I’m wondering if it’s pseudo religious with humans being created in God’s image (Ancient Aliens stuff), the human-centric idea that intelligent life must resemble us, it being easy to make costumes for movies and TV when all you need to do is paint someone’s skin, or if SciFi writers were going for the uncanny valley effect for example.
Maybe https://en.wikipedia.org/wiki/A_True_Story from the 2nd century - although even that is a parody of existing stories. So the origin dates back a long time!
Budgetary restrictions.
One of my favorite trivia bits from Deep Space Nine;
In order to have a bustling station with weird, exotic, new aliens, the production team took to mixing up alien makeup appliances. A Cardasian neck ridge, with a Klingon forehead, maybe a fish-species mouth, paint it all a different color and baby, you got an alien stew goin’.
In written media, including scripts, it is just easier for readers to understand sci fi aliens as ‘human but different’ which is along the same lines as why robots are mostly bipedal human shaped. It also allows for stories about humans, since that is the basis for a lot of sci fi stories as well.
So time and effort restrictions too!
One of the many things I liked about Hail Mary Project was that the aliens are extremely non-humanoid, but you still develop empathy for them. It’s my favorite Andy Weir book by far.
It’s interesting to look at what is actually required to be a technological species (assuming they develop it themselves).
- Dextrus Manipulators.
To make technology, you need something to manipulate the world reliably. Hands are the most obvious method, but not the only ones. Octopus tenticles could also likely fill the roll.
- Social groups and communication.
Developments are useless, if they can’t be passed on to the next generation, or shared around. Technology requires building on the work of others.
- Brain development.
There needs to be something to drive early brain development. With humans, it was likely sexual preferences. It could otherwise become a chicken and the egg type problem.
- Generalist.
A specialist species will tend to lean into their strengths. There’s far less need for intelligence when you have big claws, or heavy armour already. This also applies to size. Too big, or too small tends to specialise in a why the precludes other developments.
There are several species on earth that hit some of these points, but not all. E.g. Dolphins hit all but the manipulator issue. Octopus are completely solitary. Many mammals hit all but brain development, and crabs overspecialise.
I could easily see a small tweak leading to a radically non human technological intelligence. That is also based only on what has already developed and stabilised in the earth’s biome. The cambrian explosion showed that far more body forms are at least viable.
In my opinion, it’s always been about determinism and convergent evolution. Determinism states that if the cards were reshuffled and evolution were to take place again from the beginning, more or less the same would happen. There wouldn’t be sentient octopuses or hive mind ants controlling the planet, because there are simple evolutionary pressures giving rise to features that eventually lead to more or less bipedal apes.
This hooks into convergent evolution. This is about the fact that features like wings and eyes were so successful in terms of evolution they actually evolved independently of each other multiple times. Eyes evolved in different lineages and evolutionary pathways around 65 times during the history of earth. This indicates that simple evolutionary pressures (like needing to look around) will always end up with something that is a lens based retinal pigmented organ. This deterministic view of evolution leads many to believe that on another planet that looks like earth, inhabitants will look like us due to the rules and constraints of evolution.
This is my understanding, and rightly or wrongly it’s the theory underlying the artistic license supporting popular fiction like the star trek and star wars universes.
Obviously my views are supported by confirmation bias, but in the only ecosystem we know of the hominid body plan is the most successful.
Things would be different in different environments, like higher gravity or ocean planets, but in the absence of any data about those the safe bet is that most intelligent life looks similar to us.
May I suggest Solaris by Stanislaw Lem? The alien is a sentient ocean that doesn’t understand the distinction between past, present, or future, or between dreaming and wakefulness. It causes some issues…
Also Project Hail Mary by Andy Weir: Great book about communicating with species that differs from humans in almost every possible way.
Lack of creativity from the first people claiming to have seen one. The rest just piled on.
If you’re asking why it appears in our sci-fi, you were correct in assuming it was mostly about cheap costuming and special effects. If you’re asking for a general canonical reason for it, there isn’t one, but many sci-fi shows have come up with unique ones (for example, Star Trek had the Progenitors, a species of humanoids that seeded world with their DNA). If you’re looking for a possible real-world explanation that could account for it, Convergent Evolution might explain why intelligent species wind up being bipedal tetrapods.
Sex. When the story tellers became horny, the aliens became fucky.
Everything we imagine looks like humans. God looks like a human in nearly all portrayals - our consciences look like humans. Even death is an ᴀɴᴛʜʀᴏᴘᴏᴍᴏʀᴘʜɪᴄ ᴘᴇʀꜱᴏɴɪꜰɪᴄᴀᴛɪᴏɴ.
Aliens are just a projection of our fear of the unknown.
Even death is an ᴀɴᴛʜʀᴏᴘᴏᴍᴏʀᴘʜɪᴄ ᴘᴇʀꜱᴏɴɪꜰɪᴄᴀᴛɪᴏɴ.
GNU STP
For Star Trek, there is an in-universe explanation which is essentially that Humanity and many other classic humanoid species you see (Klingons, Vulcans, Romulans, et al) were all essentially “seeded” by the same ancient race of aliens. That race (the Progenitors) evolved way earlier than everyone else and found themselves alone in the galaxy, so they got down to the seeding. (I know this has also been touched on in S5 of Discovery so please forgive me if they changed anything lol)
I’d say that’s more of the excuse/rationale for it. The underlying reason is hot much not expensive it would have been to do otherwise.
We’re all aware that that’s the original reason but the point is that the franchise made an effort to come up with an answer that makes sense in-universe.
Yup, you got my point exactly! Appreciate ya.
