Age of Opportunity: Ch.(s) 3 - 4
What physical marker was used to study possible changes in pubertal growth in males across the decades/centuries, and what was discovered?
"Voice breaking" (deepening), Which typically occurs around 3 years prior to maturation being complete (post-puberty)
This is why exposure to substances that stimulate the nucleus accumbens - nicotine, alcohol, cocaine - are especially powerful during adolescence and why use during this time can so easily lead to ____.
"addiction."
During the first half of adolescence, then, the prefrontal cortex improves by ___, which works fine as long as challenges aren't impeded by stress or anxiety. During the second half of adolescence, self-control gradually becomes governed by ___
"becoming more focused;" "a well-coordinated network of brain regions."
This is why nothing will ever ___ as it did when you were a teenager.
"feel as good"
Today, it turns out, these sex hormones, which are designed to promote reproduction, are also responsive to many other _____, such as risk-taking, thrills, recreational drugs.
"reward-seeking behaviors";
As self-control (compared to novelty seeking) is less influenced by sex hormones, we should expect to see teens in cultures that demand a lot of self-control, such as in Asia, ______
"should develop this capacity faster."
It is no coincidence that adolescent risk-taking occurs around the same age that its potential payoff - ___ - is greatest.
"successful reproduction"
Adolescent risk-taking is only different around the globe because ___ are different.
"the contexts in which they live"
The underlying inclinations that lead adolescents to take risks appear to be ___.
"universal"
Why does the timing of puberty matter? What are the consequences?
1. Early maturers are treated differently by others, which affects the way they act and feel about themselves. Maturing early is psychologically tougher on girls + risk of sexual abuse 2. Early-maturing adolescents experience a greater gap between when they mature physically and when they mature in other ways
We need to understand the underlying causes of adolescent risk-taking. Studies by LS and colleagues have consistently documented two important differences between adolescents and other age groups. What are they?
1. People's sensitivity to the potential rewards of a risky choice - s/a possibility of winning a low-probability bet - peaks around age 16 or so. 2. Children make more impulsive decisions than teenagers, and teenagers make more impulsive decisions than adults. *reward sensitivity + impulsivity = a very dangerous and vulnerable time in middle adolescence
What brain regions are most importantly reorganized during adolescence? What are these regions responsible for?
1. The Prefrontal Cortex - responsible for self-regulation & making us rational. 2. The Limbic System - plays an especially important role in generating emotions.
So what are the arguments for why there is a delay in entrance to adulthood today? Why this "arrested development"?
1. Young people have chosen not to take on adult roles because they're lazy, self-absorbed, and spoiled 2. The changes reflect rational choices. (Jobs that pay well demand more education, gender roles have changed, etc. *the world is different) 3. "Arrested development" view starts from the premise that healthy development is facilitated by the demands of adulthood - responsibilities of marriage and parenthood, expectations of a job, challenges of self-sufficiency...
What do we know about caucasian and African-American girls and the onset of puberty today?
1/10 of white girls and 1/4 of black girls had begun breast development around 1st or 2nd grade (avg. age 7)
Are changes occurring earlier in males today as well? What changes?
10% white boys and 1/5 black boys were showing signs of development as early as 1st grade
How long did it take in 2010?
15 years
The myelinated white matter connections between distant brain regions become stronger during adolescence, up through age __ or so.
22
So for boys and girls, adolescence starts earlier, ends later, and lasts longer than it every has; ___ times as long as it did 150 years ago, and ___ as long as it was in the 1950s.
3 times as long as it did 150 years ago; over twice as long as it was in the 1950s
How long did it take for the next 100 years?
A little less than 7 years
Using puberty (menarche) and marriage as markers of the length of adolescence in females, how long did it take in the mid-1800s?
About 5 years
Considering the end of puberty and time of marriage in males, how long was adolescence 50 years ago compared to today?
About 7 years; whereas today it is about 15 years (like female adolescence)
How long will it take in 2020?
Almost 20 years (from start to finish)
In the animal kingdom, the rapid increase in dopamine ensures animals will do whatever is necessary to ____
Attain a mating partner
Our ancestors evolved a brain system that _____.
Can regulate the passions stimulated by puberty
Connections between neurons in the prefrontal cortex proliferate until around age __, and are then pruned until about age __. Between 10 and 25 there is a steady increase in ____, as the circuits that survive the pruning process become myelinated.
From birth until around age 10; and then are pruned until about age 25; Between 10 and 25 there's a steady increase in white matter in the prefrontal cortex.
What is the difference in the last 50 years regarding the onset of puberty in girls?
Girls begin the changes earlier, on average, than boys, and this trend has continued
What determines whether delayed adulthood is an opportunity or risk depends is
How these extra adolescent years are spent
What happens to the nucleus accumbens as we age from childhood to adolescence to adulthood?
It gets bigger as we grow from childhood to adolescence BUT then it gets smaller from adolescence to adulthood
A human female reaches her maximum fertility in her ______.
Late teens
How is low birth weight and insulin related to pubertal growth?
Low birthweight leads to overproduction of insulin, and abnormally high levels of insulin in the blood lead to excess weight gain (& frequently - obesity).
What do we use as a typical marker of the end of adolescence?
Marriage
All of the above are related to the evolutionary "purpose" of adolescence, which is to _____
Mate
How does this affect how they do or do not work together?
More connections results in them working more effectively & better (overall) together
Is risk-taking higher in adolescence because they're not as intelligent as adults?
No - it has more to do with the development status of certain parts of their brain.
What happens in the three phases of reorganization? (Limbic system, prefrontal cortex, interconnectivity)
Phase 1: Limbic system becomes more easily aroused; sensation-seeking; feeling "higher highs and lower lows;" Phase 2: Prefrontal cortex slowly becomes more organized through synaptic pruning and myelination; Phase 3: Connections between the prefrontal cortex and the limbic system strengthen; becomes overall more interconnected;
The ____ is the brain's CEO, responsible for higher-level cognitive skills, like thinking ahead, weighing costs and benefits, and coordinating emotions and thoughts.
Prefrontal cortex
What part of the brain controls whether or not we act on a stimulus?
Prefrontal cortex
What is the marker for the beginning of adolescence?
Puberty
How is family stress related to pubertal growth?
Puberty begins earlier among adolescents who grew up in families in which there is relatively more conflict between parents and children.
What changes occur in the dopamine system during puberty?
Puberty triggers a dramatic increase in the concentration of dopamine receptors - especially having to do with rewards & feelings of pleasure.
This VTA - nucleus accumbens - prefrontal cortex circuit doesn't just respond to ingested substances, it reacts to ______
Social rewards s/a praise and attention from others
When does risk-taking tend to peak?
Someplace during the late teens.
What is the "accident hump" and what is the trend across decades?
Spike in mortality rate of boys for a few years once they've entered adolescence; It has dropped by about 3 months per decade over the past several centuries
How is the limbic system the brain's "sentry"?
Structures of the limbic system have roles in detecting certain elements of the immediate environment they need to pay attention to & work together in detecting rewards and threats therein
In what ways are diet and nutrition part of the explanation for earlier puberty today?
The healthier and better-fed you are, the more likely you are to mature earlier
What indicators are there that adolescents are more likely to take risks than children and adults?
The same age pattern has been seen across an incredibly varied group of reckless behaviors.
Are adolescents different regarding awareness of the consequences of risky behaviors, or delusions of invulnerability?
They are NOT more likely than adults to suffer from these delusions.
Parents and teachers need to keep this in mind. Adolescents are more likely to change their behavior if ______
They are motivated with a reward rather than threatened with a punishment
LS and colleagues studied adolescents and risk-taking in China, Colombia, Cyprus, India, Italy, Jordan, Kenya, the Philippines, Sweden, and Thailand. What did the research team find, compared to U.S. teens?
They discovered the same age patterns in reward sensitivity and self-control that they;d seen in their earlier study of Americans (their results were also evident in these very different countries)
How are endocrine disruptors involved in changes in pubertal growth?
They influence the timing of puberty by altering the production and effects of naturally produced sex hormones and, as well, by mimicking the hormones themselves.
How are adolescents different than adults regarding responsiveness to rewards and sensitivity to loss?
They're less sensitive to losses - less likely to avoid situations where they have something to lose (yet more likely to approach a situation in which a reward may be likely - care about others opinions of them)
Intercourse during ovulation in the late teens will result in a conception ____ times in the late teen years, while only ____ times by the late twenties.
about 1 out of every 3 times; about 1 in 4 times.
When given a self-control task, 16 year olds perform ___ adults when there are no distractions or strong emotions. But being tired, excited, or upset results in ___, compared to adults.
as well as (or better than if they're motivated by a reward); interference with prefrontal functioning.
These behaviors manifest themselves in activities that are ___ in different cultures.
dependent on opportunities (according to different cultures) *they're culturally dependent because different countries give young people differing levels of opportunity to try risky behaviors.
The additional wrinkle to this story, however, is that because puberty is starting earlier than ever before, and the sex hormones rise earlier, the age at which the brain's risk and reward system becomes so easily aroused occurs ___.
earlier as well. *but the development of self-control hasn't been affected (it's not driven by puberty...)
But the self-control system is not driven by puberty, so the ability to modulate or inhibit risk-taking ___.
has seen a widening in the year gap (between these occurrences)
Adolescence is characterized by heightened ___ and still-maturing __, as well as greater willingness to __.
heightened sensation seeking; still-maturing impulse control; greater willingness to take risks.
How are kisspeptin, leptin, and melatonin involved in puberty?
kisspeptin - this brain chemical increases in the brain and signals ovaries/testicles to produce estrogen/testosterone leptin - suppresses desire to eat when we're full, regulates our hunger and appetite melatonin - regulates sleep levels/pattern
Adolescence is, therefore, not only ___ today than it was in the past, it is also more _____.
longer; perilous.
When asked to perform decision-making tasks on computers, ___ prior to mid-adolescence become active; after this time, it is the ___ that becomes highly active.
more areas of the brain (not all useful); pattern using more focus...
So the length of time young people are vulnerable to the mismatch between the power of the accelerator (limbic system) and the strength of the breaking system (prefrontal cortex) is ____.
widening/increasing
