HDFS 201 LECTURE 7 Moving Beyond Facts Critical thinking about the facts Synthesis bringing things together Application optimizing development Now that we now this so what o For self personal development In professional application o Evaluation Limits o Strengths Weaknesses Teratogen Disease or environmental agent causing harm during prenatal development Diseases Rubella Syphilis HIV AIDS Drugs Thalidomide tobacco alcohol cocaine Environmental hazards radiation pollutants Useful Constructs from Prenatal Teratology Critical defined as all or nothing development has to happen during that period or it will not happen There is debate whether these really exist 6 weeks post conception the optic nerve proliferates rapidly If that development doesn t take place then it won t Some say there is enough plasticity This is the most rapid time of development for that system either physical like the optic nerve or emotional like parent infant attachment You are highly susceptible to exterior conditions like teratogens influencing your development Sensitive not quite as do or die optimal time for development to take place but it may be fixed later if it doesn t Critical and sensitive periods Some physical critical periods Some psychological sensitive periods Developmental sleeper effects When it looks like you have escaped any negative outcome from exposure to teratogens but Smoking and 5th grade reading comprehension scores the scores will be lower if there was a later it manifests in an unexpected way prenatal exposure to nicotine or smoke The effects of a teratogen on an organ or system are greatest during the critical period when that organ grows most rapidly Susceptibility to harm is influenced by multiple factors The unborn child s genetic makeup And the mother s genetic makeup And the quality of the prenatal environment Teratological Lessons 1 The same defect can come from different teratogens Example Microcephaly smaller cerebral cortex can be caused by Radiation environmental condition Alcohol legal drug Herpes disease Example atypically slow growth can be caused by Alcohol Cocaine Heroin Nicotine Equifinality or Equipotential as a GENERAL PRINCIPLE Equifiniality different environmental conditions can lead to the same developmental manifestations Same is true of common developmental status like compromised growth or microcephaly there are different paths to get to the outcome Equipotential Trajectories into divergence The slide shows different starting points and each one is has a different pathway to get to the same point On the right time of assessment People may look the same at this time but they got there by very different pathways Teratological Lesson 2 The same teratogen can cause different effects Example marijuana can cause Low birth weight LBW premature birth compromised motor control infant irritability paradoxical effects what is a stimulant for an adult is a depressant for a child and what is a depressant for an adult is a stimulant for a child Example syphilis can cause Central nervous system problems bone defects teething problems and miscarriage Multifinality or Multipotentiality as a GENERAL PRINCIPLE Multifinality same set of conditions can lead to different developmental outcomes We re all here at UD but we are all not going to end up in the Same is true of developmental status or conditions Trajectories into convergence The slide shows the same place with many different paths leading to different places Multipotential Teratology Lesson 3 Not all fetuses or infants are affected and not all are equally affected There is an interaction of the TIMING DOSE and DURATION of the exposure Timing when it was taken The effects will be different at 6 weeks and 8 weeks Dose how much Duration how long it was and different infants have different genetic predispositions towards risk and resilience that is to say different reaction ranges The slide shows many paths leading to the same place and many paths leaving that place People start in different places but all end up in the same place at a certain time and because of those individual differences being in the same place at the same time doesn t mean you re all going to same place again Developmental Reality Check If all this variability is real and expected in the HARD SCIENCES of teratology then why do we expect a particular set of infant outcomes from a specific pattern of social conditions Family and school effects would be Timing dose and duration dependent And embedded in a complex array of other relationships and contexts of development o Toward a Balanced Approach No Silver Bullets There is no one explanation that is going to cover everything in human development Development is a very long and complicated story consisting of many interacting factors Determinisitc vs probabilistic thinking You can a lot of things to tip the balance a certain way but it may not always work PROBABILISTIC UNDERSTANDINGS OF DEVELOPMENT ARE MORE ACCURATE THAN DETERMINISTIC You can do the right stuff and some people still crash and burn even with all the risk factors some people will thrive Nugget 3 Professor believes that that all of development can be explained by examining the interactions of TIMING DOSE and DURATION of various factors Further timing dose and duration coupled with reaction ranges can explain both equifinality and multifinality Early Brain Development Neurulation Early in embryonic stage part of the ectoderm is differentiated into neural tissue and in which the neural tube which develops into the brain and spinal cord is formed Proliferation of neurons 250 000 per minute prenatally prime time 10 20 weeks PC born with over 100 billion neurons 40 50 more than needed Migration 6 24 weeks PC Genetics and biochemistry drive it Proximodistal inner first then outer Teratogenic problems Largely complete by birth Organization Differentiation of neurons migration and biochemistry affect both Synaptogenesis formation of synapses prenatally and first 2 years Neuronal Pruning apoptosis A normal genetically regulated process leading to the death of cells and triggered by the presence or absence of certain stimuli as DNA damage Myelin Production Myelin increases the speed and direction of transmission Plasticity Lack of normal experiences Addition of stimulation experiences Limiting of biopotential by experiences Plasticity greatest at critical period Late prenatal early infancy Visual cortex first 6 years Language prior to puberty Brain