Presentation on theme: "Physical, Sensory, and Perceptual Development In Infancy"— Presentation transcript:
1 Physical, Sensory, and Perceptual Development In Infancy Chapter 4:Physical, Sensory, and Perceptual Development In Infancy
2 In This Chapter Physical Changes Health and Wellness Infant Mortality Sensory SkillsPerceptual Skills
3 Physical Changes The Brain and Nervous System Rapid development during the first 2 yearsMidbrain and medulla most fully developed at birthThe cortex is the least developed.The medulla regulates vital functions such as heartbeat and respiration, attention, sleeping, waking, elimination, and movement of the head and neck.The cortex is responsible for perception, body movement, thinking, and language.
4 Figure 4.1 Parts of the Brain The medulla regulates vital functions such as heartbeat and respiration, attention, sleeping, waking, elimination, and movement of the head and neck.The cortex is responsible for perception, body movement, thinking, and language.Figure 4.1 Parts of the Brain
5 The Brain and Nervous System Physical Changes: Synaptic Development SynaptogenesisCreation of synapses or connections between neuronsSynaptic pruningElimination of unused neural pathways and connectionsEarly in development, each muscle cell seems to develop synaptic connections with several motor neurons in the spinal cord. But after the pruning process has occurred, each muscle fiber is connected to only one neuron. Some neurophysiologists have suggested that the initial surge of synapse formation follows a built-in pattern (Greenough et al., 1987). The organism seems to be programmed to create certain kinds of neural connections and does so in abundance, creating redundant pathways. According to this argument, the pruning that takes place beginning at around eighteen months is a response to experience, resulting in selective retention of the most efficient pathways.
6 The Brain and Nervous System Plasticity Neural plasticity: Brain’s ability to change in response to experienceUse it or lose itChanges in psychological functioningRat infants reared in a highly stimulating environment have a denser network of neurons, dendrites, and synaptic connections.Young infants need sufficient stimulation and order in their environments to maximize the early period of rapid growth and plasticity.Use it or lose itAn intellectually challenging environment creates a more complex network of synapses.Changes in psychological functioningDevelopmental changes in brain across lifespanInfant brains have greater plasticity but more vulnerability to major deficits.
7 The Brain and the Nervous System Myelinization Myelin: Insulating layer of proteins and fatty substancesDescriptionTimingMyelin: Insulating layer of proteins and fatty substancesDescriptionForms myelin sheath covering individual axonsProvides insulation and speeds up neuronal processesFollows cephalocaudal and proximodistal patternsTimingMost rapid during first two yearsContinues at slower pace throughout childhood and adolescenceCephalocaudal: head to toeProximodistal: near to far
8 Reflexes and Behavioral States Adaptive Reflexes Adaptive reflexes: Reflexes that help survivalWarn of possible neuronal development problems when weak or absentSome persist throughout life.Help survivalSuckingWithdrawal from painOpening and closing of pupilWarn of possible neuronal development problems when weak or absentSome reflexes, such as sucking, will be replaced by voluntary behaviors, while others are available throughout the lifespan.
9 Reflexes and Behavioral States Primitive Reflexes Primitive reflexes: Reflexes controlled by less sophisticated parts of brainShould appear at birth and disappear by 6 to 8 months.May indicate neurological problems if persistent.Controlled by less sophisticated parts of brainMoro (or “startle”) reflexBabinski reflex (curled toes)Should disappear by six to eight months.May indicate neurological problems if persistent.Less sophisticated parts of the brain include the medulla and midbrain.
10 Reflexes and Behavioral States States of Consciousness Sleep, Baby, sleepPatterns of sleep and wakefulness stabilize with age.Neonates sleep 80 percent of the time.By 8 weeks, babies begin to sleep through the night.By 6 months, babies average 14 hours of sleep per day.Sleep patterns are individualized and some babies may not develop nighttime patterns until one year of age.Patterns of sleep and wakefulness stabilize with age.Neonates sleep 80 percent of the time.By eight weeks, babies begin to sleep through the night.By six months, babies average fourteen hours of sleep per day.Clear nighttime patterns and daytime naps are established.
11 Reflexes and Behavioral States Five States of Sleep and Wakefulness Deep sleepLight sleepAlert wakefulnessFussingDrowsySleep patterns are individualized and some babies may not develop nighttime patterns until one year of age.Patterns of sleep and wakefulness stabilize with age.Neonates sleep 80 percent of the time.By eight weeks, babies begin to sleep through the night.By six months, babies average fourteen hours of sleep per day.Clear nighttime patterns and daytime naps are established.Most infants move through these states in the same sequence every 2 hours
12 Reflexes and Behavioral States Crying Baby, Not Crybaby! Cries differ by need.Cross-cultural studies suggest crying increases until 6 weeks then tapers off.Prompt attention to crying in the first 3 months leads to less crying later.Cries differ by need.Basic cry signals hunger: rhythmic patternAnger cry: louder and more intensePain cry: very abrupt onsetColic: a pattern involving intense bouts of crying for no immediately apparent reason, as much as three hours a day. Appears at about two weeks then disappears by three to four months of age.
13 Growth, Motor Skills, and Developing Body Systems Physical Changes: Growth By age one10 to 12 inches of growthInfants triple body weightAround age twoToddlers reach half their adult height.Proportionately much larger heads than adults
14 Growth, Motor Skills, and Developing Body Systems Growth and Motor Skills: Overview Inborn timetable of motor skills interacts with other aspects of physical development (Thelen).Muscles, bones, weight—all work together.Opportunities to practice motor skills are important.
15 Stop and Think!Researchers suggest there is a difference in the rate but similarity in the sequence of motor skill development. Using this information as a base, what advice would you give to parents of toddlers?
16 Developing Body Systems and Motor Skills Bones Ossification: Process of hardening of bonesBegins during prenatal developmentContinues through pubertyMotor development depends to a large extent on ossification.Changes in number and density of bones are responsible for improved coordination.At birth, wrist is cartilage; by one to three years of age, it is separate bones: by adolescence, nine separate bones. This improves manipulative skills.Standing is impossible without ossification.
17 Developing Body Systems and Motor Skills Muscles Full complement of muscle fibers present at birthDecline in muscle tissue to fat ratio occurs by age 1.Change in muscle composition leads to increase in strength.Stamina: ability to maintain activityGross motor skills exhibit predictable changes over time.Fine motor skills, such as palmar grasp and pincer grasp, take longer to develop.Motor skills follows cephalocaudal and proximodistal development.Gallaway and Thelen (2004): infants can reach for objects more efficiently with their legs—just the opposite of cephalocaudal development.
18 Developing Body Systems and Motor Skills Lungs and Heart Rapid growth during the first 2 years leads to stamina.Ability to sustain motor activity without rest by end of infancyStamina: ability to maintain activityGross motor skills exhibit predictable changes over time.Fine motor skills, such as palmar grasp and pincer grasp, take longer to develop.Motor skills follow cephalocaudal and proximodistal development.Gallaway and Thelen (2004): infants can reach for objects more efficiently with their legs—just the opposite of cephalocaudal development.
19 Cross-Cultural Research Developing Body Systemsand Motor SkillsCross-Cultural ResearchExperience influences motor development!African motor developmentThe pattern of traditional cultural practices promotes motor development.Precocity does not persist into early childhood.Stamina: ability to maintain activityGross motor skills exhibit predictable changes over time.Fine motor skills, such as palmar grasp and pincer grasp, take longer to develop.Motor skills follow cephalocaudal and proximodistal development.Gallaway and Thelen(2004): infants can reach for objects more efficiently with their legs—just the opposite of cephalocaudal development.
20 ??Questions To PonderDo you or your spouse plan on breastfeeding? What factors would make you want to breastfeed? What factors would cause you not to breastfeed? What are the 3 most important factors that influence physical growth? Why are they important?
21 Health and Wellness Nutrition: Breastfeeding and Bottle feeding Nutritionally superior: More rapid weight gain and sizeEarly health benefitsOnly nutrition needed for first 4 to 6 months of lifeMay not be possible for all mothersMay be needed supplement for preterm babiesSpecial-needs formulas availableCan be high qualityAllows more father participationCommon illnesses: diarrhea, gastroenteritis, bronchitis, ear infections, and colic, as well as infant deathMothers should not breastfeed if using drugs, if they are substance abusers, or if they have AIDS.
22 Health and Wellness Nutrition: Solid Food Solid FoodsEarly introduction can interfere with nutrition.Do not help babies to sleep through the nightShould start between 4–6 monthsBaby is ready for solid foods when he or she can:Hold head in steady, upright positionSit with supportShow interest in what you are eating
23 Health and Wellness Malnutrition Macronutrient malnutritionMarasmusKwashiorkorMicro-nutrient malnutritionMacronutrient malnutritionDiet containing too few caloriesLeading worldwide cause of death in children under fiveMarasmusSevere calorie deficitExtremely smallCan cause permanent brain damageKwashiorkorDiet too low in proteinMicronutrient malnutritionDeficiency of certain vitamins and/or mineralsMarasmus and Kwashiorkor are found in many developing countries.Industrial societies suffer more from micronutrient malnutrition—a deficiency of certain vitamins or minerals. Iron deficiency leads to anemia, which may impede both social and language development.
24 Health and Wellness Health Care and Immunization Health Care and ImmunizationsRoutine health professional visits are important.Overall health and motor skills are assessed during visitsVaccinations are given to prevent diseases.Vaccinations: three for hepatitis, four for diphtheria/tetanus/pertussis, three for influenza, one for measlesU.S. vaccination rates are high, but declining.Continued education efforts and government support are needed.Daycare babies have twice as many respiratory illnesses as stay-at-home babies.
25 Health and Wellness Health Care and Illness Illnesses in first 2 yearsRespiratory illnesses commonHigher in children participating in childcare programsChronic ear infectionsDaycare babies have twice as many respiratory illnesses as stay-at-home babies.
26 Health and Wellness Infant Mortality Death within the first year of life7 babies per 1000 in the U.S.Related to prenatal careVaries widely among U.S. ethnic groupsLet’s look at Figure 4.3 to examine group differences in infant mortality.Racial differences occur in infant mortality (Figure 4.2): lowest among Asian-American infants; African-American infants have the highest.7 babies per 1000 in the U.S.Has declined steadily for several decadesHigher in U. S. than in other industrialized countriesPoverty is still a leading cause of infant mortality regardless of race.
27 Figure 4.2 Group Differences in Infant Mortality
28 Next Let’s Look at Early Prenatal Care and Ethnicity See if you can identify disparities across ethnic groups with regard to access to prenatal care. Do you see any correspondence to these disparities and infant mortality?
30 Health and Wellness Sudden Infant Death Syndrome (SIDS) Incidence: Leading cause of death in U.S. in infants 1–12 monthsRelationships:ApneaSleeping on stomachMaternal smokingMore common in babies with apnea (brief cessations in breathing)Racial differences occur in infant mortality (Figure 4.2): lowest among Asian-American infants; African-American infants have the highest.Poverty is still a leading cause of infant mortality regardless of race.
31 Sensory Skills Vision Rapid development of visual acuity 20/200 at birth; 20/20 at 2 yearsColor visionRed, blue, green at 1 monthTrackingTracking slow-moving object before 2 months and skilled at 6–10 weeksInfants younger than two months show some tracking ability for brief periods; by 6–10 weeks, babies become skillful at tracking.20/200 at birth20/20 by 2 yearsColor visionRed, green, and blue present by one monthColor sense almost identical to an adult’sTrackingProcess of following moving objectInitially inefficient but improves rapidlyTracks for short period of time when younger than two months (slow-moving target)By ten weeks, skillful
32 Sensory Skills Hearing Adult voices heard well and some directional loud-sound locationSmelling and tastingNewborns react differently to each basic taste as early as birth.Touch and motionBest developed of all sensesHearingAdult voices heard wellHigh-pitched noises must be loud to be heard.Some directional sound locationSmelling and tasting are intricately related.Four basic tastes: sweet, sour, bitter, and saltySensitive to touches on the mouth, hands, soles of feet, and abdomen
33 Taste Responses in Newborns What responses do you see? Ask: What responses do you see? Sour, sweet, bitter?
34 Taste Responses in Newborns Ask: How many did you correctly identify?
35 Stop and Think!In what ways do babies’ sensory skills contribute to the development of the parent–infant relationship?
36 Perceptual Skills Studying Perceptual Development Preference techniqueStudy how long baby attends to a particular stimulus.Habituation/dishabituationStudy loss of interest in particular stimulus after repeated exposures.Operant conditioningVary the stimulus and study the learned responses.How does a baby interpret or combine sensory experience? The process is called perception.Preference technique: baby is shown 2 pictures and researchers keep track of how long the baby looks at each one.Habituation: show a baby something over and over until the baby stops looking at it.Dishabituation: renewed interest in something that is slightly different than the original stimulus
37 Looking Skills Depth Perception Depth perception can be judged by:Binocular cuesMonocular cuesKinetic cuesDo you know the differences amongthese cues?Binocular cuesInvolve both eyesThe closer an object, the more the views from the two eyes differ.Information from eye muscles tells about distance.Monocular cuesInput from one eyeInterpositionLinear perspectiveKinetic cuesMotion from objects or the eyes
38 Depth Perception A Walk on the Wild Side—Almost Visual Cliff: Gibson and Walk (1960)Initial findings: 6-month-old babies would not cross the visual cliff.Recent findings: 3-month-olds have some depth perception.Recent findings:Babies use kinetic information as early as three months.Binocular cues are used at four months.Linear perspective cues are used last, at five to seven months.
39 Perceptual Skills What Babies Look At: Scanning Initially scan for sharp, light/dark contrasts and then scan edges2 months: scan entire object and look for patterns2-3 months: shift from where to what object3-4 months: attention to patterns, not just specific stimuliVisual attention: guided by search for meaningful patternBabies demonstrate a preference for light/dark contrasts.Albert Caron and Rose Caron used habituation (Figure 4.5); small over big.
40 What Babies Look At What Babies Look At: Faces Face NOT uniquely interesting to infantsAttractive faces and mother’s face preferredBefore 2 months: Scan edges (hairline, chin)2–3 months: Scan internal facial features, especially eyesResearch by Gail Walton (1992), using the preference technique, compared sucking rates of babies only a day or two old when looking at either a picture of their mothers or someone else. The babies clearly preferred to look at their moms.Walton’s subjects spent at least an hour with their mothers immediately after birth—even when the birth was by cesarean section.
41 Listening What Babies Hear: Discriminating Speech Sounds 1 month: discriminate between “pa” and “ba”3 months: respond to male, female, and children’s voices similarly6 months: discriminate between 2-syllable words6 months: distinguish sound contrasts in any language; fades by 1 yearPrefer the mother’s voice above all othersVery young infants make fine discriminations among individual sounds and pay attention to patterns.
42 Perceptual Systems Combining Information from Several Senses Intermodal perception: Formation of single perception of stimulus that is based on information from 2 or more sensesPossible by 1 monthCommon by 6 monthsImportant in infant learningGibson and Gibson argue that cross-modal transfer is an inborn set of skills.Learn in one sense modality, transfer information to another modalityIntersensory integration is essential to infant learning.
43 Perceptual Systems Explaining Perceptual Development NativistsEmpiricistsMost perceptual abilities inbornMany of these abilities present at birthMost perceptual abilities learnedExperience needed to develop perceptual systemsGibson and Gibson argue that cross-modal transfer is an inborn set of skills.Intersensory integration is essential to infant learning.A compromise position: Perceptual skill development is the result of interaction between inborn and experiential factors.