Hurst, with Ivana Gudelj of the Imperial College London and their colleagues, worked with two strains of yeast, “cheaters” and “cooperators.” The cooperating yeast cells produce a protein that breaks down sucrose, which is tough for the cells to eat, into glucose and fructose, which are easier to eat and convert to growth. The cheaters don’t produce the protein (called invertase) but still partake in eating the broken-down sugars.

After giving sucrose to yeast, the researchers were floored to find the populations that included a mix of both givers and takers grew more than those with only the straight shooters. The team also found similar results using a computer model of the scenarios.

Here’s what they think is going on: Since the cooperators are the ones churning out the broken-down sugars, it is nearest to them, and they pay no mind to efficiency.

The cooperators “are sitting in a puddle of their own self-made glucose, using it very badly,” Hurst told LiveScience. “Because they see so much of it, they’re not converting it very efficiently into growth.