Emily Ratajkowski ― an actress-model you might know from the “Blurred Lines” music video, or just from various bros or fangirls talking about her ― has more than 22 million followers on Instagram.

Like any Instagram model worth her salt, the “likes” pour in when she posts a selfie or bikini pic. (And then there are the inevitable weird-ass, grammatically interesting comments: “Those eyes are so hipnotising,” and “So good I could drink horchata off you.”)

Ratajkowski ― or “EmRata” ― inspires intense loyalty among her fans, but so do so many other high-profile hot people on Instagram. Many of us contribute to those “like” counts, even when we know one more “like” isn’t going to make a difference; who doesn’t mindlessly double tap pics of celebs or hot people who seem to be perpetually on vacation? (Please, don’t ask me to revisit how many pics of Tom Hardy I’ve “liked” over the years. Answer: A depressing amount of Tom Hardy pics.)

“It’s like a herd mentality thing,” Elijah Jay, a YouTuber and frequent “liker,” told HuffPost. “I feel like people see a massive amount of other people doing something and subconsciously think, ‘I want to be a part of this because other people are.’”

And then there’s the obvious reason: We’re just really thirsty.

“I like hot peoples’ pics because they radiate confidence and then also, my male brain goes, ‘Oh, a hot woman, let’s hit ‘like,’” Jay said.

For what it’s worth, your “likes” and comments are very much appreciated.

Take it from a hot person on Instagram. Lindsey Pelas is model with 8.6 million followers and a podcast called “All Eyes Up Here.” Like any of us, she experiences that lovely, addictive rush of dopamine when the double taps start coming in. (Except, while we get approximately, like, 64 “likes” on pics, Pelas is raking up 195K.)

“For me, posting a picture basically has one underlying message every time: ’I’m feeling myself,’” Pelas told me. “So, when other people post their pics, I assume it’s an expression of self-love and them feeling themselves, which is what I love more than anything. Liking photos is like an internet clap.”

Even if you’re a “like” agnostic, every now and then you get tempted by the siren song of a thirst pic. That summarizes poet and author Olivia Gatwood’s current Instagram activity.

“I do like photos, but then I’m like, too fucking lazy or something to double tap,” she said.

“The other day, though, I liked Zac Efron’s photo and the actual thought that went through my head was, ‘Maybe if I do this he’ll penetrate me,’” she joked.

Clearly, there’s a lot going on here: A singular “like” might say, “Hey, I like that you’re confident and having fun ― and werk! You’ve clearly done a ton of squats to get that butt” ― but it also might covertly suggest, “Heyyy, I’d probably have sex with you.” (That last line of thinking is probably why some have people gotten in hot water with their S.O.s for being a little too overzealous with their “likes.”)

Interestingly, there’s some science behind this modern phenomenon, according to Frank T. McAndrew, an evolutionary social psychologist at Knox College in Galesburg, Illinois.

It all goes back to some pretty basic studies of group behavior: As humans, we have an evolutionary drive to form cohesive social groups and then self-identify. Social tribalism, as it’s called, can play out in our political affiliations, religion, place of residence, social status and aesthetic values. We’ve always “liked” to associate with attractive people.

Because our tribes are much bigger now ― and since celebrities give us unprecedented access to their lives ― it’s easy to assume a sense of closeness to really, really, ridiculously good-looking strangers, McAndrew said.

Intellectually, we know these people shouldn’t matter to us, but emotionally? They kind of do.

“At the very least, we get the satisfaction of seeing our name in proximity to the celebrity and perhaps feel a slight boost in status in knowing that other people may associate us with them, however remotely.” - Frank T. McAndrew, an evolutionary social psychologist at Knox College in Galesburg, Illinois

“Because these are people that we know in common with others, they become topics of conversation,” McAndrew said. “These people worm their way into our social world.”

In this respect, there’s some logic to “liking” or commenting, he said.

“At the very least, we get the satisfaction of seeing our name in proximity to the celebrity and perhaps feel a slight boost in status in knowing that other people may associate us with them, however remotely,” McAndrew said.

It’s also kind of zany, though, said Glenn Geher, professor of psychology and author of Mating Intelligence Unleashed: The Role of the Mind in Sex, Dating, and Love.

“We can call this behavior an evolutionary mismatch,” Geher said. “Knowing someone via TV or the internet or Instagram was not an option on the African savanna, but today, our minds have evolved to pretty much ‘know’ everyone whom we encountered. This is why I feel like know all four of the stars of ‘Impractical Jokers’ as if they are my best friends!”

It also makes some biological sense for us to get peeved when our significant others “like” thirst or fit pics.

“Under ancestral conditions, someone publicly expressing an attraction to someone outside their pair-bond would have been a signal of potential infidelity,” Geher said.

While “liking” someone’s shirtless pic on Instagram in 2019 is not likely to lead to an affair, “Our minds evolved under very different conditions,” he said. “Before, we only had the chance to interact with others whom we actually knew.”

@lindseypelas/@maxisms Model and podcaster Lindsey Pelas (left) is no stranger to thousands and thousands of "likes." Nor is writer and director Max Emerson.

A word to the wise, though: Don’t let all that “liking” and ruminations on your Instagram feed mess with your offline confidence. Make it rain “likes” on Insta pics all you want. But remember, you’re worth those “likes,” too.

“Instagram is like a locker room: There’s always someone bigger,” said Max Emerson, a writer-director and Instagram babe (he has over 1 million followers). “It’s important to not compare too closely with others or insecurity is inevitable. That’s why I think it’s totally healthy to give certain accounts a break in order to maintain a more grounded perspective on life.”