One of the hoariest cliches of alien-visitor films — and a lot of other SF — is that being superior intellects, they no longer possess emotions.
There’s an assumption in our culture that emotions are a leftover of our primitive past — references to our “lizard brain” driving our decisions for instance — whereas intelligence represents our more evolved future. As we evolve we’ll get bigger heads holding much larger brains — like the Curt Swan cover here showing a super-evolved Batman — but our hearts will shrivel. Once Batman accidentally super-evolves, he becomes cold, logical, ruthless: rather than share his advanced condition with Superman he uses the machine to devolve him into a caveman instead.
Similarly in Outer Limits: The Sixth Finger, coal miner Gwyllm (David McCallum) volunteers as guinea pig for an evolution experiment, hoping it will give him a path out of the coal mines. He gets the big brain and a sixth finger (greater dexterity) and begins lashing out with TK at everyone who’s pissed him off. Then he evolves again, beyond revenge but also beyond feeling. His disgruntled lover reverts him back to normal.
Alien visitors are clearly more advanced than we are so it’s a simple jump to assume they’ve also evolved superior intelligence. Not a logical jump: as far as I know, we’re not significantly more intelligent than Babylon despite having what would be unimaginably superior technology to theirs. But it’s a staple assumption: they have higher intelligence so they must have given up on feelings. Nothing left but cold, rational logic. If it’s logical to eliminate us as a threat or to conquer us, they’re going to do it. Dispassionately of course.
In the 1978 Invasion of the Body Snatchers, Kibner (Leonard Nimoy) informs Matthew (Donald Sutherland) that the pods taking over the world isn’t anything personal, just a matter of survival. The pods aren’t destroying us out of hate or malice; they’re as incapable of those as of love.
In another Outer Limits episode, Keeper of the Purple Twilight (an evocative title that has no relation to anything in the episode), the alien Ikar gives a human scientist his people’s emotionless mindset, taking on the scientist’s emotions in return. In a nice, twist, this is a scam: the aliens need the scientist to build a stargate that will let them invade. Without emotions, he’s willing to dive into the research without distractions such as his wife. Ikar, of course, starts to discover feelings, particularly for the scientist’s wife, are good. At one point he informs her that on his loveless world women exist solely as breeders: if they can’t contribute to the race, they’re eliminated.
The implicit assumption that logically women have no other purpose but childbearing is way sexist. It gives me fresh appreciation for Star Trek where Vulcans repress emotion but they’re apparently egalitarian, appointing T’Pau as one of their leaders. Repressing emotion on Vulcan doesn’t mean becoming malevolent or misogynist; they’re pacifist. In comparison to most emotionless aliens, they’re outliers.
Of course there are lots of aliens who, like Ikar, discover emotion is actually fun. In the alien-abduction stories Taken, Beyond the Sky and Visitors of the Night, the aliens are studying us because they’d like to regain the ability to feel. In Starman, Jeff Bridges admits his people’s peaceful unity lacks some of Earth’s fun, like singing, dancing, food and sex.
Antonio Damasio’s Descartes’ Error argues persuasively that the higher/lower approach to Brains and Heart is wrong in any case. Emotions can be an effective part of our decision-making process; if we don’t know what we want, decisions would be abstract navel-gazing. For example the logical response to someone offering to pay for sex with our child “Hmm, the odds of getting punished are low, I’ll have a fortune left over even after paying for Mandy’s therapy” or to flatten the scumbag with a lug wrench? But in fiction, the divide remains strong.