Dinner last Friday was a hoot. Wine and conversation flowed; dishes were perfectly seasoned. The reward center of your brain lit up like the Fourth of July.
This week you have a decision to make: where to eat? The choices are infinite. Remembering last week’s raving success, you quickly make a reservation at a restaurant owned by the same chef.
Studies show that rewards—food, social events, money—spread through our memories, creating a mental treasure map of associations. These associations help us decide whether a new choice might lead to something good.
But how many mental steps can a reward travel? Your brain might associate the same chef with a great night out, but what about the same neighborhood? Or the song that was playing on the ride over?
In a new study published Aug. 8 in Cognition, psychologists at the University of Chicago looked at how many jumps a reward can travel in our memory.
Turns out, pretty far.
“The idea that reward spreads through memory is not a new one,” said Asst. Prof. Akram Bakkour, who led the study alongside first author and UChicago graduate student Seoyoung Lee. “But we show that reward can spread through relatively complex memory structures more so than previously thought.”
Mental gymnastics
To test how far a reward can travel, researchers first built a map.
At each point of the map, Lee and Bakkour placed a colorful disc (think pogs if you’re a ‘90s kid) with a unique pattern. Each disc was connected to two others, creating a web-like network—an approximation of how memories get grouped and associated in our minds. Some were more tightly grouped in a “community,” while others maintained only a single, weaker connection.
With the map now built, it was time to test if people could remember it.
Importantly, participants never saw the whole network. Instead, they were shown linked discs either in pairs or one at a time as they were “walked” through the map at random.
“We've really blown up the complexity of this problem,” said Bakkour, whose lab’s mission is to understand how memory supports decision making.
After viewing about 1,000 sequences of images on their screens, participants were quizzed on what they thought the map looked like. Researchers asked them to group images in a way that made sense to them, then draw lines between them.
The maps they remembered weren’t perfect, but participants picked up on a key detail—the clustered “communities” of images.
“They're very bad at the line drawing, and they're only somewhat good at grouping them,” Bakkour explained. “But we do have evidence that they group items that are within the community. That's our main measure of learning.”
Reward unlocked
With the mental map now locked in, it was time to introduce the reward.
In another experiment, researchers deemed one random disc “the reward,” demarcated with a green dollar sign. After viewing the patterned discs one at a time, participants were asked to choose which ones were most likely to lead to a reward.
What researchers expected was that participants would choose the colorful discs within the same community as the reward. Likewise, they guessed that the further from the reward a disc was, the less likely participants would choose to associate it with the reward.
Their hypothesis was confirmed, with one major caveat.
Participants chose discs nearest the reward, even several steps away, but only based on their memory of the map, not the actual map. And their memories weren’t always accurate.
“It's an interesting little twist,” Bakkour said. “We know memory is not perfect; there are distortions that get inserted. Our argument is that there is a spread of reward that is graded, but based on what's in their mind, not what we taught them.”
The research team notes that if participants learned the map over a longer period of time, or even slept between sessions, their recall might improve. But even in 40-minute sessions, people were able to build a linking chain of memories leading them to treasure.
According to Bakkour, this is even more proof of how amazing our memories are. In unfamiliar situations, our minds can leap between memories and generalizations to help us navigate infinite possibilities.
“We can’t experience everything in the world,” Bakkour said. “But having this intricate, complex memory system allows us to reminisce and imagine the future in service of making the best decisions.”
Citation: Lee, S., & Bakkour, A. (2026). Reward selectively preserves relational structure in memory. Cognition, 277, 106673. https://doi.org/10.1016/j.cognition.2026.106673
