Is there a possibility that human-level intelligence and technological civilization will develop on other worlds? If so, what kinds of sensory and cognitive systems might aliens have? This was the topic of the seminar "SETI Intelligence: Cognitions and Communication of Extraterrestrial Intelligence" held in Puerto Rico on May 18, 2016. The conference was put together by the newly formed METI International, an organization that is trying to communicate with extraterrestrial intelligence, transmitting a message to it. One of the organization's central missions is to create an interdisciplinary community of scientists involved in the design of interstellar communications that can be understood by unearthly intelligence.
At present, the only clues we have to the nature of extraterrestrial intelligence and perception can be gleaned by carefully studying the evolution of consciousness and perception on Earth. The seminar was attended by nine speakers from US and Swedish universities, specialists in biology, psychology, cognitive sciences and linguistics.
Doug Vakoch, psychologist, founder and president of METI International, notes that astronomers and physicists are predominantly concerned with the technology required to detect alien intelligence. But finding and successfully communicating with aliens also requires attention to evolution and the possible nature of alien intelligence. What is interesting about this workshop, Vakoch writes, is that the speakers give concrete advice on how to apply ideas from fundamental research in biology and linguistics to construct interstellar communications. But the first session was devoted to how possible the technological evolution of an extraterrestrial society, how rare or widespread it can be.
Now we know that most stars have planets, and most of them are solid planets, similar to Earth or Venus. In this very abundant class of worlds, there will certainly be tens of billions of planets with conditions allowing liquid water to exist on the surface. We do not yet know how likely life will appear on such worlds. But we assume, like many scientists, that there really is simple life in the Universe. How likely is it that there will be an alien civilization with which we could communicate and exchange ideas and which will let us know about its presence by a signal into space? This question became central to the conference.
Scientists are guided by two main sets of key ideas in solving such questions. The first stems from the study of the gigantic variety of behaviors, nervous and sensory systems of animal species that inhabit the Earth; this is called cognitive ecology. The second set of ideas comes from a central tenet of modern biology; theory of evolution. Evolutionary theory can provide a scientific explanation of how and why different sensory and cognitive systems come to exist on Earth, and therefore can direct our expectations about the existence of life elsewhere.
The fundamentals of electrochemical signaling that make possible animal nervous systems have deep evolutionary roots. Even plants and bacteria have an electrochemical signaling system similar to that found in our brains. Dr. Anna Dornhouse, a professor at the University of Arizona, studies how social insects collectively make decisions. She defines cognitive ability as the ability to solve problems using the nervous system and sometimes social cooperation. An animal is considered more "intelligent" if its problem-solving abilities are more generalized. From this point of view, intelligence in animals is widespread. Skills that have long been attributed only to primates (apes and humans) are surprisingly common.
For example, many arthropods (an animal group including insects, spiders, and crustaceans) have exhibited cognitive skills like social learning and teaching, deduction, tool use, recognizing individuals of a particular species, planning and understanding spatial relationships. These findings point to the amazing power of insect small brains and how little we know about the relationship between brain size and cognitive ability.
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Different animals often have different sets of cognitive skills, and if a species is good at one cognitive skill, it doesn't necessarily mean that it is well developed in others. Human beings are special, not because we have some specific cognitive abilities that other animals lack, but because we have a wide range of cognitive abilities that are more exaggerated and highly developed than other animals.
Although the Earth as a planet has existed for 4.6 billion years, complex animals with hard body parts appeared in the fossil record only 600 million years ago, and complex life developed only 400 million years ago. Looking at the animal kingdom as a whole, three groups of animals can be distinguished, which went along different evolutionary paths and developed extremely complex nervous systems and behavior. We have already mentioned arthropods, whose complex behavior at first glance does not match their tiny but powerful brains.
Molluscs, a group of animals including slugs and all kinds of molluscs, also created a group of brainy animals: the cephalopods. Cephalopods include octopuses, squid, and cuttlefish. The octopus has the most complex nervous system of any animal without a backbone. The product of a completely different evolutionary path, the sophisticated octopus brain is completely unlike any other brain found in animals with bones.
The third group is vertebrates; animals with ridges. These include fish, amphibians, reptiles, birds, and mammals, including humans. Although all vertebrate brains have family similarities, complex brains have evolved from simple brains many times, following different paths of vertebrate evolution, so each such brain has unique characteristics.
For example, birds have a complex front of the brain, and with it the flexible and creative ability to make and use tools, break objects into classes and categories, and even a rudimentary understanding of numbers. Mammals took a different path and got a completely different organization of the front of the brain. Three groups of mammals - elephants, cetaceans (a group of aquatic mammals including dolphins, porpoises and whales) and primates - have evolved to have some of the most complex brains on Earth.
Given the evidence that intelligent problem-solving skills of various kinds have evolved over and over again and followed vastly different evolutionary paths in a wide variety of animal groups, one would think that Dornhaus believes that cognitive abilities like humans and civilizations are widespread throughout the universe. But she doesn't think so. She believes that humans, with their extremely pronounced cognitive abilities and unique ability to use language to express complex and new types of information, are the exception to evolution rather than the rule, and will be unlikely to be repeated. Her argument that extraterrestrial civilizations are unlikely to be widespread echoes that of the prominent American evolutionary biologist Ernst Mayr.
There are currently more than 10 million different animal species on Earth (and possibly trillions of microbial ones). Only one species has managed to develop the human level of intelligence. This implies that the chance of developing human intelligence is less than one in ten million. Over the past six hundred million years since the advent of complex life on Earth, there have been tens of millions of different animal species, each of which has existed for one to ten million years. But as far as we know, only one of them, Homo sapiens, made it to the technological society. The human race split off from other great apes some 8 million years ago, but it wasn't until 50,000 years ago that we saw evidence that dramatically differentiates humans from other species, which may be another sign of the rarity of such an event.
Despite the seeming improbability of the linear development of human-level intelligence, this did happen on Earth, despite a wide range of evolutionary lineages. What does this tell us? At present, the Earth is the only inhabited planet about which we know at least something. And since we were born on Earth, our sample cannot be impartial. We cannot be completely sure that the presence of human civilization on Earth means the development of such civilizations everywhere.
All we know is that the bizarre set of events that brought humans to life could be so wildly incredible that human civilization will be unique in a hundred billion galaxies. But we don't know if extraterrestrial civilizations can be just as wildly incredible. Dornhaus admits that neither she nor anyone else knows how unique human intelligence can be, since the evolution of intelligence is extremely poorly understood.
Most evolutionists, following in the footsteps of Mayr and others, believe that human civilization was not an inevitable product of a long-term evolutionary trend, but rather a strange set of successive events that led to a series of unique evolutionary turns. What were these events and how unique are they? We don't know yet.
ILYA KHEL