How do you decide when to stick with a goal or when to abandon it for a potentially better option? Recent research published in Human behavior highlighted this dilemma. The study reveals that a brain region known as the ventromedial prefrontal cortex (vmPFC) plays a central role in our tendency to stay committed to our goals.
One of the main motivations for the study was to bridge the gap between behavioral economics, which provides many examples of overcommitment, and neuroscience, which can offer insight into the brain regions and processes involved. Previous research has shown that people often stick to their chosen goals due to emotional and cognitive biases, but the specific brain mechanisms behind this behavior were not well understood. Researchers hypothesized that the ventromedial prefrontal cortex (vmPFC) may play a central role in mediating goal engagement by influencing attention and decision-making processes.
“Economists and psychologists are often interested in describing how humans are “irrational.” One example is “sunk cost bias,” which occurs when people are too reluctant to abandon a goal even if it fails. We wanted to study how these trends relate to brain processes that could actually help us function in the real world,” explained study author Eleanor Holton, a doctoral student at the University of Oxford.
To explore this, researchers used a two-pronged approach: functional MRI (fMRI) and studies involving patients with brain damage. They recruited 30 participants for the fMRI study and 26 patients for the lesion study.
In the fMRI study, participants engaged in a task designed to mimic real-world decision-making scenarios. They were asked to fill virtual nets with seafood, with each net representing a goal. Participants could choose from three types of seafood (crab, octopus and fish), each associated with different quantities displayed as bars on the screen. The challenge was to decide whether to continue enriching the current network or move to another, knowing that changing networks would mean losing all the progress accumulated in the current network.
The task was carried out in several phases. Initially, participants were trained outside the scanner, followed by a main session inside the fMRI scanner during which they completed 300 decision trials. Then, they performed 100 additional trials outside the scanner with an additional spatial attention task. This spatial task required participants to remember the location of seafood, looking in more detail with their attention.
The experimental setup ensured that seafood offering values varied gradually, with occasional large changes to simulate real-world fluctuations in target attractiveness. This setup allowed researchers to model different decision strategies and compare participants’ behavior to an optimal decision-making model.
Analysis of fMRI data revealed that the vmPFC played a crucial role in monitoring progress toward goals and guiding engagement. Activity in the vmPFC was observed both during decision making and between decisions, suggesting that it helps maintain focus on the current goal. This was confirmed by the results of the spatial attention task, where participants showed better memory for locations associated with their current goal compared to alternative goals.
Interestingly, the study found that participants tended to overcommit to their goals. Even when an optimal model suggested a change, participants persisted more than necessary. This bias toward persistence was linked to increased goal-directed attention, indicating that as people progress toward a goal, their focus sharpens toward achieving it, making them less sensitive to attractive alternatives.
To test the causality of the vmPFC’s role in goal engagement, researchers turned to studying lesions. Patients with vmPFC damage had significantly lower persistence biases than other patients and healthy controls. These patients were less likely to stick with a failed goal, suggesting that the vmPFC is crucial for the persistence bias observed in healthy individuals.
“We find that certain areas of the brain are necessary for people to exhibit sunk cost biases, that is, a tendency to persist with a goal even if it would be better to abandon it,” Holton said at PsyPost. “Patients with damage in this area of the brain are more flexible when it comes to moving to better goals, but they are also less focused on their chosen goals. Although brain-injured patients performed better than healthy people in this particular study, in the real world, sunk cost biases are likely to help us stay focused on the goals we set for ourselves. .
Despite this valuable information, the study had its limitations. The sample size, especially in the lesion study, was relatively small, which could limit the generalizability of the results. Additionally, although the tasks were designed to simulate real-world decision-making, they were still controlled laboratory tasks.
The study opens several avenues for future research. One direction might involve exploring how individual differences in vmPFC activity influence decision-making in various contexts, such as financial investments or personal relationships. Additionally, studying how other brain regions interact with the vmPFC during goal pursuit could provide a more comprehensive understanding of the neural basis of decision-making.
“While our work provides us with good evidence of how the brain might be able to strike a balance between goal persistence and abandonment, it will be equally important to establish any clinical relevance for psychiatric disorders such than ADHD, where people are often more likely to “give up” on a current goal, or OCD, where patients can be overly persistent,” Holton noted.
The study, “Goal commitment is supported by vmPFC through selective attention,” was authored by Eleanor Holton, Jan Grohn, Harry Ward, Sanjay G. Manohar, Jill X. O’Reilly, and Nils Kolling.