Interstellar Give-and-Take: The Idea of Sharing

Feb. 12, 2003

by Douglas Vakoch - Social Scientist / Principal Investigator

In our everyday lives, we sometimes emulate computers, though typically without their full precision. When we do a favor for someone, more often than wed like to admit, we keep an informal tally of who owes us, and how much. According to sociobiologists, who attempt to explain behavior in terms of its value for survival, such calculations might have a biological basis. And as we will see, they may also provide some clues to communicating with life beyond Earth.

Some basic notions of reciprocity seem as familiar to chimpanzees as they do to humans. When Chimp A grooms Chimp B, the giving primate might expect payback at dinner time. And often, the altruistic chimp gets whats expected. (There are some constraints: chimps seem to forget their past benefactors if more than a couple hours pass between a grooming session and the next meal. For reciprocation, its not enough to realize that someone has done you a favoryou also need to remember it.)

Insofar as we can precisely describe our interactions with others, we can translate them into a form that might be communicated to extraterrestrials. We might, for example, use radio signals to send encoded animation sequences showing acts of altruism. To the extent that such self-sacrifice in the short term is paid back in the long term, it might even make sense to extraterrestrials with a keen actuarial sense.

But is an interstellar message that casts the recipient in the role of detached observer the best way to go? If human learning is any example, it may be unwise to treat ET like a cosmic couch potato, channel surfing for Saturday morning lessons in Interstellar Esperanto.

When we humans learn, once weve progressed to a certain stage, we can absorb a lot very efficiently simply by reading a book. So it may seem natural to send extraterrestrials something like a comprehensive encyclopedia, albeit one written in some sort of universal language. For example, the logic-based language suggested by Dutch mathematician Hans Freudenthal, Lincos (short for Lingua Cosmica), starts with counting and basic arithmetic, progresses through notions of time and space, and ultimately explains something about how humans act and interact with one another.

But observation has its limits, especially early in the learning process. When learning a language, theres no substitute for experimentationearly and often. The first steps of language learning occur through interactions with others. Ideally, a childs early babbling elicits a few "oohs" and "aahs" from proud parents, and through repetition, shaping, and correction, the child learns to play the language games of its culture.

Might we use a similar approach to teach intelligence on other worlds something about terrestrial cultures? But where would we begin?

One possibility discussed in SETI circles over the past thirty years involves sending computer programs. As early as 1972, at a SETI conference in the former Soviet Union, artificial intelligence pioneer Marvin Minsky made his case for the superiority of computer programs as interstellar messages. Computers, Minsky suggested, have the advantage of being interactive. Once you can convey the notion of basic computer code, and explain as simple an operation as addition, youve introduced a powerful tool that can be developed, step-by-step, to show increasingly complex processes, even including some aspects of human behavior. In Minskys words, "It requires no other concepts because ETI are essentially building it for themselves and experimenting to see what it will do." By sending a program, we neednt develop a fool-proof scheme for laying out everything that we want to say, as one might suppose for a language like Lincos. Instead, the recipient learns the computer language by using it.

Fittingly, we might use computer programs to explainat least to some extenthow human behavior can be described through complex algorithms. Does that mean that every act of kindness can be reduced to Machiavellian plotting? Is our willingness to do something to benefit others always based on the expectation of a later payoff?

If we can trust what people say, it certainly seems as if at least sometimes people really do go out of their way to benefit others, with no tangible rewards for themselves. Nevertheless, some sociobiologists would claim that this is only self-deception, and that payoffs may be indirect, for example, in the form of an enhanced reputation for doing good.

For purposes of interstellar communication, the critical point may be whether this approach can begin to explain something about who we humans are. We may never be able to give a full explanation of what its like to be human to intelligent beings on some planet circling a distant star. As long as we include a disclaimer, noting that our self-description is incomplete, we might at least make a start at holding up our end of the conversation.

Its important to note that SETI currently listens for signals from other stars, rather than transmitting any of our own. For now, we listen, hoping that another civilization with a more advanced technology and more abundant resources will take the lead in making contact.

If we succeed in detecting intelligence on another world, and humanity decides to reply, it may be reassuring to our extraterrestrial interlocutors to hear us talking about reciprocity. It may be that young civilizations such as ours are typically so focused on what they can get in the course of an interstellar exchange, that they never consider the interests of the civilization that made the first overture. Perhaps a response that includes an up-front discussion of reciprocal altruism would help get across the idea that, now that weve been invited to join the Galactic Club, we recognize that we too will be expected to pay our dues.

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Interstellar Give-and-Take: The Idea of Sharing