You are a Martian observing life on planet Earth for the first time. Your mission: to observe the Earthlings, gather data, and report back to your home planet. What are these strange creatures who call themselves humans? 

They vary in their size and stature, the colors of their eyes and skin, the location and texture of their hair. Most of them walk upright on two legs but some move about in chairs with wheels or crawl or are carried on the bodies of others.

Some humans live in small houses, others in large groups in which everyone wears the same clothing. Some live alone, some live without other humans but with many four-legged animals. Still others are confined to cages. 

It is difficult to make sense of these creatures. The truth is, they are different from what you expected. They are not as simple or as welcoming as you thought they might be based on the messages they sent into space. And their behaviors are complex and confusing. They are at times kind and gentle, but they also bomb each other’s cities and let each other starve. 

What can you report about these creatures? What data do you collect to understand them? What, if anything, can you say about their nature? 

Difficulty understanding humans is not limited to alien species, of course. We humans have been teasing out the threads of what it means to be human for millennia. But imagining ourselves as extraterrestrial investigators does put in relief the magnitude of the task at hand—the human species is incredibly diverse, not only between different groups of humans, but among those groups as well. (And if we include the historical record, things get even more complicated.) Is it possible to generalize about the nature of humans in any meaningful way? 

The alien anthropologist exercise also raises important additional questions: How does our very presence as researchers, as well as our assumptions and ways of thinking and behaving, impact the data we record? What role does our relationship to the humans we study play in shaping the insights we glean?  Approaching the study of human nature from an anthropological perspective—alien or otherwise—requires us to ask these questions of the people we study and of ourselves.