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Out of everything you do today, eating a chocolate bar might be what you will remember best. It seems that eating sticks in our mind far more than other activities, prompting a rethink of how our memory prioritises different experiences.

We already know that memory can influence how much we eat. Thinking about food, for example, can make us feel fuller so we eat less during our next meal. Benjamin Seitz and his colleagues at the University of California, Los Angeles responded to this concept and looked at whether eating is better remembered than other behaviour.

To test this, the team asked 159 men and women to each eat 30 sweets from a bowl while watching a video on a screen that was surrounded by different symbols. They then had to repeat the task, but this time move 30 sweets from a bowl to an opaque jar to mimic eating movements, rather than actually eating them. Finally, they had to move 30 plastic beads rather than sweets while watching the video. In all cases, the participants weren’t told how many sweets or beads were in the bowl to begin with.

Afterwards, the team quizzed participants on how many items they ate or moved, what was in the video and how the symbols were arranged. The team found that, on average, people guessed they ate 20 sweets, but thought they had only moved 15 sweets and 15 beads. How well they remembered the video or symbols didn’t differ across all three tasks, suggesting that eating was responsible for the more accurate guessing.

“Eating is important for evolutionary fitness and survival and that’s a reason why we expected memory for eating to be really active and strong,” says Seitz.

Why we remember eating better than other activities is still unknown, but it could simply be that our normal memory machinery is kicked up a notch when we eat. Or it might be because extra brain regions are recruited for more evolutionarily important tasks. If so, current models of memory that don’t consider the biological significance of different behaviours may be missing something, says Seitz.

The idea that eating is easier to remember has previously been theorised, says Suzanne Higgs at the University of Birmingham, UK, but moving sweets or beads may be too simple a task to accurately test this. “Maybe it isn’t specifically the act of eating, but there’s something about having that sort of sensory stimulation,” she says.