Because my genre of choice is Science Fiction, at some point or another, aliens are going to come into play. Because I have only ever been a human, and thus have no other real frame of reference, I sometimes wonder how real my creations are insomuch as representing a race of beings from elsewhere. I would have to assume that creatures that develop somewhere else would be vastly different. Just look at the diversity of life we have on this one planet! I’m not talking about shape, size, colour, or number of appendages. I can work out a logical reason for having an alien appear as it does. James White’s Sector General novels are a great place for inspiration! What I’m talking about is getting into my alien’s head. How and why does this creature behave as it does? I would love opinions outside of my own head, please!
Although everything would clearly be different on another planet, the same general rules for personality are likely to apply. An alien's personality would likely be affected by its unbringing, the place of its upbringing, its age, those with whom it communicates, its level of communication, and its own choices in life. It would be advisable to create the world you want this race to originate from, and plan out the evolution and development of the race. You also need to consider factors such as hygiene, practicality, illness, emotions, lifestyle, and so forth. Do your aliens have different emotions compared to those we have? What is generally expected of a citizen in their world? Does their world have a currency, a system, laws, and technology? Also, do aliens love? Do they develop emotional attachments to others? These points all reflect on how the aliens live, and therefore, on their personalities.
Well if it is intelligent, and has advanced mechanical technology it has to be logical. We may not be able to communicate with it but it has to be able to think in a linear fashion and understand math. So that is a place to start. They will have some kind of logic behind them, even if it's the logic of a fanatic. If it uses organic technology all bets are off. Growing a spaceship, or a coat, or a car is probably very different from building it. How do they see the world? Do they have eyes, or do they move by echolocation? If they can't see the stars they are less likely to develop a space agency, at least early on. Why investigate something you don't even know exist? It may happen given time, but it seems unlikely. At least using our logic. What senses do they have? If they use smell more than anything else, they will think differently from us. Can they touch electricity, taste fire, and see air? It will affect how they think. We fly planes, and usually avoid living in the dark underground, because we use sight so much. We want to see the open sky over our heads, and we want to see what predators might be about to eat us. How would something that instinctively digs underground for a living and can't see more than 5 feet ahead, react to flight? Can they communicate through some type of telepathy? Or almost as quickly through scent? They might find our reliance on sound and sight that takes time and effort to be insanely lonely. If they are instinctive loners, seeing anyone in groups larger than 2 outside of mating season (if they have one), would be uncomfortably crowded. Being in a crowd of 4 might put them into a rage. They would likely only want to deal with the most anti-social humans they can find, if they wanted to at all. Consider what types of aliens you want. Think about how they see, taste, touch, hear, smell, and any possible 6th senses. Then think about how they react with their own species? Think about how humans would react if they were dealing with an alien that due to extremely powerful echolocation could tell what you had for breakfast, and that you are lying by listening to the blood rushing through your veins. Good luck.
There's lots of ways you can go obviously. You just have to think for a moment. Let's say an alien was raised on a warlike, tribal planet (cliche', I know). This alien would be: 1. Quick to grab a weapon vs. talk. 2.The most calm in a fight. 3. Straight foward, not really a lateral thinker. 4. Consider honor in a fight a very high priority. There's lots more you can go off of. You just gotta take your time and get in the spot of your alien.
Plus, just because an alien is from a different planet doesn't mean it's gonna be this really freaky personality. They can act just like us if you wanted. The story is yours. But I'm agreeing basicly with what has already been said. Review your alien's attributes, and branch off from there.
I think to an extent the amount of development that's needed depends on what the aliens' purpose is in the story. If your plot is "Aliens invade the earth OMG!" then it doesn't matter so much what the aliens are like, the story is the invasion. If on the other hand you are writing a deep philosophical novel about different cultures then obviously more work needs to go into it, but on the other hand novels like that usually try to have something to say about the human condition, so the more you distance the aliens from humanity the more diluted that message will become.
