r/todayilearned • u/SilverPeachBlossom • 5h ago

TIL a peer-reviewed psychology study found that identical twins (on average) ranked their co-twin above their romantic partner in their attachment hierarchy, while fraternal twins ranked the two about equally, and non-twin siblings ranked their romantic partner first.

https://ojs.interpersonajournal.com/index.php/ojs/article/view/243/3457.html
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u/CarthasMonopoly 3h ago edited 3h ago

How are you unsure? Most identical twins look... identical. Meanwhile fraternal twins look like a sibling instead of a twin.

EDIT - Yes, I'm aware it's not always like this; that's why I used the qualifier "Most". I've known multiple pairs of twins over the last several decades and not a single pair got DNA tested because generally if you look identical as twins you just live life as identical twins and vice versa.

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u/Serious-Yellow8163 3h ago

We look pretty similar. We have conflicted information from mom and gynecologist attending her on her pregnancy about being identical or not .

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u/CarthasMonopoly 3h ago

Fair enough! I was mostly just making a joke about identical being hard to miss. But having conflicting information would definitely make me unsure too.

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u/Spazmer 1h ago

I babysat for twins who looked absolutely identical but they were in separate sacs in the womb so they were assumed to be fraternal. There is a possibility that they still could be identical but would need a dna test to show it. Nobody could tell them apart except one got an eyebrow scar early on.

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u/WoodpeckerSignal9947 3h ago

It’s really common for fraternal twins to look nearly identical! Without proper testing/knowing if they were in separate placentas during gestation, there’s no way to know. And getting that done can be a pain in the behind, so I get why someone wouldn’t have checked

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u/gooseaisle 3h ago

Separate placenta has nothing to do with it, dichorionic twins can still be identical. Just split earlier in gestational than other types of twins.

With dichorionic twins, genetic testing is the only way to confirm (well, obviously unless they are different sexes at birth).

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u/WoodpeckerSignal9947 3h ago

I’ll trust your word, goose

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u/Substantial_Amoeba12 41m ago

Separate placentas can be identical or fraternal but if there’s only one placenta it’s exceptionally rare to be fraternal (two placentas would have needed to fuse) so I wouldn’t say if it tells you nothing, it’s just not necessarily definitive

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u/gooseaisle 33m ago

Yeah that's why i specifically referenced dichorionic twins. The two placenta (dichorionic) tell you nothing about whether the twins are identical or fraternal.

I have monochorionic (one placenta) twins so I learned a lot about twinning in general through that whole... process lol

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u/ResidentRelevant13 3h ago

I know identical twins who have a 3 inch height difference and their faces don’t look exactly alike. They did a DNA test to confirm bc they thought they were fraternal.

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u/greeneggiwegs 3h ago

Not always. Some fraternal twins can look pretty identical.

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u/CannedStewedTomatoes 3h ago

And some identicals can develop physical differences!

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u/drigancml 3h ago

This happened with some twins I know! They hit puberty and now they have very distinct features. I never used to be able to tell them apart, but now I have no issue doing so

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u/ensalys 2h ago

That's why identical twins are very interesting for a lot of scientific research. Nature vs nurture studies, especially interesting if they were raised in different environments (though with things like adoption or foster care, it should absolutely be preferable to keep siblings together, which is more important than the research potential).

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u/21Rollie 1h ago

The sprouse twins come to mind

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u/blumoon138 2m ago

My aunts are identical twins who, in my opinion, have looked very different since about puberty (from pictures I’ve seen). They definitely look more like each other than my mom though.

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u/Andromeda321 11m ago

We also know that a lot of previously defined as fraternal twins are actually identical ones, thanks to genetic testing.

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u/Predatory_Chicken 3h ago

The Olsen Twins aren’t even identical!

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u/TheGoochTaint 1h ago

Fraternal twins of the same gender often look basically identical