through the birth canal exposes baby to bacteria that shape gut microbiome. - C-section babies miss this microbiome exposure, which may impact immunity. Summary Prenatal development occurs in three stages: zygote, embryo, and fetus, with key milestones such as organ formation, sensory system development, and brain differentiation. Teratogens (e.g., infections, drugs, malnutrition) can cause severe birth defects, depending on timing, dosage, and genetic sensitivity. Prenatal learning occurs, with infants preferring familiar voices and rhythms after birth. The birth process affects brain wiring and microbiome development, and C-section births may impact immunity. Chapter 3 reading notes Cues Notes Sex & Gender - Sex determined by chromosomes (XX = Female, XY = Male). Development - Y chromosome triggers testes development → androgen release → male differentiation. - Androgen Insensitivity Syndrome (AIS): XY individuals develop as females due to lack of androgen response. - Congenital Adrenal Hyperplasia (CAH): XX individuals overproduce androgens, leading to masculinized features. - Classifies drugs based on pregnancy safety: FDA Classification for Category A: No risk (e.g., prenatal vitamins). OTC Drugs Category B: No human risk but some animal studies suggest risk. Category C: Risk not ruled out, but benefits may outweigh risks. Category D: Evidence of fetal harm but may be used if necessary. Category X: Known teratogens (e.g., Accutane, Thalidomide) - completely avoided. Taste & Smell: Development of - Develops early; the fetus detects flavors from amniotic fluid. Sensory Systems - Exposure to a mother's diet can shape postnatal taste preferences. Touch: - First sensory system to develop. - Essential for reflexes (e.g., grasping, rooting). Hearing: - Functional by 5 months. - Newborns recognize their mother's voice & speech rhythms. Vision: - Least developed sense at birth. - Newborns focus best on objects 8-12 inches away (e.g., caregiver’s face). - Newborn states: Alternates between quiet sleep, active sleep, drowsiness, quiet alert, Newborn States & active alert, and crying. Sleep - Newborn sleep: - Sleeps ~16-18 hours per day but in short cycles. - Primarily REM sleep, essential for brain development. - Circadian rhythms are not fully developed, leading to frequent night awakenings. - Swaddling & white noise can help regulate sleep. - Crying = communication for needs (hunger, discomfort, attention). - Colic: Excessive, unexplained crying in the first 3 months. Newborn Crying & - Soothed by rhythmic sounds & rocking. Colic Summary Sex and gender development is influenced by chromosomes and hormones, with variations like AIS and CAH. The FDA classification system ranks OTC drugs from Category A (safe) to Category X (teratogenic). Sensory systems develop before birth, with touch developing first, followed by hearing, taste, and smell, while vision is the least developed. Newborns sleep ~16-18 hours daily, mostly in REM sleep, with immature circadian rhythms causing frequent night awakenings. Crying and colic are early communication tools, with colic causing excessive crying in the first three months. Chapter 4&6 lecture notes Cues Notes Goal of Perceptual - To build a coherent knowledge base of the world. Development - Requires gathering, integrating, and using information at appropriate ages. Goal of Basic Visual - The world consists of objects, made up of features. Functioning - Before recognizing objects, infants must see and process individual features. - Vision develops rapidly in infancy. Basic Visual - Sensory processes are the limiting factor in early perception. Processing in Infants - Development is tied to the nervous system’s maturation. - Acuity & Contrast Sensitivity: Detecting fine details. Aspects of Spatial - Orientation Selectivity: Identifying edges & patterns. Vision - Eye Movements: Tracking stationary & moving objects. - Measures the sharpness of vision. Visual Acuity - Tested with Preferential Looking & Visual Evoked Potentials (VEP). - VEP provides more accurate acuity measures. Development of - Improves rapidly in the first 6 months. Visual Acuity - Levels off after 6 months, reaching adult levels by 1 year. - Measures ability to detect misalignments in visual patterns. Vernier Acuity - At birth, grating acuity (contrast detection) is better than vernier acuity. - By 5 years, vernier acuity surpasses grating acuity. - Ability to detect differences between light & dark regions. Contrast Sensitivity - Improves in infancy, shifting to higher spatial frequencies (finer details). - Cone density in the fovea is 1/3 of adult’s. Factors Influencing - Cone length is 1/10 of adult’s. Acuity & Contrast - Lens does not accommodate well at birth. Sensitivity - Retinal ganglion cells & optic nerve continue developing. Orientation - Detects patterns of light & dark for object recognition. Selectivity - Processing occurs in the early visual cortex. Research on - Braddick, Wattam-Bell & Atkinson (1986): Orientation - Used VEP to show that 6-week-olds detect orientation shifts. Selectivity - Maurer & Martello (1980): - 6-week-olds show orientation discrimination via habituation. - Slater (1989): - Found newborns exhibit orientation discrimination using novelty-preference tasks. Types of Eye - Saccades: Used to localize stationary objects. Movements - Pursuit: Used to track moving objects. - By 1 month, infants can localize targets, but movements are slow & inaccurate. Saccadic Eye - By 3 months, they make predictive saccades. Movements - By 6 months, saccades resemble adult movements. Research on - Canfield, Smith, Brezsnyak, & Snow (1997): Saccades - Found saccade latency stabilizes by 6 months. - Smooth tracking of moving objects. Pursuit Eye - Aslin (1981): Pursuit tracking is difficult before 2 months. Movements - By 6 months, pursuit tracking is adult-like. - Phillips, Finocchio, Ong, & Fuchs (1997): Research on Pursuit - Infants under 2 months can track slow-moving objects (10° per second). Movements  Summary Basic visual functioning develops rapidly in infancy, helping infants recognize objects by processing individual features. Visual acuity improves significantly within the first year, with VEP providing more precise measurements than preferential looking. Contrast sensitivity increases, allowing detection of finer details. Orientation selectivity, crucial for pattern recognition, emerges by 6 weeks, and eye movements (saccades & pursuit tracking) mature by 6 months. Research highlights how sensory limitations, neural development, and experience shape early visual perception. Chapter 4&6 reading notes Cues Notes Defining Perception - Perception is the interpretation of sensory input to understand the world. - Knowing where an infant is looking ≠ knowing what they see. - Perception goes beyond sensory processing (e.g., retina, optic nerve) to include how infants interpret their experiences. Nature & Nurture in - Infants experience lots of sights, sounds, smells, and so on, but have no way of Perceptual understanding them. Development - Perception changes with experience. - Sensory experience alone is random & meaningless—infants must learn to interpret it. - Forming associations helps the brain make sense of sensory input. - Piaget’s Constructivist View: Perception is a constructive process, where infants actively build perception from experience (nurture). - Some aspects of perception may be innate, but others require learning (nature). - It is also a combination of nature and nature - Cyclopean image: When two eyes receive slightly different images, the brain merges them into a single 3D perception. Studying Perceptual - Habituation refers to the fact that infants' response to stimulus decreases when that stimulus Development is repeated (Infants prefer relatively new things and lose interest as things become familiar) - Visual Preference Method: Measures which stimuli infants prefer to look at. - Visual Habituation: A procedure in which infants are repeatedly shown a visual stimulus and they're looking time decreases as the stimulus becomes familiar. -habituate- As infants learn or form a memory of a stimulus, they're looking time decreases or habituates -dishabituate- If infants can discriminate or tell the difference between the old familiar stimulus and this new stimulus, they will look for a long time at the new stimulus or does habituate - Visual Paired-Comparison Task: Infants are shown a familiar vs. novel stimulus; preference for the novel stimulus = recognition & memory. Visual Acuity - Visual activity refers to the amount of detail you can see. (Sharpness of Vision) - Newborns have poor acuity (~20/400), improving to near-adult levels (~20/20) by 6-12 months. - Acuity is linked to development of the retina, optic nerve & cortical processing. Methods for Assessing Visual Acuity in Infants: Teller Acuity Cards: Assess infants' looking behavior by presenting a pattern alongside a solid gray field to determine the finest detail they can detect, such as the smallest stripes they prefer. Optokinetic Nystagmus (OKN): Measures reflexive eye movements in response to moving patterns (e.g., stripes) to estimate the smallest detail that triggers the response. Visual Evoked Potentials (VEPs): The most accurate method, recording brain activity from the scalp in response to visual patterns (e.g., stripes, checkerboards) to determine the smallest detectable detail. Color Vision - Infants to see some colourful birth, but their colour perception is not the same as it is an adults - The visible spectrum of light those wavelengths humans can actually see range from relatively long wavelengths (infrared light) which is red to short wavelengths (ultraviolet light), which we see as blue. - Trichromatic Theory: The retina has three cone types (red, green, blue) that allow color perception. - Color Vision Deficiency (Color Blindness): Some individuals lack one or more cone types,  leading to difficulty distinguishing colors. - Infants can see some colors but struggle with blues & purples initially. Young infants are only sensitive to bright colours in that object or patches of color. Need to be big for infants to see. Depth Perception - Gibson created the visual cliff to provide crawling infants with the illusion that they were crawling over deep clip with more experience, crawling or more reluctant to cross the deep side of the cliff, then infants who have just learned to crawl one conclusion from this might be that infants learn to perceive depth from their experience. - Ability to perceive distance & 3D space. - Emerges gradually through experience & brain development. Types of depth cues: Kinematic Cues (First to Develop - Motion-Based Perception) - Motion parallax: Objects closer move faster than distant ones. - Optical expansion: Approaching objects appear larger. Binocular Cues (~4 months) - Stereopsis: The brain fuses images from both eyes to create 3D vision. Monocular (Pictorial) Cues (~5-7 months) - Uses size, texture, and occlusion (one object blocking another) to infer depth. What is Attention? - Attention = selecting important information while ignoring distractions. Attention makes processing information manageable, but it's also why we miss some things that happened around us. If we don't attend to something, we don't process it. This is why we think that infants' attention and especially visual attention is an important mechanism of information gathering. - Infants must focus on objects before learning from them. Aspects of Attention: - Orienting Attention: Directing attention to a stimulus. (i.e., An infant turning her gaze to her mother's face) {attention getting} If you're currently attending to something orienting to something new requires disengaging from the current focus of your attention, orienting and disengagement develop over the first month after birth. - Selecting Attention: Filtering out irrelevant stimuli. (i.e., An infant looking at the shape of her mother eyes, ignoring her mouth and nose) - Maintaining Attention: Staying focused on a task over time. (i.e., An infant continuing to look at her mothers face, even as her older sibling is singing and dancing nearby) {attention holding} - Looking Time Methods: Measures how long an infant looks at a stimulus. How Do We Measure - Eye-Tracking: Records gaze patterns to track attention shifts. Attention? - Covert Attention: Attending to something without directly looking at it. - Brain Activity (EEG/VEPs): Measures neural responses to attention tasks. Selection Selective attention is needed when the visual world is cluttered, and there are many things that you could look at, for example when looking at a living room filled with toys, people and furniture. Maintaining attention Infants need to maintain their attention to process stimuli, and younger infants look longer because they require more time. This trend is seen in the first six months, often observed in controlled environments with minimal distractions. After six months, attention maintenance depends on the stimulus. Younger infants are more easily distracted by competing stimuli. Attention development varies with environmental factors, suggesting differences in attention can be influenced by socioeconomic status. Summary Perception is the active interpretation of sensory input, shaped by both nature (innate abilities) and nurture (experience). Visual acuity develops rapidly, measured using Teller’s Task, OKN, and VEPs. Color vision follows the trichromatic theory, with cones maturing by 3-4 months. Depth perception emerges gradually, with motion-based (kinematic), binocular, and monocular depth cues. Gibson emphasized perception as an active process, supported by the Visual Cliff Experiment. Attention develops through orienting, selecting, and maintaining focus, measured by eye-tracking, EEG, and looking time methods. Memory & categorization help infants recognize objects, faces, and sounds, forming the foundation for learning. Chapter 5 lecture notes Cues Notes Newborn Physical - Behavior is linked to neurological mechanisms. Assessment - Identifies infants at risk for developmental delays. At-Risk Infants - Causes: Teratogen exposure, poverty, teenage mothers, unmarried mothers, lack of education. - Low birth weight and C-section delivery may increase risk. Low Birth Weight - Two Categories: Pre-term infants (born too early) & Small for gestational age (born smaller than expected). - Complications: Breathing issues, poor muscle tone, long-term academic & behavioral difficulties. Newborn - APGAR Exam: Evaluates heart rate, respiration, muscle tone, skin color, reflex response Assessment at birth & 5 minutes. Methods - Hammersmith Infant Neurological Exam: Conducted at 3 months, tests posture, movement, reflexes, cranial nerve function. - Brazelton Neonatal Behavioral Assessment Scale (NBAS): Assesses attention, movement, alertness, and response to stress. APGAR Score & - Scores below 4 indicate risk. Predictions - Drug exposure & C-section deliveries linked to lower scores. - Low scores predict growth and ability at 4.5 years but not at 6 months. Brazelton NBAS - Preterm infants: Lower attention thresholds. Findings - Cocaine-exposed infants: Poor habituation & attention scores. Sleep/Wake - Total sleep time decreases with age. Development - REM sleep drops from 50% in newborns to ~20% in adults. Sudden Infant - Most vulnerable at 2-4 months. Death Syndrome - Risk factors: Sleep position, soft bedding, overheating, maternal smoking. (SIDS) - Rooting reflex (disappears ~3 months): Helps with feeding. Newborn Reflexes - Palmar reflex (disappears ~4 months): Infant grips objects in hand. - Stepping reflex (disappears ~2.5 months): Prepares for walking. Early Behaviors - Looking, sucking, crying regulate infant interaction. - Crying-produced forgetting: Infants may forget distress when crying. Motor - Two Types: Locomotion (moving) & Prehension (grasping objects). Development - Motor progression follows two principles: - Proximodistal: Control develops from the center of body outward. - Cephalocaudal: Control develops from head to feet. Standing & Walking - Follows a regular sequence based on proximodistal & cephalocaudal principles. Nature vs. Nurture - African infants walk earlier, some Asian infants walk later. in Motor - Experience (e.g., tummy time) influences motor milestones. Development - Motor development is adaptive: Infants adjust movement to achieve a goal. Thelen’s Dynamic - Thelen’s Experiment: Tied infants’ legs together → They learned to kick both legs Systems Approach simultaneously for efficiency. Visual Cliff - Gibson & Walk (1960): Tested depth perception & fear of heights. Experiment - Infants avoided deep side despite mother’s encouragement. - Locomotion supports perceptual growth (spatial & 3D perception). Function of Motor - Prehension allows object exploration & interaction with the environment. Development  Summary Physical and motor development involve early assessments (APGAR, Hammersmith, Brazelton NBAS) to detect at-risk infants. Low birth weight and preterm birth are linked to health & behavioral challenges. Motor skills follow proximodistal & cephalocaudal principles, with nature and nurture both influencing development. Reflexes guide early movement, and Thelen’s research supports a dynamic systems approach to motor learning. The Visual Cliff Experiment demonstrated depth perception and fear of heights in infants. Locomotion and object manipulation support cognitive and perceptual growth. Chapter 5 reading notes Cues Notes Physical development Growth charts: - Used to track height, weight, and head circumference over time. - Compares an infant’s growth percentile to population norms. Failure to thrive: - A condition where infants do not gain weight or grow as expected. - Causes: Malnutrition, illness, neglect, poor feeding practices.It could also likely mean that they're not getting enough nutrition. This puts them at risk for other problems, such as delay in other developmental milestones like rolling over. Secular Trends in Growth: - Generational changes in physical growth patterns. - Children today are taller & reach puberty earlier than past generations, likely due to improved nutrition & healthcare. Factors That Influence Growth Role of Nutrition - Breastfeeding provides immune support & reduces infection risks. - Formula Feeding: Alternative to breastfeeding but lacks certain immune benefits. - Malnutrition leads to stunted growth, cognitive delays, weakened immune function. - Micronutrient Deficiencies (e.g., Iron, Iodine, Vitamin A) can impair brain & motor development. Influence of Toxins - Lead exposure can cause neurological damage & slow growth. - Prenatal alcohol exposure can lead to growth deficiencies (Fetal Alcohol Syndrome - FAS). Infant Reflexes & Their - Reflexes are automatic responses to stimuli, essential for survival & early Appearance movement patterns. Newborn Reflexes: Elicitors & Responses: Babinski Reflex - Elicitor: Stroking the bottom of the infant’s foot. - Response: Toes fan out and curl. Grasping (Palmar) Reflex - Elicitor: Placing an object in the infant’s palm. - Response: Infant grips object tightly. Moro (Startle) Reflex - Elicitor: Loud noise or sudden movement. - Response: Infant extends arms & legs, then pulls them back in. Rooting Reflex - Elicitor: Stroking the infant’s cheek. - Response: Infant turns toward stimulus & opens mouth (assists feeding). Stepping Reflex - Elicitor: Holding infant upright with feet touching a surface. - Response: Infant makes stepping motions. Sucking Reflex - Elicitor: Touching the roof of the infant’s mouth. - Response: Infant begins sucking motion. Tonic Neck Reflex ("Fencer’s Pose") - Elicitor: Turning infant’s head to one side. - Response: Arm on that side extends, opposite arm flexes. Disappearance of Infant Reflexes:  - Reflexes fade as voluntary motor control develops. - Stepping reflex disappears (~2 months), reemerges as walking (~12 months). Motor Milestones - Development follows cephalocaudal (head-to-toe) & proximodistal (center-outward) principles. -Gesell's Maturation Theory: Infants worldwide follow the same motor milestone sequence at similar ages, emphasizing nature over experience. He argued that parenting, culture, race, and socioeconomic status do not affect motor development norms. Early walkers are "precocious," while late walkers are "delayed." Classic Motor Milestones & Approximate Ages: - Prone, Lifts Head → ~6 weeks. - Prone, Chest Up (Uses Arms for Support) → ~3 months. - Rolls Over → ~4-5 months. - Sits Without Support → ~6 months. - Crawls → ~7-10 months. - Stands With Support → ~8-9 months. - Pulls to Stand → ~9-10 months. - Cruising (Walks With Support) → ~10-11 months. - Stands Alone → ~11-12 months. - Walks Alone → ~12-15 months. Criticisms of Gesell's theory: 1. Milestones are problematic → Assumes all infants must reach certain milestones, but some skip them (e.g., crawling) and develop normally. 2. Not all infants follow the same path → Different infants move differently (e.g., crawling vs. scooting) & cultural differences affect timing. 3. Ignores experience & environment → Motor skills are shaped by practice, culture, & environment, not just biology. 4. Fails to explain delays & disabilities → Does not account for children with motor impairments (e.g., cerebral palsy, Down syndrome). 5. Motor development isn’t always step-by-step → Some infants develop skills at the same time or regress before progressing. 6. Modern research sees motor development as dynamic → Thelen’s Dynamic Systems Theory shows that movement comes from brain, muscles, experience, & environment working together. Handling Practices - Swaddling: Restricts movement but may provide comfort & warmth. - Gahvora Cradle (Central Asia): Restricts movement, delaying motor milestones. Experience & Practice Effects - Active Exercise: Encouraging movement accelerates motor development. - Passive Exercise: Restricted movement delays milestone achievement. Multiple Domains of Motor Motor Development & Perception Development - Motor skills depend on perceptual input (e.g., infants must see an object before reaching for it). Perception & Action - Optic Flow: The visual changes infants perceive as they move. - Moving Room Experiment: Infants adjust posture based on perceived motion cues. - Proprioception: Awareness of body position & movement. - Locomotion & Prehension: Walking & grasping require integration of vision & movement. - Affordance = an action an environment allows (e.g., a small ledge can be stepped over, a deep hole cannot). - Infants learn to perceive what actions are possible based on body size & surroundings. - Example: A toddler may try to sit in a tiny chair, misunderstanding its affordance (Scale Error). Summary Physical growth follows predictable trends tracked using growth charts. Failure to thrive (FTT) occurs when infants do not grow as expected, and secular trends show increasing height & earlier puberty over generations. Nutrition (breastfeeding, micronutrients) and toxins (lead, alcohol) significantly impact growth. Infants are born with reflexes (Babinski, Grasping, Moro, Rooting, etc.), which disappear as voluntary control develops. Motor milestones follow a sequential pattern, influenced by biological maturation (Gesell’s Theory), cultural handling practices (swaddling, Gahvora cradles), and experience effects (active vs. passive exercise). Motor development is closely tied to perception, allowing infants to adjust movement based on visual cues (optic flow, proprioception, locomotion). Infants also learn to perceive affordances for action, recognizing what their body can and cannot do in different environments.