If you’ve ever felt like just a face in a crowd (particularly if you’re a big city dweller) you’re very likely more unique than you think. A new study finds that the larger the society in which one lives, the more distinct each of its members, which makes sense, if you think about it in an evolutionary light. The need to be recognized by our neighbors as a distinct individual is greater when the social group is very large.

The phenomenon may be particularly relevant as our social networks continue to grow, due at least in part to new technologies that connect people in new ways.

In the new study, the researchers studied the alarm calls of eight different species of rodents in the family that includes ground squirrels, prairie dogs, and marmots. The species varied in the size and complexity of their societies, but tended to rely on other members for help in tricky situations (hence, the alarm calls). In societies like these, researchers say, there is a benefit to being recognized individually: that is, one is more likely to be helped if he or she is individually recognized by group members.

The researchers found that the larger or more populous the society, the more distinctive the members tended to be. In other words, the size of the group in which an animal lived explained the vast majority (88%) of the variation in "individual distinctiveness" across the eight species. This makes sense: it’s harder to be picked out of larger crowds, so for those who live in larger societies there’s evolutionary pressure to have more distinguishing characteristics.

In the paper’s press release, lead researcher Kimberly Pollard likens the effect to a well-known children’s book, Where's Waldo? "Nature has solved the 'Where's Waldo' problem by endowing highly social creatures with more unique features, which helps them find their pals in the crowd." The results likely apply to many other species of animals, including humans. Pollard points out that "humans and other social creatures can't just give up when crowds get large. We still must be able to identify our friends, our family and our rivals within that crowd."

The phenomenon may be particularly relevant as our social networks continue to grow, due at least in part to new technologies that connect people in new ways. "The number of individuals that humans must recognize seems to be growing, especially as we become more globally connected and as social groups become less clearly defined," Pollard says. "This is probably increasing the evolutionary pressure on our own individuality."

People who come from large families probably understand the phenomenon best of all. As the authors conclude, "[t]he bigger the crowd, the more it takes to stand out."

The research was conducted at UCLA and published in the February 16, 2011 issue of Current Biology.