Week 9 - Adolescence

Week 9

Where does the term adolescence come from

The latin verb adolescere, meaning ‘to go into adulthood’

Adolescence

Period of rapid physical, sexual, cognitive, social and emotional changes between childhood and adulthood

How much of England/Wales population were under 25 in 2021

29.5%

Stages in adolescence

1. Early adolescence (11-14)

2. Middle adolescence (14-16)

3. Late adolescence (16-18)

Early adolescence

Period of rapid pubertal changes

Middle adolescence

Pubertal changes now nearly complete

Late adolescence

Young person achieves full adult appearance and begins to assume adult roles

What changes in adolescence

Physical

• Physical growth

• Maturation of sex organs

Psychological

• Thinking and reasoning

• Identity

Social

• Role transition

• Responsibility

Differences of growth in girls and boys

Growth spurt occurs around 2 years earlier for girls at around 9 years, whereas occurs around 11 years for males.

Boys increase in 4inches a year whereas girls increase in 3 inches a year.

When is the peak of pubertal change reached for boys and girls

Girls - 11 years

Boys - 13 years

Sexual maturation in puberty

Development of primary and secondary sexual characteristics, controlled by sex hormones

Pituitary gland

Master gland in the brain controlling other target glands in the body.

• Releases hormones that stimulate adrenal glands that sit on top of kidneys, as well as ovaries and testes to initiate growth and development

Hormones that express sexual differentiation

• Estrogens

• Progesterone

Associated with female hormone system, released by ovaries and prepare woman for menstruation and pregnancy.

Small amounts of estrogen in boys released by tests and contribute to breast enlargement in boys.

• Androgens (testosterone)

Associated with male hormone system, released by testes and leads to muscles growth, body growth, facial hair etc.

Testosterone released by female adrenal glands and stimulate growth of underarm pubic hair in girls.

Male secondary sexual characteristics

• Increase in penis size, followed by appearance of pubic hair

• Minor voice change at start of puberty

• First ejaculation at 13-14 called Spermarche, signals start of sperm development

• Male ejaculate contains few living sperm for for few years - initial period of reduced fertility

• Deepening of voice as larynx enlarges and vocal cords lengthen

• Voice change occurs at peak of male growth spurt and not complete until puberty is over

Female secondary sexual characteristics

• First menstruation comes rather late in puberty (around 12) - nature makes sure girls have grown sufficiently in height and weight before onset on menstruation to ensure girl’s body is large enough for childbearing

• Breast enlargement

• Pubic hair

• Hips become wider than shoulders

• Irregular menstrual cycles

• Some girls aren’t fertile until 2 years later

Adolescent sexuality

Adolescence is a time of sexual exploration and experimentation.

• Simultaneously, adolescents are often concerned about managing sexuality in social relationships:

  • uncertainty about partner’s expectations, concerns about body image - great focus on physical attraction at this age

  • improved cognitive capacities influence sexuality through self-reflection and perspective taking

Changing sexual habits in adolescents

• Adolescent contraceptive use has increased in recent years

• Reduced teen pregnancies through sex education programs

• In 2021: 13,200 conceptions in girls under 18 (Office for National Statistics, 2021) - when asked, people say that they weren’t expecting to have sex, were underprepared, felt pressured etc. (all of these things could be due to the strong impulses felt at this age)

Lewis et al. (2017)

• In 1990-1991, 1 in 10 men and women aged (16-24) said they had sex during the previous year, compared to:

• 1 in 5 women and 1 in 4 men in 2010-2012

Puberty and body image

Pubertal timing: early-maturing girls and late-maturing boys suffer low self-esteem.

• Puberty brings boys closer to ideal physical image (muscle definition, strength, stamina).

• Girls have increased body fat and weight gain, plus menstruation. This takes them further away from the Western cultural ideal (e.g. heterosexual men value lower-medium waist-to-hip ratios in females)

Stigma around early-maturing girls

Parents may not want their late-maturing daughters to hang out with them because they assume the early-maturing girls may be involved in sexual encounters etc.

Late maturing girls…

Retain their ‘girly behaviours’ and are perceived as attractive, lively and sociable

Late maturing boys…

Tend to come across as more anxious, overly talkative, and attention-seeking to compensate their late maturity

Butovskaya et al. (2017)

Study examined reproductive history of over 900 females across 7 indigenous, non-industrial societies. Measured females WHR, BMI and number of children.

• Larger WHR is associated with greater fertility, although a small WHR is considered more attractive in our western society.

  • The larger the WHR, the more children women had.

Erikson’s (1980) psychosocial stages of personality development

• Emphasised social/environmental influences.

• Core concept of ego identity during Adolescence - crucial to optimal personality functioning, involves developing a sense of inner self-continuity

• In the 5th of his 8 psychosocial stages, he mentions identity versus role confusion (at 13 – 18 years), adolescents actively attempt to construct a stable sense of identity.

Marcia’s theory of identity achievement (1966, 1980)

Four identity types:

1. Identity achievers

2. Identity moratoriums

3. Identity foreclosures

4. Identity diffusers

Identity achievers

Extensive soul-searching and exploration produced stable identity

Identity moratoriums

Engaging in self-exploration but not yet formed stable identity.

• Experiencing anxiety/worry and frequent identity crisis due to uncertainty of belonging and full commitment

Identity foreclosures

Automatically adopt others’ values without extensive critical reflection - easy for them to be led astray

Identity diffusers

Lack firm commitments, not actively engaged in self-exploration, apathetic, lack of anxiety/worry about themselves and others

Adolescent rites of passage in pre-industrial societies

A ceremony or ritual that marks individuals’ transition from one status to another.

• In many cultures, adolescent rites of passage involve dramatic practices through which adolescents gain access to adult practices, knowledge and sexuality

Quinceanera

Hispanic communities celebration of girls’ 15th birthday

Involves four steps:

1. Separation - separation of the adolescent from the community for a while to learn to cope on their own

2. Training - learning appropriate behavior for the new phase being entered

3. Initiation - adolescents are made aware of service to the community that will be part of their new adult role

4. Induction - ceremony itself, with all formal announcements, speeches and celebrations that are unique to a given culture

Function of Quinceanera

• Sense of adult responsibility.

• Lessen ambiguity - may protect adolescents from feeling alienated and joining gangs, or engage in criminal activities, etc.

• Bond - with community and society at large, feeling accepted

Quinn et al. (1985)

Say adolescent rites of passage would help adolescents through the difficult transition into adulthood

Psychosocial changes

Greater autonomy and less dependence on parents.

• Need increased age-appropriate independence and freedom.

• Parental support is still necessary.

• Parents and adolescents to create a relational dialogue, finding a balance between autonomy and curfews.

Relationship with parents during adolescence

Relationship with parents changes in three ways:

1. As cognitive ability increases, their perceptions of parents change. Now, view them as individuals as well as parents.

2. Less time is spent with parents and families - they usually want to spend more time with their peers/friends

3. More conflict with parents: “Adolescent moodiness” – rapid, situational mood swings and increased irritability

Brain development in infancy

Lower-order sensory cortices (e.g. visual, auditory) mature earliest with synapses forming rapidly through early sensory experiences

Brain development in childhood

Parietal and temporal association cortices mature during childhood, largely responsible for spatial attention, language development and memory

Brain development in adolescence and early adulthood

Areas such as PFC mature last

• There is Synaptic pruning, therefore refinement of PFC-functions are slow and continue well into adolescence (aged 16-17)

  → As PFC involved in higher order cognitive processes, can understand why adolescents are still developing these behaviours

• Continued myelination of axons

Cognitive development in adolescence

Higher-order cognitive processes, inc. cognitive control and inhibition:

• Increased activation of slow maturing prefrontal cortex from childhood to young adulthood

• Decreased activation of lower-level sensory and parietal regions from childhood to young adulthood

• Higher-order cognitive abilities support by PFC become more fine-tuned while unspecific posterior regions become attenuated (reduced in thickness)

Stroop task

Measure of inhibitory control, heavily relies on functions of PFC.

Name colour of word but ignore actual word.

Typical findings of adolescent stroop task

• Young adults show greater PFC recruitment than adolescents (Adleman et al., 2002)

• Behaviour speed-accuracy trade-off - adolescents respond faster but at the expense of accuracy

Translates to fast/impulsive reactions and risk-taking behaviours

Social-emotional development in adolescence

The ‘social brain’ involved in:

• Social cognition - recognising, understanding and interpreting social cues

• Mentalising - ability to interpret mental states, feelings and actions of others

There is functional maturation and connectivity between fronto-parietal and limbic regions which improves social cognition, mentalising and emotion regulation skills

Social cognition supported by…

• dmPFC

• Inferior frontal gyrus

• Amygdala

Mentalising supported by…

• Precuneus

• Temporal-parietal junction (TPJ)

• Superior temporal sulcus (STS)

• Anterior temporal cortex (ATC)

Schmalzle et al. (2017)

• Adolescents played cyberball during fMRI (social inclusion vs. exclusion)

• Examined activity in mentalising network

• Related data to Facebook network density (how interconnected friends were)

Found:

• Greater mentalising network connectivity during social exclusion vs. inclusion

• More activation during exclusion linked to lower Facebook network density

Brain development during adolescence is characterised by

1. progressive structural changes

2. regressive structural changes

3. ongoing myelination

Adolescence in industrialised nations, as compared to non-industrialised nations, is…

1. extended into three phases: early, middle, and late adolescence

2. extended due to longer education and changes in job market

Adolescents’ cognitive performance on the Stroop task is best explained by:

1. behavioural impulsivity

2. incomplete myelination of axons to help refine information processing

   Correct answer

3. reduced frontal activation relative to young adults

In Schmälzle et al.’s (2017) study, how did adolescents’ Facebook network density relate to their brain’s mentalising network connectivity during social exclusion?

Teens with low network density showed the greatest increase in connectivity, reflecting greater mentalising effort when excluded.