Summary: New research sheds light on how the brain’s
prefrontal cortex evaluates whether to persist or quit in uncertain
situations. Using tasks mimicking real-life dilemmas, researchers found
that different brain regions influence patience and adaptability.
Damage
to the ventromedial prefrontal cortex reduced persistence, while damage
to other areas impaired learning from feedback. These findings
highlight the complex calculations our brains perform to weigh rewards,
shedding light on behaviors tied to anxiety, addiction, and depression.
Key Facts:
- Brain Regions and Patience:
The ventromedial prefrontal cortex is crucial for evaluating the value
of waiting, while other regions affect adaptability in decision-making.
- Lesions and Impairment:
Individuals with brain damage in specific areas showed reduced
persistence or struggled to learn when quitting was the better choice.
- Broader Implications:
Insights could help address conditions like addiction and depression,
where persistence and reward processing are often altered.
Source: University of Pennsylvania
You’re
standing at a bus stop, waiting for a ride that seems like it will
never come. At first, you’re hopeful that it will be here any second.
But as the minutes laggardly drag on, doubt creeps in. Should you keep
waiting, or is it smarter to start walking or call for a ride?
“It’s
a classic dilemma. “Do you persist with the belief that the bus is on
its way, or do you cut your losses and move on to something else?”
asks Joe Kable, a psychologist in the School of Arts & Sciences at
the University of Pennsylvania.
The question isn’t just whether you have the patience to wait, he says.
“It’s about understanding when it pays off to stick with something and when cutting your losses is the better choice.”
Kable
draws parallels to two competing ideas on perseverance: Penn
professor Angela Duckworth’s bestseller “Grit,” which champions the
value of persistence, and “Quit” by Penn alum Annie Duke, which explores
the wisdom of knowing when to let go.
In a paper published in the Journal of Neuroscience,
Kable, collaborator Joe McGuire of Boston University, and a team of
researchers examine the neural underpinnings that belie one’s decision
to persist or quit, “and how the brain’s executive function helps us
decide when to wait or walk away.”
The
research looks at individuals with damage to different parts of the
prefrontal cortex, the seat of executive decision-making, revealing how
the brain evaluates uncertainty and guides those split-second
decisions.
These findings could bear implications for understanding and
potentially treating conditions like anxiety, depression, substance
abuse, and addiction, which often involve altered reward processing and
persistence behaviors.
Lessons gleaned from the waiting game
Kable
and his team investigated how different regions of the frontal cortex
influence decisions to persist or quit using a task designed to mimic
real-world dilemmas.
In the experiment, participants decided when
to “cash out” coins that increased in value over time. Some coins
matured quickly while others required a longer wait, depending on the
task condition.
“We wanted to create a situation where persistence sometimes paid off and sometimes didn’t,” Kable says.
In
the high-persistence (HP) condition, maturation times were uniformly
distributed, so always waiting until the coin reached its maximum value
was optimal.
In the
limited-persistence condition, the maturation times followed a
heavy-tailed distribution, meaning that if the coin did not mature
within the first couple of seconds, it was better to stop waiting.
Participants weren’t told about these distributions, forcing them to learn from experience.
Their study had 18 controls and 31 participants with brain lesions, grouped by the affected regions of their frontal cortex.
The
lesion groups included people with damage to the ventromedial
prefrontal cortex (vmPFC), the dorsomedial prefrontal cortex (dmPFC), or
anterior insula (AI), and a “frontal control” group with lesions in
other areas of the frontal cortex.
By comparing these groups, the
researchers aimed to pinpoint the specific contributions of different
brain regions to persistence and quitting.
“By studying
individuals with these specific lesions, we could directly test how
different parts of the brain contribute to persistence versus quitting,”
says Camilla van Geen, first author of the study and a Ph.D. candidate
in the Kable Lab.
The team found
that participants with vmPFC damage waited less overall, particularly
in the HP condition where persistence was the optimal strategy.
“The vmPFC seems to play a crucial role in evaluating the subjective value of waiting,” van Geen says.
“Damage
to this area doesn’t just reduce patience; it fundamentally alters how
people assess whether persistence is worthwhile in the first place.”
However,
participants with lesions in the dmPFC or AI showed a different pattern
of impairment, Kable says. They waited about the same amount of time in
both conditions, failing to distinguish between situations where
persistence was advantageous and those where it wasn’t.
“It wasn’t just a matter of self-control,” Kable says.
“These
participants couldn’t adjust their strategies based on feedback from
the environment, particularly from experiences where quitting was the
better decision.”
Van Geen also used a computational model to
further analyze these decision-making processes, which revealed that the
vmPFC group had a lower baseline willingness to wait, while the
dmPFC/AI group struggled to learn from quit trials.
A dynamic relationship with rewards
“This
isn’t just about self-control or impulsivity; it’s about how our brains
estimate value and adapt in real time to decide when waiting pays off,”
van Geen says.
One surprising finding was that individuals with lesions in the
lateral prefrontal cortex, a region often associated with self-control,
performed just as well as healthy controls.
This result suggests
that while the vmPFC helps determine the baseline value of waiting and
the dmPFC and AI contribute to learning from feedback, the lateral
prefrontal cortex may not be as central to persistence as previously
thought.
“We often think of persistence as a good thing and quitting as a failure,” van Geen says.
“But
really, they’re two sides of the same coin. Both require complex mental
calculations and both can be the right choice depending on the
situation.”
As a follow-up, the researchers are turning their
attention to neurotransmitters like dopamine and serotonin to better
understand how these systems influence persistence.
“We’ve
completed a study where participants take drugs that enhance these
systems to see how it affects their willingness to wait,” Kable says.
“The preliminary results suggest serotonin plays a particularly interesting role, but we’re still working through the data.”
Future
work will also focus on how brain regions and neurotransmitter systems
interact. “Do these systems influence each other, or do they operate
independently? That’s one of the big questions we’re tackling next,”
Kable says.
Joseph W. Kable is the Jean-Marie Kneeley President’s
Distinguished Professor of Psychology at the University of
Pennsylvania’s School of Arts & Sciences.
Camilla van Geen is a Ph.D. candidate in Penn Arts & Sciences.
Other
authors are Yixin Chen of Boston University, Rebecca Kazinka of the
University of Minnesota, and Avinash R Vaidya of the NIDA Intramural
Research Program.
Funding: The research was
supported by the National Institutes of Health (grants R01-DA029149,
F32-DA030870, and R21-MH124095 and award ZIA DA000642), and the
National Science Foundation (Grant BCS-1755757).
About this self-control and neuroscience research news
Author: Nathi Magubane
Source: University of Pennsylvania
Contact: Nathi Magubane – University of Pennsylvania
Image: The image is credited to Neuroscience News
Original Research: Closed access.
“Lesions to different regions of frontal cortex have dissociable effects on voluntary persistence” by Joe Kable et al. Journal of Neuroscience
