WEBVTT

00:00:00.000 --> 00:00:02.411
Can week-old pizza cause 
psychedelic hallucinations?

00:00:02.411 --> 00:00:03.596
Does coffee makes you smarter

00:00:03.596 --> 00:00:05.658
or does it just make you 
do dumb stuff faster?

00:00:05.658 --> 00:00:06.690
Like much much of psychology itself,

00:00:06.690 --> 00:00:08.810
questions like this can seem pretty intuitive.

00:00:08.810 --> 00:00:11.571
I mean, people may not be the easiest 
organisms to understand, but...

00:00:11.571 --> 00:00:13.111
You're a person, right?

00:00:13.111 --> 00:00:16.891
So you must be qualified to draw, like,
some conclusions about other people,

00:00:16.891 --> 00:00:18.105
and what makes them tick.

00:00:18.105 --> 00:00:21.412
But it's important to realize that 
your intuition isn't always right.

00:00:21.412 --> 00:00:24.701
In fact, sometimes it is exactly wrong,

00:00:24.701 --> 00:00:28.195
and we tend to grossly underestimate 
the dangers of false intuition.

00:00:28.195 --> 00:00:31.277
If you have some idea about a person and
their behavior that turns out to be right,

00:00:31.277 --> 00:00:34.212
that reinforces your trust in your intuition.

00:00:34.212 --> 00:00:35.329
Like if I warned my buddy Bob

00:00:35.329 --> 00:00:38.332
against eating the deep-dish pizza 
that's been in the fridge for the past week,

00:00:38.332 --> 00:00:40.649
but he eats it anyway and
soon starts to wig out,

00:00:40.649 --> 00:00:43.219
I'm gonna say: "Dude, I told you so!"

00:00:43.219 --> 00:00:45.196
But if I'm wrong, and he's totally fine,

00:00:45.196 --> 00:00:48.473
I'll probably won't even
think about it ever again.

00:00:48.473 --> 00:00:52.445
This is known as hindsight bias, 
or the "I-knew-it-all-along" phenomenon.

00:00:52.445 --> 00:00:54.634
This doesn't mean that common sense is wrong,

00:00:54.634 --> 00:00:56.331
it just mean that our intuitive sense

00:00:56.331 --> 00:01:00.143
more easily describes what JUST happened 
than what WILL happen in the future.

00:01:00.143 --> 00:01:02.666
Another reason you can't 
blindly trust your intuition

00:01:02.666 --> 00:01:05.120
is your natural tendency toward overconfidence.

00:01:05.120 --> 00:01:09.461
Sometimes, you just really, really 
feel like you're right about people

00:01:09.461 --> 00:01:11.945
when actually, you're really, really wrong!

00:01:11.945 --> 00:01:13.112
We've all been there...

00:01:13.112 --> 00:01:15.654
We also tend to perceive order in random events,

00:01:15.654 --> 00:01:17.437
which can lead to false assumptions.

00:01:17.437 --> 00:01:19.526
For example, if you flip a coin five times,

00:01:19.526 --> 00:01:25.018
you have equal chances of getting all tails 
as you do getting alternating heads and tails,

00:01:25.018 --> 00:01:28.821
but we see the series of five tails 
as something unusual, as a streak,

00:01:28.821 --> 00:01:33.138
and thus, giving that result some kind of 
meaning that it very definitely does not have.

00:01:33.138 --> 00:01:35.432
That is why we have the methods and safeguards

00:01:35.432 --> 00:01:38.757
of psychological research and experimentation,

00:01:38.757 --> 00:01:41.533
and the glorious process of scientific inquiry.

00:01:41.533 --> 00:01:43.623
They help us to get around these problems

00:01:43.623 --> 00:01:48.184
and basically, save the study of our 
minds from the stupidity of our minds.

00:01:48.184 --> 00:01:52.523
So I hope that it won't be a spoiler if I 
tell you now that pizza won't make you trip,

00:01:52.523 --> 00:01:55.999
and coffee doesn't make you smart. Sorry.

00:01:55.999 --> 00:01:59.639
[on-screen animations and 
ribbons of science sentences]

00:02:03.679 --> 00:02:05.946
Title screen says "Episode 2: 
Research & Experimentation."

00:02:05.946 --> 00:02:07.683
In most ways, psychological research

00:02:07.683 --> 00:02:10.440
is no different than in the 
other scientific discipline.

00:02:10.440 --> 00:02:14.830
Like, step one is always figuring out how to 
ask general questions about your subject,

00:02:14.830 --> 00:02:18.420
and turn them into measurable, 
testable propositions.

00:02:18.420 --> 00:02:21.354
This is called "operationalizing" your questions.

00:02:21.354 --> 00:02:22.708
So you know how the scientific method works.

00:02:22.708 --> 00:02:24.965
It starts with a question and a theory.

00:02:24.965 --> 00:02:28.153
And I don't mean theory in the 
sense of like, a hunch that says

00:02:28.153 --> 00:02:30.489
"a quad-shot of espresso 
makes you think better."

00:02:30.489 --> 00:02:36.107
Instead, in science, a theory is what explains 
and organizes lots of different observations

00:02:36.107 --> 00:02:37.308
and predicts outcomes.

00:02:37.308 --> 00:02:39.383
And when you come up 
with a testable prediction,

00:02:39.383 --> 00:02:40.788
that's your hypothesis.

00:02:40.788 --> 00:02:42.771
Once your theory and hypothesis are in place

00:02:42.771 --> 00:02:45.675
you need a clear and common 
language to report them with.

00:02:45.675 --> 00:02:47.702
So, for example,
defining exactly what you mean

00:02:47.702 --> 00:02:50.204
by "thinking better" with 
your espresso hypothesis

00:02:50.204 --> 00:02:53.107
would allow other researchers 
to replicate the experiment.

00:02:53.107 --> 00:02:55.152
And replication is key.

00:02:55.152 --> 00:02:57.722
You can watch a person exhibit 
a certain behavior once,

00:02:57.722 --> 00:02:59.514
and it won't prove very much.

00:02:59.514 --> 00:03:03.641
But if you keep getting consistent results 
even as you change subjects or situations,

00:03:03.641 --> 00:03:05.117
you're probably onto something.

00:03:05.117 --> 00:03:08.559
This is a problem with one popular
type of psychological research:

00:03:08.559 --> 00:03:11.972
case studies, which take an 
in-depth look at one individual.

00:03:11.972 --> 00:03:13.976
Case studies can sometimes be misleading,

00:03:13.976 --> 00:03:16.432
because by their nature, 
they can't be replicated;

00:03:16.432 --> 00:03:18.428
so, they run the risk of over-generalizing.

00:03:18.428 --> 00:03:20.974
Still, they're good at showing 
us what CAN happen,

00:03:20.974 --> 00:03:24.822
and end up framing questions for more 
extensive and generalizable studies.

00:03:24.822 --> 00:03:26.301
They're also often memorable

00:03:26.301 --> 00:03:30.384
and a great story-telling device psychologists
use to observe and describe behavior.

00:03:30.384 --> 00:03:34.494
Like, say, the smell of coffee makes 
Carl suddenly anxious and irritable.

00:03:34.494 --> 00:03:37.358
That obviously doesn't mean that it 
has the same effect on everyone.

00:03:37.358 --> 00:03:41.179
In fact, Carl has terrible memories
associated with that smell,

00:03:41.179 --> 00:03:43.277
and so his case is actually quite rare.

00:03:43.277 --> 00:03:44.032
Poor Carl... :(

00:03:44.032 --> 00:03:45.808
But, you will still have to look at lots of

00:03:45.808 --> 00:03:47.895
other cases to determine that conclusively.

00:03:47.895 --> 00:03:51.685
Another popular method of psychological 
research is naturalistic observation,

00:03:51.685 --> 00:03:55.493
where researchers simply watch 
behavior in a natural environment,

00:03:55.493 --> 00:03:57.912
whether that's chimps poking 
anthills in the jungle,

00:03:57.912 --> 00:04:01.160
kids clowning in a classroom, 
or drunk dudes yelling at soccer games.

00:04:01.160 --> 00:04:03.852
The idea is to let the subjects 
just "do their thing"

00:04:03.852 --> 00:04:06.451
without trying to manipulate 
or control the situation.

00:04:06.451 --> 00:04:08.732
So yeah, basically just spying on people.

00:04:08.732 --> 00:04:12.456
Like case studies, naturalistic observations 
are great at describing behavior,

00:04:12.456 --> 00:04:14.819
but they're very limited in explaining it.

00:04:14.819 --> 00:04:18.435
Psychologists can also collect behavioral
data using surveys or interviews,

00:04:18.435 --> 00:04:21.379
asking people to report 
their opinions and behaviors.

00:04:21.379 --> 00:04:24.426
Sexuality researcher Alfred Kinsey
famously used this technique

00:04:24.426 --> 00:04:27.580
when he surveyed thousands of men 
and women on their sexual history

00:04:27.580 --> 00:04:28.914
and published his findings.

00:04:28.914 --> 00:04:32.668
in a pair of revolutionary texts: 
"Sexual Behavior in the Human Male"

00:04:32.668 --> 00:04:34.834
and "Sexual Behavior in the Human Female."

00:04:34.834 --> 00:04:36.852
Surveys are a great way to access people's

00:04:36.852 --> 00:04:38.760
consciously held attitudes and beliefs,

00:04:38.760 --> 00:04:43.498
but how to ask the questions can be tricky;
subtle word choices can influence results.

00:04:43.498 --> 00:04:46.552
For example, more forceful 
words like "ban" or "censor"

00:04:46.552 --> 00:04:49.606
may elicit different reactions
than "limit" or "not allow."

00:04:49.606 --> 00:04:53.261
Asking: "Do you believe in space aliens?" 
is a much different question than

00:04:53.261 --> 00:04:56.080
"Do you think that there is intelligent 
life somewhere else in the universe?"

00:04:56.080 --> 00:04:59.341
It's the same question, but in the first, 
the subject may assume that you mean

00:04:59.341 --> 00:05:01.794
"aliens visiting the Earth 
and making crop circles

00:05:01.794 --> 00:05:03.697
and abducting people and poking them."

00:05:03.697 --> 00:05:05.677
And if how you phrase surveys is important,

00:05:05.677 --> 00:05:07.332
so is who you ask.

00:05:07.332 --> 00:05:10.543
I could ask a room full of students at a pacifist 
club what they think about arms control,

00:05:10.543 --> 00:05:13.896
but the results wouldn't be a representative 
measure of where the students stand,

00:05:13.896 --> 00:05:16.640
because there's a pretty clear
sampling bias at work here.

00:05:16.640 --> 00:05:20.125
To fairly represent a population,
I'd need to give a random sample

00:05:20.125 --> 00:05:21.973
where all members of the target group

00:05:21.973 --> 00:05:25.995
(in this case, students) had an equal chance
of being selected to answer the question.

00:05:25.995 --> 00:05:27.905
So, once you've described behavior

00:05:27.905 --> 00:05:30.496
with surveys, case studies, 
or naturalistic observation,

00:05:30.496 --> 00:05:34.357
you can start making sense out of it 
and even predict future behavior.

00:05:34.357 --> 00:05:35.568
One way to do that is to look at

00:05:35.568 --> 00:05:39.462
how one trait or behavior is related 
to another or how they correlate.

00:05:39.462 --> 00:05:41.120
So let's get back to my buddy Bob,

00:05:41.120 --> 00:05:44.419
who seems to think that his refrigerator
is actually some kind of time machine

00:05:44.419 --> 00:05:46.241
that can preserve food indefinitely.

00:05:46.241 --> 00:05:48.962
Let's say that Bob is just tucked into 
a lunch of questionable leftovers...

00:05:48.962 --> 00:05:51.687
Pizza that may very well have 
had a little bit of fungus on it...

00:05:51.687 --> 00:05:55.402
But he was hungry. And lazy.
And so he doused it in sriracha.

00:05:55.402 --> 00:05:57.342
Suddenly, he starts seeing things.

00:05:57.342 --> 00:05:59.520
Green armadillos with laser-beam-eyes.

00:05:59.520 --> 00:06:02.910
From here we can deduce that eating 
unknown fungus predicts hallucination.

00:06:02.910 --> 00:06:06.617
That's a correlation; 
but correlation is not causation.

00:06:06.617 --> 00:06:10.758
Yes, it makes sense that eating questionable 
fungus would cause hallucinations,

00:06:10.758 --> 00:06:14.223
but it's possible that Bob was already 
on the verge of a psychotic episode

00:06:14.223 --> 00:06:16.691
and those fuzzy left-overs were actually benign!

00:06:16.691 --> 00:06:19.689
Or, they could be an entirely 
different factor involved,

00:06:19.689 --> 00:06:21.658
like maybe he hadn't slept in 72 hours

00:06:21.658 --> 00:06:23.799
or had an intense migraine coming on,

00:06:23.799 --> 00:06:26.279
and one of those factors 
caused his hallucinations.

00:06:26.279 --> 00:06:28.369
It's tempting to draw 
conclusions from correlations,

00:06:28.369 --> 00:06:30.114
but it's super important to remember

00:06:30.114 --> 00:06:34.159
that correlations predict the POSSIBILITY 
of a cause-and-effect relationships;

00:06:34.159 --> 00:06:35.821
they can not prove them.

00:06:35.821 --> 00:06:38.827
So we've talked about how to describe 
behavior without manipulating it,

00:06:38.827 --> 00:06:41.959
and how to make connections and 
predictions from those findings,

00:06:41.959 --> 00:06:43.595
but that can only take you so far.

00:06:43.595 --> 00:06:46.445
To really get to the bottom of 
cause-and-effect behaviors,

00:06:46.445 --> 00:06:48.323
you're gonna have to start experimenting.

00:06:48.323 --> 00:06:51.184
Experiments allow investigators
to isolate different effects

00:06:51.184 --> 00:06:53.494
by manipulating an independent variable

00:06:53.494 --> 00:06:57.214
and keeping all other variables constant
(or as constant as you can).

00:06:57.214 --> 00:06:59.643
This means that they need at least two groups:

00:06:59.643 --> 00:07:02.354
the experimental group, which is 
gonna get "messed with";

00:07:02.354 --> 00:07:04.816
and the control group, which is 
not going to get "messed with".

00:07:04.816 --> 00:07:06.547
Just as surveys use random samples,

00:07:06.547 --> 00:07:09.813
experimental researchers need to 
randomly assign participants to each group

00:07:09.813 --> 00:07:14.482
to minimize potential confounding variables 
or outside factors that may skew the results.

00:07:14.482 --> 00:07:16.794
You don't want all grumpy teenagers in one group

00:07:16.794 --> 00:07:19.047
and wealthy Japanese servers
in the other; they gotta mingle.

00:07:19.047 --> 00:07:24.185
Sometimes one or both groups are not
informed about what's actually being tested.

00:07:24.185 --> 00:07:27.285
For example, researchers can test
how substances affect people

00:07:27.285 --> 00:07:30.027
by comparing their effects to
placebos, or inert substances.

00:07:30.027 --> 00:07:32.453
And often, the researchers themselves

00:07:32.453 --> 00:07:35.164
don't know which group is experimental
and which is control,

00:07:35.164 --> 00:07:39.031
so they don't unintentionally influence
the results through their own behavior.

00:07:39.031 --> 00:07:41.044
In which case, it's called...

00:07:41.044 --> 00:07:43.335
You guessed it! A double-blind procedure.

00:07:43.335 --> 00:07:46.178
So let's put these ideas into practice
in our own little experiment.

00:07:46.178 --> 00:07:48.698
Like all good work, it starts with a question.

00:07:48.698 --> 00:07:51.003
So the other day, my friend 
Bernice and I were debating.

00:07:51.003 --> 00:07:53.531
We were debating coffee 
and its effect on the brain.

00:07:53.531 --> 00:07:56.882
Personally, she's convinced that coffee 
helps her focus and think better,

00:07:56.882 --> 00:08:00.294
but I get all jittery, like a caged meerkat 
and can't focus on anything.

00:08:00.294 --> 00:08:03.806
And because we know that over-confidence 
can lead to belief that are not true,

00:08:03.806 --> 00:08:05.783
we decided to do some critical thinking.

00:08:05.783 --> 00:08:07.422
So let's figure out our question:

00:08:07.422 --> 00:08:10.071
"Do humans solve problems 
faster when given caffeine?"

00:08:10.071 --> 00:08:13.086
Now we've got to boil that down 
into a testable prediction.

00:08:13.086 --> 00:08:16.941
Remember: Keep it clear, simple, and 
eloquent so that it can be replicated.

00:08:16.941 --> 00:08:20.002
"Caffeine makes me smarter" 
is not a great hypothesis.

00:08:20.002 --> 00:08:21.774
A better one would be, say...

00:08:21.774 --> 00:08:26.941
"Adults humans given caffeine will navigate 
a maze faster than humans not given caffeine."

00:08:26.941 --> 00:08:30.852
The caffeine dosage is your independent
variable (the thing that you can change).

00:08:30.852 --> 00:08:32.261
So, you'll need some coffee.

00:08:32.261 --> 00:08:34.118
Your result or dependent variable--

00:08:34.118 --> 00:08:37.125
(the thing that depends on 
the thing that you can change),

00:08:37.125 --> 00:08:40.279
is going to be the speed at which the 
subject navigates this giant corn maze.

00:08:40.279 --> 00:08:42.794
Go out on the street, wrangle up a 
bunch of different kinds of people,

00:08:42.794 --> 00:08:44.986
and randomly assign them 
into three different groups.

00:08:44.986 --> 00:08:48.132
Also at this point, the American 
Psychological Association suggests

00:08:48.132 --> 00:08:50.972
that you acquire everyone's 
informed consent to participate.

00:08:50.972 --> 00:08:53.708
You don't want to force anyone
to be in your experiment,

00:08:53.708 --> 00:08:55.285
no matter how cool you think it is.

00:08:55.285 --> 00:08:58.184
So the control group gets 
a placebo (in this case, decaf).

00:08:58.184 --> 00:09:00.603
Experimental group 1 gets 
a low dose of caffeine,

00:09:00.603 --> 00:09:02.253
which we'll define at 100mg

NOTE Paragraph

00:09:02.253 --> 00:09:04.595
(just an eye opener, 
like a cup of coffee's worth).

00:09:04.595 --> 00:09:07.411
Experimental group 2 gets 500 mg

00:09:07.411 --> 00:09:10.334
(more than a quad-shot of espresso
dumped in a Red Bull).

00:09:10.334 --> 00:09:12.619
Once you dose everyone, 
turn them loose in the maze

00:09:12.619 --> 00:09:14.803
and wait at the other end with a stopwatch.

00:09:14.803 --> 00:09:18.063
All that's left is to measure your 
results from the three different groups

00:09:18.063 --> 00:09:19.910
and compare them, just to see if 
there were any conclusive results.

00:09:19.910 --> 00:09:21.940
If the highly-dosed folks got through it

00:09:21.940 --> 00:09:23.970
twice as fast as the low dose, placebo groups

00:09:23.970 --> 00:09:25.962
then Bernice's hypothesis was correct

00:09:25.962 --> 00:09:29.043
and she can rub my face in it, 
saying she was right all along,

00:09:29.043 --> 00:09:32.521
but really, that would just be 
the warm flush of hindsight bias

00:09:32.521 --> 00:09:35.493
telling her something she didn't 
really know until we tested it.

00:09:35.493 --> 00:09:38.336
Then, because we've used clear 
language in defining our parameters,

00:09:38.336 --> 00:09:41.443
other curious minds can easily 
replicate this experiment and

00:09:41.443 --> 00:09:43.588
we can eventually pool all the data together,

00:09:43.588 --> 00:09:47.809
and have something solid to say about what
that macchiato was doing to your cognition.

00:09:47.809 --> 00:09:50.732
Or at least the speed at which 
you can run through a maze.

00:09:50.732 --> 00:09:51.702
Science!

00:09:51.702 --> 00:09:54.107
Probably the best tool that you have
for understanding other people.

00:09:54.107 --> 00:09:56.513
Thanks for watching this episode
of Crash Course Psychology!

00:09:56.513 --> 00:09:57.745
If you've paid attention,

00:09:57.745 --> 00:10:00.517
you've learned how to apply the scientific
method to psychological research

00:10:00.517 --> 00:10:05.387
through case studies, naturalistic observation, 
surveys and interviews, and experimentation.

00:10:05.387 --> 00:10:08.850
You've also learned about different 
kinds of bias in experimentation,

00:10:08.850 --> 00:10:11.443
and how research practices help us avoid them.

00:10:11.443 --> 00:10:13.352
Thanks specially to our Subbable subscribers,

00:10:13.352 --> 00:10:15.815
who make this and all of Crash Course possible.

00:10:15.815 --> 00:10:20.255
If you'd like to contribute to help us keep 
Crash Course going and also get awesome perks,

00:10:20.255 --> 00:10:24.559
like an autographed science poster or 
even be animated into an upcoming episode

00:10:24.559 --> 00:10:27.574
go to subbable.com/crashcourse to find out how.

00:10:27.574 --> 00:10:40.885
[Host reads the credits]