HDFS 201 LECTURE 8 Physical Development Orientation Points Outcomes of physical development are mediated by social conditions e g SES What kind of food you can afford There are ex differences Males and females have differences in terms of developmental trajectories some things are highly desirable from a cultural perspective for males are not desirable for females Some course of development has both positive and negative consequences Differences in maturation rates early maturation in males is good because they take on more leadership positions seem more attractive and are given more respect etc You don t decide this though which makes it prejudicial EXCEPT when you re 12 and you were an early matured child you re supposed to know what you want to do with your life and are expected to act like an adult they often have identity problems Importance of systems perspective Factors Influencing Growth Genetic factors similarities between parents and kids familial looks Nutritional factors Racial differences Seasonal influences grow more in summer Disease general health Stress 1951 nutritionist looked at orphan children and compared 2 orphanages one with good food with a nutritionist and good cook the other with no nutritionist and not high quality food Growth records of these kids showed that the bad food orphanage kids were growing normally and the good food orphanage were not growing as much The good food orphanage had a really stern head master and when they head master left all the kids went through a period of catch up growth The only change was the reduction of stress of living with the head master Body Growth and Change Patterns of growth Cephalocaudal pattern Proximodistal pattern extremities Orthogenetic pattern Werner s Orthogenetic Principle Growth sequence that gradually works from top to bottom of the body head to tail Growth sequence in which growth starts at the center of the body and moves toward the Undifferentiated to differentiated plastic or biopotential to specialized Werner adopted the biological principle or orthogenesis as a process that governs psychological development over long term The idea is that the direction of development is towards 1 Increasing differentiation and specification of primitive action systems that were initially fused in a global organization that causes 2 The emergence of action systems that are more differentiated and that begin segregated and develop to be more integrated over time such that 3 The more advanced systems more differentiated specified and internally integrated hierarchically integrate subordinate and regulate the less developed systems Secular Trend A trend in industrialized society toward earlier maturation and greater body size Secular Trends in Growth Height Menarche first menstrual cycle getting younger Reasons for secular trends Improved health Nutrition Hormones in food supply Diets Medicine vaccinations Reduced family size Genes for height partially dominant over genes for shortness Stern s rubber band hypothesis the rubber band represents genes genetic potential You have genetic potential to be 6 4 and you are The environment puts the stretch on the potential so you reach the highest if it s an optimal environment There is a certain point where you won t go further Reaction ranges Sexual Maturation Secular trend In 1840 average age of menarche was 16 years a full four years later than it is today General Body Development Average infant about 7 5 lbs at birth 5 7 loss in first days typical Double birth weight by 5 months Triple by 12 months By age 2 about 30lbs By age 3 about 33lbs Decelerating curve from birth on Slow weight gain of about 10 per year in early elementary school Prepubescent Growth Spurt Right before puberty increase to about 20 per year Corresponds to height spurt Increase in skeletal size weight Increase in musculature Increase in internal organs Increase in fat Early and Late Maturation Girls mature earlier than boys Difference in BMR Some adolescents are preoccupied with their bodies Body dissatisfaction is more acute during puberty than late adolescence Girls tend to be less happy with their bodies and have more negative body image than boys Boys become more satisfied with their bodies as they move through puberty Body Growth and Change Body image Gender differences Sexual Maturation Tanner Scale Measures progression through puberty and attainment of sexual maturity Prepubertal to adult secondary sexual characteristics Rates of Sexual Maturation Genes set the process in motion Hormones responsible for changes Environment also Secular trend better nutrition Earlier maturation larger body size Poorly nourished mature later Heavy tall mature earlier Regular strenuous exercise mature later Gender Differences in Early and Late Physical Maturation Early males advantage More positive reactions from others Late males disadvantage More behavior adjustment problems Early females disadvantage Subject of ridicule lower self esteem Older peer group problems Late females academic advantage Differences tend to fade with time Sexual Maturation Girls experiencing puberty tend to become self conscious about their appearance Boys are more likely to welcome their weight gain and voice changes Boys who experience slow growth and or short stature may experience difficulties 62 of boys regard semenarche positively 23 of girls view menarche positively Body Growth and Change Early and late maturation Early maturing boys perceived themselves more positively and had more successful peer relationships than late maturing boys Similar findings with girls but not as strong Early maturation may increase girls vulnerability to problems Smoking drinking depression eating disorder struggle for independence early dating and sexual experiences Body Growth and Change Subtle physical changes happen through early adulthood Peak functioning of joints occurs in the twenties Peak of muscle tone and strength in late teens and twenties Begins to decline in thirties Body Growth and Change Middle Adulthood Physical changes are gradual Genetic and lifestyle factors play a role in chronic disease Physical Appearance Lose height and gain weight Noticeable signs of aging by forties or fifties Strength joints and bones Sarcopenia age related loss of lean muscle and strength 1 2 per year after age 50 Body Growth and Change Sexuality Climacteric Midlife transition in which fertility declines Menopause Females Usually in late 40s or 50s Menstrual