After you eat the mixed nuts, there's nothing else to do.
I'm Angela Duckworth.
I'm Stephen Dubner.
And you're listening to No Stupid Questions.
Last episode, Stephen and Angela talked about cognitive fatigue and the kinds of work that
make your brain tired.
Today, what can be done about it?
When my attention is the opposite of the flow state, it's divided, it's not unified, and
I hate it.
Angela, last time on the show, I asked you a question, the answer to which was so interesting.
You and I went down a series of rabbit holes.
We answered about 10% of the question for all the best possible reasons.
And so here we are, part two.
For the first time in our lives.
The question last time concerned a new paper by four economists.
The paper is called Cognitive Endurance as Human Capital.
The four authors are Christina Brown, Spreak Kaur, Geeta Kingdon, and Heather Schofield.
And we discussed the paper a little bit, the experiments that went into it, but we didn't
even get to the findings.
So let's go back to the paper and then let's get to the findings.
So this paper has a field experiment with 1600 elementary school students in India,
and they are randomly assigned to condition.
There is a control condition and in the treatment condition, these elementary school students
are given cognitively challenging things to do.
In one case, it was math problems.
And in another case, there were like mazes and puzzles that were cognitively challenging
but not traditional academic stuff.
The question is, after 20 or 30 hours of these cognitively challenging tasks, what is the
effect on your future performance as a student and on tasks of intellectual ability?
And the reason these economists are looking into this question of cognitive fatigue or
cognitive endurance is because, as they note in the paper, students from low income backgrounds
exhibit cognitive fatigue more quickly than high income students.
I assume, therefore, that if you experience cognitive fatigue more quickly, that leads
to worse outcomes in your educational experience and therefore worse outcomes in your income
and health experience and so on.
Is that necessarily the case?
I think that is the idea.
I don't know that there is a lot of direct evidence of that.
It is true that kids from lower socioeconomic status households do worse on tasks of executive
functions, so these very cognitively challenging tasks like hold these numbers in your working
memory.
I don't know that I could go as far as saying exactly what you're proposing is factually
backed up, but it is certainly the animus for this paper.
If you are a poor child and you are not given the opportunity to do a lot of cognitively
hard things in your school, then maybe that is the reason why you don't do well later
in life.
So, these four economists run a series of studies in which they randomize school children
in India, have some of them do one type of cognitive task, have some of them do a different
type of cognitive task, and then they have control groups where they don't do these cognitive
tasks.
And then, correct me if I'm wrong, these economists set out to measure what's the
difference in these kids when performing actual schoolwork, is that what it is?
Well, I know they had a variety of outcomes.
Some of them were just like other cognitive tasks, but I think they also actually had
standardized tests of achievement, which are closer to the things that kids are doing in
school, and they found that either of those training cases did better than the control
group on all of the outcomes.
But I'll just say, what you find over and over again when you give people cognitively
challenging tasks, they don't even have to be sophisticated tasks.
Some of these tasks are incredibly simple, like you're just watching a screen for a signal,
and anytime you see the signal, you press a spacebar.
That's not mental arithmetic.
That's not GRE problems.
But what you find over time is if you ask somebody to do that for minutes and then hours,
they miss the x, they're very slow.
And so, this decline is just what you find in general.
What you find in this study is that when you have 20 to 30 hours of cognitive endurance
training, the decline is less.
So what makes this a little complicated is everybody's getting worse, but the treatment
group gets worse less.
The authors of this paper write that the students who had this cognitive endurance training,
they exhibit increased attentiveness in the classroom and score higher on psychological
measures of sustained attention.
So that's encouraging.
But one might also say, hang on, what's the result of this increase?
Each treatment improves student school performance by 0.09 standard deviation, so one tenth.
Can you describe what that means in real world terms?
Is that going from a C minus to a C plus?
Not even that.
Hard to say.
How do you describe it?
What does it mean to change your grades by a tenth of a standard deviation?
It's a lot.
Let me say that all things are relative.
In a national study of growth mindset, the idea of a growth mindset is that you believe
that your abilities are malleable, that they can grow.
And it's the opposite of a fixed mindset, believing that abilities like intelligence
are simply fixed and they'll never change.
There was a random assignment study.
I was part of the scientific team, but it was a very large scientific team.
The two most important people on the team were David Yeager, who was the lead, and Carol
White, the whole idea.
We randomly assigned ninth graders to growth mindset versus a control condition, and we
found something like half the size of the effect of this paper that we're talking about.
It was not 0.09 or 0.1, it was more like we found 0.05 or 0.04.
In other words, this treatment that was studied had twice the effect on grades as ours did.
Wow.
Let me ask you the cost of the two programs.
In the paper we're discussing, where these economists were running a field experiment
with 1,600 elementary school kids in India, they were having them do this cognitive attention,
building task work using math problems or games.
One can imagine how much cost that takes.
I would think that, quote, building a growth mindset is more extensive than that, no?
I think the costs are not that different for any of these.
Let me talk about the growth mindset intervention.
These kids would march into the school computer lab, and they would sit down in front of a
computer, and then they were randomly assigned.
The computer would either give them the growth mindset activity or a control activity.
But if you are the secretary of education or a school principal or superintendent,
the marginal cost to you of having kids do this mindset activity, even to do it twice,
is close to zero because it's an online activity.
There's some opportunity costs, though, right?
There's the time not spent pursuing their regular academic work, for instance.
Yeah, because as we all know, two class sessions in a public school are incredibly valuable, right?
Not my words.
Those are your words.
Dear Teacher's Union, Angela's email address is—
I'm a former New York City public school teacher, San Francisco Unified School District teacher,
and I would just say that we could do better.
There's some opportunity costs, but I'm just saying it's not like,
well, we need to buy new buildings, books, or computers for all these kids.
Now, let's talk about this experiment in India, the cognitive endurance training.
So there was the cost of the tablets, but really, this activity itself has no marginal cost.
It's just math problems.
So yes, there's the opportunity cost, and yeah, you need a school computer lab or you need tablets.
But in so many ways, when you think about this compared to one-on-one psychotherapy,
when you think about this relative to reducing class size,
when you talk about extending the school year or the school day,
there are a lot of interventions that might be actually very valuable.
But the marginal cost of this kind of stuff is almost zero.
So to summarize, cognitive endurance is really important in a variety of contexts,
especially education. As this experiment shows, when you devote a little bit of time and energy
to increasing cognitive endurance among students who come from a background where
they're pretty low in cognitive endurance, it turns out they can improve quite rapidly
at very low cost. And since education is a really big driver in general life outcomes,
and since cognitive endurance increases educational ability, this seems like a pretty
fantastic thing to at least be aware of, if not to do.
I would agree with that. And if somebody says, like, yeah, but I saw that paper and I think the
effect size was only a tenth of a standard deviation, I would say, show me the intervention
that has a bigger effect than that. And I think you would be hard-pressed to do that.
Let's talk now about interventions. Can you talk about whether this paper offers advice on the
best types of activities or training to build cognitive endurance for students, especially?
I don't know that this paper is going to be able to answer that question because they just tried
probably what they thought was a good idea, but they weren't doing a horse race among 10 ideas.
I do think, though, where I want to go with this is what did they actually change,
because that has the biggest implications for what you would do in the future.
Did they actually change the capacity of these students in the strength sense?
What happens is that these young girls and boys learn to experience fatigue like, wow,
you just did all these math problems. And I think what happened there is they found
some way to find that rewarding. In other words, it wasn't that they actually had stronger brains
in any physical sense. But the experience of fatigue was something they learned to interpret
as a good thing. And I want to go back a few decades to a researcher named Robert Eisenberger,
who also asked this question, what happens when people do hard things? Do you know what
operant conditioning is? I do not. One of the basic findings of animal learning is that animals,
including humans, can learn that a behavior is rewarding if you're training a rat. And every
time it presses this one button in the cage, it gets a pellet of rat chow. It will learn that
behavior. Pressing the button is rewarding. So what Robert Eisenberger asked is, can you learn
to be a hard worker? He believed that there are these signals of effort and fatigue and that in
the absence of learning, you just avoid them. We've kind of been genetically wired to take the
path of least resistance, you know, what a young person learns when they go through life and they
go through school. You learn to interpret that signal of fatigue, of effort as being potentially
a good thing. And the way he did these experiments is that he paired effort with reward. I think in
one study, kids were doing problems. They may have been math problems were very similar to the ones
that were being done by these Indian schoolchildren in the paper that we're describing. But he gave
them pennies or candies after they got one right to really make sure that they got the signal that
like, good, yay, effort, reward. And then he found that later on, these kids worked harder.
His theory of learned industriousness is about you are interpreting that feeling of fatigue in a way
which is different than what you did before. Reading this paper that we're talking about,
the cognitive endurance paper, they did not reward kids with candy or points or anything like that.
But I have to believe that the feedback that these kids got when they were doing these problems,
like, you know, you're leveling up. Yes, you got that correct, etc. They were learning that this
was good because they were getting some kind of reward, even if it wasn't financial or tangible.
Let me take a slight left turn because I'm thinking about different realms. I'm thinking
about work and professional realms. But I'm also thinking about physical realms, athletics and so
on. I read a piece in Psychology Today not written by a psychologist, but by an ultra-endurance
athlete who's now a science writer. His name is Christopher Bergland. He was talking about
different habits that athletes have to improve cognitive function generally. And with many of
these, there are some overlaps with the research in India we were just talking about. One of them
is brain training games, but there's also curiosity and creativity, mindfulness meditation.
And this should not be surprising because this is an ultra-endurance athlete writing about this.
He makes the argument that physical activity is incredibly strongly connected to cognitive
function. Now, I don't think anyone would dispute that, but what it got me thinking about is if
we're talking about school kids, whether it's in India, the U.S., wherever it is, if we believe,
as the literature encourages us to believe, that physical activity is a big driver of
cognitive function. And if we know that students in low-income schools tend to do much worse with
cognitive endurance, I wouldn't be shocked to learn that there's also less emphasis and less
resources for physical activity in those schools, whether it's sports teams, sports activity,
even just exercise and things like that. I guess what I'm asking you is if we are talking about
low-cost interventions that can drive cognitive endurance in a school setting,
wouldn't physical activity be another one? There is a neuroscientist named Adele Diamond
who has suggested that certain kinds of physical activities like dance and martial arts and so
forth, because they're both physical and mental, there's a cognitive element, you're thinking of
these moves, you're like concentrating, but also it's physically demanding. She actually believed
and she's an expert in executive function and its development. She believed that's the royal
road. I will say though, I sat in the back of a lot of classrooms and a lot of school districts
and there is never enough physical activity except in the really she-she private schools.
I remember when I was just starting out working with the KIPP charter schools, some of their
classrooms were in Harlem and some of them were in the Bronx. And I remember saying to your point,
Steven, hey, one of the emerging findings when it comes to school performance and overall brain
health is that physical activity, especially aerobic activity, getting your heart rate up,
running around, breaking a sweat, this is good for kids' healthy brain development.
What can we do about that? And what the school principals told me is that they couldn't let
their kids out of the classroom sometimes because it was not safe. They're like, I know you want
these kids to take a two mile run. There's literally nowhere they can run. I know you
want them to go and have recess. I don't even know if it's safe to go outside.
This really gets to the impulse behind this research paper in the first place. These
scholars wanted to know what's going on in these schools where the kids have really low
cognitive endurance. They feel that even a school with low resources can and should be spending more
time building up that cognitive endurance by doing this sort of work for these students.
But it does raise the question of how much do we think what we refer to so blithely as the
education gap is really a resource gap and how much is a strategy gap? Because it seems to me
that if I'm a low income school or if I'm a low income student, I hear about this finding from
India. I'm encouraged by the idea that actually the gap can be closed somewhat significantly
with relatively low cost and little effort. I think yes. And there is so much that we could
do better. I mean, if the pandemic taught parents anything, when you got to actually see your kid
going to zoom school, and I know zoom school is not the same as school school. I think there are
many parents who are just a guest for a lot of parents. They were like, wow, I thought school is
better than this. And again, not to underestimate the enormity of what schools and teachers are
doing, because when parents had to just take over teaching their kids fractions or whatever, they
learned how hard it was. But I do think that even with the same school day, should it be longer?
Probably the same school year. Should that be longer? Probably. Should there be more resources?
Probably. But even within the constraints of the day and the year and the budget that we have,
I think we can do massively better. I don't recommend personally putting kids on iPads to
do 20 or 30 hours of training. I think you can do better than that. Can't we give kids things that are
cognitively hard and also interesting and also just what they're supposed to be studying in the
first place. And by the way, that's what private school looks like in the most elite places that
I've been. What you're describing is what I would call thinking. Right. It is cognitively taxing.
It's also interesting. Yes. A thousand times. Yes. I mean, what I found in many urban under-resourced
schools, I would sit there for hours in the back of these classes and just wait for kids to be
taught anything. There was no kind of like, I am going to engage you in thought. I remember going
through one entire school day in a school that shall not be named and thinking to myself,
if my daughter went to the school, she would come home and have learned exactly nothing. There was
literally no information transacted, no thinking, no challenge. And so if this paper shines a light
on anything, there's an enormous opportunity to ask our children to do cognitively hard things,
to think. I think they will learn to interpret the feeling of mental fatigue as a signal that
they're on the right track. But I also agree with you that it doesn't necessarily cost an
enormous amount of money to do that. Still to come on No Stupid Questions,
Stephen and Angela discuss the significance of developing cognitive endurance outside of an
educational setting. You can give somebody a five minute task and you can watch their performance
go down within the course of five minutes. That's like two Adele songs.
Now back to Stephen and Angela's conversation about closing the education gap.
How would you advise that educators interpret and learn from these research findings? What
are some actual things that should be done based on this finding? I think school can be
entirely different than what it is today. You can't learn without struggle. But let me use this
illustrative example to give you a picture of what school could be. Some months ago,
this guy emails me, his name is Ed Lopez, and he is a teacher. He teaches in a district I think
that's near Palo Alto. It's a very under resourced district. And his kids are the ones who have
failed in high school repeatedly. And in a way, he's the teacher slash class of last resort.
It's a semester long class. And he basically teaches them a ropes course. And they are not
just learning it for themselves. What they're learning is how to become instructors. If I'm
not mistaken, when they get through the course and they pass, they become immediately the
instructors of ropes course for like all the firefighters in San Francisco. So you get these
kids who have failed out of everything to be completely devoted students to what they're
doing. What they're doing matters. You better learn this ropes thing because first of all,
somebody is dangling on the end of the rope that you're belaying. Oh, by the way, within weeks,
you're going to be teaching firefighters the very thing that you're learning. So it's not this thing
which is completely separate from what you really care about. It has urgency. It has meaning. It has
importance. Also, it's interesting. It's physical. It's much more engaging than so many of the things
that these kids have failed out of. He also builds the whole course around this relationship.
