This is the second part of a series on extraterrestrial psychology. Read part 1 here!

In Part 1 of this series, I discussed how the interdisciplinary field of evolutionary psychology can help us explore similarities between the human mind and possible extraterrestrial ones. One common potential feature is how we search for resources, which often involves a trade-off between exploring wide swaths of the environment and exploiting a patch of resources once you find that patch. Although humans have greatly improved our exploration skills in terms of searching for life beyond our planet, we have yet to reach an exploitation phase, and – more concerning – we have not thoroughly considered how to prevent others from exploiting our patch of resources, the Earth. Can evolutionary psychology inform us about this aspect of alien intelligence as well?

Species like us, who are intelligent enough to search for life elsewhere in the universe, are incredibly likely to have another common feature of intelligent life on earth: signalling. As with search, signaling theory can inform our understanding and approach to communicating with extraterrestrials. For example, what and how you communicate, as well as how you understand others’ signals, depends heavily on what you think of these others’ intentions. In this post, we’ll explore what signalling systems on Earth can tell us about how, or how not, to communicate with extraterrestrial life.

Research on the fundamentals of social signaling suggests that, as with search behaviors, there is a trade-off at the evolutionary core of signaling systems. This trade-off is between accurately signaling one’s current state, and falsely signaling some other state (typically signaling one’s fitness as more optimal than it really is, i.e., lying). Most Earthly signaling systems are inherently physical, or costly – for example, flamboyant pigmentation in males across many species signals fitness, because the male has to actually have enough resources and energy to produce the pigments – here, “costly” basically means that false signals are often much harder to send than honest ones.

Of course, human language is arguably the richest signaling system on Earth, and it is now so abstracted as to be relatively easily faked, making it a potentially dangerous, or even toxic, signaling system. Evolutionary psychology can help us understand this phenomenon as well. Just as animals must find resources and mates, they must also stay away from danger, predation, and illness. In their paper in Biological Theory, PBS Professor Peter Todd and his colleague Geoffrey Miller bring up a less commonly-discussed component of signaling, which relates to avoidance or aversion. Research has shown that we have similar aversions to basic biological threats as we do to abstracted or ideological ones. For example, sickness related to legitimate toxins has similar response patterns to disgust towards cilantro, a genetically inherited but not life-threatening trait, and even to aversion for gossip, hearsay, or “fake news,” which are incredibly abstracted cultural signals.

So what’s the take-home message (pun intended) then? In cases where little is known about the receiver of one’s communications, a signaler should convey very little about oneself, as such information could be used against the signaler’s own best interests. This is of direct and utmost importance because humanity has been sending overly “personal” signals into space since the 1970’s, in the form of radio waves and spacecraft plaques with our home address (Earth). Intelligent extraterrestrial beings who understand signaling theory would likely not make the same mistake; instead, their interstellar signals will likely convey little information about themselves or the threat they might pose.

Given the uncertainties involved in possible future encounters with extraterrestrials, it may be prudent for us to do the same. According to Todd and Miller, being silent might be our best strategy for now; we can still listen, however. And as we do, evolutionary psychology might help us to understand and communicate with life as it conceivably exists beyond our planet.

Edited by Jennifer Sieben and Taylor Nicholas