Identical twins aren't that identical

https://stuartritchie.substack.com/p/identical-twins-arent-that-identical

by paulpauper • 4 years ago

42 51 4 years ago

stuartritchie.substack.com

gregw1342• 4 years ago

I'm an identical twin. I remember twice in high school we were accused of cheating because we wrote extremely similar essays, but in fact we both randomly came up with the same very specific idea at the same time.

cperciva2• 4 years ago

All you know for certain is that you didn't cheat and your twin claims that he didn't copy your work. ;-)

Retric• 4 years ago

Hardly, they also know if their twin had the opportunity to copy their work etc.

cjbgkagh• 4 years ago

Thoughts are highly genetic.

lukas0992• 4 years ago

I think you can make a pretty strong case for nurture here. The twins talk and hang out a lot, so they develop similar thought patterns.

senectus1• 4 years ago

oooh not sure i agree with that.

Thats a very slippery slope as well.

ARandomerDude• 4 years ago

I wish I could agree with you but I’m helplessly bound by my DNA to think you’re wrong.

pge• 4 years ago

identical twin too - my brother and I were accused of cheating on standardized test once in elementary school because our answers were so similar. Got called into the Principal's office. Fortunately, we were sitting far enough apart that there was no way we could have cheated. Certainly with my brother and me, our answers to any kind of test at that age were highly correlated, just from having had similar (or the same) teachers and having similar aptitude.

giantg2• 4 years ago

The more interesting part for me would be if they explored more about how it was determined they were cheating and what the punishment was - ie the entire basis for the case. Imagine all the money wasted on this case when a simple solution existed.

Think they cheated? Create a different test of the material and administer it separately.

sorenjan• 4 years ago

I don't like the term identical twins, it confuses some people and invites the kind of anecdotes described in the article. People are different individuals even when they have the same DNA. I prefer the term monozygotic twins.

overgard• 4 years ago

Identical twin here. I know me and my brother were very similar academically despite being in different classes and never studying together.

I imagine if these twins happened to study together, it seems plausible they scored similarly, and if you factor in pace, they probably think and work at a similar energy level. They dont get into how they got to the 10^38 figure, but to me that seems like the most fishy part. To prove cheating you need more than odd movements and similar scores in my opinion.

runsWphotons• 4 years ago

You dont need more than odd movements for the invigilator to suspect them of something weird going on and remove them from the test. They could have just retested them later.

The calculation was done only after the invigilator noticed strange movements and noted them so that the tests were looked into more.

thayne• 4 years ago

They dont get into how they got to the 10^38 figure, but to me that seems like the most fishy part

If the test was multiple choice with 5 options for each question, and you assume that if they got the question wrong, they randomly guessed the answer, and their answers to all incorrect questions were independent of each other, and forget to account for the fact that one of those 5 options is correct (or there were 6 options, which is less common for exams in my experience), then you get approximately 1 in 10^38 for the probability their wrong answers were all the same.

But those are bad assumptions. People don't randomly guess the answer every time they answer incorrectly, and people who have shared experiences (like say taking the same classes) are more likely to answer the same way. And answers to different questions are probably correlated, especially in such a long test, where there are likely multiple questions covering similar material.

Now, it is possible that computed the probability a different way, and it is just a coincidence they came to the same number. After all, the above method doesn't account for how likely it is that they answered correctly on the 242 other questions they answered the same, which would probably require some analysis of other students who took the same exam and maybe how similar the twins were on previous exams. But it does seem suspicious that it is easy to get the same number with a very naive estimation.

pram• 4 years ago

I have twin girls and they’re not similar at all. I don’t believe the hive-mind hypothesis.

TBH they do a lot of shenanigans to screw with people who aren’t familiar with them, like going by the opposite name. An elaborate cheating scheme seems like something they’d enjoy.

CalChris• 4 years ago

Identical twin here. In high school, we had a brutal geometry problem set. The only people in the school who got it right were my twin brother and I. Pretty cool.

We were in separate sections; by then, we really didn't like being the same class. I was in the second section and was accused of cheating by the teacher with zero evidence; the correct answers, it was math, were going to be the same. My response was the fuck we did; we were competing against each other. The teacher knew he wasn't going to get past that and changed the subject. But going from only to cheater to next didn't sit well.

As for the article, what is the bitrate of odd movements?

BTW, we may have cheated at one point. 24 Hour Fitness had a less well known half-price for twins membership. Or at least, I think they did.

gregw1342• 4 years ago

My favorite cheat was when my identical twin forgot his id and couldn't get in the bar. I had someone run out my driver's license to him and he got in.

ProllyInfamous• 4 years ago

Ahhh... the ole "bar trick." With a good attitude, I've definitely done a 2for1 entry.

A further biometric "hack" :

Many facility doors use a "hand scanner" to secure certain doorways, which combined with your RFID tag "authenticate" the potential entrant.

All that most of these "hand scanners" are doing is very hazily checking finger lengths and hand ratios (i.e. NOT FINGERPRINTS).

So in certain limited access situations my twin and I were able to share certain similar privileges, including a "50% off safe deposit box."

nanidin• 4 years ago

redacted

EGreg• 4 years ago

Actually, he was right, and your version is incorrect.

“I was the only one who…”

On the other hand you’d be correct in a phrase like:

“The only people who were cheated were his brother and me.”

The word me is an object of a sentence, not the subject.

singlow3• 4 years ago

The "brother and I" are a compound complement, not an object. Complements use the same form as the subject. Were is a form of "to be" which generally sees subject forms on both sides, such as "It is I".

The only one who got it right was I.

The only ones who got it right were he and I.

cryptonector• 4 years ago

As for the article, what is the bitrate of odd movements?

This. The claim that they were seated close-by, made odd movements, and progressed at the same rate is very suspicion-inducing. If the test was multiple-choice it really wouldn't have been hard to have one sibling copy the other's answers. Having and resolving disagreements would have required much higher bandwidth, but just playing follow-the-leader would have required a bitrate of, what a few bits a minute?

phlipski2• 4 years ago

Identical twin here. My brother and I are/were completely different academically. I excelled in math/school - he struggled. I graduated with an engineering degree, he didn't and struggled in high school and college. He ultimately did earn his bachelors degree - but not until his late 30's. There are some area's where we share similar thoughts, and some where we drastically diverge. To this day when I look at baby pics from ages 0 to around 3 I have no clue which one is me unless the pic has been labeled.

I'm now the father of twin girls (fraternal) and they are basically two completely different human beings who happened to share the same womb and birthday. They are NOTHING alike.

I also have 2 other siblings, and though I communicate the least with my twin these days - I still feel and share a bond with him that I'll never have with my other siblings and I can't quite explain it.

All that said I can't wrap my head around this idea that twins "think alike because they're twins." I think the simple answer to this case is that both of those women are smart and studied hard. And if you're really worried about it - put them in different classrooms and make them re-take the test. Sure would have saved a bunch of time and legal fee's!

dotancohen2• 4 years ago

  > I still feel and share a bond with him that I'll never have with my other siblings and I can't quite explain it.

May I bother you with a request for perspective? A neighbour lost one of his identical twins at 6 months old. Both twins were born around 700 grams, and were under treatment (incubation possibly, but I'm not sure) in the house for many months. I do not know if they were together during treatment or not.

The twin who lived does not know that she had a twin sister - at around age two or maybe three the family took down the photographs of the deceased twin and stopped talking about her. Might that have some lingering effects on the living twin? Of course I'm asking about the general case, not this specific case, because obviously I cannot provide enough information over a short HN comment. But in your opinion, as someone with an unexplainable bond unlike that with other siblings, might such a bond persist even had you not known about the existence of your twin? How might that affect you if so?

To be clear, I have no intentions of revealing what I know and would never betray the parent's wishes.

pkrotich• 4 years ago

Intereting question... my younger brother was a twin as well, born prematurely and incubated for months. His twin didn't make it and to this day he claims his twin took part of his brain or will (not sure exactly what he means)

I've always dismissed it as an excuse for not doing well in school & life... but I sometimes wonder if it's a legit phychological "hold" of some sort.

phlipski2• 4 years ago

I'm hard pressed to think I'd have the same bond if I had lost my twin at 6mo. I don't really have any memories pre age 3 so I'd assume I'd grow up just thinking I was an only child. This also assumes my parents removed all trace of my twin.

It's an interesting thought experiment.

Seeing someone who looks just like you every day for 18 years (and being constantly called by two different names) I think does something to you. It's an experience most people don't have.

bagels2• 4 years ago

The statistics presented in the case were probably pretty flawed. The telepathy stuff also seems rediculous.

The part I don't understand is: if the proctor sees identical twins sitting near eachother, and suspects them of communicating, why not just separate them instead of waiting until the test is over and then accusing them of cheating? Why not just remove the possibility for them to cheat?

thaumasiotes4• 4 years ago

The part I don't understand is: if the proctor sees identical twins sitting near eachother, and suspects them of communicating, why not just separate them instead of waiting until the test is over and then accusing them of cheating?

Because by the time you notice that they're cheating, it's too late to retroactively prevent them from starting?

bagels2• 4 years ago

There was a lunch break, so it seems like it must have been a lengthy test. They could have at least stopped it from continuing.

phire• 4 years ago

Much harder to move students now that tests are computerized. The software might not even support that functionality.

Also, we have no idea what their suspected cheating procedures are. Maybe they deliberately avoid acting early on a hunch so they get a full test worth of data to run an statistical analysis on.

zupa-hu• 4 years ago

I had a classmate in secondary school with whom we seem to have shared a very similar brain wiring to the point where we wrote identical tests in physics. I believe for maybe two years. As soon as he got his result, I knew mine & vica versa. Was a strange experience, we did develop a special bond.

We were never accused of cheating, it was a tiny group though (20).

Edit: By identical, I do mean _literally_ the same mistakes, same points. Not 99% similar. 100%.

robertakarobin3• 4 years ago

We have identical boys, James and Charlie, about to turn 5. Got a DNA test for a holiday present that confirmed it. They're very healthy and happy kids, and are each other's best friend.

When they were about 3, James asked to wear a dress. Now James wears a dress every day, and is -- for lack of a better word -- extremely flamboyant. At first Charlie wanted to wear a dress too, but that seems to have just been FOMO because now he never wears them. Charlie is maybe more cerebral and cautious than your average boy, but still very clearly feels like a boy.

This has all been really interesting and mystifying to us. My wife and I and most of the people we interact with are pretty ordinary cisgendered, heterosexual people. We've never consciously pushed the boys toward any particular social norm. And we both figured one's sexuality and gender identity was hardcoded in one's DNA. Now we have living proof that doesn't seem to be the case. Our best uneducated guess is that something in utero caused the boys to develop with different levels of hormones, and that caused their "wiring" to diverge.

thaumasiotes4• 4 years ago

And we both figured one's sexuality and gender identity was hardcoded in one's DNA.

There are some good reasons not to believe this. From a Darwinian perspective, we can easily observe that homosexuality is one of the worst possible phenotypes an organism can have, so we'd expect genes to be adamantly opposed to it. Or in other words, heterosexuality definitely should be hardcoded in, in several different ways, but homosexuality should not.

And the evidence, such as it is, tends to bear that out: concordance of homosexuality in identical twins is, if I remember correctly, about 40%. That sounds high, but it isn't -- concordance for randomly chosen traits in identical twins is much, much higher than 40%.

robertakarobin3• 4 years ago

Yes, that certainly all makes sense. If I recall correctly, growing up in the 90s we were sort-of put under the impression that DNA determines almost everything about a person. It's only more recently that science and society have discovered how much is actually determined by things like gut bacteria.

tzs• 4 years ago

Would we still expect such adamant evolutionary opposition to homosexuality if we took into account kin selection or that sexuality is a complex thing whose genetic component is likely to be influenced by many different genes and it is possible that the set of genes that in some particular combinations give homosexuality give in other combinations heterosexuality plus some additional survival benefits that make it overall worthwhile to preserve those genes that can give homosexuality?

malux85• 4 years ago

Very interesting! I went to high school with identical twins, and even though they were quite hard to tell apart in terms of looks, they were wildly different in terms of intelligence - one was in the class for the gifted and the other was in the class for the struggling, they had quite different personalities too. Really fascinating.

guntri• 4 years ago

Please don't trans your kid just because he likes wearing dresses.

robertakarobin3• 4 years ago

Yes, we're careful to not put any labels on him. In his words, he doesn't like it when people call him a girl, and wants people to know he's a boy, but he does like to do things that girls do.

Waterluvian• 4 years ago

Is there any legal backstop in the US stopping someone from deciding to give both twin newborns the exact same name?

Imagine the potential for criming.

Cerium• 4 years ago

At least they would be different on their birth certificate. I know that California certificates have fields for number of births and birth number (eg: twins, 1/2).

ly3xqhl8g9• 4 years ago

One step is to stop caring so much about DNA, glorified run-of-the-mill recipe for proteins and alike (is it really important with what soldering iron was the RAM soldered on your computer?), and start looking at bioelectrical patterns. If all a "person" is is some kind of dynamical pattern, a state machine, if you will, drawn by voltage-gated ion channels [1] and mechanisms alike, then there is nothing mysterious when similar state machines are in the same state: nothing out of the ordinary if I boot up two different but same specification devices with the same operating system and I land, even with different RAM mappings, on the "same" desktop.

[1] Michael Levin: "Non-neural, developmental bioelectricity as a precursor for cognition" https://youtu.be/3Cu-g4LgnWs

machina_ex_deus• 4 years ago

They probably calculated the original chances assuming independent random variables for answers, and the truth is that those variables are dependent and highly correlated because they are twins.

Both the articles and the original out of thin air calculations are completely made up, but it's pretty conceivable that the cheating program had a mistaken assumption of variable independence, which is clearly false in this case.

Identical twins aren't that identical

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