summary: Researchers have found that a child's socio-economic status (SES) influences the brain's sensitivity to reward. In their study, children from lower SES backgrounds showed lower reward-related striatal activation during money-winning games compared to children from higher SES backgrounds.
This reduced sensitivity to reward in low SES children may be an adaptive response to a less consistent reward environment. This study highlights the profound influence that socio-economic factors have on brain development and behavior.
Important facts:
- The study showed that children from lower SES backgrounds had slower brain responses to reward than children from higher SES backgrounds.
- This reduced reward sensitivity in lower SES children is hypothesized to be an adaptation to an environment that typically provides less consistent rewards.
- This study highlights the importance of including diverse SES backgrounds in research to fully understand the diversity of brain development.
sauce: Massachusetts Institute of Technology
Neuroscientists at the Massachusetts Institute of Technology have found that the brain's sensitivity to rewarding experiences, a key component of motivation and attention, can be shaped by socioeconomic status.
In a study of 12- to 14-year-olds with widely varying socio-economic status (SES), researchers found that children from lower SES backgrounds were less sensitive to rewards than children from more affluent backgrounds. discovered.
The researchers used functional magnetic resonance imaging (fMRI) to measure brain activity as children played a guessing game in which they earned extra money for each correct answer. When participants from higher SES backgrounds guessed correctly, a part of the brain associated with reward called the striatum lit up much brighter than children from lower SES backgrounds.
The brain imaging results were also consistent with behavioral differences in how participants from low and high SES backgrounds responded to correct guesses. The results of this study suggest that low SES environments weaken the brain's response to rewards, and that rewards are often lacking in low SES environments, which may encourage adaptation.
“When you're in an environment with abundant resources and lots of rewards, your brain adjusts in a certain direction. When you're in an environment with fewer rewards, your brain adapts to that environment. “Rather than being overreactive to rewards, we seem to be underreacting on average, perhaps because the environment in which the rewards are available is less stable,” said John, the Grover Herman Professor of Health Sciences and Technology.・Mr. Gabrieli says. He is a professor of brain and cognitive science and a member of the McGovern Institute for Brain Research at the Massachusetts Institute of Technology.
Gabrieli and Rachel Romeo, a former MIT postdoc who is now an assistant professor in the Department of Human Development and Quantitative Methodology at the University of Maryland, are the study's senior authors. MIT postdoctoral researcher Alexandra Decker is the lead author of the paper, which is published today. neuroscience journal.
reward response
Previous research has shown that children from lower SES backgrounds tend to perform worse on tests of attention and memory, and are more likely to experience depression and anxiety. However, until now, few studies have examined the possible association between SES and reward sensitivity.
In the new study, researchers focused on a part of the brain called the striatum, which plays a key role in reward responses and decision-making. Studies in humans and animal models have shown that this region is highly activated during rewarding experiences.
To investigate the potential association between reward sensitivity, striatum, and socio-economic status, the researchers studied different SES backgrounds, as measured by household income and degree of parental education. gathered over 100 young people with
Each participant underwent an fMRI scan while playing a deduction game. Participants were shown a series of numbers from 1 to 9 and asked to guess whether the next number was greater or less than 5 before each trial. They were told that they would receive an additional prize for each correct answer. He would win 1 dollar and lose 50 cents for each guess that is wrong.
Unknown to the participants, the game was set up to control whether the guess was correct or incorrect. This allowed the researchers to ensure that each participant had similar experiences, including periods of rich reward and periods of low reward. In the end, everyone received the same amount of money (in addition to the stipend each participant received for participating in the study).
Previous research has shown that the brain appears to track the proportion of available reward. When rewards are abundant, humans and animals tend to react faster because they don't want to miss out on the many available rewards. Researchers confirmed the same in this study. When participants had most of their answers correct, they tended to respond faster.
“When the brain determines that there is a high probability of receiving a reward in this environment, it becomes motivated to collect the reward, because if you don't act, you're missing out on a lot.” The abundance of rewards ,” Decker said.
Brain scans show that the degree of activation in the striatum appears to track changes in the proportion of rewards over time, and researchers believe this may be due to the motivation to have more rewards to collect. We believe that it may function as a signal.
The striatum lit up more during reward-rich periods and less during reward-poor periods. However, this effect was less pronounced in children from lower SES backgrounds, suggesting that their brains are less well-adapted to changes in reward rates over time.
The researchers also found that during periods of poor reward, participants tended to take longer to react after making a correct guess, another long-established phenomenon. It's unclear exactly why this happens, but two possible explanations are people savoring the reward or pausing to update the reward rate.
But once again, this effect was less pronounced for children from lower SES backgrounds. That is, during periods of low reward, they did not stand still very long after making a correct guess.
“The reduction in reward responsiveness is really surprising. Lower SES environments may be less reliable environments for earning rewards, so the next response may have similar benefits. They may not really expect to get that,” Gabrieli says.
“This just shows the power of the environment. In these adolescents, psychological and brain responses to reward opportunities are being shaped.”
Environmental impact
fMRI scans conducted during the study also revealed that children from lower SES backgrounds had lower striatal activation when they guessed correctly. This suggests that their brains are less responsive to reward.
The researchers hypothesize that these differences in reward sensitivity may have evolved over time depending on the children's environments.
“Socioeconomic status is related to the degree to which rewards are experienced over the lifespan,” Decker says.
“Therefore, receiving more rewards may perhaps reinforce the behavior of receiving more rewards, somehow conditioning the brain to be more sensitive to rewards. Conversely, when rewards If you're exposed to less, your brain may become less able to adapt to rewards over time.”
The study also points to the value of recruiting research subjects from a variety of SES backgrounds, which requires more effort but yields important results, the researchers said. ing.
“Historically, many studies have focused on those who are easiest to recruit: those from advantaged backgrounds. Without efforts to recruit diverse participants, most , children and adults from higher education settings will participate,” Gabrieli said.
“Until recently, we didn't realize that the principles of brain development change depending on the environment in which we grew up, and there was little evidence for the effects of SES.”
Funding:
This research was funded by the William and Flora Hewlett Foundation and the Natural Sciences and Engineering Research Council of Canada Postdoctoral Fellowship.
About this neuroscience research news
author: sarah mcdonnell
sauce: Massachusetts Institute of Technology
contact:Sarah McDonnell – MIT
image: Image credited to Neuroscience News
Original research: Closed access.
“Striatal and behavioral responses to reward vary by adolescent socio-economic statusWritten by John Gabrieli et al. neuroscience journal
abstract
Striatal and behavioral responses to reward vary by adolescent socio-economic status
Disparities in socio-economic status (SES) lead to unequal access to economic and social support. These differences are thought to influence reward sensitivity, which is hypothesized to shape how individuals respond to and pursue rewarding experiences.
However, surprisingly little is known about how SES rewards adolescent sensitivity. Here we investigated how SES influenced adolescents' responses to reward, both behaviorally and in the striatum, a brain region highly sensitive to reward.
Because these different signals independently shape learning and motivation, we examined responses to both immediate reward (tracked by transient dopamine) and mean reward rate variation (tracked by tonic dopamine). Adolescents (n=114, 12-14 years old, 58 females) performed a gambling task during functional magnetic resonance imaging.
We manipulated reward and loss outcomes on a trial-by-trial basis, causing variation between periods of reward scarcity and abundance. We found that high reward rates promoted behavioral responses and increased guess switching. This is consistent with the idea that reward abundance increases response vigor and exploration. Furthermore, immediate rewards reinforced previously rewarding decisions (win, stay, lose, switch) and slowed responses (post-reward pausing), especially when rewards were scarce.
Notably, lower SES adolescents slowed less even after rare rewards compared to higher SES adolescents. In the brain, striatal activation covaried with average reward rate over time, showing greater activation during reward blocks. However, these striatal effects were reduced in lower SES adolescents.
These findings indicate that the striatum tracks fluctuations in reward rates, which shape decision-making and motivation. Furthermore, lower SES is thought to weaken reward-driven behavioral and brain responses.
Statement of materiality
Low socio-economic status (SES) reduces access to resources and opportunities. Such disparities can shape reward sensitivity, which in turn can influence how individuals respond to and pursue rewarding experiences.
Here we show that low-SES adolescents have reduced reward sensitivity in their brains and behaviors. The striatum, a brain region highly sensitive to reward, showed greater activation during periods of high reward and tracked fluctuations between reward-rich and reward-poor task phases. However, lower SES correlated with reduced reward-driven striatal responses and decreased infrequent post-reward responses.
These findings link lower SES to lower reward responsiveness, which may trigger a cycle of reduced reward seeking, leading to fewer positive experiences, and further reducing reward sensitivity.
