Intelligent Aliens
Summary Quick Facts
Alien species creation is the entry point for "Soft sciences" like anthropology and sociology. As fiction is ultimately about emotional resonance, alien species are the canvas upon which a writer (or exo-archeologist or exo-sociologist) uses to contrast with human cultures, and give your characters interesting people to talk to. There are several "tiers" of alien species, ranging from Exaggerated Human Cultural Trope Aliens, all the way to fully realized alien cultures.
Historical Context
The first alien species in SF were thinly veiled "savages and sages" tropes, dating back to Edgar Rice Burroughses novels of Pellucidar and Barsoom. E.E. "Doc" Smith carried many of these tropes forward in the Skylark series, and eventually the Lensman series. In the earliest tradition, aliens are nearly always "people in need of a Western White Man" to lead them. They might be amazingly technologically advanced, they might be some decadent elder civilization overcome with sloth and ennui, but they were always in need of the Bold Dashing Earthman to get them out of their cultural decline and to aid the hero in things. In this, they are direct inheritors of the Penny Dreadful pulp tradition and stories of Darkest Africa from the 19th Century.
John W. Campbell, the original editor of Astounding Science Fiction, and the editor who discovered many of the Golden Age authors (Heinlein, Asimov, van Vogt, and several others), reputedly challenged his authors to "Make something that thinks as well as a man, but different." Some authors (Stanley G. Weinbaum, and to a lesser extent, van Vogt) made their reputations from doing this, during SF's Golden Age. Later authors, like Larry Niven, refined the techniques they used to make aliens, aiming to have some aspects of biology influence how their aliens thought. While the "New Wave" of science fiction in the late 1960s and through the 1970s de-emphasized the "classic stuff," it made it more respectable to focus as much on sociology, feminism and psychology for stories, rather than just on physical sciences and fantastical engineering. David Brin's Uplift series is, in many ways, the high point of "John W. Campbell"-style aliens.
A sea change in alien portrayals came with C.J. Cherryh, whose earliest books covered alien species in contrast with human cultures, then had a diversion through her all-human Alliance-Union setting, and then the Novels of the Compact, starting with the Pride of Chanur. A high school Latin teacher who was well read in history, mythology, anthropology and sociology, and a determined researcher, Cherryh's aliens were well realized enough that she could write entire series of novels totally from an alien's point of view. Other writers have built on the foundation that Cherryh laid.
Types of Fictional Aliens
In modern SF, aliens tend to fit one of three "tiers" of complexity: Television aliens, biologically deterministic aliens, and sociologically complex aliens.
Aliens for television are *generally* constrained to humanoid bipeds with lines that miraculously translate to English, due to the limitations of the medium. These limitations also make it easier to find actors, although motion capture technology may greatly expand what can be portrayed on screen. Sometimes called "bumpy forehead" aliens or "latex aliens," if much thought has been put into what makes them "alien," it's often a human characteristic carried to an extreme: Klingons are the Honorable Warrior Race, Vulcans are Stoics, Narns are Oppressed Rebels about to re-enact a cycle of vengeance, the Centauri are stand-ins for decadent Romans. While some details are Clearly Different (most often hinted at with sexual reproductions, with Vulcan pon farr, Narns being marsupials, and Centauri males having six penes...), in most cases, their culture has strong and obvious human analogs. It's also worth looking at your own cultural assumptions when making aliens of this type; Star Trek's Ferengi are an overt port of anti-Semitic tropes, for example. Most Honorable Warrior Race aliens seem to have dark skin in Western media, because it's a way to incorporate 'savage barbarian' tropes in a way that makes people 'formidable' without granting them cultural parity or equivalency.
Biologically deterministic aliens range from the Slan of A.E. van Vogt to the aliens of Larry Niven, and to some extent, the aliens of the later Lensman books. These aliens aren't constrained to "bipedal humanoids" and will have a few traits that are clearly derived from their biology, whether it's a Rigellian's sense-of-perception being an advantage on their homeworld with an opaque atmosphere, to Niven's Kzinti being obligate carnivores (and aggressive) and his Puppeteers being herbivores and obligate cowards, through to Niven's later alien species like the Moties and the Fthip.
Biologically deterministic aliens are still used as a contrast to human society; there is often an unspoken bias of showing "how the aliens are less effective than humans are due to the tragedy of their biology." Biologically different aliens are still quite useful for SF writers; they often start by looking into some of the odder corners of terrestrial biology, and templating off their reproductive strategies, what they eat, or how they contest for territory. The advantage (for the SF writer) is that it's a lot easier to research an alien species based off of a translation of a terrestrial animal type than it is to come up with an entire alien culture! Again, Brin's Uplift books, along with Vernor Vinge's Zones of Thought books are good examples of biologically deterministic aliens.
Sociological aliens are aliens made by a process, and if your book is going to be about aliens, putting more work into your aliens at the beginning will pay off later.
Sociologically Complex Aliens
Making sociologically complex aliens means asking questions and taking notes. There are two techniques that work well in tandem to make well realized aliens that are more versatile and interesting than The Honorable Warrior Race aliens, or the Declining Elder Species Aliens and similar. These techniques are the Seven Sociological Questions (which also brush onto biology) and the Three Ripple Rule, and social adaptations to overcome limits like Dunbar's Number.
The Seven Sociological Questions
Ask yourself what things are true about the aliens you're creating, working from this list:
The physical environment the species evolved in, and how that shapes the environments they seek out. The manner in which the species bears its young, how it raises them, and how both instinct and nurturing imprint culture. The way the species conducts spatial and living space planning, including how personal and family dwellings are arranged, with distances between buildings, how family groups do (or don't) live together, hunting territories, agricultural areas and animal husbandry if practiced. This also covers using architecture for ceremonial purposes and showing status. What the species eats, the relative difficulty of getting enough calories per day, what methods are used to obtain and prepare food, how food is stored, and cultural practices and taboos for food preparation and consumption. The mechanisms and processes used for recording new discoveries, transmitting and sharing new discoveries, and how this is used to reinforce prejudices, tribal identity and culture. How the species views death, mourning, dying, handling of family members who won't live out a season, rituals for the benefit of the dead, or their family members, or society with the death of a member. How are the bodies of the dead prepared? Does the species believe in an afterlife, or some method by which the dead influence the living? How does the species think about thinking, self-definition and identity, and what conceptualizations do they have for the universe they think they inhabit?
There are no 'right' answers to these questions, but the more thoroughly you interrogate these questions, the more different you can make your aliens.
The Three Ripple Rule
The Three Ripple Rule holds that any technology that makes transportation, commerce, entertainment or communications easier will have consequences unforseen by its inventors or the people who promulgate it. The typical example from Western cultures is that anyone could've predicted the automobile, and several people did. The combination of the automobile and movies led to drive-in theaters. The combination of automobiles, movies and drive in theaters led to a sweeping change in sexual mores, which terrified local political structures.
So the automobile is the change, the first ripple was drive through theaters, the second ripple was more freedom for teenagers and young adults to experiment sexually, in the privacy of cars. The third ripple is the dawn of female birth control and the sexual revolution. A good resource for thinking about the Three Ripple Rule is the television series by James Burke from the late 1970s called Connections. Burke mostly focuses on technology, but covers a bit of sociology here. He did a similar series for the BBC called The Day The Universe Changed.
When you answer the Seven Sociological Questions, look for ripple effects that follow through from the answers you make.
For example, human females are constantly in estrous, and much of the daunting history of maternal risks in childbirth comes from the fact that the human pelvis can *just barely* accomodate the diameter of a newborn baby's skull as it's squeezed out the birth canal. Remaining in estrous constantly makes the risks inherent in a "just barely works" birthing mechanism less likely to result in the collapse of the species at a genetic bottleneck or climate disaster. Much of our society's historically awful treatment of women as chattel derives from this, as does the peculiar obsessions humans have with sex.
Let's contrast this with a species that lays and broods eggs, but the females only go into estrous at certain times of the year. In a wide range of species, estrous can be triggered by diet, or by the time of the year, and species that go into estrous based on the time of the year often do it based on the number of hours of daylight. So, that's the starting point. The first ripple is that a species with this birthing strategy might be able to trigger mating seasons with artificial lights, or practice birth control by sequestering females during the time(s) of the year when estrous might happen. The second ripple to consider is that unlike humans, who think about sex from puberty to late middle age, sex and reproduction might be a seasonal thing. They may completely lack the concept of romance novels and might lack erotic fiction entirely. The third ripple is that because of the ease of birth control for this hypothetical species, a lot of competition for mates is also seasonal, and may be alarmingly intense! (Shades of Vulcan pon farr here!) They would certainly consider the human near constant obsession with sexual signaling to be decidedly odd by comparison.
Similarly, an alien species with different childhood development patterns (and a larger load of instincts) may have parenting styles that humans find appalling, with resulting differences in spiritual beliefs.
Social Adaptation To Compensate For Instincts
Instincts are a shorthand imposed by evolutionary adaptation to keep members of a species alive long enough to raise children. In human societies, we have a solid instinct to seek out sugar, salt and fats in foods, because in the environment we evolved in, sugars and fats were signs of high caloric density foods, and eating a lot of them when they were available would allow you to put on the weight needed to get through the next famine. Now that we've made foods that fit those cravings *exceptionally* cheap and greatly reduced how often famines occur, the Western diet has well documented health effects. When looking at your alien species, look for instincts that don't quite fit a technological civilization.
A useful point of differentiation when making alien species is a disputed sociological concept called Dunbar's Number. On average, a human being can keep track of 100 to 150 distinct relationships, in varying degrees of closeness (about 20 close friends, about 70 to 100 intermediate friends, and 30 to 50 second order relationships, based on "friends of friends." Humans have remarkably high Dunbar's numbers; our closest genetic cousins, bonobos, have Dunbar's numbers that seem to cap out at 50 to 70 members. Even so, a lot of human society can be looked at in terms of 'how do we circumvent the limits of Dunbar's Number?" In parts of the world where tribal and clan loyalties run paramount, you can see how Dunbar's Number shapes society, as the mechanisms that Westerners assume always work...don't. For example, it's not that Afghans are materially more corrupt than Westerners; it's that their cultural incentives don't give them many reasons to think beyond the group of 100 to 150 people that they have relationships with, many of whom are tied by familial bonds. This makes perfect sense in situations of periodic scarcity; it also makes trusting in the law and police departments to do their job rather than favor family members seem like incredible naivete...
And that's just human cultures. What other mechanisms are there to compensate for lower Dunbar's numbers? What does a society where individuals with a higher Dunbar's number look like? In most Earthly societies, *people* who can maintain larger social networks gain wealth and status. How does that work for your alien species? What does that look like? What do higher status members of your society do that others cannot, or are not permitted to do?