Psyc355 – Developmental Psychology Conceptualizations of Prenatal Development Preformationism Epigenesis (emergence of new structures and functions during development) o Predetermined Genetic activity structure function Probabillistic o Genetic activity structure function o Emphasizes the reciprocity of influences within and between levelsNormally Occurring Environmental and Behavioral Influences onGene ActivityConception Key terms: o Gameteso Meiosiso Zygote (fertilized egg half from each parent) Marks the beginning of prenatal development4 Developmental Processes Cell division cells divide creating more cells (mitosis) Cell migration movement of cells from point of origin to somewhere else in the embryo Cell differentiation creates 350 types of cells Selective death of certain cells (or apoptosis) 3 Periods of Prenatal Development Germinal (conception – 2 weeks) zygote becomes implanted in the inner uterine wall (rapid cell division takes place) blastocyst forms into the embryo Embryonic (3rd to 8th week) neural tube is formed (U-shaped groove formed on the top layer that becomes the brain and spinal cord/male or female genetailia) rapid growth of the body and increased levels of behavior, sensory experience, learning Fetal (9th week – birth) Support System Includes: o Placenta o Umbilical cordo Amniotic sac Prenatal development of animation Cephalocaudal DevelopmentAssisted Reproductive Technology Problems of infertility In vitro fertilization o 1978/1981 striking correlateso increase of multiple births outcomeso main health risks associated are those associated with multiple births Assisted Reproductive Technology problems of infertility in vitro fertilization o in 1978/1981 striking correlates o increase of multiple births outcomeso main health risks associated are those associated with multiple birthsFetal Behavior an active contributor to its own development by 12 weeks, most movements that will be present at birth have appearedo swallowing o breathingo limb movemento sleep-wake cyclesFetal Experience sensory structures are present relatively early the fetus experienceso tactile stimulation o tastes and smells o responds to sounds o visual experience, however is negligible Fetal Learning Fetal senses play a vital role in fetal development and learning Decreases in response to repeated or continued stimulation reflects a simple form of learning called habituation Newborn infants prefer smells, tastes, and sound patterns that arefamiliar because of prenatal exposure They can even recognize rhymes and stories presented before birth Human Fetus is listening and learning Does this mean that to-be-parents should sign up for programs that promise to “educate” their unborn child?Hazards to prenatal development (“environmental”) Miscarriage Environmental agents o Teratogens Maternal factors Principles of teratogenic influences 1. Timing2. Dose3. Duration4. Individual differences Difficult to identify due to sleeper effects o Fetal programming Include legal and illegal substancesComplexity of teratogenic influences Fetal programming o Later emergence of effects of prenatal experience Program the physiological “set points” that will govern physiology in adulthoodo Sleeper effects (you don’t see it/doesn’t emerge until later) o Individual differences (individual differences in terms of the mother and fetus’s response on multiple levels) Study: women took hormone and then their offspring showed elevated rates of testicular cancer Some Environmental Hazards to Fetus or Newborn Legal and illegal substances (teratogens) come from a variety of diff sourcesMaternal Factors Age (infants born to mothers over 35 years have increased risk to genetic disorders) Disease Stress-level Nutrition My Research Prenatal exposure to cocaine & heroin Prenatal iron deficiency Conclusions 36 studies up to age 6 years many findings though to be specific effects of in utero cocaine exposure are correlated with other factors o ex: prenatal exposure to tobacco, marijuana, or alcohol, and the quality of the childs environment effects that remain are seen in o motor scores (up to 7 months)o attentiveness and emotional expressivity no convincing evidence that prenatal cocaine exposure is differentin severity, scope, or kind from other risk factors PEDIATRICS ages 6 to adolescence 38 unique studies Conclusions associations between prenatal cocaine exposure to growth, IQ, academic achievement, and language functioning are small and attenuated by environmental variables negative associations exist between prenatal cocaine exposure and o sustained attention, inhibitory control, behavioral regulation, and brain function even with covariate
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