Religion affects our behavior by shaping neural rewards
- Published: 14 September 2016
- Written by Jonathan Morgan
- Hits: 1101
If I were to offer you $50 today or the chance to wait four months for $70, which would you take? The way you answer that question reflects what psychologists call delay discounting. That's just a fancy term to describe the way value changes over time – $70 is clearly more than $50, but when that $70 is four months away, it's not worth as much. People vary pretty widely in their discounting rates, and there's lots of research sorting through the various factors that influence these preferences.* As you might have guessed, religion is one of those factors. A new study from our team at Boston University helps explain some of the reasons why.
Most of the work on this relationship suggests that the more religious individuals are, the more likely they are to wait for that larger later reward. Early studies of this relationship were pretty strong, even showing that subliminally exposing people to religious concepts made them more likely to hold out. Things got a little more complicated, however, when a research group studied the difference that culture makes. In the Netherlands, Dutch Calvinists followed the established pattern – the more religious they were, the more often they'd choose the larger later option. But in Italy, the trend reversed! It was the non-religious Italians who were most likely to wait. This raises the question – why?
The researchers from that study explain the difference as rooted in the beliefs of Calvinist Protestants and Catholics. Believing in predestination (a tenet of Calvinism that claims that God decides who’s saved and who isn’t, regardless of people’s actions) is very different than believing in the release from sins through confession (a Catholic sacrament) – so it makes sense that these would give rise to very different behaviors. Our study further complicates the relationship, but also helps to shed light on how this dynamic works within the brain.
While most previous studies in the US were done with college students, our research focused on older adults. We also included a group of participants with Parkinson's disease – a neurodegenerative disorder that damages the dopamine system. This is significant because the dopamine system is involved in making choices involving value. It's also important because there's been some indication that the dopamine system is also crucial for religious thought! So, by looking at behavioral differences between folks with Parkinson's and those without the disease, we hoped to gain some insight into how the brain supports this relationship between religiosity and perceptions of value over time.
Here’s how we set the study up. We had two groups of participants – one group of folks with Parkinson’s disease and one without the disease. Other than this, the two groups were alike in pretty much every other way. Then, using a computer, we gave each person a standard test for delayed discounting (built from questions like the one above). But, sneakily, we gave them the same test twice – the questions from each were randomly interspersed with each other. Before each question of one test we flashed a religious word (like Saint, Temple, or Heaven) and before each question of the other we flashed a neutral word (like Butter, Axe, or Cabin). This technique is called "semantic priming" and works by activating the various networks of associations that we all hold in our minds. So we expected that the religious primes would create different outcomes on the two tests. After they were done with that, we had everyone fill out a number of demographic surveys, one of which asked about various aspects of their religiosity. What did we find?
Contrary to past results, our study found that the more religious participants were the most likely to choose the smaller sooner option! That is, the previous trend reversed. Why would this have occurred? Well, lots of past studies have shown that older age gradually leads people to prefer those smaller sooner options. This is partially due to shortening time horizons (a nice technical way to say there are fewer years left), but also caused by shifting priorities. One study showed that when you use money as the reward, older folks tend to prefer the smaller sooner amount, but if you use other things of value, like spending time with friends and family, then age makes no difference. But, you might protest, all of your participants were older – so this shift doesn't explain your reversal. That's true. But, it has been argued that religion helps people reflect on their priorities and actions more often. This process of reflection could accelerate the way values naturally change over time. To really know if this is the case, though, we'd need more evidence... like maybe some neural evidence!
In order to build that evidence, we looked at the impact of the religious primes. And, in fact, the religious primes didn’t change what people choose – folks were steady in their preferences for smaller sooner or larger later rewards. But the primes did change how quickly people answered. For the questions that were preceded by religious words, people answered more quickly. This suggests that the religious primes were somehow making these choices easier, more fluid, for individuals.
Even more interestingly, this difference only occurred within the group of subjects who did not have Parkinson's. The folks with Parkinson's answered both surveys at about the same speed. This difference between the two groups sheds light on the neural systems that must be facilitating the impact of religion of these choices. In other words, it's very likely that the neural systems damaged by the disease are also those that facilitate this relationship between religion and impulsivity.
To gain more insight into these specific brain regions, we also used neuroimaging – specifically, functional connectivity magnetic resonance imaging, or fcMRI. This allowed us to compare differences in brain connectivity with differences in how dramatically the religious primes quickened people's responses. The results are here to the left – the image only shows regions of the cortex (areas on the outermost part of the brain), but really we were looking at the connection between these regions and the mesolimbic structures of the dopamine system.
You'll notice two regions that are particularly interesting. One is the dorsolateral prefrontal cortex. This area, in connection with mesolimbic structures, is involved in executive processing, thinking about the future, and making decisions, to name a few functions. Crucially, past studies on religious cognition have also pointed to this network. In the left hemisphere, the most interesting region is the caudal anterior cingulate cortex. This region is necessary for making decisions that are based in one's sense of value.
Collectively, this neural evidence and the behavioral differences suggest that religion is influencing people’s decisions by activating particular values for people. Those values may be patience, frugality, or savoring the present. But, once activated, these values – whatever they happen to be – help guide the way we make decisions about whether to hold out for the larger payoff, or take the money and run!
So, think about your church or temple and let me ask you again– would you rather have $50 today or $70 in four months?
*This changing sense of value over time is incredibly important for all sorts of behaviors – from investing for retirement, spending with a credit card, or even substance addictions. It's even present in animals! Psychologists have tested this in pigeons by presenting them with two piles of food – a smaller one closer by and a larger one further away. If you change the amounts and the distances between the two, then you'll get discounting curves (graphs representing that loss of value over time) that look very similar to those of humans!