We Asked Psychologists About the 'Siblings or Dating' Instagram Account

In 2009, there was no pandemic. Obama took office. The Great Recession ended. And Folgers released a Holiday advertisement colloquially known as the "Folgers Incest Commercial," an ad spot in which two siblings reunite over the holidays and intensely flirt over some coffee, warranting an oral history a decade later. 

 An Instagram account, which grew by over 100,000 followers this month, touches on the same taboo theme: "Siblings or Dating?" Though unlike the Folgers commercial, the question implies mutual exclusivity. The account's premise is very simple: on Instagram stories, followers can participate in a poll: are the two people shown siblings, or are they dating? After the poll is closed, the voting results are shown, with the big reveal whether the two people are siblings or dating. The owner of the Instagram account did not respond to a request for comment from VICE.

The majority of the couples appear to be white heterosexual couples. Sometimes I feel like I'm less able to tell the difference between them than couples of color, like a facial recognition algorithm turned on its head. Some of the alleged "siblings" are interacting with each other in a way that signals "dating" to me, whether it's the hand-holding, waist-holding, or other displays of affection I'd not expect outside the Folgers universe. And there is definitely confirmation bias at play here: the sample size is less than a few hundred photos, and one can assume only photos where there is a possible sibling connection are being sent in. 

We’ll never know if some of the most sibling-like romantic couples are actually dating, or whether the joke’s on us, but the account reflects a phenomenon we’ve all observed from time to time: People sometimes seem to like dating people who look like them. It raises a question—why? 

I reached out to psychologists to ask what phenomenon might be at play here. The answers were not satisfying or definitive, but illuminated the power of social media, confirmation biases, and what we should look for in potential partners. 

"Similarity of values matters more than most things," said Arthur Aron, professor of psychology at the State University of New York at Stony Brook. "There's not much research on similarity of physical appearance and initial attraction." What little research there is, Aron said, " is more focused on similarity to looking like your opposite-sex parent."

One popular 1987 study headed by social psychologist Robert Zajonc at the Research Center for Group Dynamics at University of Michigan showed that couples tend to look more alike as they get older. Part of the explanation for this convergence is based on a theory which states that repeated use of facial expressions will permanently affect facial musculature. As the theory goes, when people live together, they begin to emotionally mimic each other, and then their faces begin to look similar. As such, the theory suggested, siblings looked alike not just due to shared DNA, but because their cohabitation and emotional mimicry shaped their faces to be more similar over time, like two piles of sand shaped by the same gust of wind. 

A study published this October by Stanford University, however, found that spouses didn't look more similar over time, but their faces did tend to be similar in the first place. "This brings facial appearance in line with other traits—such as interests, personality, intelligence, attitudes, values, and well-being," the study concluded. Both studies provide heft to the Siblings or Dating inquiry. But equally important is to remember that a photo of a couple (or siblings) doesn't tell the whole story. 

You've heard the phrase 'love is blind'," said Beverly P. Palmer, a psychologist, professor emeritus at California State University, and author of Love Demystified: Strategies for a Successful Love Life. "Well, it's not exactly blind, it's just a little myopic," she said. "We have an ideal person, an ideal attractiveness in mind. We tend to have an ideal of someone that—not in a conscious level, but in the lowest unconscious level—does have some physical characteristics similar to us."

Most couples now meet online. Palmer told VICE that people make their initial partner selections by selecting the most attractive person, though if they are continuously rejected, they will cast a more realistic net. 

Palmer also made an important clarification. "We know nothing about these people," she said, regarding the status, health, length of their relationship, or if they are really even dating in the first place. 

"What you can see from these photographs is something that has been proven by psychological research," Palmer said. "On initial dates, our initial selections, which of course is intensified by looking at the person on social media, we tend to try to get the most attractive person." 

So grab a cup of Folgers and scroll through the Siblings or Dating Instagram account, and enjoy knowing these people might simply think they themselves are hot, and have subconsciously selected their romantic partner because they have similar features. Or they might just be siblings.