It seems obvious that if a species has the brainpower for speech, along with the sort of appendages that can manipulate a pair of pliers, it will eventually blunder into science, technology, and radio.

Explorers tend to be the aggressive types - why else would they risk scurvy, mutiny and other bad things to go out there? So, you could say that any aliens that are actually moving and interested in going somewhere are likely to be more aggressive. But who knows?

In general, when moviemakers talk to scientists, they usually see them as a resource to solve particular technical problems or script problems for them. So, something like: what sort of weaponry would aliens be able to wield?

Seth Shostak Quotes