While everyone was freaking out last week about a study showing a 43% increase in ADHD diagnoses, the results of another ADHD study were also released. The second study didn’t receive media attention, but as far as I’m concerned it’s a lot more interesting than the reports about rising diagnosis rates.

In the second study, researchers looked at how different people solved a virtual maze. The maze consisted eight pathways radiating from the center in a landscape that included rocks, trees and other landmarks.

ADHD Maze Learning and Reward

A birds’-eye view of the virtual maze. Image taken from the original paper: http://dx.doi.org/10.1016/j.bbr.2015.08.019

Each of the eight paths in the virtual maze had a staircase at the end. Four of the eight staircases (marked with red asterisks) had objects hidden at the bottom – so in other words, half the paths contained hidden rewards at the end. Children participating in the study were asked to learn which four paths contained the hidden objects and to complete the maze several times. Ideally their performance improved over time.

At the end of the experiment, participants were asked to complete the maze by finding the hidden objects one more time, but with a twist: the landmarks were removed from the maze.

So what’s this all about?

Researchers were interested not just in how well participants were able to learn which paths contained the rewards but also in how participants learned to navigate the maze.

Specifically, people learning the maze tend to use one of two possible types of strategies: response and spatial.

Response strategies involve learning some sort of fixed pattern about how to get to all the rewards. For instance, numbering the paths, and then remembering to go down paths 1, 2, 4 and 8, would be a response strategy. Memorizing a sequence of actions (“First go down the path directly in front, then go down the one next to it, then skip a path”) would be another response strategy. Thinking of the maze in relation to a single fixed landmark would be yet another example of a response strategy.

Spatial strategies involve building a mental map of which rewards are near which landmarks. The researchers determined that participants were using a spatial strategy if, when describing how they solved the maze, “the participant mentioned at least two landmarks and did not mention using a pattern.”

Now, remember how the researchers ended the experiment by taking away all the landmarks and seeing if the participants could still solve the maze? For people using spatial strategies, this was a big problem because suddenly all the landmarks they were using to map out the maze were gone. People using response strategies had less of a hard time with this because they were relying on a fixed pattern rather than using multiple landmarks to orient themselves. So the people using response strategies were more likely to solve the maze perfectly (without going down any of the wrong paths), even when the landmarks were taken away.

OK, it’s somewhat thought-provoking that people fall into one of these two different groups when solving this simple maze task, but that’s not the most interesting part. Here’s the especially interesting part.

What strategy you use depends partly on how your brain processes reward. If you think about it, learning a response strategy is a more reward-oriented way of doing things because it involves reinforcing a fixed sequence or pattern of actions. On the other hand, spatial strategies rely more on executive functions and being able to take a high-level, objective view of things.

So it turns out that people who use response strategies instead of spatial strategies tend to choose the more reward-based strategy because they’re more reward-seeking. This is where ADHD comes in: people with ADHD process rewards differently and in general are more reward-seeking than people without ADHD. In the study, the researchers found that children with at least one ADHD symptom were more likely to opt for response strategies.

Adults follow a similar pattern. A previous study by the same researchers found that adults who used response strategies smoke more cigarettes, use more cannabis and consume more alcohol.

I think it’s mostly just fascinating that how we process rewards is reflected in this simple maze experiment, but there’s also a practical takeaway: people with ADHD may do better with learning strategies that emphasize reward and repetition.

I’m also curious about what strategies readers think they’d use to solve this maze. If you have any thoughts on this, leave them in the comments!