Presentation on theme: "Developmental Psychology Week 2: From conception to infancy"— Presentation transcript:
1Developmental Psychology Week 2: From conception to infancy Module leader: Dr. Antonia Svensson-Dianellouslides by K. Kostakou (IST)
2Prenatal developmentThe Germinal Stage The germinal stage begins with conception, when the sperm and egg cell unite in one of the two fallopian tubes. The fertilized egg, known as a zygote, then moves toward the uterus, a journey that can take up to a week to complete. Cell division begins approximately 24 to 36 hours after conception. Cell division continues at a rapid rate and the cells then develop into what is known as a blastocyst. Finally, the blastocyst arrives at the uterus and attached to the uterine wall, a process known as implantation. (almost 8-10 days after conception)
4Prenatal development The Embryonic Stage The mass of cells is now know as an embryo.The embryonic stage begins after implantation and continues until cell differentiation has been mostly completed. (until the end of 8th week)Structures important to the support of the embryo develop, including the placenta and umbilical cord.During this time, cells begin to differentiate into the various body systems.The basic outlines of the organ, body, and nervous systems are established.By the end of the embryonic stage, the beginnings of features such as fingers, eyes, mouth, and ears become visible.
5Prenatal developmentThe Fetal Stage (9th week until birth) Once cell differentiation is mostly complete, the embryo enters the next stage and becomes known as a fetus. The early body systems and structures established in the embryonic stage continue to develop. The neural tube develops into the brain and spinal cord and neurons form. Sex organs begin to appear during the third month of gestation. The fetus continues to grow in both weight and length, although the majority of the physical growth occurs in the later stages of pregnancy.
6Movement Between week six and ten: Hand to head, hand to face, hand to mouth movements, mouth opening, closing, and swallowing are all present at 10 weeks (Tajani and Ianniruberto, 1990).By 14 weeks, the complete repertoire of fetal movements are already in evidence (deVries, Visser, and Prechtl, 1985).Movement is :spontaneous, endogenous, and typically cycles between activity and rest. Breathing movements and jaw movements have begun.Hands are busy interacting with other parts of the body and with the umbilical cord.From this early stage onward, movement is a primary activity, sometimes begun spontaneously, sometimes provoked by events.Spontaneous movement occurs earliest, probably expressing purely individual interests and needs.Evoked movement reflects sensitivity to the environment. For example, between 10 and 15 weeks g.a., when a mother laughs or coughs, her fetus moves within seconds.The vestibular system, designed to register head and body motion as well as the pull of gravity begins developing at about 8 weeks.This requires construction of six semicircular canals, fluid-filled structures in the ears, which are sensitive to angular acceleration and deceleration, and help maintain balance.
7Tasting and SmellingThe structures for tasting are available at about 14 weeks and experts believe that tasting begins at that time. Tests show that swallowing increases with sweet tastes and decreases with bitter and sour tastes. Tests made at birth reveal exquisite taste discrimination and definite preferences.The nose develops between 11 and 15 weeks. Many chemical compounds can cross the placenta to join the amniotic fluid, providing the fetus with tastes and odors. The amniotic fluid surrounding the fetus bathes the oral, nasal, and pharyngeal cavities, and babies breathe it and swallow it, permitting direct access to receptors of several chemosensory systems: taste buds in three locations, olfactory epithelia, vomeronasal system, and trigeminal system (Smotherman and Robinson, 1995).Associations formed in utero can alter subsequent fetal behavior and are retained into postnatal life. Products of the mother's diet reach the baby via the placenta and the blood flowing in the capillaries of the nasal mucosa. Thus, prenatal experience with odorants from both sources probably prepare this sensory system to search for certain odors or classes of odors.In one experiment, babies registered changes in fetal breathing and heart rate when mothers drank coffee, whether it was caffeinated or decaffeinated.Newborns are drawn to the odor of breastmilk, although they have no previous experience with it. Researchers think this may come from cues they have learned in prenatal life.
8Listening and HearingThe fetus lives in a stimulating matrix of sound, vibration, and motion.Many studies now confirm that voices reach the womb, rather than being overwhelmed by the background noise created by the mother and placenta.Intonation patterns of pitch, stress, and rhythm, as well as music, reach the fetus without significant distortion.A mother's voice is particularly powerful because it is transmitted to the womb through her own body reaching the fetus in a stronger form than outside sounds.Sounds have a surprising impact upon the fetal heart rate: a five second stimulus can cause changes in heart rate and movement which last up to an hour.Some musical sounds can cause changes in metabolism. "Brahm's Lullabye," for example, played six times a day for five minutes in a premature baby nursery produced faster weight gain than voice sounds played on the same schedule (Chapman, 1975).Researchers in Belfast have demonstrated that reactive listening begins at 16 weeks g.a., two months sooner than other types of measurements indicated.Working with 400 fetuses, researchers in Belfast beamed a pure pulse sound at Hz and found behavioral responses at 16 weeks g.a.--clearly seen via ultrasound (Shahidullah and Hepper, 1992). This is especially significant because reactive listening begins eight weeks before the ear is structurally complete at about 24 weeks.These findings indicate the complexity of hearing, lending support to the idea that receptive hearing begins with the skin and skeletal framework, skin being a multireceptor organ integrating input from vibrations, thermo receptors, and pain receptors.This primal listening system is then amplified with vestibular and cochlear information as it becomes available.With responsive listening proven at 16 weeks, hearing is clearly a major information channel operating for about 24 weeks before birth.
9Development of VisionVision, probably our most predominant sense after birth, evolves steadily during gestation. However, at the time of birth, vision is perfectly focused from 8 to 12 inches, the distance to a mother's face when feeding at the breast.Although testing eyesight in the womb has not been feasible, we can learn from testing premature babies. When tested from 28 to 34 weeks g.a. for visual focus and horizontal and vertical tracking, they usually show these abilities by weeks g.a.Abilities increase rapidly with experience so that by weeks g.a., both tracking in all directions as well as visual attention equals that of babies of 40 weeks g.a. Full-term newborns have impressive visual resources including acuity and contrast sensitivity, refraction and accommodation, spacial vision, binocular function, distance and depth perception, color vision, and sensitivity to flicker and motion patterns (Atkinson and Braddick, 1982). Their eyes search the environment day and night, showing curiosity and basic form perception without needing much time for practice (Slater, Mattock, Brown, and Gavin, 1991).In utero, eyelids remain closed until about the 26th week. However, the fetus is sensitive to light, responding to light with heart rate accelerations to projections of light on the abdomen. This can even serve as a test of well-being before birth. Although it cannot be explained easily, prenates with their eyelids still fused seem to be using some aspect of "vision" to detect the location of needles entering the womb, either shrinking away from them or turning to attack the needle barrel with a fist (Birnholz, Stephens, and Faria, 1978). Similarly, at 20 weeks g.a., twins in utero have no trouble locating each other and touching faces or holding hands!
10Development of the senses Sense modalities are not isolated, but exist within an interconnecting, intermodal network. The gustatory and olfactory systems are closely allied, skin and bones contribute to hearing, and vision seems functional even with fused eyelids. When prenates experience pain, they do not have the air necessary to make sound, but they do respond with vigorous body and breathing movements as well as hormonal rushes. Ultrasonographers have recorded fetal erections as early as 16 weeks g.a., often in conjunction with finger sucking, suggesting that pleasurable self-stimulation is already possible. In the third trimester, when prenates are monitored during parental intercouse, their hearts fluctuate wildly in accelerations and decelerations greater than 30 beats per minute, or show a rare loss of beat-to-beat variability, accompanied by a sharp increase in fetal movement (Chayen et al, 1986). Other experiments measuring fetal reactions to mothers' drinking one ounce of vodka in a glass of diet ginger ale show that breathing movements stop within 3 to 30 minutes. Although the blood alcohol level of the mothers was low, as their blood alcohol level declined, the percentage of fetal breathing movements increased (Fox et al, 1978). Babies have been known to react to the experience of amniocentesis (usually done around 16 weeks g.a.) by shrinking away from the needle, or, if a needle nicks them, they may turn and attack it. Finally, researchers have discovered that babies are dreaming as early as 23 weeks g.a.when rapid eye movement sleep is first observed (Birnholz, 1981). Studies of premature babies have revealed intense dreaming activity, occupying 100% of sleep time at 30 weeks g.a., and gradually diminishing to around 50% by term.
11Prenatal Memory and Learning Memory is the quintessence of human experience without which we cannot make progress, cannot learn from experience, and cannot develop a personal identity. Learning and memory are interlocked: learning depends on memory, and learning is evidence of memory. Psychology traditionally placed the beginnings of memory at about age three because few people have conscious recall of events before that time. However, an accumulating volume of research demonstrates memory in the first years of life and in the prenatal period as well. Some children spontaneously recall birth events (even secrets) but expression of these memories is delayed until they can speak. Before they use words they can express their memories non-verbally by drawing pictures, acting out scenes using pantomime, pointing to body locations, and by providing authentic sound effects for equipment (like suction devices) used at the birth. These children warn us that early memory and learning are real. The documentation of learning and memory months before birth is surprising. Some of this has been made possible by direct ultrasound observations of fetal behavior. Twins can be seen developing certain gestures and habits at twenty weeks gestational age which persist into their postnatal years. In one case, a brother and sister were seen playing cheek-to-cheek on either side of the dividing membrane. At one year of age, their favorite game was to take positions on opposite sides of a curtain, and begin to laugh and giggle as they touched each other and played through the curtain.
12Prenatal developmentIn a famous experiment by Anthony DeCasper and colleagues at the University of North Carolina, Greensboro, mothers read the Dr. Seuss story, The Cat In the Hat, at regular intervals before birth.At birth, babies were hooked up to recordings which they could select by sucking on a non-nutritive nipple.After a few trials, babies cleverly sucked at whatever speed was necessary to obtain their mother's voice reading "The Cat in the Hat.Similarly, in utero, musical passages repeated regularly--such as theme music for the British soap opera Neighbors or the bassoon passage from Peter and the Wolf--are identified and preferred immediately after birth. In a recent experiment, French mothers repeated a children's rhyme each day from week 33 to week 37 of gestation.At the end of this time (still inside the womb) the babies showed memory and learning for this particular rhyme as opposed to similar rhymes they had not heard.
13Prenatal developmentBabies are learning their native language before birth. This is made possible by the development of hearing as early as 16 weeks gestational age. A mother's voice reaches the uterus with very little distortion as the sound waves pass directly through her body. Acoustic spectroscopy, which makes possible elaborately detailed portraits of sound similar to fingerprints, has documented prenatal learning of the mother tongue. By 27 weeks of gestation, the cry of a baby already contains some of the speech features, rhythms, and voice characteristics of its mother. Newborn reactions to language are based on the sounds heard in utero: French babies prefer to look at persons speaking French while Russian babies prefer to watch people speaking Russian.Unexpected evidence for prenatal learning and memory comes from studies of taste and olfaction (See The Fetal Senses). Until recently, olfaction was thought to require air, hence, learning of odors was not considered possible before birth. Current understanding, however, recognizes the complex interaction of chemosensory receptors in utero. Many chemical compounds, including those from the mother's diet, pass through the placenta and reach the baby in utero while others flow in the capillaries of the nasal mucosa. By breathing and swallowing amniotic fluid, a baby becomes familiar with the mother's diet, including things like garlic. Even before post-nasal exposure to breastmilk, babies already know and prefer their own mother's milk. Abrupt changes in her diet during the perinatal period can confuse babies and upset breastfeeding.
14Prenatal developmentTraumatic events in neonatal intensive care are indelibly imprinted in memory and intrude on adult life, often in the form of fear. Edward, who was born prematurely and entered the NICU at 29 weeks, learned to fear the sound and sight of adhesive tape. He learned this from the experience of having sections of his skin accidentally pulled off during removal of monitor pads. When he was a young man, he still feared adhesive tape.Babies can learn their mother's emotional state. Experiments in Australia revealed that unborn babies were participating in the emotional upset of their mothers watching a disturbing 20-minute segment of a Hollywood movie. When briefly re-exposed to this film up to three months after birth, they still showed recognition of the earlier experience. Studies of a thousand babies whose mothers had experienced various degrees of depression during pregnancy themselves displayed depression at birth and in proportion to the depression scores of their mothers.An important message of these diverse findings is that memory and learning seem to be a natural part of being human, including the first nine months in the womb and the years of infancy, defined as the time before speech. Perhaps the biggest surprise is that life in the womb is extremely active and interactive and the womb is, in fact, a classroom.
15Genetic conditions Problems During Prenatal Development Most prenatal develop occurs normally, following the established patterns with little variation. However, there are a number of things that can go wrong during this time, which are usually caused by genetics or environmental problems.Down Syndrome – Also known as trisomy 21, Down syndrome is the most common genetic anomaly during prenatal development. Down syndrome is caused by and extra copy of the 21 chromosome (meaning there are three chromosomes instead of the usual two) and impacts approximately 1 out of every 1,000 infants. Typical features of Down syndrome include flattened facial features, heart defects, and mental retardation. The risk of having a child with Down syndrome increases with maternal age.Inherited diseases – A number of illnesses can be inherited if one or both parents carries a gene for the disease. Examples of inherited diseases include Sickle-cell anemia, Cystic fibrosis, and Tay-Sachs disease. Genetic tests can often determine if a parent is a carrier of genes for a specific disease.Sex-Chromosome Problems – A third type of genetic problems involves sex-chromosomes. These includes conditions such as Klinefelter’s syndrome (an extra X-chromsome) and Turner syndrome (a single X-chromosome).
16TeratogensHarmful environmental elements that can effects the fetus are known as teratogens. There a number of teratogens that can harm the fetus, including:Maternal Drug Use – The use of substances by the mother can have devastating consequences to the fetus.Smoking is linked to low birth weight, which can result in a weakened immune system, poor respiration, and neurological impairment.Alcohol use can lead to fetal alcohol syndrome, which is linked to heart defects, body malformations, and mental retardation.The use of illicit drugs such as cocaine and methamphetamine is also linked to low birth weight and neurological impairment.Maternal Disease – There are a number of maternal diseases that can negatively impact the fetus, including herpes, rubella, and AIDS.Herpes virus is one of the most common maternal diseases and can be transmitted in the fetus, leading to deafness, brain swelling, or mental retardation. Women with herpes virus are often encouraged to deliver via cesarean to avoid transmission of the virus.
18Pregnancy and birth Effects of maternal stress Psychosocial stress during pregnancy has longed be linked to negative birth outcomes:Miscarriage, long and painful childbirth (Blomberg, 1980;Sameroff and Chandler, 1975)Low birth weight and prematurity (Istvan, 1986;Lobel,1994;)Effects on neurobehavioral development (Monk et al, 2000)Irritable, hyperactive infants, with feeding problems, sleep and digestion (Friedman &Sigman, 1980; Van Den Bergh, 1992).
19Pregnancy and birth Effects of maternal prenatal attitudes Children whose mothers had negative attitudes towards pregnancy:may have more difficulties in school,may be referred for psychiatric help more often during pubertyare more likely to find themselves in jail,are in increased risk for abuse of toxic substances or alcoholmay not consider their social relations satisfactory
20Neonatal period First two weeks of life Marks transition from womb to independenceReflexively grasps anything placed in hand
21Developmental Psychology Testing the neonatalApgar ScoreThis test is used to assess overall condition immediately 1 and 5 minutes after birth. The Apgar score is used to determine the baby's current health following the delivery, but it is not used to predict future health.Five factors are used to evaluate the baby's condition and each factor is scored on a scale of 0 to 2, with 2 being the best score:activity and muscle tonepulse (heart rate)grimace response (medically known as "reflex irritability")appearance (skin coloration)respiration (breathing rate and effort)newborns are given a score of 0, 1, or 2 on each of the health signsa score of 7 to 10 indicates the newborn is in good conditiona score of 5 to 7 indicates fair conditiona score of 3 or below indicates poor conditionReflex AssessmentThis assessment tests for several specific reflexes in baby, including the rooting and grasping reflexes. If a particular reflex is not observed further evaluation will be done.
22Infancy Infancy Emotional and social development during infancy Age: 2 weeks until 2 yearsTime of rapid physical, perceptual, cognitive, linguistic, social, and emotional growthDuring sensorimotor stage – infants stare at interesting visual stimuliPreference for human facesEmotional and social development during infancyVisual cliff and depth perceptionAttachmentStrong attachments formed between infants and caregiversSeparation anxietyFear of strangers
23Infancy Reflexes automatic responses to certain stimuli indicate the integrity of the nervous system; if they fail to appear or disappear at the appropriate time can indicate a probleminvoluntary behaviors that are replaced by voluntary behaviors as the infant gets older
25InfancyRooting - turning the head and opening the mouth in the direction of a touch on the cheekSucking - sucking rhythmically in response to oral stimulationBabinski - fanning and curling toes when foot is strokedMoro - throwing the arms out, arching the back and bringing the arms together as if to hold onto something (in response to loud noise or sudden change in position of the head)Grasping - curling the fingers around an object
28Infancy Perceptual Abilities at Birth Infant vision is poor at birth (equivalent to 20/200 to 20/600)Functionality of other sensory systems:Hearing is functional prior to birthSmell is functional at birthTouch and pain are functional at birthInfant perception can be inferred by changes in heart rate upon stimulus exposure or by changes in sucking rate
29InfancyMeltzoff, showed that newborn infants were capable of producing a range of responses to gestures modeled by an actor.Meltzoff, across two experiments, showed that infants of days old were capable of producing a range of responses to gestures modeled by an actor.
30InfancyOlder infants can also imitate intentions of actors, even when they don’t see the completed action. They do not imitate machines.
31Developmental Psychology Piaget and CognitionCognitive reasoning is primitive at birth and changes from infancy to adulthoodSchemas are the basic units of intellectOrganization of ideasCognitive adaptation reflects the actions of two complementary processes:Assimilation allows an existing schema to adapt to the environmentAccommodation allows the schema to change in order to handle a new environmental situation
32Developmental Psychology What is a scheme?A scheme is a mental process responsible for activities as simple as naming and labeling, and as complex as creating experiments. Schemes guide behavior.Assimilation: fitting new information into existing schemesAccomodation: refers to creation or modification of schema to make them fit with new experience
33Developmental Psychology Cognitive Development StagesSensorimotor period: Birth through age 2Infant schemes are simple reflexes and interactions with people and objectsPreoperational period: Age 2 to 7Child begins to use mental representations, but problem solving is limitedConcrete operations: Age 7 to 11Child performs mental operations (conservation)Formal operations: Age 12 through adulthoodChild can use formal problem solving and higher level abstract thinking
34Developmental Psychology Sensorimotor: Object PermanenceThe principle that objects continue toexist even when out of viewThe understanding of thephysical properties of objectsAchieving object permanence isthe major task of the sensory motor stage
35Developmental Psychology Simple Hiding Problem0-5 monthsan attractive toy is shown to the baby and then is placed under a napkin as the baby watcheschildren typically follow the toy with their eyes as it disappears under the napkinbut no active searchMastered between 6 and 9 months
36Developmental Psychology Changed Hiding Place8-12 monthsthe toy is first placed under napkin A for a series of trials and the baby retrieves it each timethen the toy is a hidden under napkin B, next to the first, in plain view of the childdespite having watched the object disappear under the new napkin, the baby reaches under the original napkinMastered between 10 and 12 months
37Some revision Questions What is maternal stress during pregnancy linked to?What are teratogens?What are the reflexes? Do all of them serve survival?How is hearing at birth?Do infants imitate?What kind of visual stimuli do infants prefer?What is the rooting reflex?Baby girl-3 months old stops looking at the ball, when her mother hides it under a cloth. Is this normal for her age?What does an Agpar score of 3 or less mean?What do the terms prenatal and neonatal mean?
38Recommended reading Core textbooks: Chapter 3, Smith et al. or Chapter 4, Slater & Bremner