- [Narrator] After more than a year
of living with COVID-19 safety precautions,
quarantines and social isolation,
life is starting to return back to pre-COVID normal.
(dog barking)
And that's forcing our brains
to rethink how we behave socially.
- Now we have to make individual decisions
about what are environments
in which we feel comfortable
and what are environments where we don't feel comfortable?
- [Narrator] Should I eat indoors,
go to that concert, wear my mask?
A new mental toll is emerging.
Many people are reevaluating the habits they formed
during the pandemic
and reassessing how safe it is
to resume once-normal activities.
But why do some of us find it difficult
to make these choices?
It has to do with how our brains process information.
Let's take a look at what happens
when you're finally reunited with friends
and you're faced with a choice.
(people murmuring)
Mia is in her 40s, healthy, fully vaccinated
and is attending a backyard barbecue party.
But it starts to rain
and the party moves indoors.
Though CDC guidelines say the risk
of infection is minimal for people like Mia
who are fully vaccinated, she has to decide
whether she feels comfortable going indoors
with a big group of people.
- When we're making those decisions in our brains,
what we're really doing is weighing three sets of factors.
The first factor's almost the easiest to understand
and that's what risks am I willing to take
when I understand the risks completely?
- [Narrator] Making a choice can happen quickly
as several parts of the brain work together
to come to a decision.
When people begin to move indoors,
Mia faces a known risk:
the chance she could get exposed to COVID-19.
Her prefrontal cortex starts to assess that risk
and the possible outcomes of her actions.
The second is uncertainty aversion.
Things that are ambiguous and obscure.
That assessment happens in part in the amygdala,
which is associated with processing fear,
distress or anxiety.
The more ambiguous a situation is,
the more likely someone is to be cautious.
For Mia, the ambiguous risk is tied
to how much she doesn't know.
Is everyone vaccinated?
How high are infection rates in town.
Is there enough ventilation in the house?
If she has a good handle on all this information,
her ambiguous risk is lower
and she may opt in favor of the reward
to go inside and continue spending time
with her friends.
The third factor is the habit system.
That's located in the dorsal striatum,
near the amygdala.
- When we come into an environment
that we've been to a million times before the pandemic
and we have some set of behaviors
that we've learned to produce in those environments,
like walking up to someone and hugging them,
these habits are gonna also influence our behavior.
- [Narrator] Prior to the pandemic,
Mia used to hang out at her friends' homes regularly.
But COVID changed a lot of her habits.
She only saw people outdoors.
- In each of these brain areas,
there are millions of brain cells.
And those brain cells generate action potentials,
these little electrochemical impulses
with which they send information from one part
of the brain to another.
- [Narrator] So as Mia weighs her choice,
the brain is calculating the risk and reward
of going inside versus going home.
In the final stage of decision making,
information from multiple parts of the brain
is integrated to make a final choice.
This includes the prefrontal cortex
at the very front of the brain
and the ventral striatum,
a neighboring region to the dorsal striatum and amygdala.
- So there is where we find groups of nerve cells
that represent each of the options
and have aggregated together all of the different factors
that are gonna influence how much you like
or don't like doing that.
And then in these areas, in areas closely associated
with them, that's where we expect to see this competition
where the group of cells that is most active,
the ones that are encoding the more desirable option
with greater electrochemical activity
will sort of take control
and lead us to the behavior
that we've chosen to make.
- [Narrator] But we're all different.
Our personalities, age and life experiences influence
all three systems uniquely.
So what Mia decides could be different
from her friend Mark.
- Some of us are more concerned about ambiguity.
Maybe because of prior life trauma.
Some of us are more concerned about risk
and some of us are more driven by habits.
So there're individual differences
in the way we weigh each of these three sets of factors.
And then, of course, we all have different inputs
from the world around us.
- [Narrator] Another factor
that could influence our decisions
over the next few months may be related
to trauma from the pandemic.
Dr. Glimcher's actively studying
how the events of the last year can affect our choices.
He says there's still a lot of unknowns but.
- We do know that while trauma changes the way people decide
and changes the way people behave,
it makes them more ambiguity averse, for example,
it doesn't completely disorder the brain.
The basic rules and structures
for making decisions remain the same.
It's the weightings that are different.
- [Narrator] So for Mark, who lost his grandfather
to COVID-19, the decision of whether to stay
or leave the party could be weighted differently due
to that trauma.
As the pandemic eases in many parts of the world,
it's unclear how trauma and fear associated
with the past year
will continue to impact people's lives.
But the brain is flexible.
It constantly learns from experience
and as we're testing our boundaries of what feels safe
and what doesn't, we're learning to adjust
to all situations that now feel new.
It's that learning that will ultimately help us get back
to a new normal.