Psychology Professor Examines Relation of Fear, Empathy Through Subject With Rare Brain Disorder

Psychology professor Abigail Marsh says fear is one of the greatest determining factors of our behavior and how we relate to those around us. She and a team of researchers published a study today in Proceedings of the Royal Society B to explore the concept of fear through a woman born with a rare brain disorder that prevents her from experiencing fear. 

Understanding Fear in Others

The woman, referred to as SM, has been featured in NPR’s Invisibilia, The Wall Street Journal and Time due to her Urbach-Wiethe syndrome, a rare genetic disorder that resulted in the loss of her amygdala. As a result, SM cannot experience fear and is unable to recognize signs of fear in others. 

The amygdala is a part of the brain implicated in both the expression of conditioned or learned fear and social fear recognition. 

“SM’s willingness to participate in research studies over the years has made invaluable contributions to science,” says Marsh. “This is one of many studies for which she has volunteered that has allowed us to better understand fundamental phenomena like emotion, empathy and morality.”

Marsh co-authored the study with Dr. Peter Turkletaub, associate professor of neurology and rehabilitation medicine at Georgetown, Elise Cardinale (C’10, G’17), a postdoctoral fellow at the National Institute of Mental Health and Katie O’Connell, a Ph.D. student in Georgetown’s Interdisciplinary Program in Neuroscience. The team sought to answer whether losing the ability to feel fear causes someone to not understand fear in others.

“If so, this would tell us something really interesting about empathy,” says Marsh. “It would strongly support the idea that when we empathize with people, we do it by trying to imagine or simulate their experience. If you can’t feel a state, you can’t simulate it in others, either. Therefore you cannot stand in their shoes and understand where they are coming from.”

Predicting the Emotion 

The researchers conducted a study in which SM read a series of short, hypothetical statements that one person could make to another. Each statement was designed to elicit one of five emotions from her – anger, disgust, fear, happiness or sadness. 

Cardinale, who worked in Marsh’s lab as an undergraduate research assistant and who went on to earn her Ph.D. in psychology from Georgetown, developed the statements that have been used in several subsequent studies. 

The fear statements are very direct and include phrases such as  “I want to punch you,” or “I could kill you if I wanted to.” After reading each statement, SM and control participants were asked to predict what emotion someone would probably feel in response to each statement.

Control participants in the study – all of whom were adult women and demographically similar to SM – had little difficulty predicting the statement “I could kill you if I wanted to” would most likely invoke a feeling of fear that Marsh says suggests they were successfully simulating the likely state of the target of these statements. 

The results for SM were somewhat different. 

“Whereas SM was generally successful predicting when others would feel anger, happiness or disgust, she could not predict when others would feel fear,” Marsh explains. “This suggests her amygdala lesions have not only robbed her of the experience of fear, but of the ability to understand others’ fear.”

Similarities and Crucial Differences

This inability to understand others’ fear indicates that SM is similar in one way to another group that Marsh’s lab studies – psychopaths. Both have impaired experiences of fear and have difficulty empathizing with the fears of others. 

However, there are crucial differences between them. 

While neither psychopaths nor SM can predict the fear of others, psychopaths also lack the ability to appreciate that making others feel fear is morally wrong. SM has normal judgments about causing others to feel fear. 

Marsh explains, “This distinction is important because it suggests that difficulty empathizing with others’ fear doesn’t automatically make a person psychopathic.”

Marsh explains that the difference between the two is likely due to developmental factors. 

“People with psychopathy have problems in their amygdala from very, very early in childhood, which affect the development of their brain during childhood,” Marsh says. “But SM’s amygdala is believed to have been intact when she was a child, and only later did her Urbach-Wiethe syndrome cause it to be destroyed.” 

Marsh says this gives an important indication that links empathy and morality.

“They are often related, but can be dissociated,” she says, “and it is likely that very early childhood is important for learning to connect your empathic responses to your moral judgments.”

-by Shelby Roller (G’19)