- Hey, y'all my name is Prashanth Kumar or PK
and I'm an MCAT tutor at Shemmassian academic consulting.
Today, we're gonna be doing a passage walkthrough
in the MCAT psych soc section.
You should be taking roughly five minutes on this passage
but I've added one more bonus question at the end.
So, today we're gonna be going more in depth
so you can see exactly what's going on in my head
as I tackle this section.
Let's get it.
(keyboard rattling)
All right, great.
So, I've gone ahead and put the passage on the left
and the questions we're going through on the right.
So, feel free to take a moment, pause the video,
and come back to us.
I'm gonna go ahead and zoom in on the passage.
So, we have a better read.
So, there's the passage, feel free to pause there,
and then here are the questions.
Great, so right away, let's get right into talking strategy.
For me, I like to maintain the same exact strategy
regardless of what passage I'm working on.
The reason for this is,
I like to have something to come back to.
It kinda boosts my confidence
when I know it my game plan going into test day
and I'm able to repeat that over and over and over
for any type of passage.
For me, the strategy looks like, read the paragraph,
write a quick three to five word summary,
then go on to the next paragraph
and on and on and on.
Doing so provides a little mental check in with me.
After the paragraph, I need to understand what's going on
on a big picture level, not really the detail level
but a big picture level.
And I need to be able to summarize that.
And once I do that, I can say,
"I know this passage and I can go onto the next paragraph."
Oftentimes I find myself reading through an entire passage
and then not understanding something halfway through
and then that ruining the rest of the passage,
and I have to reread the entire passage again.
So, doing this, if we don't understand a paragraph
we can go back and reread it
and make sure that we understand it
before we come back to the entire passage,
and that saves a bunch of time.
But with that, let's talk, first paragraph.
Researchers have discovered that childhood exposure
to secondhand smoke can have detrimental effects
on child's health and development.
Studies have shown that secondhand smoke can,
one, increase adulthood incidence of asthma,
two, decrease dopamine levels during adolescence,
three, affect cognitive processes like decision making,
and four, increase adulthood incidence of cancer.
All right.
So, right away, I always ask myself one question,
what's happening? What's going on?
And so this big picture question
doesn't really rely on details
but what is the summary or the thesis of this paragraph?
And so here, I'm gonna write secondary smoke, right?
Secondhand smoke
four effects, all right?
And remember, I'm not gonna write out all four effects.
This is sort of a roadmap,
if I need to come back to the passage or the paragraph
I will come back to the specific spot
by using my like table of contents.
And so we can go right onto the next paragraph now.
To study the effect of secondhand smoke during childhood
on adult health outcomes,
researchers conducted a longitudinal study
tracking 938 individuals
who lived in homes from age to zero through 10
with guardians who smoked at least
one pack a day of cigarettes
As a control, researchers also recruited 912 individuals
who lived in homes from ages zero to 10
with guardians who did not smoke any cigarettes.
Beginning at the age of 15 through age of 60
the researchers sent a survey to the study participants
to assess any physical or mental health conditions
that the participants had, such as asthma, hypertension,
diabetes, schizophrenia depression, anger issues, or cancer.
All right.
So, the question we ask again, what's happening?
And so here we have some sort of longitudinal study,
so, I always write S to indicate study.
And so here we have
guardians smoking
versus
guardians no smoke, okay?
So, I'm just gonna write no smoke.
Okay?
And so who are we looking at though?
We're looking at individuals who lived zero to 10,
okay?
And then zero to 10 years old.
Okay, so, this is what we're looking at.
We're looking at sort of an experimental time
of zero to 10 year old smoking versus not smoking.
And then the outcomes,
I guess you could write outcomes right here.
But something simple,
remember, the only person that's reading this,
is gonna be you.
So, feel free to use symbols,
abbreviations, whatever you want
to make it as seamless as possible to understand
and as quickly as possible to write down.
And so with that, we'll go on to the right next
right to next paragraph.
In the group that experienced secondhand smoke,
researchers found in higher incidents
of all seven physical and mental health conditions.
The greatest difference between the two groups
was found in the incidence of asthma.
54% of the individuals in the group
that experienced secondhand smoke
developed some form of asthma by the age of 60
compared to the 23% of the control group individuals.
Researchers also found that individuals
in the secondhand smoke condition
developed schizophrenia by the age of 60,
at a higher percentage than control group individuals.
All right.
So here what's happening?
We have our same thing, our quick summary,
outcome
and then we're gonna have asthma and schizophrenia.
So, I'll just write it like secondary
asthma
plus schiz
greater,
okay?
So, however you wanna write it
just indicating that these two sort of outcomes
are increased in the secondary smoke conditions.
All right, final paragraph.
In that follow-up investigation,
researchers decided to broaden the scope of the study
to analyze socioeconomic factors,
using average household income
and neighborhood public house school funding
as a proxy for SES,
researchers found that low SES individuals
had poor health outcomes
irrespective of secondhand smoke during childhood.
All right, so exactly what's happening here?
We're gonna write a quick summary about SES
impact health
outcomes.
Okay?
And so we can come back to that paragraph,
if a question asks about, ask about socioeconomic factors
or socioeconomic status but for now we have done it.
We have written our summary.
We have a good understanding
of the entire structure of this passage.
And we can go right into question number one
A researcher points out that there is a difference
in the size of the secondhand smoke group
and the control group,
which would invalidate the results of the study.
This concern is, a, valid
because the sample size must be equal
in order to achieve statistical significance.
B, valid because these unequal sample sizes
will produce bias.
C, invalid because the difference of 26 individuals
for two large sample sizes will not be significant.
D, invalid because statistical significance
is not based on sample size.
All right.
So right away, we have a question
that's asking about validity vs invalidity.
So, valid means, does the experiment actually test
and qualify or quantify exactly what we want it to?
Does this whatever significant differences is,
is it a valid significant differences
based on our experimental setup
does it make, does it actually like work?
And so here, they're talking about
the difference in the size, right?
Of the secondhand smoke.
So, let's go back to our experimental setup
and see the difference of the size.
So, here where's our experimental setup.
We started talking about it in the second paragraph, right?
That's why I have the S right there.
So, it says there's 938 individuals who smoked
and then 912 individuals who did not smoke.
So, we're looking at a difference of 938
versus 912.
Okay, so right away, I want you to think
of any experiments you've read about or seen
in a study, or journal, whatever.
Usually these types of numbers, 900, thousands, right?
These are large sample sizes.
So, we're not always gonna be too concerned
with any small differences in number, right?
938 is pretty close to 912.
So right away, we're thinking, oh, yeah
you're never gonna have a perfectly equal number
of patients in a longitudinal study, right?
The groups might vary a little bit, whether
it's based on the experimental setup, attrition,
whatever, right?
So 938 versus 912, we have a large enough sample size
and the difference is small enough, right?
Now, let's imagine if this was like 50 versus 10, right?
Now we have a much smaller sample size, sample size
and the difference is like roughly 40
but this is an incredibly stronger difference
compared to the 938 versus 912, right?
40 in comparison to 10 and 50 versus 912 and 938, right?
You can see that proportion of difference
to like what the sample size is
matters, right?
And so this, in this case, we'd say this is invalid,
but this is valid.
And that's kinda just a judgment call type thing.
And as you get more and more comfortable
with experimental designs
you should be able to help make this judgment call.
All right.
So right away, I'm thinking
that we can eliminate answer choice, a, right?
Because we know sample sizes don't have to be equal, right?
For a statistical significance.
We've seen studies where
you will have different numbers of samples.
So, we can eliminate that.
B, valid because the unequal sample size it'll produce bias.
We can eliminate that as well
because we said we have a large enough sample size
and the difference is so small comparatively
that if any bias is produced it will be such a small margin
that it will not affect it.
So, C, invalid because the difference of 26 individuals
for two large sample sizes will not be significant, right?
This is making sense, right?
This is exactly what we said.
We have 26 individuals that are different
but the sample sizes are so large
that we don't have to worry about it.
So, C, is looking like a pretty good answer.
So, we'll mark that off.
And then D, invalid because statistical significance
is not based on sample size.
This is also not true.
The statistical significance is based on sample size.
If you've heard of anything called a power analysis
or effect size, these are statistical terms
that you don't really need to understand in depth
for the MCAT
but are very, very important in determining
the level of statistical significance.
And so we can eliminate d even though it is invalid
the sort of concern, the justification is wrong.
So, we can stick with c as our answer choice.
And we're on to question number two.
All right.
Question number two,
which of the following
most likely explains the increased incidence
of schizophrenia in the secondhand smoke group?
Is it a, the dopamine hypothesis,
b, the serotonin hypothesis,
c, the acetylcholine hypothesis,
d, the epinephrine hypothesis?
All right.
So, right away, we need to ask ourselves,
what is so associated with schizophrenia?
What neurotransmitter is associated with it?
And right away we should think from our content review phase
schizophrenia is associated with dopamine levels.
So, a dopamine imbalance
caused by increased dopamine levels in the brain
is often associated with increases
of schizophrenia incidents.
And so right away, based on this fact,
we can pick, a, as our answer.
But let's go through the other three.
So, epinephrine and acetylcholine
are not usually talked about as a hypothesis of any disease
but serotonin is the serotonin hypothesis of depression,
right?
When we have decreased levels of serotonin
we're gonna have increased levels of depression prevalence.
And so we can eliminate, b,
since serotonin is talking about depression
and in this case we're talking about schizophrenia, right?
And so these are two very, very important hypotheses
that are dealing with mental illness
but just have a understanding
that schizophrenia is associated with dopamine
and depression is associated with serotonin.
And right away we can go onto question number three.
All right.
In a new study, researchers discovered
that individuals with low SES experience
experience worse health outcomes than individuals high SES.
This result is explained by which of the following?
Is it, a, gender inequality, b, food deserts,
c, socioeconomic gradient of health, or d, epidemiology?
All right.
So right away we can understand
what we're looking for, right?
Low SES experience versus individuals with high SES
and what is explaining this, right?
And so right away, we have good answer choices of words
that will see over and over again on the MCAT
psych soc section, right?
My one piece of advice
is to always understand every single term
that comes up in the answer choices,
even if it's not the right answer choice,
especially on psych soc
because they pull from a pool of terms
that you need to have a mastery of.
So, let's go one by one, through these terms.
Gender inequality is differences associated
with success or ability to thrive,
ability to earn associated with gender.
So, this is basically gendered,
gendered differences
in
work,
life,
et cetera,
harming.
Okay, food deserts are when you're in an area
without an adequate supply of healthy, fresh food.
And so this is a term that you'll see over and over again
especially as we relate to obesity rates, right?
Obesity rates are higher in areas of food deserts.
So, food deserts are areas
without access
to healthy foods,
grocery stores
slash produce, right?
So, all of these are indicative of food deserts.
C, socioeconomic gradient of health.
This is the combined differences
of socioeconomics affecting health.
So, differences
in health
associated
with
SES, right?
So, as we decrease our sort of income
or money or socioeconomic class
our health is also gonna decrease, right?
So, decrease SES
results in
decrease health.
And then epidemiology, the study of disease,
the study of human disease and how it spreads, right?
And so right away having this understanding
is very, very important of all these terms, right?
And so in this case, we're looking at SES experience
health at worse health outcomes compared to high SES, right?
And so what's gonna explain that
that is, c, the socioeconomic gradient of health
is gonna be what defines exactly this, right?
Increased health outcomes are associated with higher wealth,
higher social class, higher access to hospitals
whereas lower health outcomes
are associated with lower socioeconomic class.
And so with that, we've knocked out the three questions
for this psycho soc passage.
But I have a bonus question since it's only three
for a standalone question,
okay?
Researchers find that elderly individuals
are slower at solving logic puzzles compared to young adults
which type of intelligence do elderly individuals
have less of?
Is it, a, crystal, b, fluid, c, unrealized, or d, hidden?
So, this is another thing, right?
We wanna understand the terms
like I said in the previous question,
even if it's not the right answer choice.
So, crystallized intelligent
is what I call wisdom, right?
It's that knowledge that you build up over time
you sort of have it built up
like facts, information,
facts, info,
right? It's like the cold, hard wisdom
or brain power that we think of
whether we can memorize things
or whether we have a lot of information in our head.
Fluid intelligence is kinda like the more adaptive, right?
We think fluid is moving.
Fluid intelligence is the adaptive thinking.
Whether we can solve problems.
I like to think of this
as
the ability to solve a Rubik's cube kinda,
like, sure you might have
basic understanding of how to do it
but you'll have different positions
where you need to adapt and think and all of that, right?
So, you gotta be able to go with the flow and think.
So, this is an adaptive thinking sort of intelligence.
And unrealized and hidden intelligence
aren't even terms that we know
they're not associated with any types of intelligence
that we've studied, so, we can eliminate c and d.
So, now the question is asking
which type of intelligence do elderly people have less of?
So, elderly,
less,
okay?
So, the understanding is that elderly people
will have a greater amount of wisdom, right?
They'll have more information in their head.
They'll have more facts, all of that,
but they'll be less able to solve these problems
that require adaptive thinking or able to think on the spot
or think on the move, right?
And so they will have less of fluid intelligence, right?
Elderly people are not gonna be able to think on the spot
as well as a younger person.
And so with that, we have knocked out four questions,
great work team, crushed it.
All right, great work team.
We crushed another psych soc passage,
kudos for you for getting it done.
A lot of great information from statistical tests
to the hypotheses of depression and schizophrenia
to types of intelligence.
So, great job getting it done.
If you like this video, give us a like down below
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Additionally, check out our 528 strategy series from Vikram.
Some super, super helpful tips and tricks
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Happy studying and let's get it.
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