Social: Why Our Brains Are Wired to Connect (30 page)

Let the willpower games begin.
None of these children were on a diet, so to them, the more sugar the better: they all wanted two rather than one marshmallow.
Despite their intention to last the full waiting period, less than a third did so; the temptation was too great.
On average, the children lasted about five minutes before giving in.
Over the years, Mischel found ways to help the children last longer in their quest for the most marshmallows.
Replacing the actual marshmallows with pictures
of marshmallows dramatically increased how long the children could wait.
In essence, children were better able to resist the idea of marshmallows than real marshmallows (even though the reward was real marshmallows in both cases).
Symbolic replacements are less tempting than the real thing.
Mischel also investigated how the children could mentally approach the task in different ways to improve their odds of success.

Even when the marshmallows were left on the table, the children were able to demonstrate impressive waiting abilities if they were given tricks for how to think about the marshmallows.
Mentally focusing on aspects of the marshmallows
that had nothing to do with eating them (for example, “marshmallows are the same colors as clouds”) increased waiting times considerably.
Shockingly, if the children just imagined that the marshmallows in front of them were in a picture rather than actually there,
they were able to wait three times as long
as when they were looking at a picture of
marshmallows but pretended they were real.
Under the right circumstances, the power of mind is remarkable.

All of Life’s Good Stuff

In the United States, there is no more pivotal moment in determining ambitious adolescents’ future than finding out which college they did or did not get into.
Getting into Georgetown rather than Greendale will open a variety of doors, confer higher prestige, and typically lead to a higher paying job.
This, in turn, improves one’s dating pool, the house one can buy, and the vacations within reach.
For most students, high school grade point average (GPA) and Scholastic Aptitude Test (SAT) scores disproportionately influence the odds of getting into any particular school.

Ability to delay gratification makes remarkable contributions to both GPA and SAT scores.
Mischel retested his preschoolers
once they had taken the SAT years later.
Those who had lasted longer at age four scored better on the SATs.
In fact,
preschoolers who could wait
until the experimenter returned of his own accord scored more than 200 points better on the SAT than those who gave up after thirty seconds.
More recently, Angela Duckworth found that
GPA was better predicted
by a person’s ability to delay gratification than by their IQ.

Since the discoveries linking self-control and academic outcomes, various other findings also point to self-control as the key to the good life.
People with higher levels of self-control
have higher incomes, higher credit scores, better health, and better social skills from childhood to adulthood, and they report being happier with life.

Self-control is clearly one of the greatest assets a person can have, but you might be wondering what it has to do with the social brain.
We will get there, but before we do, let’s be clear about what we mean when we talk about self-control.
Self-control typically
involves some impulse, urge, or reaction that we want to stop or prevent.
Our impulses and emotional reactions
are essential in guiding us toward desirable outcomes and away from danger, but they also seem to have a mind of their own and often need to be restrained.
Whether it’s avoiding that extra slice of pizza at 2 a.m., not telling your boss what you really think of him, or overcoming the urge to drive on the right side of the road when you are visiting London, your habitual responses need to be put in their place from time to time.

When you feel yourself exerting effort targeted at overcoming one of these undesired responses, that’s self-control.
Why does self-control relate to GPA?
Probably because kids who can keep the urge to play videogames at bay long enough to do their homework will do better in school.
Why does self-control improve SAT scores?
In part, because self-control helps a person to persist in the face of the colossal boredom that is the SAT test and all the preparation that goes into getting ready for it.
And rather than going with the first answer that comes to mind and moving on to the next problem, which is driven by the impulse to be done with the test, self-control allows the students to stay focused on each problem until they are sure they have the best possible answer.

One of the defining characteristics of self-control is that it seems to be a limited resource.
Essentially, we can engage in only one kind of self-control at a time.
Try to actively control two things at once (for example, resisting pizza and memorizing a poem for class), and one or both of these efforts will most assuredly suffer.
More surprisingly, engaging in two forms of self-control in sequence can be problematic as well.
Trying very hard not to laugh during a funny scene right now will actually make it harder for you to stay focused while taking an analogies test five minutes from now.

In order to explain the discovery that self-control exertion now can undermine self-control later, social psychologists Roy Bau-meister, Todd Heatherton, and Katherine Vohs have theorized that
self-control is like a muscle
.
They argue that this effect occurs because the self-control muscle can get fatigued and needs time to recover.
Similarly, a muscle can do only one thing at a time.
Just like a muscle, self-control is powerful but limited.
The muscle perspective has also been extended to suggest that self-control can be strengthened by exercising it.
Lifting weights depletes our muscles in the short run but makes them stronger in the long run.
The same may be true of our “self-control muscle.”

The Brain’s Braking System

Part of what makes the sequential self-control findings surprising is that the kinds of self-control we engage in are so different from one type to the next that it is hard to believe that each of these really depends on the same processes in the brain.
What does holding back laughter at a comedian’s jokes have to do with the focusing you do when you take an analogies test?
Why should driving on the left side of the road to get to a business meeting in London affect your ability to keep your cool if the meeting goes poorly?

Although various mechanisms are at work in the different kinds of self-control we exert, one mechanism seems to be at work in nearly every instance.
The
ventrolateral prefrontal cortex
(VLPFC) of the brain (see
Figure 9.1
), especially in the right hemisphere (rVLPFC), activates reliably in numerous types of self-control exertions, irrespective of how different our experiences of self-control feel from one to another.
It is the only region in the prefrontal cortex
that is larger in the right hemisphere than in the left, but this asymmetry doesn’t emerge until late adolescence, when self-control skills significantly improve.
For these reasons,
it is appropriate to characterize the rVLPFC
as the central hub of the
brain’s braking system
.
Let’s take a little tour of some of the diverse ways we engage in self-control, and let’s examine the VLPFC’s involvement.

Figure 9.1 Ventrolateral Prefrontal Cortex (VLPFC) Involved in Self-Control

Motor self-control.
The psychologist’s favorite motor self-control task is the
go/no-go task
(the
stop-signal task
, discussed in
Chapter 3
, is a variant of this task).
In it, participants are shown an endless series of letters, about one per second, and they are asked to press a button as quickly as possible when each letter appears.
They do this for every letter except for one that is predesignated as the
no-go letter.
Whenever this letter appears, the participants do nothing at all (that is, “no-go”-ing).
The task is difficult because the no-go letter appears only 15 to 20 percent of the time, so participants ease into the habit of pressing the button once every second or so, and this prepotent motor response has to be overcome when the no-go letter appears.
Although subjects are instructed to do nothing in the no-go trials, restraining themselves from pushing the button feels like more work than other trials.

Countless studies have observed increased activity in the rVLPFC
(also called the
right inferior frontal gyrus
) when individuals successfully avoid pressing the button in no-go trials.
One study examined patients with different kinds of brain damage and found that only brain damage in the rVLPFC was
associated with deficits on the no-go task
.
Decades after Mischel performed the initial marshmallow tests
, a subset of his preschoolers were brought back
in as grownups to perform a go/no-go task in an MRI scanner.
Mischel found that the adults who as four-year-olds had been best at delaying gratification also produced the most activity in the rVLPFC as adults, suggesting that this response might have been at the root of their real-world self-control successes over the years.

Elliot Berkman and I tested the idea that rVLPFC
activity during this motor self-control task is a proxy for real-world self-control.
We tested a group of smokers who had made the decision to quit smoking.
First, we scanned these individuals performing the go/no-go task the day before their “quit day”—the day they had chosen to start trying to quit.
This battle for self-control over an intense undesired habit consists of an endless series of skirmishes, in which our urges and our better angels clash several times each day.
We wanted to see whether the rVLPFC played a role in tipping the advantage to self-control.

To get at the moment-to-moment self-control conflicts, we texted the participants several times a day and asked them how strong a craving to smoke they were having right at that moment, and whether they had smoked since the last time we had texted them.
Here’s how we made use of those two bits of information.
Say you get a text at 2 p.m.
and you indicate that you really crave a cigarette right now.
When you get another text at 4 p.m.
and report that you haven’t smoked in the last two hours, it means you didn’t give in to the craving and won that particular battle.
We could essentially code each battle as to whether self-control or the craving won out.

As expected, the participants were more likely to have smoked by 4 p.m.
if they had a strong craving to smoke at 2 p.m.
But rVLPFC activity had a major impact on the relationship between craving and smoking.
Those with the weakest rVLPFC responses days earlier, during the go/no-go task, tended to go straight from craving to smoking.
In contrast, for those with the strongest rVLPFC responses, cravings did not typically lead to smoking between texts.
The cravings were still present for these individuals,
but the individuals were better equipped to fight the battle.
These results imply that the rVLPFC not only is clearly linked to performing self-control tasks in the scanner but plays a significant role in real-world self-control success.

Cognitive self-control.
Let me ask you a question.
Does the conclusion of the following syllogism logically follow from the premises?

No addictive things are inexpensive.
Some cigarettes are inexpensive.
Therefore, some cigarettes are not addictive.

The question posed to participants is whether the conclusion would have to be true
if
the premises were true.
The answer is yes.
This conclusion is logically valid, yet
fewer than half of the participants answer the question correctly
.
Why?
Because of
belief bias
.
We are biased against affirming the conclusion because we know it to be false.
The reason it is false is that the first premise of this syllogism is false, but that doesn’t make the conclusion logically invalid.
Overriding our knowledge of reality in order to imagine a world in which the premises are true requires mental self-control.
Although we may not have as much control
over our thoughts—our cognitive processes—as we would like, we do have some control, and this control often involves the VLPFC.

To study the neural bases of cognitive self-control
, neuroscientists Vinod Goel and Ray Dolan asked people in an MRI to make logic decisions for a series of syllogisms that either invoked or did not invoke the belief bias.
They looked at which brain regions were more active when people overcame the belief bias and delivered the correct answer, compared to trials when they did not.
The only region of the brain that showed this pattern was the rVLPFC.
Another study of the belief bias
observed that the strength of activity in the rVLPFC (but not the left VLPFC) predicted how accurately an individual performed.
Additionally, being mentally distracted
while performing the task led to reduced accuracy and rVLPFC activity.
That is consistent with an rVLPFC account of effortful self-control.
Finally,
a third study used transcranial magnetic stimulation (TMS)
, described in
Chapter 6
, to temporarily knock either right or left VLPFC offline for about 20 minutes.
Participants were presented with belief bias and nonbelief bias syllogisms both before and after TMS was applied.
Individuals who had TMS applied to the rVLPFC, temporarily frazzling the region, performed worse on the belief bias trials.
This finding suggests that when the rVLPFC is impaired, self-control is also impaired, leaving individuals less able to overcome their own beliefs to provide the logically correct answers.