Location Memory Dictates Your Food Choices

Remember your basic psychology class in college, and watching those videos with rats poking their noses around mazes trying to find that glorious, glorious cheese? Those exercises looked at how rewards -- in the form of food -- can develop an animal's memory. It makes sense, then, that there would be some overlap between how we choose what to eat and our memories of where that food is located.

A new study out of Switzerland proves that this is true.

The study asked participants to rate 48 different snacks, each presented in a specific location on a computer screen. The participants were split into two groups and hooked up to an MRI machine: One group was shown only the location of the snack, the other with the snack in the center of the screen. They were then asked to choose between two snacks. Crunching those numbers, it showed that locational memory was a more powerful indicator of snack choice than preference.

This makes sense: We've all had those moments of trying to decide which restaurant to eat at but end up going to the usual place. But what does this study mean? I emailed Dr. Sebastian Gluth, the study's lead author, about the findings from the study.

Did the findings surprise you?

Dr. Sebastian Gluth: The behavioral findings (that better memorized choice options and snacks are preferred) did not surprise us. It is known that decisions are influenced by many contextual and psychological factors. For example, options that receive more attention during the choice process are also preferred. In fact, it was our hypothesis that memory would induce such a choice bias.

The MRI results are indeed a bit surprising. We found that the hippocampus, a region strongly associated with long-term memory, mediates the behavioral bias via a region associated with decision-making. One could have expected that the hippocampus plays a "neutral" role, but it seems as if the hippocampus is involved in the choice process more directly.

Why do you think our brains work this way?

Gluth: In many cases, it might be adaptive to choose options that are better memorized. Previous research has shown that valuation has an impact on decisions, meaning that better things are usually also better remembered (but the same is true for very bad things). We went the other way, and asked whether better remembered things are preferred. Still, it might often make sense to let yourself be guided by your memory.

How important is location memory compared to other factors we use to decide what to eat?

Gluth: When our participants were able to remember both choice options, they were not biased by memory (since memory strength was equally high for both options). However, when they remembered only one option, then memory came into play. We saw this by comparing how often they chose the better of two options, depending on whether only the better or only the worse options was remembered. In both cases, participants tend to choose the better option, but this was about 25% less likely when only the worse option was remembered.

In other words, the subjective value of the snacks (i.e., the attractiveness of the snacks) is most important, but memory also had a substantial effect on the decisions. Of course, this effect becomes stronger, and the more likely it is that some options are forgotten. In other words, people with poor memory abilities might also be more prone to this memory bias on choices.

Is there a way we can use these findings in order to promote better health? Can we hack decision-making in order to get people to eat better?

Gluth: This is difficult to answer and I am a bit hesitant to do so. I have to emphasize that what we did is basic (and not applied) research, and the extent to which our findings are important for every-day life still have to be investigated. Apart from that, it might be that some strongly advertised but not very healthy food options get chosen due to this memory bias (they might just be the first things that come to our mind). In such cases, it would be important to try to make deliberate choices and to always think about alternatives instead of simply choosing one's (unhealthy) default food option.