Understanding human behavior is the crux of psychologists’ work and neuroscience is part of that understanding. To better grasp the mental processes that undergird thoughts, emotions, and behaviors, psychologists have long worked together with the neuroscientists who study the structure and processes of the brain and nervous system. Psychology and neuroscience overlap now more than ever as technology advances, which means psychologists have more opportunities to improve people’s lives by understanding how nervous system activity drives complex thoughts and behaviors linked to mental health treatment and prevention. Neuroscientists, too, can learn more about their field through the work of psychologists.
“The brain creates the mind, so understanding how this happens shines new light on our psychological theories and interventions,” said Kristen A. Lindquistopens in new window, PhD, an associate professor of psychology and neuroscience at the University of North Carolina (UNC) at Chapel Hill. “In turn, understanding psychological theory and measurement of behavior means we can understand the functional meaning of firing neurons and blood flow to brain regions.”
While psychologists’ understanding of the biological processes involved in behavior has been evolving for years, a few neuroscience-related trends stood out in 2021.
Brain connectivity
Neuroimaging has long helped researchers understand the brain regions associated with specific traits or behaviors. More recently, psychologists have begun to study the connectivity between various regions. Rather than simply identifying increased blood flow in one area, psychologists are using advanced technology to study the correlation between blood flow changes in more than one brain region. While typical brain imaging suggests the magnitude of change, connectivity highlights possible dynamics at play in more complex behaviors.
A simple example: If you see a piece of chocolate, your prefrontal cortex may light up along with your pleasure center, suggesting you’re trying to resist the thing you crave. Studying this type of connectivity helps psychologists understand the processes behind certain behaviors and psychological disorders and create better treatments, says Lindquist.
For instance, a psychologist studying self-regulation already knows which area of the brain is active during moments of stress. Understanding how the prefrontal cortex and amygdala engage, and in what direction, could help psychologists diagnose and more effectively treat a patient who struggles to self-regulate.
A meta-analysis published by Lindquist and colleagues in 2020 examined brain connectivity patterns in younger and older adults (Affective Scienceopens in new window, Vol. 1, 2020). They found younger adults have more connectivity in the subcortical regions of the brain that impact reactivity, while those ages 65 to 80 have greater connectivity in the prefrontal cortex, with less neural activity between the prefrontal cortex and other regions—suggesting that young adults may be more responsive to emotional stimuli, while older individuals tend to be less sensitive to these stimuli (and, in general, more content).
While this analysis suggests important ways emotional responses to external stimuli can change across the life span—and that older adults tend to have better emotional experiences than younger ones—it also identifies an important baseline that could help psychologists understand and identify aging-related brain disorders such as geriatric depression and dementia.
“Connectivity research is setting the stage for understanding how brain connectivity is different in people who exhibit typical versus atypical behaviors, which can both help psychologists treat these affective outcomes and help caregivers and family members understand what’s happening in their loved ones,” Lindquist said.
Lindquist is also studying the neural networks at play during episodes of anxiety, and she has found evidence that different connectivity patterns can produce the same experiences of anxiety.
In other words, people can have the same output but different neural pathways to produce it. Jessica Cohen, PhD, director of the Cohen Lab and an assistant professor in the Department of Psychology and Neuroscience at UNC Chapel Hill, and fellow researchers have made significant inroads to measuring these pathways by comparing resting brain activity in people who perform differently on various cognitive tasks. They found that resting patterns of brain connectivity change much more than previously understood, and in ways that are related to subsequent task performance (Network Neuroscience,opens in new window Vol. 5, No. 1, 2021).
As scientists continue to study how brain connectivity relates to active cognition and behavior, “these findings offer the possibility that neural networks are more flexible and encode more detailed information in those who perform better,” said Derek J. Snyder, PhD, APA’s senior director for science strategic partnerships. “Overall, studies like these offer new insights on individual differences in brain plasticity across networks that process information and shape complex behaviors linked to well-being,” he said.
Brains converging
Understanding the human mind also requires understanding the social environment—what happens in the brain when we interact with other people. Using brain-imaging studies of pairs in social interactions, psychologists are now able to understand how social dynamics affect cognition, according to Thalia Wheatleyopens in new window, PhD, a professor of human relations at Dartmouth College.
“We’re constantly influencing and adapting to others, relying on one another to help us think,” said Wheatley. “We’ve been so focused as psychologists on mapping out the single brain, and now we’re beginning to understand what happens in the brain when two minds are dynamically engaged.”
A growing body of research has provided a foundation for newer, more complex research about the effects of social interaction on cognition. Uri Hassonopens in new window, PhD, a professor of psychology and neuroscience at Princeton University, has studied how two brains temporarily converge during communication.
For example, in one 2017 study, Hasson and his colleagues suggested different interpretations of a short story to two groups of participants and used neuroimaging to understand how each interpretation affected their brain activity as they listened to the story. Listeners’ brain activity aligned depending on the context they received before the story, suggesting that information from news sources can shape people’s beliefs and essentially result in groupthink (Psychological Scienceopens in new window, Vol. 28, No. 3, 2017). “If one line is enough to make you similar to other people, imagine how what you are listening to all day does,” Hasson said.
What’s important, Wheatley says, isn’t just that taking in the same information can result in similar brain activity. Science also suggests people are naturally drawn to those who think like them. In one study, Wheatley and colleagues found that friends shared similar brain activity (Nature Communicationsopens in new window, Vol. 9, No. 332, 2018). “The further out you go in a person’s social network, the more dissimilar people’s minds are,” she said.
Wheatley says future work could help psychologists understand not only the importance of conversation between peers, but how couples or parents and children interact. In a 2020 studyopens in new window, Hasson, Wheatley, and colleagues showed participants ambiguous video clips and then had them interpret what they saw in groups. After a period of discussion, the researchers scanned the group and found group members’ brain waves were more synchronized, suggesting conversation can help align people’s brains.
While understanding when synchrony happens is an important piece of the puzzle, Wheatley says, research should also investigate other dynamics such as when people may want to diverge in their thought patterns, breaking synchrony to facilitate independent thought. This understanding not only will help researchers understand cognition but also could help clinicians in practice. “When we understand more about the hidden dynamics of conversation, there will be natural implications for talk therapy,” she said.
Using polygenic risk scores
Thanks to recent advancements in the field of genetics, psychologists are seizing on new opportunities to study the specific genes associated with susceptibility for certain behaviors and, more important, how to use this knowledge to help people.
Even 20 years ago, psychologists referred to a now outdated form of genetic paneling called candidate-gene paneling, which identified individual genes that could predict people’s behaviors. “We thought then, by focusing on just one specific gene rather than a constellation of genes, that if you show expression on a particular candidate gene related to serotonin, you’re more likely to get depressed,” said Daniel S. Shawopens in new window, PhD, a professor of psychology at the University of Pittsburgh.
A more comprehensive approach to research known as genome-wide association studies uses algorithms to study the entire genome and identify genes that could contribute to specific behaviors using a scoring model called polygenic scoring, which means psychologists have more basis for understanding risk factors that contribute to hereditary behavioral patterns.
Jinni Suopens in new window, PhD, an assistant professor of psychology at Arizona State University, says psychologists have been combining their knowledge about the impact of environment on behavior with these polygenic risk scores to help people develop better coping mechanisms.
“The idea that both genes and the environment contribute to complex psychosocial outcomes is not new,” Su said. “Polygenic scoring is a new method that can help psychologists characterize people’s genetic predispositions toward certain behaviors and help us address questions about environmental factors that could exacerbate or lessen that genetic risk.”
For example, Shaw and his colleagues conducted a randomized controlled study to understand how an 8-session, family-based intervention for children ages 2–10 (called the Family Check-Up) might help those with genetic risk factors for aggressive behavior. While untreated children with high genetic susceptibility showed the highest levels of aggressive and oppositional conduct during childhood and adolescence, those receiving the Family Check-Up showed much lower levels. These results suggest that children who are genetically sensitive to adverse environmental influences may benefit the most from early interventions (Development and Psychopathology, Vol. 31, No. 5, 2019).
Su’s work focuses on genetic and environmental influences on alcohol use disorder, which usually occurs in the teen or adult years. Her studies that show how a genetic predisposition toward alcohol abuse manifests in youth enable families to recognize the signs and respond with evidence-based interventions that can prevent progression of the disorder.
Su found in a study published in 2021 that people with a genetic propensity for alcohol use disorder are more likely to have sensation-seeking personality traits, and that social support can prevent those traits from developing into problem drinking (Journal of Abnormal Psychologyopens in new window, Vol. 130, No. 5, 2021). This is consistent with earlier research that found that individuals who have a higher polygenic risk score for alcohol dependence are less likely to abuse alcohol if they are in a Family Check-Up intervention group (Kuo, S. I., et al., Prevention Scienceopens in new window, Vol. 20, No. 7, 2019).
“Knowing how the genetic risk for alcohol manifests can help us work with sensation seekers and help them find healthy ways to channel their predisposition,” said Su.
In the future, Shaw hopes to see more diverse genetic risk scores—currently, psychologists rely on scoring developed using data from primarily White participants—and further studies that measure genetic susceptibility for other attributes and behaviors. He also hopes geneticists and neuroscientists can work together to more accurately link specific genetic profiles to individual differences in activation or volume in specific areas of the brain. “For example, polygenetic risk scores capturing impulsivity could be linked with the frontal limbic system, so it makes sense a person would be impulsive,” he said.
