As an astrobiologist I often get the question: What would aliens be like? By “aliens” the questioner usually means complex, animal-like beings we can communicate with in some way, implying that they would be a technologically advanced intelligent species like us.
In part one of this new series, I’ll consider whether, despite likely superficial differences in how we look, extraterrestrial civilizations would share some common behavioral patterns with humans. My sense is that they would. In fact, that was the topic of a 2010 paper by my former doctoral student, Marina Resendes de Sousa Walther-António.
In the movies we see aliens portrayed across a broad spectrum, from the brutish killers in the Alien and Predator series to the benign and empathetic being in E.T. the Extra-Terrestrial. Can science help us determine which would be more likely?
To start with, any intelligent alien species would likely have predatory roots, because the evolutionary trait of intelligence is promoted if you have to hunt for your food. A lion has to be smarter than a grazing antelope. A wolf has to be smarter than a mountain lion—because it’s not as strong, it has to anticipate the prey’s next move and communicate with other wolves in the pack. At some point, a predatory species has to learn to hunt sustainably, otherwise prey—and eventually predator—become extinct. More likely, they would come to rely on additional food sources, more predictable and long-term, as humans did when they developed agriculture. This requires even more social structure and communication.
When Marina and I looked at this problem in 2010, social structure turned out to be the key. It is critical to pass on knowledge gained through experience from one generation to the next. And a species’ social behavior cannot be too aggressive. Our close relatives, chimpanzees and gorillas—with whom we share 99 and 98 percent of our genes, respectively—are characterized by male competition, aggression, and instigation of fear. Compare this to our hominid ancestor from more than four million years ago, Ardipithecus ramidus, who had a social system in which females chose their own partners. That led them to have reduced levels of aggression and more stable social arrangements, meaning that outsiders were more tolerated and innovations (such as the use of new tools) were more easily accepted by the community.
Of course, we humans—the more “benign” lineage of the great apes—have a history marred by episodes of violence and savagery. But most of the time, even for long periods, we get along with each other. Collaboration prevails over competition. Without that cooperation, complex societies would be impossible. It would likely be the same for technologically advanced aliens, although their specific social structure may look very different.
Here on Earth, the extreme case of eusociality may be relevant to our speculation about alien civilization. The “swarm intelligence” of social insects such as bees, ants and termite colonies is quite astonishing, and is even found in a few mammal species such as the naked mole rat. Eusocial species are very sophisticated, with social cohesion, rudimentary language, sustainable farming practices, and self-built complex housing structures that they keep in sanitary conditions. The naked mole rat could serve as a model for how a species could become dominant on a planet whose surface has become otherwise uninhabitable.
There is a drawback to eusociality, however. Much of the individual organism’s behavior is genetically programmed, and there is little ability to adapt to changing environmental conditions. A more individualistic approach to social structure, as with humans, seems more advantageous. Personally, I value my individuality quite a bit. Let’s hope the aliens do so as well.
Perhaps the biggest threat from intelligent extraterrestrials would come not from a desire to dominate—we love our dogs and cats, after all, even though they are less intelligent than we are—but from misunderstandings. Like humans, they would likely still have aggressive traits—since both of us, in our past, had to fight to arrive at the top of the food chain.