Similarity Discrimination Effect (IMAGE) University of Leicester Caption This shows the similarity discrimination effect in a hypothetical population of microorganisms, starting with a diverse population containing two similar pairs at the tops. The similar pairs cooperate with each other and thus leave more offspring in the following generation. Credit University of Leicester Usage Restrictions Use with credit License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.