Many of us will experience some kind of trauma during our lifetime.
Sometimes, we escape with no long-term effects.
But for millions of us, those experiences linger, causing symptoms like flashbacks, nightmares, and negative thoughts that interfere with everyday life.
This phenomenon, called post-traumatic stress disorder, or PTSD, isn’t a personal failing; rather, it’s a treatable malfunction of certain biological mechanisms that allow us to cope with dangerous experiences.
To understand PTSD, we first need to understand how the brain processes a wide range of ordeals, including the death of a loved one, domestic violence, injury or illness, abuse, rape, war, car accidents, and natural disasters.
These events can bring on feelings of danger and helplessness, which activate the brain’s alarm system, known as the “fight-flight-freeze” response.
When this alarm sounds, the hypothalamic, pituitary, and adrenal systems, known as the HPA axis, work together to send signals to the parasympathetic nervous system.
That’s the network that communicates with adrenal glands and internal organs to help regulate functions like heart rate, digestion, and respiration.
These signals start a chemical cascade that floods the body with several different stress hormones, causing physiological changes that prepare the body to defend itself.
Our heart rate speeds up, breathing quickens, and muscles tense.
Even after a crisis is over, escalated levels of stress hormones may last for days, contributing to jittery feelings, nightmares, and other symptoms.
For most people, these experiences disappear within a few days to two weeks as their hormone levels stabilize.
But a small percentage of those who experience trauma have persistent problems —sometimes vanishing temporarily only to resurface months later.
We don’t completely understand what’s happening in the brain, but one theory is that the stress hormone cortisol may be continuously activating the “fight-flight-freeze” response while reducing overall brain functioning, leading to a number of negative symptoms.
These symptoms often fall into four categories: intrusive thoughts, like dreams and flashbacks, avoiding reminders of the trauma, negative thoughts and feelings, like fear, anger, and guilt, and “reactive” symptoms like irritability and difficulty sleeping.
Not everyone has all these symptoms, or experiences them to the same extent and intensity.
When problems last more than a month, PTSD is often diagnosed.
Genetics, on-going overwhelming stress, and many risk factors like preexisting mental illnesses or lack of emotional support, likely play a role in determining who will experience PTSD.
But the underlying cause is still a medical mystery.
A major challenge of coping with PTSD is sensitivity to triggers, physical and emotional stimuli that the brain associates with the original trauma.
These can be everyday sensations that aren’t inherently dangerous but prompt powerful physical and emotional reactions.
For example, the smell of a campfire could evoke the memory of being trapped in a burning house.
For someone with PTSD, that memory activates the same neurochemical cascade as the original event.
That then stirs up the same feelings of panic and helplessness as if they’re experiencing the trauma all over again.
Trying to avoid these triggers, which are sometimes unpredictable, can lead to isolation.
That can leave people feeling invalidated, ignored, or misunderstood, like a pause button has been pushed on their lives while the rest of the world continues around them.
But, there are options.
If you think you might be suffering from PTSD, the first step is an evaluation with a mental health professional who can direct you towards the many resources available.
Psychotherapy can be very effective for PTSD, helping patients better understand their triggers.
And certain medications can make symptoms more manageable, as can self- care practices, like mindfulness and regular exercise.
What if you notice signs of PTSD in a friend or family member?
Social support, acceptance, and empathy are key to helping and recovery.
Let them know you believe their account of what they’re experiencing, and that you don’t blame them for their reactions.
If they’re open to it, encourage them to seek evaluation and treatment.
PTSD has been called “the hidden wound” because it comes without outward physical signs.
But even if it’s an invisible disorder, it doesn’t have to be a silent one.
I'd like you to take a moment and consider what you are wearing right now.
I have a deep, philosophical question for you.
Why are we not all wearing comfortable pajamas right now?
(Laughter) Well, I'm a psychologist and not a mind reader, although many people think that's the same thing.
I can bet you that your response is somewhere along the lines of, "I'm expected to not wear pj's in public" or "I don't want people to think I am a slob."
Either way, the fact that we all chose to wear business casual clothing, as opposed to our favorite pair of sweatpants, is not a silly coincidence.
Instead, it reveals two defining human characteristics.
The first is that we are cognizant of what other people value, like what they will approve or disapprove of, such as not wearing pj's to these sorts of settings.
And two, we've readily used this information to guide our behavior.
Unlike many other species, humans are prone to tailor their behavior in the presence of others to garner approval.
We spend valuable time putting on make up, choosing the right picture and Instagram filter, and composing ideas that will undoubtedly change the world in 140 characters or less.
Clearly, our concern with how other people will evaluate us is a big part of being human.
Despite this being a big human trait, however, we know relatively little about when and how we come to care about the opinion of others.
Now, this is a big question that requires many studies.
But the first step to uncovering this question is to investigate when in development we become sensitive to others' evaluations.
I have spent the past four years at Emory University investigating how an infant, who has no problem walking around the grocery store in her onesie, develops into an adult that fears public speaking for fear of being negatively judged.
(Laughter) Now, this is usually a point when people ask me, "How do you investigate this question, exactly?
Infants can't talk, right?"
Well, if my husband were up here right now, he would tell you that I interview babies, because he would rather not say that his wife experiments on children.
(Laughter) In reality, I design experiments for children, usually in the form of games.
Developmental psychologist Dr. Philippe Rochat and I designed a "game" called "The Robot Task" to explore when children would begin to be sensitive to the evaluation of others.
Specifically, the robot task captures when children, like adults, strategically modify their behavior when others are watching.
To do this, we showed 14 to 24-month-old infants how to activate a toy robot, and importantly, we either assigned a positive value, saying "Wow, isn't that great!"
or a negative value, saying, "Oh, oh.
Oops, oh no," after pressing the remote.
Following this toy demonstration, we invited the infants to play with the remote, and then either watched them or turned around and pretended to read a magazine.
The idea was that if by 24 months, children are indeed sensitive to the evaluation of others, then their button-pressing behavior should be influenced not only by whether or not they're being watched but also by the values that the experimenter expressed towards pressing the remote.
So for example, we would expect children to play with the positive remote significantly more if they were being observed but then choose to explore the negative remote once no one was watching.
To really capture this phenomenon, we did three variations of the study.
Study one explored how infants would engage with a novel toy if there were no values or instructions provided.
So we simply showed infants how to activate the toy robot, but didn't assign any values, and we also didn't tell them that they could play with the remote, providing them with a really ambiguous situation.
In study two, we incorporated the two values, a positive and a negative.
And in the last study, we had two experimenters and one remote.
One experimenter expressed a negative value towards pressing the remote, saying, "Yuck, the toy moved," while the other experimenter expressed a positive value, saying, "Yay, the toy moved."
And this is how the children reacted to these three different scenarios.
So in study one, the ambiguous situation, I'm currently watching the child.
She doesn't seem to be too interested in pressing the remote.
Once I turned around -- now she's ready to play.
(Laughter) Currently, I'm not watching the child.
She's really focused.
I turn around.
(Laughter) She wasn't doing anything, right?
In study two, it's the two remotes, one with the positive and one with the negative value.
I'm currently observing the child.
And the orange remote is a negative remote.
She's just looking around, looking at me, hanging out.
Then I turn around ...
(Laughter) That's what she's going for.
I'm not watching the child.
He wants the mom to play with it, right?
Take a safer route.
I turn around ...
(Laughter) He wasn't doing anything, either.
Yeah, he feels awkward.
(Laughter) Everyone knows that side-eyed glance, right?
Study three, the two experimenters, one remote.
The experimenter that reacted negatively towards pressing the remote is watching the child right now.
She feels a little awkward, doesn't know what to do, relying on Mom.
And then, she's going to turn around so that the experimenter that expressed a positive response is watching.
Coast is clear -- now she's ready to play.
(Laughter) So, as the data suggests, we found that children's button-pressing behavior was indeed influenced by the values and the instructions of the experimenter.
Because in study one, children did not know what would be positively or negatively evaluated, they tended to take the safest route and wait until I turned my back to press the remote.
Children in study two chose to press the positive remote significantly more when I was watching, but then once I turned my back, they immediately took the negative remote and started playing with it.
Importantly, in a control study, where we removed the different values of the remotes -- so we simply said, "Oh, wow" after pressing either of the remotes -- children's button-pressing behavior no longer differed across conditions, suggesting that it was really the values that we gave the two remotes that drove the behavior in the previous study.
Last but not least, children in study three chose to press a remote significantly more when the experimenter that expressed a positive value was watching, as opposed to the experimenter that had expressed a negative value.
Not coincidentally, it is also around this age that children begin to show embarrassment in situations that might elicit a negative evaluation, such as looking at themselves in the mirror and noticing a mark on their nose.
The equivalent of finding spinach in your teeth, for adults.
(Laughter) So what can we say, based on these findings?
Besides the fact that babies are actually really, really sneaky.
(Laughter) From very early on, children, like adults, are sensitive to the values that we place on objects and behaviors.
And importantly, they use these values to guide their behavior.
Whether we're aware of it or not, we're constantly communicating values to those around us.
Now, I don't mean values like "be kind" or "don't steal," although those are certainly values.
I mean that we are constantly showing others, specifically our children, what is likeable, valuable and praiseworthy, and what is not.
And a lot of the times, we actually do this without even noticing it.
Psychologists study behavior to explore the contents of the mind, because our behavior often reflects our beliefs, our values and our desires.
Here in Atlanta, we all believe the same thing.
That Coke is better than Pepsi.
(Applause) Now, this might have to do with the fact that Coke was invented in Atlanta.
But regardless, this belief is expressed in the fact that most people will chose to drink Coke.
In the same way, we are communicating a value when we mostly complement girls for their pretty hair or their pretty dress, but boys, for their intelligence.
Or when we chose to offer candy, as opposed to nutritious food, as a reward for good behavior.
Adults and children are incredibly effective at picking up values from these subtle behaviors.
And in turn, this ends up shaping their own behavior.
The research I have shared with you today suggests that this ability emerges very early in development, before we can even utter a complete sentence or are even potty-trained.
And it becomes an integral part of who we grow up to be.
So before I go, I'd like to invite you to contemplate on the values that we broadcast in day-to-day interactions, and how these values might be shaping the behavior of those around you.
For example, what value is being broadcasted when we spend more time smiling at our phone than smiling with other people?
Likewise, consider how your own behavior has been shaped by those around you, in ways you might not have considered before.
To go back to our simple illustration, do you really prefer Coke over Pepsi?
Or was this preference simply driven by what others around you valued?
Parents and teachers certainly have the privilege to shape children's behavior.
But it is important to remember that through the values we convey in simple day-to-day interactions, we all have the power to shape the behavior of those around us.
Thank you.
(Applause)