[Music] hey students i hope you're all having a great day today my name is torres and i want to take a moment thank you for joining me for a little psych 101 in this video we will learn about developmental psychology with an emphasis on the role of biology in developmental psychology this is the first part of a three-part video series on developmental psychology this video has three overarching ideas lifespan development explores how humans change grow and remain the same from conception to death human development can be studied scientifically across three domains physical development cognitive development and psychosocial development different theories focus on the processes patterns generalizability biological influences and environmental influences on human development the topics of this three-part video series on developmental psychology will focus on the vocabulary on these three slides again it's a lot and i'm so sorry you can find this information in the google slide presentation and in the psyc101 key vocab doc both of these files are linked in the description box below developmental psychologists study how students change and grow throughout their entire life from conception through childhood adolescence adulthood and death they view development as a lifelong process that can be studied scientifically across three developmental domains physical cognitive and psychosocial development physical or biological development involves growth and changes in the body brain senses motor skills and health and wellness cognitive development involves learning attention memory language thinking reasoning and creativity psychosocial development involves emotions personality and social relationships there is much debate on what could be considered normal development normative psychologists have studied large numbers of children to determine norms or average ages of when children reach specific developmental milestones like crawling walking speaking and sentences and starting puberty biological milestones such as starting puberty are universal social milestones such as starting school can vary considerably across cultures developmental psychologists have come to different conclusions concerning how exactly humans develop biologically cognitively and psychosocially some psychologists believe that children develop smoothly and continuously but other psychologists believe that children develop more discreetly in a series of stages each of which is fairly stable developmental psychologists who believe children develop continuously believe that kids constantly add new lessons and skills on top of old lessons and skills as they get older they believe that children grow at a steady uniform speed even though parents can't see it with their eyes children are growing all the time in front of them their bodies are making new cells their minds learn new skills as they play and interact with people every day on the other hand developmental psychologists who believe children grow discontinuously believe children grow in stages as they seem to develop chunks of abilities and to experience events at certain times in life to some parents it may seem that their children learn to do things all of a sudden like when a baby goes from only being able to crawl to being able to toddle around on two feet almost overnight to kindergarten and first grade teachers it seems as though their students just learned a few sight words and now all of a sudden they can read a whole book by themselves in these examples it seems that these children are making physical and cognitive gains in spurts at special times and then are not making any gains as quickly for a while in between the spurts another question of interest in developmental psychology is whether or not development is universal for everyone in other words is development essentially the same or universal for all children is there only one course of development or does development follow a different course for each child depending on the child's specific genetics and environment are there many courses of development do people across the world share more similarities or more differences in their development and how much does culture and genetics influence a child's behavior stage theories hold that the sequence of development is universal for example in cross-cultural studies of language development children from around the world reach language milestones in a similar sequence infants in all cultures coup before they can babble they begin babbling at about the same age and utter their first word around 12 months old yet we live in diverse contexts that have a unique effect on each of us for example researchers once believed that motor development follows one course for all children regardless of culture however more recent research indicates that child care practices can have a significant effect on various motor skills such as sitting crawling and walking depending on the child care practices of a culture this can either accelerate or inhibit achievement in the developmental milestones associated with these physical tasks the nature versus nurture debate is concerned with the extent to which particular aspects of behavior are either inherited or genetic and which ones are acquired or learned in this debate nature is influenced by genetic inheritance and other biological factors where nurture is generally taken as the influence of external factors after conception so it is the product of exposure life experiences and learning the general consensus is that both nature and nurture are important in development but psychologists debate the contributions of each the focus of this video will be biological development biological development describes the physiological changes that occur in order to transform a zygote into an adult human being stages critical for development include the prenatal period infancy adolescence and adulthood prenatal development is broken down into three main stages the germinal stage the embryonic stage and the fetal stage the germinal stage is the first one to two weeks after conception conception occurs when a sperm fertilizes an egg and forms a zygote which begins as a one cell structure the mother and father's dna is passed on to the child at the moment of conception at this time the genetic makeup and biological sex of the baby are set within 24 hours to 36 hours of fertilization the zygote will begin to divide and grow in a process called mitosis one cell will become two cells and two cells will become four cells and four cells will become eight cells eight cells will become 16 cells and so on at the 8th cell mark the multiplying cells will begin to differentiate this means that each one will take on certain characteristics that will determine the type of cell it will eventually become like will it become a skin cell or a brain cell or a lung cell or a kidney cell as the cells multiply they will also separate into two layers the inner layer will eventually develop into the fetus and the outer layer will eventually become the placenta after the zygote has about 150 cells it starts to travel down the fallopian tubes and it plants itself in the lining of the uterus the zygote is now called an embryo at this point the organs begin to function and the heart will actually start to beat basic structures develop that will become a head chest and abdomen remember that i mentioned the outer layer of the embryo cells becomes the placenta the placenta is an organ that develops in the uterus during pregnancy this structure is very important for the baby as it will provide oxygen and nutrients to help the baby grow but it also removes waste products from the baby's blood the placenta attaches to the wall of the uterus and the baby's umbilical cord arises from it in another three weeks the pregnancy will have ended its first trimester at this point the baby's heartbeat can be heard at prenatal checkups and add ultrasounds key milestones in the second trimester are at 14 to 16 weeks the baby will be able to make facial expressions and may begin sucking on his or her thumb at 16 weeks the baby's gender might be detectable 23 weeks the baby's sense of motion has developed and hearing continues to improve at age 27 weeks the baby's lungs are developing quickly the baby will inhale and exhale amniotic fluid and will have begun sleeping and waking at regular intervals they will also be likely to open and close their eyes and suck on their fingers the third trimester begins at 28 weeks at this point they will have eyelashes and improved eyesight the baby will have grown fingernails and toenails and will begin to increase weight rapidly by 37 weeks the baby is considered early term babies born at this time usually do very well but in an ideal situation birth won't take place for a few more weeks to allow the brain and lungs time to mature fully by 39 weeks the baby is now considered full term and ready for birth the average weight will be roughly 7.5 pounds and the average length will be about 20 inches pregnancies that last 41 weeks or more are considered past due date and the baby is now considered late term anything after 42 weeks is post term at this point the baby's health might be monitored with tests and doctors might begin discussing inducing labor with the family the average time of delivery is 280 days from the beginning of the last menstrual period whereas the duration of pregnancy or the age of the baby is about 266 days or 38 weeks pregnancy may extend to 300 days or even more in which case the baby tends to be heavier premature babies born under 27 weeks are less likely to survive even when treated in a neonatal unit whereas those more than 30 weeks old usually do survive for a brand new human being to be able to develop in less than 300 days is amazing but when you also consider the complexities of the human brain also being developed at the same time it's an absolute miracle the fetal brain starts to develop after the second or third week after conception the brain originally appears as a small smooth structure and it develops the sulci and gyri and brain regions throughout the pregnancy using fmri we can now capture functional fetal brain images genetic and environmental factors can affect development during each prenatal stage so it's important for the mother to receive prenatal care medical care during pregnancy to monitor the health of the mother and the fetus teratogens are anything that can cause damage to the embryo or fetus research shows that the use of tobacco alcohol or illicit drugs or misuse of prescription drugs by pregnant women can have severe health consequences for infants this is because many substances pass easily through the placenta so substances that a pregnant woman takes also reach the fetus toxic exposures can interfere with the brain's ability to distinguish important connections from unimportant ones altering the development of the synapses for instance lead can cause neurons to fire spontaneously in the absence of a proper signal or neurotransmitter fetal alcohol disorders are a group of conditions that can occur in a person who is exposed to alcohol before birth we don't know exactly how many people have fetal alcohol disorders several different approaches have been used to estimate how many persons are living with this in the population fetal alcohol disorders may include several diagnoses related to exposure of the baby to alcohol during pregnancy more specifically fetal alcohol syndrome is the most involved diagnosis used when several physical and developmental abnormalities are present current estimations show that one to two babies of every 1 000 live births since the united states have fetal alcohol syndrome studies using an in-person assessment of school-aged children in several u.s communities report even higher estimates of fetal alcohol syndrome these estimates can be as high as six to nine babies of every 1 000 babies born in the u.s outside of the u.s some western european countries might have an even higher number some studies show that as high as one to five per 100 school children or one percent to five percent of the population may have fetal alcohol syndrome children born with fetal alcohol syndrome will exhibit physical and cognitive developmental abnormalities physically their head might be smaller in size than what would be considered normal and they might have abnormal facial features such as a flattened midface a smooth philtrum an underdeveloped jaw a low nasal bridge a thin upper lip and small eye openings the effects of fetal alcohol syndrome influence cognitive development even worse fetal alcohol syndrome has been associated with poor judgment poor impulse control higher rates of attention deficit hyperactivity disorder also known as adhd learning issues and lower iq scores when the baby is born they are born with an automatic response to particular forms of stimulation these are called newborn reflexes and they help newborns survive examples of newborn reflexes are the rooting reflex where a baby will turn its head towards something that touches its cheek the sucking reflex which is when babies suck on any object that's placed near its mouth the grasping reflex which will allow the baby to cling onto objects that are placed in their hands and the moral reflex where a baby spreads their arms and pulls them back in when they are startled or feel like they are falling sensory abilities like sight smell hearing are not fully developed at birth vision is the least developed sense babies can hear human voices and they prefer human voices specifically their mothers over a stranger's and they can distinguish between the smell of their mother and others during infancy and childhood there are many biological developments growth occurs rapidly during infancy and slows down around the ages of 4 years old to 6 years old girls might have a growth spurt at about 8 to 9 years old to about 12 years old in the nervous system the brain and neural pathways are undergoing lots of changes the brain continues to increase in size rapidly especially the frontal lobe during the ages of three to six at age two the brain will be about 55 of the adult-sized brain and it will reach about 90 percent of the adult-sized brain by age six the neurons are also undergoing lots of changes during the blooming period neural pathways form thousands of new connections during infancy and toddlerhood during childhood and adolescence neural connections are reduced to allow the brain to function more efficiently and this is called the pruning period during infancy and childhood motor skills are also developed and fine-tuned motor skills are the ability to move our bodies and manipulate objects gross motor skill development involves the large muscles in the arms legs and torso gross water activities are important to everyday physical activities like walking running throwing lifting kicking etc gross motor abilities also form the basis of fine motor skills and relate to body awareness reaction speed balance and strength as a newborn babies exhibit their gross motor development by kicking their legs from around three to four months they might be able to roll themselves from their belly to their back by about five months they might be able to go the other way around and roll from their back to the belly they will likely be able to push up on their hands with their arms extended while on their belly at six to eight months babies will start to sit by themselves and reach out to toys to play with when they are sitting they might begin to crawl nine to 11 months babies will move between lying down and sitting upright without any help they'll be crawling on their hands and knees and start to stand and pull themselves up on furniture and they might walk with both their hands being held by 11-12 months they're probably walking with one hand held and soon after they'll be able to walk alone by themselves at about a year and a half they'll be able to walk stairs with hands or rails to help they'll be able to run but they will likely fall down easily and they'll be able to kick a ball by two years old a child will be able to walk and run fairly well and jump in place with both feet off the ground at three years old they should be able to balance on one foot for a few seconds and jump forward 10 to 24 inches at this point they might begin to ride a tricycle at four years old the child can run jump and climb well and is beginning to skip they can hop well on one foot catch a ball reliably and they can even start gymnastics by five years old a child can likely skip on alternate feet and jump rope they might begin to skate and to swim ride a bike with or without training wheels and they should be able to climb very well fine motor skills are finger and hand skills such as writing cutting opening lunch boxes and tying shoelaces the development of these skills relies upon the age-appropriate development of physical skills such as core trunk control and shoulder strength providing the stable base from which the arm and hand can then move with control when the child is born they should have the grasping reflex but this will turn into a voluntary grasp at about three months old from six to 12 months babies will begin to pick things up using their thumb and one finger they might transfer objects from one hand to the other and be able to drop and pick up toys from one to two years children with well-developed fine motor skills should be able to place pegs on a pegboard scribble turn knobs feed themselves with minimal assistance hold a cup and drink from the cup and also build small towers with blocks from two to three years old children should be able to turn single pages of book cut with scissors hold crayon with thumb and fingers not a fist play with play-doh and eat without any assistance from four to five years old they should be able to draw shapes write their name and they will have exhibited a preference for either their left hand or their right hand they're also very likely to be able to dress undress independently from five to six years old children will be able to color within lines paste and glue appropriately and draw basic pictures from six to seven children with well-developed by motor skills should demonstrate controlled pencil movement and be able to tie their shoes independently by seven to eight years old they should be able to write legibly the beginning of adolescence occurs around the onset of puberty and is marked by dramatic changes in hormone levels and in physical appearance early adolescence is characterized by changes to the body as a result of puberty which comprises three endocrine events adrenarchy gonadarki and the activation of growth axis adrenarchy which is the activation of the hypothalamus pituitary and adrenal glands in the brain often begin earlier than gonodarchy adrenarchy typically begins between the ages of six to nine in females and a year later in males adrenal androgens which are weaker forms of testosterone begin to rise at the start of adrenarchy and continue to increase until they reach their peak in their early 20s these increases in adrenal androgens contribute to the development of secondary sexual characteristics such as armpit and pubic hair and changes to the sweat glands and body odor girls will start to develop breasts and hips and boys will grow facial hair and their voices will deepen gonodarki is the activation of the hypothalamus and the pituitary gland in the brain and ends with reproductive maturity this process usually begins between the ages of 8 and 14 years and females with the average age being 11 and between the ages of 9 to 15 in males with the average age being 12 hormones released during gonodarcy like estrogen and testosterone as well as weaker adrenal counterparts influence the physical appearance of the body but they also affect the brain and behavior menarche is the first period of menstruation in females and usually occurs between the ages of 13 and 16. from both a social and medical perspective it is often considered the central event in female puberty as it signals the possibility of fertility the counterpart of monarchy and girls is supermarket and boys it is the beginning of development of sperm and boyce's testicles at puberty unlike monarchy spermarcy is not physically notable the most significant and noticeable puberty related change for a young man is their first ejaculation this happens between the ages of 12 and 16. spur market indicates a boy is now producing sperm and could fertilize a female egg through sexual activity which would result in female pregnancy research indicates that american girls and boys are undergoing puberty earlier than ever though the reasons are unclear many believe that our widespread exposure to synthetic chemicals is at least partly to blame but it's hard to pinpoint exactly why our bodies react in certain ways to various environmental stimuli environmental stressors could also induce monarchy earlier the role of environmental stressors on monarchy has been studied since the 1990s when cases of early menarch were reported to the cdc there is substantial research that indicates that girls from divorced families will have an earlier onset of monarchy as compared to girls from intact families the research also showed that homes with inter-parental conflict meaning parents fought a lot girls in those homes began menstruating earlier the third hormonal event that occurs during puberty is the activation of the growth axis resulting in a linear growth spurt at around age 12 in girls and age 14 in boys this also will result in changes to body size and composition adulthood has three stages early adulthood middle adulthood and late adulthood at around 20 years of age physical maturation is complete in young adulthood our physical capabilities are at their peak which includes muscle strength reaction time sensory abilities and cardiac functioning most athletes are at the top of their game during the stage many women have children in young adulthood years so they may see additional weight gain and breast changes the brain continues maturing and fine-tuning itself well into your 20s as you remember between childhood and adulthood the brain loses excess neurons and synapses during pruning the rate of pruning slows down by a person's late 20s at the same time some brain regions strengthen their connections with one another and the major nerve tracts become wrapped in additional myelin which increases the brain's cerebral cortex the cerebral cortex's volume peaks around age 40. the most important development is the full development of the prefrontal cortex the front portion of the frontal lobe this area handles many of our higher level cognitive abilities such as planning solving problems and making decisions it is also important for cognitive control the ability to suppress impulses in favor of more appropriate actions the adult brain is better wired for cognitive control compared to the adolescent brain which is more influenced by emotions rewards social acceptance when it comes to making decisions the process of aging occurs in the biological psychological and social sphere as well it is complex and individualized as far as evolution is concerned we are here to reproduce and our bodies must be fit and healthy in our younger years for such childbearing just as monarchy marked the start of fertility menopause marks the end of fertility menopause marks the depletion of eggs and the ovaries as well as dropping hormone levels fertility normally peaks at around ages 25 to 30 and starts to decline after age 35. the precursor of menopause is perimenopause which can occur as early as 35 but mostly around age 40 the menstrual cycle starts to ease and halts around age 50. menopause may be marked by symptoms like hot flashes and mood swings there is much debate on whether male menopause also called andropause even exists this stage refers to a drop in testosterone in men however unlike menopause which is universal it will happen to all women andropause is not universal it will not happen to everyone a drop in testosterone does happen to some men around the age of 60. about 20 of men in their 60s and as many as 50 percent of men in their 80s will go through such a drop in testosterone men could feel a drop of energy increased fatigue low mood as well as difficulty with sleep in advanced years after reproduction the negative effect of our genes become more apparent as there is no evolutionary benefit in prolonging our lifespans but modern medicine has changed the human lifespan has increased and we're seeing more health related problems as a result in terms of the brain the brain starts to lose brain mass around age 60 or 70. shrinkage of the frontal lobe and the hippocampus which are areas involved in higher cognitive function and encoding new memories start around this age the outer ridge surface of the brain starts to thin due to declining synaptic connections at the neural level neurons shrink and retract their dendrites and the fatty myelin that wraps around the axons deteriorates this was the first part of a three-part video series on developmental psychology this video focused on the role of biology in developmental psychology in part one we learned lifespan development explores how humans change grow and remain the same from conception to death human development can be studied scientifically across three domains biological development cognitive development and psychosocial development and different theories focus on the processes patterns generalizability biological influences and environmental influences on human development for reflection please take a few moments to consider the following open-ended question how are you the same and how are you different today from the person you were at 15 years old i'd love to get your thoughts in the comments below that's it for this lecture in the next lecture we will continue to discuss developmental psychology more specifically the development of cognition before you go don't forget to like this video and subscribe to stats with taurus for more psych 101 looking forward to it ciao [Music] you