Identical twins aren't that identical
stuartritchie.substack.com
stuartritchie.substack.com
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.
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."
“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.
The only one who got it right was I.
The only ones who got it right were he and I.
I looked at myself in the mirror. She looked at me.
I have decided to just be myself. Kind of an odd case there.
I, myself, love to go to the movies. Here it is just used for emphasis, not as an actual reflexive pronoun.
Some people do use the reflexive pronoun as an object in certain cases, often with compound objects, but it is not proper under any prescriptive English grammar that I have studied.
I assure you, "it's me" is in far more general use than "it is I". The latter, and the purported rule that copular be takes two subjects, is at best exceptionally formal, and many English-speakers don't readily produce it in any context. Quick litmus test: check how acceptable the equivalent constructions are to you for "us" vs "we" or "them" vs "they": "The only ones who got it right were they."
And then conjunctive compound NPs are clear as mud; you routinely run into otherwise impeccable speech where the governing rule seems to be that local euphony trumps long-range syntactic agreement. There's no good prescription here; there's a pretty wide range of pronoun conjunction constructions where you're going to want to either rephrase or just suck it up and let it sound intuitively wrong to somebody.
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?
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!
> 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.
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.
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.
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.
Think they cheated? Create a different test of the material and administer it separately.
Sadly for science but happily for the families involved, these are getting harder to do; the primary source of such twins used to be unmarried women who became pregnant, but between the availability of birth control and a dramatic reduction in the social stigma, far fewer children are being "hidden" by being adopted away.
Thats a very slippery slope as well.
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?
Because by the time you notice that they're cheating, it's too late to retroactively prevent them from starting?
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.
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%.
[1] Michael Levin: "Non-neural, developmental bioelectricity as a precursor for cognition" https://youtu.be/3Cu-g4LgnWs
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.
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.
The calculation was done only after the invigilator noticed strange movements and noted them so that the tests were looked into more.
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.
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.
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%.
Of course that division of influence (1) varies by the particular trait; and (2) is itself dependent on environmental conditions; when the general background is extremely impoverished, shared environmental influences may matter in a way that they don't when the background is lush.
Steven Pinker writing in The Blank Slate pounded on the message that it is essentially impossible for parents to have any predictable non-genetic influence on their children, but that there was still plenty left to be determined after the genes had their say. He recommended greater acceptance of the concept of fate.
Yes. For example, a kin selection argument would need to assume that the number of additional surviving children produced by the homosexual's siblings was at least double the number of children forgone by the homosexual. This does not come anywhere close to being plausible. Things only get worse as the relationship becomes more distant.
> 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?
Is it possible? Sure; that's the sickle-cell anemia model. But as previously noted, what evidence we have tells us that homosexuality is already one of the least genetically-determined traits we're aware of.† And this theory shares the same problem as your first idea: the cost of homosexuality is so staggeringly high that we would never expect an offsetting benefit to be able to make up for it.
Suppose there is a genetic complex that arranges for various effects, and if everything goes wrong it causes homosexuality. Assume this failure occurs 5% of the time.
Our homosexual produces zero children. But a decline in relationship coeffiecients, which trashes the kin selection idea, is not a problem here: we're worried about comparisons of self-to-self, so as long as the expected number of children produced by this genetic complex is greater than otherwise, the complex can persist despite the occasional catastrophic failure.
In other words, we need 19 out of every 20 people expressing this genetic complex to have as many children as 20 baseline people would, an increase of 5.2%.
Compare this discussion of the inhabitants of Madagascar ( https://razib.substack.com/p/the-unreal-voyages-and-trials-o... ):
> Might adaptive selection pressures have reshaped the genomes of the Malagasy, altering the proportion of African and Asian ancestry and leaving a signature in their very DNA?
> A research group tested this hypothesis by sampling the genomes of 700 Malagasy from 257 villages across the island. What they immediately remarked on was a sharp drop in Asian ancestry across much of chromosome 1:
> The target of selection on chromosome 1 in this case is the Duffy locus; and specifically, the null allele that fails to produce the Duffy antigen is under selection. This gene is well known in population genetics because of a marked contrast in variants between African and non-African populations; most Africans are Duffy-negative while most non-Africans are Duffy-positive. Duffy-negative individuals lack the receptor used by the Plasmodium vivax malarial parasite to invade red blood cells, a deficit that confers malaria resistance on its bearer. In Malagasy populations today, the region of Chromosome 1 around Duffy spikes to over 90% African in local ancestry whereas across the rest of the genome, the African ancestry proportion hovers around only 60%. Researchers calculate that this change was driven by a selection coefficient on the order of 0.20.
> We can translate this into plain English as an individual carrying the Duffy-negative allele has 20% more surviving offspring than one who does not.
> This is a staggeringly powerful selection coefficient; very few genes have been subject to such drive in humans; indeed a coefficient of 0.01 or above is by convention usually considered strong selection.
So the effect on non-homosexual bearers of this gene complex would need to be very powerful indeed, far more powerful than almost any selective effect we know of in humans, just for the complex as a whole to break even on reproduction.
It would also have to be quite recent; over time the disastrous side effect would be separated from the beneficial primary effects. The primary effects would persist and the side effect would vanish.
† It's worth being careful here. Heterosexuality is strongly genetically determined. Homosexuality is not strongly genetically determined. As a result, it doesn't really mean anything to say that "sexual orientation is [or isn't] genetically determined" - different orientations are not the same by this metric, and so referring to an umbrella group doesn't make much sense.
By analogy, it should be easy to understand that people who have two arms are mostly that way for genetic reasons, while people with one arm are mostly that way for non-genetic reasons. Is "number of arms" genetically determined? Well, yes, but only when the number is two (or in fantastically exotic scenarios).
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.
Imagine the potential for criming.