Social: Why Our Brains Are Wired to Connect (16 page)

The Intentional stance is so ubiquitous and so easily adopted in daily life that it is almost impossible to appreciate what an achievement it is.
We are all mindreaders.
As you read this, you comprehend not just the marks on the page but thoughts that I had when I was writing them.
Similarly, in writing these words, I have to be able to predict how these marks on the page will be experienced in your mind in order to make my thoughts more easily understood.
How on earth would you go about building a machine that assumes others have these mental processes and can usefully take them into
account?
As impossible as this might sound, we do this all the time without even realizing it.
Perhaps that was why it took so long for anyone to recognize we have this capacity.
Like fish who have no idea that they are in water because they are surrounded by it, mindreading is so basic to who we are that we rarely notice it.

Just try to imagine how you would get through your day if you couldn’t make sense of the minds of others or count on others to make sense of your mind.
Consider the most trivial example.
Whenever I take a flight home to Los Angeles, a shuttle picks me up to bring me to where my car is parked.
As the shuttle approaches my terminal, I wave my hand, and the driver knows that I would like him to stop so I can get on.
When he stops and opens the door, I know the driver’s intention as well—he is inviting me to climb aboard.
It is a simple transaction between two complete strangers.
Yet without each of us having an accurate understanding of the psychological meaning of other people’s behavior, we would be unable to pull off this innocuous interaction.
Now consider a consulting team working with a company to develop new hiring plans or a math teacher instructing two dozen teenagers about the finer points of sines and cosines.
In these cases, we must have exquisite insight into how our actions will be understood by those we are working with.
The modern world would stop in its tracks if we no longer had this ability to understand or predict the minds of others.
Our ability to think allows us to imagine great achievements, but without the ability to think socially and share our vision with others in a way that engages them, we would be left to our own devices to convert our vision to reality.

Psychologists have referred to this ability to understand that other people have thoughts that drive their behavior as having a
Theory of Mind
, and when people apply this ability, it is called
mentalizing
(that is, we mentalize when we think about the mental states of others).
Just as scientists have theories that allow them to make predictions and draw conclusions based on evidence, we as human adults all operate as if we have a theory that others around
us have a mind that responds in an orderly fashion based on a set of rules (for example, losing a game makes people sad, not happy).
It is this signature achievement that allows us to coordinate our otherwise isolated thoughts with the thoughts of others to promote shared goals and cooperation.

Punch and Judy

Over the past three decades, Theory of Mind researchers have focused on two related questions: Who has it, and When do they get it?
The
who
question is usually aimed at determining which nonhuman species, if any, share this Theory of Mind capacity with us.
Are we humans alone on the planet
in our ability to appreciate the minds of others, or like so many capacities, such as using tools, are the differences between us and the rest of the animal kingdom more a matter of degree?
David Premack and Guy Woodruff were the first to take up the challenge of sorting this out.
Chimpanzees are the closest living relative to humans, genetically speaking, so if any other animal were to have a Theory of Mind, they would be the most likely candidates.
Premack and Woodruff worked with a chimpanzee named Sarah who could perform a pretty impressive trick.
The researchers would show Sarah a video of a man engaged in some activity like trying to get a banana that was too high to reach.
The video would be paused before the man had solved the problem, and Sarah would be given four photographs showing possible next steps for the banana-hunting man.
Sarah could reliably pick the photo that indicated the right solution (getting a box and standing on it).
Although that would be easy for you and me, it is remarkable that a chimpanzee could do it too.
Premack and Woodruff suggested that the only way Sarah, a chimpanzee, could do this was to understand that the man was the kind of entity that could have desires and goals and that in this case he had a particular desire-goal combination: to satisfy his hunger by getting the banana.

So chimpanzees have a Theory of Mind?
In the end, Sarah’s feat was more of a debate starter than a debate ender.
Dennett and others weighed in that impressive as this trick might have been, it may have reflected no more understanding than a parrot’s being trained to ask a question based on conditioning, or solving a problem for oneself (“What would I do?”) without thinking about the other’s mind.
Dennett (1978) proposed a more definitive
false belief task
based on the eighteenth-century comedic stylings of Punch and Judy:

Very young children watching a Punch and Judy show
squeal in anticipatory delight as Punch prepares to throw the box over the cliff.
Why?
Because
they know Punch thinks Judy is still in the box.
They know better; they saw Judy escape while Punch’s back was turned.
We take the children’s excitement as overwhelmingly good evidence that they understand the situation—they understand that Punch is acting on a mistaken belief.

Dennett’s critique led to the second dominant Theory of Mind question, which has focused on
when
humans demonstrate this ability during the course of their development.
As Dennett’s example implies, humans do appreciate false beliefs in others, but they aren’t born with this ability.
In the mid-1980s, a number of researchers
converted Dennett’s Punch and Judy thought experiment into a real one
.
The best-known Punch and Judy variant is known as the
Sally-Anne task
.
Two puppets, Sally and Anne, are both seen, along with a basket and a box.
Sally puts a marble into the basket and then leaves the stage.
While Sally is away, Anne moves Sally’s marble from the basket to the box.
When Sally returns, the child watching the performance is asked where Sally will look for her marble.
The trick here is that the child watching this mini-drama has a true belief about where the marble is, whereas Sally has a false belief.
Sally still thinks the marble is in the basket where she left it,
but she’s wrong.
If children have an egocentric view, believing that everyone knows what they know, they will say Sally will look in the box.
However, if they can appreciate that others can have beliefs that differ from their own and can have beliefs that do not line up with reality, they will be more likely to say that Sally will look in the basket.
The results from many studies provide strong converging evidence
.
Three-year-olds are lousy at the test, and five-year-olds are great at it.

As new and different tests are devised,
younger and younger children also show some evidence of this sort of social skill
.
Chimpanzees show evidence of precursors of this ability
, but no evidence unambiguously demonstrates that they can cross the threshold of thinking about the false beliefs of others.
Humans may be alone in the universe when it comes to their ability to thoroughly appreciate the nature of others’ minds.

Why is it so amazing that children think about the mental states of others?
Because mental states are invisible.
Have you ever seen a thought, feeling, or desire?
Yet somehow, we learn to infer that these invisible entities in other people’s heads are leading them to do the things they do.
When we see a rock rolling down a hill, we don’t think, “It wants to get to the bottom.”
But when we see a person running down a hill, we do.

Over time we develop a very complex theory of how different situations and outcomes are likely to affect a typical person’s thinking and how that person will subsequently behave.
If Bill and Ted are best friends, but Ted starts spending a lot more time with George, we know how Bill will feel (neglected, jealous) and how he will respond (either trying to integrate George into the group, making a stable triangle of friends, or competing with George for Ted’s affection).
I suspect I could describe just about any situation and you would feel confident about how a typical person would react.
It is this ability to consider the mental reactions of those around us, to imagine these reactions in advance, that allows us to increase our exposure to social rewards and minimize the experience of social
pain.
If you can predict that the e-mail you are about to send to someone will lead that person to reject you, you can edit the e-mail to get your point across more tactfully.
We do this countless times, in large and small ways, each day.
We use our capacity for mind-reading to support our motivation for connection.

A System for General Intelligence

How is it that we perform this trick of understanding other people’s minds?
One of the earliest accounts focused on
our general ability for abstract reasoning and effortful thinking supported by the prefrontal cortex
.
Logical reasoning comes in two flavors: deductive and inductive.

In deductive reasoning, we assess what
must
be the case if a set of premises is assumed to be true.
Consider the following premises:

1. If it rains, then the picnic will be canceled.

2. It is raining.

If those two premises are true, then we must logically conclude the picnic has been canceled.
This is an example of deductive reasoning, and this kind of
if-then
reasoning is central to our prodigious problem-solving abilities.

In contrast, inductive reasoning uses what has been true in the past to predict what will likely be true in the future.
For instance, our belief that the sun will come up tomorrow is predicated on the assumption that the sun’s having come up every day of our lives so far is strong evidence that it will continue to do so.
Unlike deductive conclusions, sensible inductive inferences are not guaranteed to be true.
There is nothing about past sunrises that actually guarantees more in the future, any more than the production of twelve
Friday the 13th
movies guarantees one more.
Inductive reasoning produces conclusions that usually turn out to be true if the conditions
of the world stay the same, which is why, so far, it has made sense to predict more sunrises and more
Friday the 13th
movies.

Figure 5.2 Lateral Prefrontal and Parietal Regions Associated with Intelligence, Reasoning, and Working Memory (LPFC = lateral prefrontal cortex; LPPC = lateral posterior parietal cortex)

Numerous neuroimaging studies have
identified regions in the lateral prefrontal cortex
and the lateral parietal cortex, also called the
lateral frontoparietal cortex
, that are more active when we are engaged in either deductive or inductive reasoning, compared with a task that involves neither kind of reasoning (see
Figure 5.2
).
Some studies of the brain have shown differences between the two kinds of reasoning, but the neuroanatomical similarities are far more conspicuous than their modest differences.

More generally, these lateral frontoparietal regions support countless kinds of effortful thinking through a process known as
working memory
.
Working memory is the psychological process commonly associated with mentally holding and updating multiple pieces of information.
If I showed you a seven-digit number on a computer screen (8675309) and then asked you to remember that number for 10 seconds once it disappeared from the screen, working memory is what keeps it active in your mind.
Similarly, working memory can be used to consider the relationship between things held in mind, like which of two numbers is larger.

To get a sense of how important working memory is to everyday functioning, consider your ability to read.
By the time you got to the end of the previous sentence, you were using working memory to hold the beginning of the sentence in mind so that you could understand the complete train of thought.
Imagine that you could process each word you read only at the moment you read it and then it was gone from your mind.
You would never have the context of earlier parts of a sentence available to clarify the meaning of the later parts.
Countless fMRI studies of working memory
have implicated the lateral frontoparietal regions of the brain.
When the degree of working memory load increases (for example, rehearsing a five-digit versus a seven-digit versus a nine-digit number), so does activity in these brain regions.
It makes sense that some of the same regions would be involved in logical reasoning and in working memory: engaging in logical reasoning involves holding pieces of information in mind and comparing them, and this is the kind of thinking that working memory helps us with.