Chapter 8: Puberty
Celebrating Puberty
Throughout history, and in some impoverished agrarian nations, puberty is considered a person’s sign to get married and give birth
Celebrated blossoming bodies through puberty rites, emotional coming of age ceremonies where children were removed from their families and forced to perform a stressful task, resulting in anxiety, awe, and a new sense of self efficacy
Ex: In one Amazonian tribe, boys would “prove their manhood“ by killing a large animal, then metaphorically “die“ by drinking a hallucinogen to be “born again“ as men
Menarche, or first menstruation, is a classic signal to celebrate a girls’ entrance into womanhood
Ex: In a traditional Navajo ceremony, girls in their first or second menstrual cycle, guided by a female mentor, perform a running ritual in which they sprint for miles, guided by a female role model. At the end of the ceremony, they build a corn cake, a symbol of fertility, and get a new adult name for their “new life“
In the past, we reached puberty at a much older age, therefore making us seem more ready for adult life. Today, many girls reach menarche at age 9 or 10, so they aren’t truly ready.
Declining Age of Puberty
Secular trend in puberty: centuries long decline in the average age at which children reach puberty
got older because of better nutrition
in less developed nations: 18
in US: before 12
Hormones
Puberty is commanded by 2 command centers
Adrenal glands: release hormones at 6 or 8, several years before children show signs of puberty
adrenal androgens: produce pubic hair, skin changes, body odor, and sexual desires, reach a peak in the early 20s
HPG Axis: involves hypothalamus, pituitary gland, gonads and produces major body changes
Puberty is set off by 3-Pronged Reaction
1. hypothalamus and hormones stimulate pituitary gland at 9 or 10, steps up production of hormones
- hypothalamic hormones are triggered by genetics, light exposure, environmental stress, and a hormone called leptin, which is tied to body fat. A certain threshold of fat must be reached to start puberty, factors like obesity and malnutrition can impact puberty
2. Causes ovaries and testes to secrete estrogens and testosterone
3. Concentrations of estrogens and testosterone unleash a physical transformation
- Estrogen causes hips to widen, uterus and breasts enlarge, stimulate ovaries to produce eggs
- Testosterone causes penis to lengthen, facial and body hair, dramatic increase in muscle mass
Physical Changes
Puberty causes psychological and physical transformation
Primary sexual characteristics: body changes directly involved in reproduction (growth of penis, menstruation, etc)
Secondary sexual characteristics: other changes that characterize puberty (breast development, pubic hair, voice change, sweat glands
Growth Spurt: dramatic increase in height and weight
Girls!
Growth accelerates, peaks, and then begins to decrease, peak at 11
6 months after growth spurt, breasts and pubic hair become visible
On average, breasts take about 4 years to grow to adult form
Menarche occurs in the middle to final stages of breast and pubic hair development when growth is winding down
Puberty is diff for every girl because pubic hair development is sometimes underway before breasts enlarge or a girl grows after menarche
Boys!
growth of penis, testes, and pubic hair
voice deepening, facial hair, body hair
grow average of 8 inches in growth spurt
spermarche: first ejaculation, typically at 13 (later than avg menarche)
Differences!
for girls, having a high BMI during elementary school predicts earlier puberty
family stress, according to evolutionary perspective can create a physiological mechanism that accelerates puberty
unhappy childhood signals the body to expect a short life and pushes adult fertility to a younger age
genetics (age when parents developed) is most important, but family life can impact temperamentally vulnerable girls
for a girl who was sexually abused, breast development began 8 months earlier than the norm
Main chances of girl reaching puberty early: parents reaching puberty early, girl being hispanic or african american, girl being overweight or rapid weight gain as an infant, stressful family life
Body Image Issues
Susan Harter 1999
5 self worth dimensions: scholastic abilities, conduct, athletic skills, peer likeability, appearance
being happy about looks seemed to outweight anything else
beginning in elementary school, girls get increasingly distressed by how they look, due to the thin ideal, the media driven pressure to be very thin
impacts during early adolescence because social sensitivities reach a peak
gay and trans males also vulnerable
epigenetic roots: mothers exposed to intense stress during pregnancy are more likely to have daughters with eating issues
Albert Bandura: latina and african american girls are less succeptible to thin ideal because their culture celebrates bodies of larger sizes (thick thighs, big butt etc)
children of color who want to fit in with mainstream western culture are just as likely to be impacted by thin ideal
Eating Disorders
Eating disorders: pathological eating behaviors that threaten well being
Anorexia nervosa:
most serious eating disorder
self starvation to the point of reaching 85% or less of ones ideal body weight
girl who should weigh 110 weighs 95, etc
8/1000
Bulimia nervosa: frequent (biweekly) cycles of binging and purging in an attempt to lose weight
not as life threatening b/c weight stays in a normal range
second most prevalent (2.6/100)
Binge eating disorder: recurrent out of control eating
tied to obesity and presents a serious threat to health
most prevalent (3/100)
could be caused by hereditary component
Sexuality
first sexual feelings at age 10
average age of first intercourse is between ages 17 and 18, though 1 in 8 children have it at age 15
teens who are more impulsive are apt to make transition earlier
abortions, adolescent pregnancies, and births have dramatically declined for the past 30 years