Probing Emotional Mysteries

What does every good emotion detective need?

That’s the question APS Past President Robert W. Levenson posed during his Award Address as a 2014 APS William James Fellow.

“Emotion is all around us, but it’s also surprisingly difficult to quantify,” Levenson said during his presentation at the 26th APS Annual Convention in San Francisco. The University of California, Berkeley, professor of psychology addressed the challenges of bringing real-world emotions into the lab.

Emotional phenomena we experience every day provide some clues to help unravel the mysteries of human emotion, he said. For example, when we see something disgusting — say, someone taking a bite out of a green, fuzzy sandwich that has been in the fridge for too long — we engage in a remarkable choreography of behavior. In response to a disgusting stimulus we not only wrinkle our noses and make a facial expression of disgust, but our heart rates and skin conductance also spike.

“Underneath the hood of emotion, there are all these wonderful clues about how the nervous system is organizing these systems that most of the time are operating in a very uncoordinated way,” said Levenson.

In order to understand these complex physiological processes, an emotion detective needs a good magnifying glass, he said. Levenson’s “magnifying glass” consists of the tools and techniques that allow him to study emotions in the most naturalistic contexts possible — even in the lab.

Levenson explained: “One of the important things about the magnifying glass is that it has to be able to focus on behavior, which is very complicated; physiology, which is arguably even more complicated; and also emotional experience, each of which has to be measured in challenging ways that don’t interrupt the flow of emotion, in ways that can be quantified quite precisely, and ways that can be compared and coordinated.”

In addition to a magnifying glass, all emotion detectives need to find some good mysteries to solve. Levenson’s research has attempted to answer one of the oldest mysteries in the field: Was William James right about the origins of our emotional experiences? James suspected that we determine that we’re experiencing an emotion based on changes in our physiology. He proposed that instead of an emotion triggering the physiological response of the body, the physiological changes in the body cause us to feel an emotion.

To determine whether James was correct, Levenson “tricked” people into making particular facial expressions by having subjects pose each part of the face until they’d ended up with the wrinkled nose and drawn eyebrows of a disgusted expression. After people had arrived at the disgusted facial expression, their heart rate and skin conductance increased. And about 60% of the time subjects reported feeling disgusted.

Levenson has also investigated how individual differences affect the experiences of emotions. In research on the effects of aging, he has found that as we age, our emotional function not only stays largely intact but in some cases may actually improve.  For example, researchers have found that older people are better at identifying emotions in others, are more skilled at down-regulating emotion using positive appraisal, and show greater emotional reactivity to the distress of others.

Figuring out what somebody else is feeling moment to moment is one of the most difficult tasks in emotional processing. Yet when Levenson had subjects watch and rate videos of couples interacting, he found that older subjects were much better at correctly evaluating emotions as they varied throughout the interaction.

“There’s something about the older brain or living a long life that helps us get better at this,” says Levenson. “But it raises the interesting question of how in the world does this happen in a brain that is getting worse at cognition and a body that is getting worse at everything.”

Therefore, aging “retunes” the brain like the dials on a soundboard, he explained. Aging reduces inhibitory circuits in the brain, potentially causing increases in generation of emotion. Essentially, losses can turn to gains when it comes to aging and emotional functionality.

Levenson has found that the serotonin transporter gene may have large implications for helping understand more distal outcomes of emotion. In people with the short allele of this gene, serotonin lingers in the synapse and is not cleared as efficiently. Levenson has found evidence suggesting that the short allele seems to increase people’s sensitivity to their environment.

People with two copies of the short allele showed greater emotional distress when they viewed upsetting images and laughed more while looking at cartoons. In a “karaoke task,” people sang an old rock ’n’ roll song out loud, then watched a video of themselves singing. People with two copies of the short allele reported more amusement and embarrassment after watching themselves singing compared to people with at least one copy of the longer allele.

Research on this gene has been controversial, Levenson cautions. Single genes account for only tiny amounts of variance, and a great challenge for psychological science is finding out how to carefully measure environments and how they enhance and depress these effects.

In studying neurological patients, Levenson has found that emotional deficits caused by diseases like frontotemporal dementia and amyotrophic lateral sclerosis (ALS) can reveal key information about how emotions work. In addition to deficits are “perforations” — the interesting places where disease modifies just a piece of the emotion system without changing the emotion completely.

“A perforation is not a wholesale deficit, but it’s something that becomes disconnected,” he said. “It either increases or decreases independent of the rest of the emotion.”

As an example, Levenson pointed to ALS, a disease that causes motor neuron degeneration. About 50% of ALS sufferers develop a symptom called pseudobulbar affect — unusually intense bouts of crying and laughing. However, they don’t have bouts of behavior that look like anger, fear, or disgust.

“There’s a perforation that packages these two emotions together in some way that’s vulnerable to this disease,” says Levenson. “They’re not interchangeable parts. We need to pay attention to which emotion we’re studying. They may function quite differently in the brain.”

In a final piece of advice, Levenson encouraged fellow emotion detectives to pick good research questions — a task that isn’t always easy. And don’t forget to polish and calibrate your magnifying glasses, he advised.