Pubertal Processes What biological changes of puberty have the biggest impact on boys or girls? What teens worry about? What teens talk about? What teens feel proud of? What teens feel ashamed of?

What is Puberty? Period of physical growth leading to attainment of reproductive capability Five areas of changes: Acceleration then deceleration of skeletal growth Changes in body composition & distribution of fat and muscle Development of circulatory and respiratory systems, increased endurance Maturation of reproductive organs, secondary sex characteristics Changes in nervous and endocrine systems

Influences on Pubertal Timing Largely genetic Influenced by nutrition and medical health Level of body fat Stress

What Changes at Puberty: Levels of Sex Hormones Endocrine system produces, circulates, and regulates the level of sex hormones: Releasing Factors Pituitary Gland Hypothalamus LH & FSH Androgens and Estrogens Monitoring Levels Sex Organs Sex hormones

What Changes: Physical Growth Hypothalamus Pituitary Gland Growth Hormones Thyroid Sex Organs These hormones stimulate physical growth Thyroid Hormones Androgens

Changes in Muscle and Fat Before puberty, boys = girls on levels of muscle and fat Both boys and girls develop muscle and increase fat during puberty Muscle grows faster in boys, fat increases faster in girls End of puberty muscle/fat ratio: 3:1 for boys, 5:4 for girls

Change in body fat (kg)

Physical Changes in Adolescent Brains may Account for Turbulent Teen Years, McLean Hospital study reveals June 11, 1998 --Belmont, MA-- Parents of teenagers can take heart in a McLean Hospital study that provides the first real look at the physiological basis for emotional and cognitive development during adolescence. In this study, scientists used functional magnetic resonance imaging (fMRI) to compare the emotional processing of healthy 10- to 18-year-olds with that of normal adults. The researchers focused on the level of brain activity in the amygdala, a region that guides instinctual or "gut" reactions, and the frontal lobe, the seat of rationalization and reasoning. They found that when young adolescents process emotion, the level of brain activity in the amygdala is higher than the activity in the frontal lobe. However, as adolescents progress into adulthood, there is an age-related shift: activation in the amygdala decreases while activity in the frontal lobe increases. Adults show greater overall activation in the frontal lobe and less activation in the amygdala as compared with adolescents. Brain Development

Brain Development, c’t’d "These results suggest that adolescents are more prone to react with ‘gut instinct’ when they process emotions, but as they mature into early adulthood, they are able to temper their instinctive ‘gut reaction’ response with rational, reasoned responses," says Yurgelun-Todd. "Adult brains use the frontal lobe to rationalize or apply brakes to emotional responses. Adolescent brains are just beginning to develop that ability." Results from this phase of the study revealed a similar shift in functional activation for language based tasks during adolescence. Data collected from the study indicated that as subjects aged, the activation in the temporal region decreased while activity in the frontal lobe increased, indicating that the reasoning/rationalization part of the brain becomes increasingly involved in the center for language production as individuals mature.

Tanner Stages Most widely used way of measuring pubertal status (Marshall & Tanner, 1969) Five stages of penis/scrotum and pubic hair development for boys; Five stages of breast and pubic hair development for girls. Developed the system by assessing nude photographs of adolescent boys and girls Unclothed adolescents are assessed by trained health professionals, with physical exam and photographs Less intrusive alternative: teens look at photos indicating Tanner stages, and rate themselves.

Appearance of Primary and Secondary Sex Characteristics

Puberty and Self-Esteem Does self-esteem drop? Girls: Puberty associated with small decrease in self-esteem Greatest impact is on girls experiencing multiple transitions at once (e.g., menarche, dating, school change)

Puberty and Moodiness Does puberty increase moodiness? Maybe. Boys: high testosterone associated with rebelliousness, aggression, sadness (Sussman) Boys: rapid increase in testosterone associated with better adjustment (Sussman) Girls: Rapid increases in estrogen associated with depression, but interpersonal stress has a bigger influence on mood than does hormonal level (Brooks-Gunn). “Beeper studies” find evidence of moodiness, but moods change with activities, not randomly.

Puberty and Family Relationships Increased distance and conflict, especially conflict with mother Conflict gradually diminishes after the growth spurt Possible explanations: Evolutionary process to achieve separation Change in established childhood relationship patterns, a transition for all family members Some variation by culture

Reactions to Sexual Development Girls are often ambivalent about menarche Prior expectations affect girls’ experience of menarche Boys do not tend to feel anxious or embarrassed about first ejaculation However, boys do not talk about it with anyone

Early vs. Late Maturation: Girls Girls: Early maturation associated with more psychological problems Poorer body image, more food intake restriction Higher rates of depression, anxiety disorders Higher rates of delinquency, substance abuse (especially if pre-existing problems), early sexual intercourse But, more popular, especially with boys

Early vs. Late Maturation: Boys Early maturation associated with better social and emotional functioning Good to be taller and stronger than one’s peers Associated with popularity, and more opportunity for contact with girls More likely to be leaders, more self-confidence But there are some down sides: more at risk for antisocial behavior, substance abuse At the time of puberty, late maturers are more intellectually curious, less prone to intense negative emotion

Why Does Early- vs. Late Pubertal Timing Matter? Deviancy hypothesis (Peterson & Taylor, 1980): Both early and late maturers at risk, because development is not in sync with that of peers. Stage termination hypothesis (Peskin & Levin, 1972): early maturation (not late maturation) is bad because it interrupts normal course of development.

Puberty and Body Image in Girls Overall, girls are less satisfied with their weight as they become pubertal. Height, weight, overall appearance: in some studies, early developers are (by the time they reach late adolescence) less satisfied than on-time or late-developers, who were most satisfied.

Pubertal Timing and Girls’ Body Image 6th 7th 8th 12th

Puberty and Body Image in Boys Early maturing boys more satisfied than on-time or late boys with their height, weight, body build But, the advantages for early maturers do not persist across adolescence

Pubertal Timing and Body Image in Boys 6th 7th 8th 12th