0:00:00.000,0:00:02.411
Can week-old pizza cause [br]psychedelic hallucinations?

0:00:02.411,0:00:03.596
Does coffee makes you smarter

0:00:03.596,0:00:05.658
or does it just make you [br]do dumb stuff faster?

0:00:05.658,0:00:06.690
Like much much of psychology itself,

0:00:06.690,0:00:08.810
questions like this can seem pretty intuitive.

0:00:08.810,0:00:11.571
I mean, people may not be the easiest [br]organisms to understand, but...

0:00:11.571,0:00:13.111
You're a person, right?

0:00:13.111,0:00:16.891
So you must be qualified to draw, like,[br]some conclusions about other people,

0:00:16.891,0:00:18.105
and what makes them tick.

0:00:18.105,0:00:21.412
But it's important to realize that [br]your intuition isn't always right.

0:00:21.412,0:00:24.701
In fact, sometimes it is exactly wrong,

0:00:24.701,0:00:28.195
and we tend to grossly underestimate [br]the dangers of false intuition.

0:00:28.195,0:00:31.277
If you have some idea about a person and[br]their behavior that turns out to be right,

0:00:31.277,0:00:34.212
that reinforces your trust in your intuition.

0:00:34.212,0:00:35.329
Like if I warned my buddy Bob

0:00:35.329,0:00:38.332
against eating the deep-dish pizza [br]that's been in the fridge for the past week,

0:00:38.332,0:00:40.649
but he eats it anyway and[br]soon starts to wig out,

0:00:40.649,0:00:43.219
I'm gonna say: "Dude, I told you so!"

0:00:43.219,0:00:45.196
But if I'm wrong, and he's totally fine,

0:00:45.196,0:00:48.473
I'll probably won't even[br]think about it ever again.

0:00:48.473,0:00:52.445
This is known as hindsight bias, [br]or the "I-knew-it-all-along" phenomenon.

0:00:52.445,0:00:54.634
This doesn't mean that common sense is wrong,

0:00:54.634,0:00:56.331
it just mean that our intuitive sense

0:00:56.331,0:01:00.143
more easily describes what JUST happened [br]than what WILL happen in the future.

0:01:00.143,0:01:02.666
Another reason you can't [br]blindly trust your intuition

0:01:02.666,0:01:05.120
is your natural tendency toward overconfidence.

0:01:05.120,0:01:09.461
Sometimes, you just really, really [br]feel like you're right about people

0:01:09.461,0:01:11.945
when actually, you're really, really wrong!

0:01:11.945,0:01:13.112
We've all been there...

0:01:13.112,0:01:15.654
We also tend to perceive order in random events,

0:01:15.654,0:01:17.437
which can lead to false assumptions.

0:01:17.437,0:01:19.526
For example, if you flip a coin five times,

0:01:19.526,0:01:25.018
you have equal chances of getting all tails [br]as you do getting alternating heads and tails,

0:01:25.018,0:01:28.821
but we see the series of five tails [br]as something unusual, as a streak,

0:01:28.821,0:01:33.138
and thus, giving that result some kind of [br]meaning that it very definitely does not have.

0:01:33.138,0:01:35.432
That is why we have the methods and safeguards

0:01:35.432,0:01:38.757
of psychological research and experimentation,

0:01:38.757,0:01:41.533
and the glorious process of scientific inquiry.

0:01:41.533,0:01:43.623
They help us to get around these problems

0:01:43.623,0:01:48.184
and basically, save the study of our [br]minds from the stupidity of our minds.

0:01:48.184,0:01:52.523
So I hope that it won't be a spoiler if I [br]tell you now that pizza won't make you trip,

0:01:52.523,0:01:55.999
and coffee doesn't make you smart. Sorry.

0:01:55.999,0:01:59.639
[on-screen animations and [br]ribbons of science sentences]

0:02:03.679,0:02:05.946
Title screen says "Episode 2: [br]Research & Experimentation."

0:02:05.946,0:02:07.683
In most ways, psychological research

0:02:07.683,0:02:10.440
is no different than in the [br]other scientific discipline.

0:02:10.440,0:02:14.830
Like, step one is always figuring out how to [br]ask general questions about your subject,

0:02:14.830,0:02:18.420
and turn them into measurable, [br]testable propositions.

0:02:18.420,0:02:21.354
This is called "operationalizing" your questions.

0:02:21.354,0:02:22.708
So you know how the scientific method works.

0:02:22.708,0:02:24.965
It starts with a question and a theory.

0:02:24.965,0:02:28.153
And I don't mean theory in the [br]sense of like, a hunch that says

0:02:28.153,0:02:30.489
"a quad-shot of espresso [br]makes you think better."

0:02:30.489,0:02:36.107
Instead, in science, a theory is what explains [br]and organizes lots of different observations

0:02:36.107,0:02:37.308
and predicts outcomes.

0:02:37.308,0:02:39.383
And when you come up [br]with a testable prediction,

0:02:39.383,0:02:40.788
that's your hypothesis.

0:02:40.788,0:02:42.771
Once your theory and hypothesis are in place

0:02:42.771,0:02:45.675
you need a clear and common [br]language to report them with.

0:02:45.675,0:02:47.702
So, for example,[br]defining exactly what you mean

0:02:47.702,0:02:50.204
by "thinking better" with [br]your espresso hypothesis

0:02:50.204,0:02:53.107
would allow other researchers [br]to replicate the experiment.

0:02:53.107,0:02:55.152
And replication is key.

0:02:55.152,0:02:57.722
You can watch a person exhibit [br]a certain behavior once,

0:02:57.722,0:02:59.514
and it won't prove very much.

0:02:59.514,0:03:03.641
But if you keep getting consistent results [br]even as you change subjects or situations,

0:03:03.641,0:03:05.117
you're probably onto something.

0:03:05.117,0:03:08.559
This is a problem with one popular[br]type of psychological research:

0:03:08.559,0:03:11.972
case studies, which take an [br]in-depth look at one individual.

0:03:11.972,0:03:13.976
Case studies can sometimes be misleading,

0:03:13.976,0:03:16.432
because by their nature, [br]they can't be replicated;

0:03:16.432,0:03:18.428
so, they run the risk of over-generalizing.

0:03:18.428,0:03:20.974
Still, they're good at showing [br]us what CAN happen,

0:03:20.974,0:03:24.822
and end up framing questions for more [br]extensive and generalizable studies.

0:03:24.822,0:03:26.301
They're also often memorable

0:03:26.301,0:03:30.384
and a great story-telling device psychologists[br]use to observe and describe behavior.

0:03:30.384,0:03:34.494
Like, say, the smell of coffee makes [br]Carl suddenly anxious and irritable.

0:03:34.494,0:03:37.358
That obviously doesn't mean that it [br]has the same effect on everyone.

0:03:37.358,0:03:41.179
In fact, Carl has terrible memories[br]associated with that smell,

0:03:41.179,0:03:43.277
and so his case is actually quite rare.

0:03:43.277,0:03:44.032
Poor Carl... :(

0:03:44.032,0:03:45.808
But, you will still have to look at lots of

0:03:45.808,0:03:47.895
other cases to determine that conclusively.

0:03:47.895,0:03:51.685
Another popular method of psychological [br]research is naturalistic observation,

0:03:51.685,0:03:55.493
where researchers simply watch [br]behavior in a natural environment,

0:03:55.493,0:03:57.912
whether that's chimps poking [br]anthills in the jungle,

0:03:57.912,0:04:01.160
kids clowning in a classroom, [br]or drunk dudes yelling at soccer games.

0:04:01.160,0:04:03.852
The idea is to let the subjects [br]just "do their thing"

0:04:03.852,0:04:06.451
without trying to manipulate [br]or control the situation.

0:04:06.451,0:04:08.732
So yeah, basically just spying on people.

0:04:08.732,0:04:12.456
Like case studies, naturalistic observations [br]are great at describing behavior,

0:04:12.456,0:04:14.819
but they're very limited in explaining it.

0:04:14.819,0:04:18.435
Psychologists can also collect behavioral[br]data using surveys or interviews,

0:04:18.435,0:04:21.379
asking people to report [br]their opinions and behaviors.

0:04:21.379,0:04:24.426
Sexuality researcher Alfred Kinsey[br]famously used this technique

0:04:24.426,0:04:27.580
when he surveyed thousands of men [br]and women on their sexual history

0:04:27.580,0:04:28.914
and published his findings.

0:04:28.914,0:04:32.668
in a pair of revolutionary texts: [br]"Sexual Behavior in the Human Male"

0:04:32.668,0:04:34.834
and "Sexual Behavior in the Human Female."

0:04:34.834,0:04:36.852
Surveys are a great way to access people's

0:04:36.852,0:04:38.760
consciously held attitudes and beliefs,

0:04:38.760,0:04:43.498
but how to ask the questions can be tricky;[br]subtle word choices can influence results.

0:04:43.498,0:04:46.552
For example, more forceful [br]words like "ban" or "censor"

0:04:46.552,0:04:49.606
may elicit different reactions[br]than "limit" or "not allow."

0:04:49.606,0:04:53.261
Asking: "Do you believe in space aliens?" [br]is a much different question than

0:04:53.261,0:04:56.080
"Do you think that there is intelligent [br]life somewhere else in the universe?"

0:04:56.080,0:04:59.341
It's the same question, but in the first, [br]the subject may assume that you mean

0:04:59.341,0:05:01.794
"aliens visiting the Earth [br]and making crop circles

0:05:01.794,0:05:03.697
and abducting people and poking them."

0:05:03.697,0:05:05.677
And if how you phrase surveys is important,

0:05:05.677,0:05:07.332
so is who you ask.

0:05:07.332,0:05:10.543
I could ask a room full of students at a pacifist [br]club what they think about arms control,

0:05:10.543,0:05:13.896
but the results wouldn't be a representative [br]measure of where the students stand,

0:05:13.896,0:05:16.640
because there's a pretty clear[br]sampling bias at work here.

0:05:16.640,0:05:20.125
To fairly represent a population,[br]I'd need to give a random sample

0:05:20.125,0:05:21.973
where all members of the target group

0:05:21.973,0:05:25.995
(in this case, students) had an equal chance[br]of being selected to answer the question.

0:05:25.995,0:05:27.905
So, once you've described behavior

0:05:27.905,0:05:30.496
with surveys, case studies, [br]or naturalistic observation,

0:05:30.496,0:05:34.357
you can start making sense out of it [br]and even predict future behavior.

0:05:34.357,0:05:35.568
One way to do that is to look at

0:05:35.568,0:05:39.462
how one trait or behavior is related [br]to another or how they correlate.

0:05:39.462,0:05:41.120
So let's get back to my buddy Bob,

0:05:41.120,0:05:44.419
who seems to think that his refrigerator[br]is actually some kind of time machine

0:05:44.419,0:05:46.241
that can preserve food indefinitely.

0:05:46.241,0:05:48.962
Let's say that Bob is just tucked into [br]a lunch of questionable leftovers...

0:05:48.962,0:05:51.687
Pizza that may very well have [br]had a little bit of fungus on it...

0:05:51.687,0:05:55.402
But he was hungry. And lazy.[br]And so he doused it in sriracha.

0:05:55.402,0:05:57.342
Suddenly, he starts seeing things.

0:05:57.342,0:05:59.520
Green armadillos with laser-beam-eyes.

0:05:59.520,0:06:02.910
From here we can deduce that eating [br]unknown fungus predicts hallucination.

0:06:02.910,0:06:06.617
That's a correlation; [br]but correlation is not causation.

0:06:06.617,0:06:10.758
Yes, it makes sense that eating questionable [br]fungus would cause hallucinations,

0:06:10.758,0:06:14.223
but it's possible that Bob was already [br]on the verge of a psychotic episode

0:06:14.223,0:06:16.691
and those fuzzy left-overs were actually benign!

0:06:16.691,0:06:19.689
Or, they could be an entirely [br]different factor involved,

0:06:19.689,0:06:21.658
like maybe he hadn't slept in 72 hours

0:06:21.658,0:06:23.799
or had an intense migraine coming on,

0:06:23.799,0:06:26.279
and one of those factors [br]caused his hallucinations.

0:06:26.279,0:06:28.369
It's tempting to draw [br]conclusions from correlations,

0:06:28.369,0:06:30.114
but it's super important to remember

0:06:30.114,0:06:34.159
that correlations predict the POSSIBILITY [br]of a cause-and-effect relationships;

0:06:34.159,0:06:35.821
they can not prove them.

0:06:35.821,0:06:38.827
So we've talked about how to describe [br]behavior without manipulating it,

0:06:38.827,0:06:41.959
and how to make connections and [br]predictions from those findings,

0:06:41.959,0:06:43.595
but that can only take you so far.

0:06:43.595,0:06:46.445
To really get to the bottom of [br]cause-and-effect behaviors,

0:06:46.445,0:06:48.323
you're gonna have to start experimenting.

0:06:48.323,0:06:51.184
Experiments allow investigators[br]to isolate different effects

0:06:51.184,0:06:53.494
by manipulating an independent variable

0:06:53.494,0:06:57.214
and keeping all other variables constant[br](or as constant as you can).

0:06:57.214,0:06:59.643
This means that they need at least two groups:

0:06:59.643,0:07:02.354
the experimental group, which is [br]gonna get "messed with";

0:07:02.354,0:07:04.816
and the control group, which is [br]not going to get "messed with".

0:07:04.816,0:07:06.547
Just as surveys use random samples,

0:07:06.547,0:07:09.813
experimental researchers need to [br]randomly assign participants to each group

0:07:09.813,0:07:14.482
to minimize potential confounding variables [br]or outside factors that may skew the results.

0:07:14.482,0:07:16.794
You don't want all grumpy teenagers in one group

0:07:16.794,0:07:19.047
and wealthy Japanese servers[br]in the other; they gotta mingle.

0:07:19.047,0:07:24.185
Sometimes one or both groups are not[br]informed about what's actually being tested.

0:07:24.185,0:07:27.285
For example, researchers can test[br]how substances affect people

0:07:27.285,0:07:30.027
by comparing their effects to[br]placebos, or inert substances.

0:07:30.027,0:07:32.453
And often, the researchers themselves

0:07:32.453,0:07:35.164
don't know which group is experimental[br]and which is control,

0:07:35.164,0:07:39.031
so they don't unintentionally influence[br]the results through their own behavior.

0:07:39.031,0:07:41.044
In which case, it's called...

0:07:41.044,0:07:43.335
You guessed it! A double-blind procedure.

0:07:43.335,0:07:46.178
So let's put these ideas into practice[br]in our own little experiment.

0:07:46.178,0:07:48.698
Like all good work, it starts with a question.

0:07:48.698,0:07:51.003
So the other day, my friend [br]Bernice and I were debating.

0:07:51.003,0:07:53.531
We were debating coffee [br]and its effect on the brain.

0:07:53.531,0:07:56.882
Personally, she's convinced that coffee [br]helps her focus and think better,

0:07:56.882,0:08:00.294
but I get all jittery, like a caged meerkat [br]and can't focus on anything.

0:08:00.294,0:08:03.806
And because we know that over-confidence [br]can lead to belief that are not true,

0:08:03.806,0:08:05.783
we decided to do some critical thinking.

0:08:05.783,0:08:07.422
So let's figure out our question:

0:08:07.422,0:08:10.071
"Do humans solve problems [br]faster when given caffeine?"

0:08:10.071,0:08:13.086
Now we've got to boil that down [br]into a testable prediction.

0:08:13.086,0:08:16.941
Remember: Keep it clear, simple, and [br]eloquent so that it can be replicated.

0:08:16.941,0:08:20.002
"Caffeine makes me smarter" [br]is not a great hypothesis.

0:08:20.002,0:08:21.774
A better one would be, say...

0:08:21.774,0:08:26.941
"Adults humans given caffeine will navigate [br]a maze faster than humans not given caffeine."

0:08:26.941,0:08:30.852
The caffeine dosage is your independent[br]variable (the thing that you can change).

0:08:30.852,0:08:32.261
So, you'll need some coffee.

0:08:32.261,0:08:34.118
Your result or dependent variable--

0:08:34.118,0:08:37.125
(the thing that depends on [br]the thing that you can change),

0:08:37.125,0:08:40.279
is going to be the speed at which the [br]subject navigates this giant corn maze.

0:08:40.279,0:08:42.794
Go out on the street, wrangle up a [br]bunch of different kinds of people,

0:08:42.794,0:08:44.986
and randomly assign them [br]into three different groups.

0:08:44.986,0:08:48.132
Also at this point, the American [br]Psychological Association suggests

0:08:48.132,0:08:50.972
that you acquire everyone's [br]informed consent to participate.

0:08:50.972,0:08:53.708
You don't want to force anyone[br]to be in your experiment,

0:08:53.708,0:08:55.285
no matter how cool you think it is.

0:08:55.285,0:08:58.184
So the control group gets [br]a placebo (in this case, decaf).

0:08:58.184,0:09:00.603
Experimental group 1 gets [br]a low dose of caffeine,

0:09:00.603,0:09:02.253
which we'll define at 100mg

0:09:02.253,0:09:04.595
(just an eye opener, [br]like a cup of coffee's worth).

0:09:04.595,0:09:07.411
Experimental group 2 gets 500 mg

0:09:07.411,0:09:10.334
(more than a quad-shot of espresso[br]dumped in a Red Bull).

0:09:10.334,0:09:12.619
Once you dose everyone, [br]turn them loose in the maze

0:09:12.619,0:09:14.803
and wait at the other end with a stopwatch.

0:09:14.803,0:09:18.063
All that's left is to measure your [br]results from the three different groups

0:09:18.063,0:09:19.910
and compare them, just to see if [br]there were any conclusive results.

0:09:19.910,0:09:21.940
If the highly-dosed folks got through it

0:09:21.940,0:09:23.970
twice as fast as the low dose, placebo groups

0:09:23.970,0:09:25.962
then Bernice's hypothesis was correct

0:09:25.962,0:09:29.043
and she can rub my face in it, [br]saying she was right all along,

0:09:29.043,0:09:32.521
but really, that would just be [br]the warm flush of hindsight bias

0:09:32.521,0:09:35.493
telling her something she didn't [br]really know until we tested it.

0:09:35.493,0:09:38.336
Then, because we've used clear [br]language in defining our parameters,

0:09:38.336,0:09:41.443
other curious minds can easily [br]replicate this experiment and

0:09:41.443,0:09:43.588
we can eventually pool all the data together,

0:09:43.588,0:09:47.809
and have something solid to say about what[br]that macchiato was doing to your cognition.

0:09:47.809,0:09:50.732
Or at least the speed at which [br]you can run through a maze.

0:09:50.732,0:09:51.702
Science!

0:09:51.702,0:09:54.107
Probably the best tool that you have[br]for understanding other people.

0:09:54.107,0:09:56.513
Thanks for watching this episode[br]of Crash Course Psychology!

0:09:56.513,0:09:57.745
If you've paid attention,

0:09:57.745,0:10:00.517
you've learned how to apply the scientific[br]method to psychological research

0:10:00.517,0:10:05.387
through case studies, naturalistic observation, [br]surveys and interviews, and experimentation.

0:10:05.387,0:10:08.850
You've also learned about different [br]kinds of bias in experimentation,

0:10:08.850,0:10:11.443
and how research practices help us avoid them.

0:10:11.443,0:10:13.352
Thanks specially to our Subbable subscribers,

0:10:13.352,0:10:15.815
who make this and all of Crash Course possible.

0:10:15.815,0:10:20.255
If you'd like to contribute to help us keep [br]Crash Course going and also get awesome perks,

0:10:20.255,0:10:24.559
like an autographed science poster or [br]even be animated into an upcoming episode

0:10:24.559,0:10:27.574
go to subbable.com/crashcourse to find out how.

0:10:27.574,0:10:40.885
[Host reads the credits]