We all know the problem, especially from video games and movies, where the super-smart aliens turn out to be really dumb. This is usually because the creator hasn't put much thought into it.
So, you're creating a super-intelligent alien or species or civilisation for your short story or novel or whatever. How do you avoid the pitfalls of dumbing them down?
First off, you have to tackle a duality problem:
In the movies, plot comes first. In Independence Day - a re-imagining of War of the Worlds - an alien is quite happy to give away their plans for no explicable reason. It turns out that you can send a computer virus out along their communications system too (let's not get into the way Goldblum was able to craft a virus overnight with no prior knowledge of their CPU architecture or operating system).
Even worse, in that movie the aliens are totally reliant on their technological superiority. Their tactics and strategies are all based on this and the fact that they have numbers on their side (there are, after all, a lot of them). If you're going to war with an alien species (which we are to them), you might want to obfuscate the true purpose of your battle plan by feints and misdirection. Having contingency plans might also be a good idea.
I recently came across this amusing video about alien civilisations (in movies) too dumb to have actually survived. I could have embedded it into the page, but I have a policy on this site of not using tracking cookies, and just by reading this page (if it had a youtube video embedded) you'd get one. If you want to watch it, feel free. It's part of a 3-part series on dumb aliens, but the remaining two videos in the series didn't really rock my boat like the first one did.
In literature, yes you have to serve the plot, but you shouldn't do so at the expense of credibility. Oh wait, I just said credibility when we're talking about aliens and interplanetary travel. These are things you have to sell to the reader, and the more holes in your story, the less credible it becomes. On the other hand, if your aliens actually do act smart and are never defeated because they did something dumb, your story will be all the stronger and better for it.
Let's look at battle plans to begin with, since they crop up a lot. Your first step is to actually have one. Just arriving and waging war isn't a plan, everything they do must have a purpose, and every part of that plan must drive toward that purpose by building on the successes of the parts of the plan that came before.
Step one then, is to make a plan. Remember the basic tenets of warfare: No plan survives first encounter with the enemy; Simple plans mean less can go wrong, and if it does, is easier to adapt to the needs of the moment.
Simple though, does not mean unsophisticated. Layered plans that hide the true purpose (goal) through feints, misdirection and confusion, work well and have served commanders through the centuries. The D-Day landings in Normandy worked because the German generals (and especially Hitler) believed they were a misdirection and the true invasion would occur at Calais.
Then, once you're happy it looks like it will actually work, put another hat on and become a general, scientist or intelligent politician on the other side (usually the humans) and see how the plan unfolds from their perspective. Can they deduce how things will progress? If they can, that's a point of weakness - predictable plans can be dealt with. Is the plan overly reliant on superior technology? That's another point of weakness, if the defenders can negate or cope with that technology.
Test your plan all the way through, and for each point of weakness, determine what the humans would do to counter, and adjust your plan to be prepared for that. Always give your aliens the upper hand. If the humans have determined a point of weakness and counter-attack, make it so that it's a trap - the aliens wanted them to do that.
In the movies, smart aliens are usually defeated because they acted dumb. This goes not just for aliens of course - super-intelligent villains often fall foul of the same thing. Impregnable fortresses that can broken into through the sewers; the super-weapon that can be turned off remotely just by pressing a big red button handily labelled so the protagonists can identify it; miscalculating the reactions of someone they care about or trust.
There is a list available called the Evil Overlord List, devised by hundreds of people of things they would do if they were the Evil Overlord to avoid being defeated by being stupid. Here's an example:
|Things I'd Do as an Evil Overlord|
|#133.||If I find my beautiful consort with access to my fortress has
been associating with the hero, I'll have her executed.
It's regrettable, but new consorts are easier to get than new
fortresses and maybe the next one will pay attention at the orientation meeting.
There are other similar things (often with the same humour), such as making air-ducts to small for even a child to crawl through, or that the position of Trusted Lieutenant should only ever be awarded posthumously.
Remember, your heroes don't have to outsmart their enemy. All they have to do is use what they have and the enemy doesn't: knowledge of home turf; experience in combat (maybe not against aliens, but often the case against villains); techniques in infiltration or covert operations. You get the picture.
The Genius Villain is often painted at being a genius in just about all fields (except perhaps, human emotions), but that is quite often a mistake. They might be brilliant at physics, but to make them a genius at waging war, a genius at running a large corporation, manipulating the economy and driving Machiavellian plots all at the same time is probably too much. They might be good at these things, but their genius is probably restricted to physics. Don't oversell your antagonist. A general might see through their battle plans, a business opponent might be outsmarted but in hindsight saw that they themselves were at fault for not paying attention. The man or woman in the street though, probably doesn't make these distinctions - to them, the antagonist might well appear to be a genius in all these fields, after all, what do they know about these things?
When crafting the super-smart alien, the vastly more intelligent alien species, or the super-villain, you have one advantage that the reader doesn't: Time.
They don't have to know that it took you six months (or ten years) to iron out all the kinks in your alien species' battle plan. They don't have to know how many nights you lay awake trying to figure out just how dumb your super-villain was being. They don't know how much time and effort it took you to get your antagonist(s) to behave the way they should and massage the plot so it suited them, and still served the story properly.
I'm going to leave you with a massive mistake made in one of our best-loved TV shows. In Star Trek, they had this wonderful thing called the transporter, which could beam you into trouble, and quite frequently, beam you out of it again. It was just a device to help the stories flow quickly, and it worked like a charm.
Then, strangely, in one of the movies, they explained how it worked. It was a totally unnecessary thing to do, but for some odd reason, the script writer(s) wanted to get geeky. The upshot is that we then knew that each time Kirk stepped onto the transporter, he died, and a perfect clone of him was created somewhere else. So perfect in fact, that the clone thought it was him.
Let me ask you: If you knew you'd die every time you stepped onto the transporter, would you ever use it? Perhaps in a dire emergency when you were going to die anyway, then it might not seem such a bad option. Otherwise, you'd probably not go near the thing. You have shuttles, after all.
What we're seeing here is a classic case of the writer getting over-enthusiastic and explaining technology that doesn't need to be explained. If you're a science-nerd, avoid the temptation of explaining technologies you've invented. It's one of the biggest pitfalls in science-fiction. When Kirk steps onto the transporter, do we think Kirk is stupid? No. We think the writer was stupid. When the hand of the author is made visible, the reader starts to wonder about the credibility of the author, and starts to question everything. It's not just the antagonist(s) who do stupid things, writers do too.
How do you avoid such a pitfall? That's pretty simple actually. Ask yourself if knowing how the technology works is actually important to the story. Usually, the answer is it isn't, it's the technology itself that's important.
It might take you a year or more to develop, write and edit a story up to publication standard. After putting in so much time and effort, why let yourself down by leaving plot holes and inconsistencies in the story? It only takes a little thought and marginally more effort to turn a mediocre plot-hole filled story into something that will dazzle the readers, simply because you filled in those plot-holes and removed those inconsistencies.
Don't use movies as your benchmark. Movies work in an audio-visual medium, and the rules are quite different. However, movies can be used to show you what not to do. When you watch a movie, remember that it works on a compressed time-frame. Often, the movie maker doesn't have the luxury of filling in the plot-holes and correcting the inconsistencies. The viewer too, is dragged from scene to scene before they have had too much time to figure things out. Plot holes, like the infamous Indiana Jones one in Raiders of the Lost Arc (where Jones is irrelevant to the plot), only occur to us after the movie has ended.
Literature doesn't work that way. Readers can figure things out as they go along. A super-villain or 'highly-intelligent' alien that is defeated because they do dumb things is unsatisfying, and will leave the reader thinking the story could have ended better. They want to see humans win because of our better qualities, such as empathy, or an instinct to protect our loved ones; maybe we win because we are survivors that have already, in our deep past, survived near-extinction, or that we have 'true-grit' and when the chips are down we can dig deep.
If you really want your aliens to act dumb, that's not actually a problem. Given enough time we'll develop awesome technology, but we won't get any smarter as we do it. Your aliens might simply be old enough (as a species) to have created interstellar travel and energy weapons (and shields), but only have the same intelligence as a below-average human. That could be fun to play with.