Lecture 12: Physical and Cognitive Development in Adolescence

Five Developmental Universal Tasks of Adolescence

1. Accept full-grown body and changes of puberty

2. Acquire adult ways of thinking

3. Develop more mature ways of relating to peers of both sexes (less rigidity of gender segregation)

4. Consolidate an identity

5. Attain greater independence from the family

Nature of Puberty

• The set of biological processes that change the immature child into a sexually mature person

Timing

• Girls: 10-15

• Boys: 11.5-17

Growth Spurt

• Girls: 10 y.o. lasts abt 2.5 years

• Boys: 12.5 y.o. and grows for a long period of time

• Reverse of cephalocaudal trend

Major changes in overall body growth

• A gradual process, not a single event/Asynchronous

• Controlled by increase in growth hormones (Thyroxine)

• Growth is first sign of puberty with large increase in size, strength, weight (Gain 50-75 lbs)

• Also increase in appetite, new sweat glands (BO), oil-producing glands (acne breakouts)

• Reverse of cephalocaudal (First is feet, legs, and hands then rest)

• Muscle-fat ratio

  • Girls with more fat than boys

  • Boys have more muscle strength vs Girls

Sexual maturation

1. Primary sexual characteristics 

• Involved reproductive organs directly  

  i.e. Ovaries, genitalia 

2. Secondary sexual characteristics 

• External physical changes that help distinguish human M + F in appearance 

  i.e. Breast development (females) + facial hair (males)  and both will have pubes  

General changes of sexual maturation

• Girls AND boys increased levels of androgens AND estrogens, level determined are sex-specific

• Boys get more androgens

testosterone -> muscle growth in body size, sex characteristics

• Girls get more estrogen

Cause breasts and uterus to mature, and fat to accumulate that regulates the menstrual cycle

• Menarche (First menstruation) – Occurs late in the sequence, typically around 12.5 y.o.

• When stored sufficient body fat (100 lbs)

Factors Affecting Timing of Puberty

Influenced by both genes and environment. 

• approx. 2/3 of variation in age of puberty is genetic  

• Identical twins hit puberty around a 2-months diff.  + Fraternal – 12-months diff.  

Environment affect pubertal timing

Nutrition, weight, dieting, exercise  

• Girls need to reach a certain weight/fat accumulation  

• High lvls of exercise could delay it (chn in sports), bad diet and nutrition 

  Psychosocial aspects: 

• Links between earlier pubertal timing + environmental stress: divorce, family conflict, father absences  

  Why might socioemotional stress matter?  

• Evolutionary model:  

  Argues humans have evolved to the emotional quality of their childhood environment,  

  In a stressful home environment, adaptive to mature early to leave + reproduce early   

Adolescents’ Psychological Response to Pubertal Timing

• Early: Boys tend to fare better than girls  

  Early boys – Higher athleticism; Closer to the cultural ideal of men, ideal for boys to have a more muscular type of body compared to skinny body 

  Early girls – Mover further from thin ideal; Vulnerable to sexual harassment; Already developed breasts than the rest of classmates 

• Late Bloomer: Girls fare better than boys  

Adolescence Body Image is Focal Concern

Strong predictor for self-esteem. Importance?

• Amazing amount of growth 

• Adolescents now aware of changing bodies (Compared to growth during infancy)  

• Adolescents as a marginal group – A group between cultures, within-group conformity is vital  

• Mass media contribute by presenting one-dimensional images of attractiveness based on gender: 

  Girls: Curvy, thin, sexy, attractive face 

  Boys: Lean, muscular, attractive face  

Eating disorders 

• Girls: Increased risk of eating disorders, such as anorexia (Peak around around 10-15 y.o)  

 

Body Image Among Boys  

• Primary concerns: Height, muscle, physical strength: At risk of steroid abuse  

• i.e. Boys talking abt body image  

Types of Eating Disorders

Anorexia Nervosa - Starve themselves in fear of getting fat and could disrupt menstrual cycles

Bulimia Nervosa - Binge eat then vomit to prevent weight gain

• Overweight and early menarche increases the risk

• Both can be caused by hereditary

Binge-Eating Disorder - Leads to obesity but is not prolonged or restrictive

Body Image: Central Findings of Jones et al., (2004)

• Multiple factors lead teens to internalize these narrow cultural ideals  

• Jones et al. (2004) tested factors among 780 7^th-10^th graders  

• In research, peer appearance conversations mattered the most 

• All the factors of BMI, appearance magazine exposure + conversations with friends, peer appearance criticism are all caused by the internalization of media that leads to body image dissatisfaction  

General Advances in Logical Thinking – Shift to Formal Operational Thinking

• Emerged from 11-15 y.o. 

• Can now deal with the abstract and hypothetical thought  

• Thinking is more enlightened, imaginative, idealistic, and rational  

• Piaget believed in this stage; reason is like a scientist (using logical = highest lvl of reasoning)  

Critique:  

• Research shows the growth of formal reasoning abilities is slower and less complete than Piaget believed  

• Adults still perform poorly with deductive reasoning some college students even fail at tests for formal operational thinking   

 

Three Advances in Adolescent Thinking 

1. Thinking about possibilities (“what if”) – propositional thought  

2. Thinking through hypotheses (“If, then”) - Hypothetico deductive reasoning 

3. Thinking about abstract concepts (i.e. love, faith, greed)

1) Thinking about possibilities (“what if”) – propositional thought 

• Able to evaluate logic of propositions without referring to real-world circumstances 

• Can better handle abstract + hypothetical thinking  

• Allows adolescents to fantasize and speculate on a grander scale (the person you are in the moment is one aspect of many things) 

• Able to consider range of alternatives in problem solving  

 

2) Thinking through hypotheses (“If, then”) - Hypothetico deductive reasoning

• Able to formulate, test, and evaluate hypotheses in an orderly fashion  

• i.e. What makes the pendulum swing faster?  

• Young chn randomly solve probs. 

• Adolescents do it more systematically (Finding variables and testing hypothesis with purpose)  

• Teens may see weight, string length, AND force play a factor in the pendulum swing

3) Thinking about abstract concepts

• Advances lead them to critically examine assumptions 

• i.e. politic, love, faith, greed

Role of Brain Development (Changes in Thinking + “What were they thinking”)

• Improvement in rational thinking fostered by extensive maturation of prefrontal cortex, gradual growth  

• Maturation takes place in important areas for planning, thinking ahead, weighing risks + rewards  

• Includes synaptic pruning, myelination, increased connectivity in PREFRONTAL CORTEX connections to other brain parts 

• Adolescents still do not fully resemble adults in their decision-making  

  See risk-taking and “What were they thinking?" moments – Why?  

  I.e. texting and eating while driving 

• Decision-making in the real world is the product of both logical reasoning and psychosocial factors (i.e. impulse control + handling peer pressure) – These two components mature at different rates 

Psychosocial immaturity stem from

• From a gap in the maturation of brain networks  

• Socioemotional networks develop early – Highlights emotion, reward, sensation-seeking, positive interactions  

• Cognitive control systems develop later and more gradually; Responsible for  

  Impulse control  

  Emotional regulation   

  Delay of gratification  

  Resistance to peer influence  

  Weigh risk + reward differently than adults  

• i.e. Push back: Too much focus on negative stereotypes?  

  Argued not ALL risk-taking is negative 

  i.e. trying a challenging sport or applying for something that is competitive  

  Cannot succeed with developmental tasks if take no risks 

“Side effects” of new thinking abilities

1. See intense pre-occupation with the self and with presenting the self in the best light  

• i.e. what other people think of them  

2. Two distortions in the relation between self and others 

• imaginary audience i.e. walking alone to the bus stop and think everyone is watching

• personal fable - specialness, one’s own experiences + feelings are unique no one else has experienced

3.  Sensitive to hypocrisy – Often leads to argumentativeness  

4.  Difficulty with everyday decision-making  

imaginary audience

Erroneous belief that one’s behavior is the subject of constant public attention

personal fable

Erroneous belief that one’s thoughts, feelings, and experiences are totally unique

• Inflated opinions abt one’s own exp

• “Mom you don’t know what it is like to fall in love”

Academic Achievement

Role of these factors

child-rearing practices

• Authoritative parenting w/ joint adolescent-parent decision-making

• Parent involvement in their education

parent-school partnerships

• Parents who continue to keep in touch with chn peer’s will lead to an emphasis on the value of academics

peers-classroom learning

• Peer valuing of and support for high achievement will find peers similar to their goals in academics

Media multitasking

Reduces learning bc multitasked activate subcortical areas in implicit memory compared to those working on a task w/o distractions activate the hippocampus (explicit memory)