In 1940, a pair of twin boys, only three weeks old, were put up for adoption in Ohio. Separate families adopted each boy and coincidentally named both James, calling them Jim for short. They grew up never knowing anything about one another, but their lives were bizarrely similar. They each had a dog named Toy and in elementary school, each both was good at math, showed talent in woodshop, but struggled with spelling. But it was as they moved into adulthood that coincidences really started to pile up. My name…
If one is good, two must be better, so today we were talking about twin on the first of a pair of twin episodes. Let’s start with a quick review. Fraternal twins occur when two eggs are separately fertilized. They are genetically distinct, basically regular siblings that happened to be conceived at the same time. Or not. There’s a rare circumstance called superfetation, where a woman ovulates while already pregnant and the second egg also gets fertilized. Multiple eggs being released during ovulation can sometimes result in heteropaternal superfecundation, meaning the eggs were fertilized by different men’s sperm, creating fraternal twins with different fathers. Identical twins occur when a fertilized egg splits, creating two zygotes with the same cells. The splitting ovum usually produces identical twins, but if the split comes after about a week of development, it can result in mirror-image twins. Conjoined twins, what we used to call Siamese twins, can result from eggs that split most of the way, but not complete. Twins account for 1.5% of all pregnancies or 3% of the population. The rate of twinning has risen 50% in the last 20 years. Several factors can make having twins more likely, such as fertility therapy, advanced age, heredity, number of previous pregnancies, and race, with African women have the highest incidence of twins, while Asian women have the lowest.
Twins have always been of great interest to scientists. There’s simply no better way to test variable vs control than to have two people with identical DNA. Identical twins share all of their genes, while fraternal twins only share 50%. If a trait is more common among identical twins than fraternal twins, it suggests genetic factors are at work. “Twins studies are the only real way of doing natural experiments in humans,” says Tim Spector, a professor of genetic epidemiology at Kings College, London. “By studying twins, you can learn a great deal about what makes us tick, what makes us different, and particularly the roles of nature versus nature that you just can’t get any other way.”
NASA was presented with a unique opportunity in the Kelly brothers, identical twins Scott, a current astronaut, and Mark, a retired astronaut. As part of the “Year in Space” project, which would see Scott spend 340 on the ISS, the brothers provided blood, saliva, and urine samples, as well as undergoing a battery of physical and psychological tests designed to study the effects of long-duration spaceflight on the human body. According to Dr Spector, twin studies are currently underway in over 100 countries. Working with data and biological samples in the TwinsUK Registry, Spector’s team has found more than 600 published papers showing a clear genetic basis for common diseases like osteoarthritis, cataracts and even back pain. “When I started in this field, it was thought that only ‘sexy’ diseases [such as cancer] were genetic,” Spector says. “Our findings changed that perception.”
Back on our side of the pond, the Michigan State University Twin Registry was founded in 2001 to study genetic and environmental influences on a wide range of psychiatric and medical disorders. One of their more surprising findings is that many eating disorders such as anorexia may not be wholly to blame on societal pressured by may actually have a genetic component to them. “Because of twins studies,” says co-director Kelly Klump, “we now know that genes account for the same amount of variability in eating disorders as they do in schizophrenia and bipolar disorder. We would have never known that without twins studies.” On the topic of body-fat, a LSU study by Claude Bouchard in 1990 overfed a dozen young male twins by 1,000 calories a day for three months. Although every participant gained weight, the amount of weight, and more importantly for the study, fat varied considerably, from 9-29lbs/4-13kg. Twins tended to gain a similar amount of weight and in the same places as each other, but each pair differed from the other pairs in the test.
Genes have also been a focus for studies on sexual orientation. In 2008, researchers in Stockholm, looked to the Swedish Twin Registry, the largest in the world, to investigate genetic and environmental influences on sexuality. They found that genetics accounted for only 35% of the differences between identical and fraternal gay men and 18% in gay women, indicating that both genetics and environment work together to shape a person’s sexual orientation. However, the study was far from perfect. Like other twin studies on sexuality, the Swedish study was criticized for recruitment bias, or not selecting subjects that represent the population you’ll apply the findings to, since only 12% of the males in the Swedish registry were included in the study.
While some twin studies, like Year In Space, are famous, others are infamous. If you’re worried where this topic is going, don’t be. We’re not talking about Joseph Mengele or the Russian conjoined twins, Masha and Dasha, though they may show up next week. Twin studies helped create the thinking and even the word “eugenics.” Francis Galton, a half-cousin of Charles Darwin, was one of the first people to recognize the value of twins to study inherited traits. In his 1875 paper, “The History of Twins,” Galton used twins to estimate the relative effects of nature versus nature, a term he is credited with coining. Unfortunately, his firm belief that intelligence is a matter of nature led him to become a vocal proponent of the idea that “a highly gifted race of men” could be produced through selective breeding and that unsuitable people should be prevented from reproducing. The word “eugenics” came up a lot during the Nuremberg trials, if it wasn’t already clear with adherents to the idea had in mind. More recently, in 2003, a psychology professor at the University of Virginia reviewed the research on the heritability of I.Q. He noticed that most of the studies that declared that I.Q. is genetic involved twins from middle-class backgrounds. When he looked at twins from poorer families, he found that the I.Q.s of identical twins varied just as much as the I.Q.s of fraternal twins. In other words, the impact of growing up poor can overwhelm a child’s natural intelligence.
Bonus fact: The trope of the evil twin can be traced back as far as 300 BCE, to the Zurvanite branch of Zoroastrianism, the world’s oldest continuously-observed religion. Of all the things inherent to and special about twins, one of the most fascinating is twin language. You might have seen the adorable viral video of a pair of toddlers having an animated conversation in their twin language. If you want to bust out your Latin, it’s cryptophasia, a form of idioglossia, an idiosyncratic language invented and spoken by only one person or very few people. It was a struggle not to throw myself head-first down the idioglossia rabbit hole; maybe for a later episode. Twin speak, or even sibling speak has existed, for as long as human language, but has only been seriously studied for the last few decades, not only to determine how the languages develop but to see if speaking a twin language could hamper the children learning their parents’ language. The reason twins are more likely than other sibling pairs to create their own language is less interesting than psychic phenomena – twins spend a lot of time together, being built-in companions, and are at the same developmental stage. They unconsciously work together to build their language by imitating and pretending to understand one another, reinforcing their use of the language. This can weaken their incentive to learn to speak to everyone else–they already have someone to talk to. Some researchers advocate treating cryptophasia as early as possible. According to Oxford neuropsychologist Dorothy Bishop, twins often get less intervention from speech therapists than nontwins. “People often assume that it’s normal for twins to have funny language, and so they don’t get a proper assessment and diagnosis. And then, when they are identified, they are often treated together as a unit, and so each gets half the attention of the professionals working with them.”
When doctors first began examining cryptophasic children, they discovered that the language isn’t created out of nothing, but is made up of mispronounced words they’ve heard or references that only work inside their family. It’s usually not a language at all. According to Karen Thorpe, a psychologist with Queensland University of Technology, you can think of it like “conversations between married couples where words are invented and abbreviated or restricted codes are used because full explanations are redundant.” That absolutely happens here. My husband and I talk like kids in a tree fort clubhouse. But sometimes, just sometimes, a full-blown language does develop, complete with syntax and totally independent of the language spoken at home. The syntax of a true twin language doesn’t arise from mistakes made while learning the family’s language. It’s similar to the syntax seen in deaf children who create their own sign language when not taught to sign. This syntax could “gives us a potential insight into the nature of language” and mankind’s “first language,” says linguist Peter Bakker. Twin languages play fast and loose with word order, putting subjects, verbs, and objects wherever, but always putting the most important item first, which makes sense. Negation, making something negative, is used as the first or last word of the statement, regardless of how the parental language handles negation. It’s almost like a Spanish question mark, letting you know where the sentence is going. Verbs aren’t conjugated–go is go, regardless of it’s attached to I, he/she, us, or them. There are also no pronouns, like he, she, or they, only the proper nouns. There is also no way to locate things in time and space; everything just is. If you’re a fan of Tom Scott’s language series on YouTube, he’s started making them again. If not, start with “Fantastic Features We Don’t Have In The English Language.” I’ll put a link to it in the show notes. If I forget, or you want to tell me what you thought, Soc Med. Breakroom Most children stop using private languages on their own or with minimal intervention, which is good, according to psychologists, because the longer they practice cryptophasia, the worse they do in tests later. If you remember nothing else I say ever, remember that correlation does not equal causation. Cryptophasia could be a symptom of an underlying handicap and that’s the cause of the low test scores.
This simple-structured language is fine for two or a few people, but once there are more people to talk to or more things to talk about, you’re going to need some more features, “unambiguous ways to distinguish between subject and object,” Bakker says. “In the twin situation these can be dispensed with, but not in languages in which it is necessary to refer to events outside the direct situation.” So do twin languages really offer insight into mankind’s first language? Could a primitive society have functioned as a cohesive unit with a language that can only refer to what can be seen at that moment? That’s what linguists are studying, but UC-Santa Barbara’s Bernard Comrie adds the asterisk that this research into the infancy of spoken language is still a baby itself. “First we were told that creole languages [that is, a distinct language that develops from the meeting a two or more languages] would provide us with insight into ‘first language,’ then when that didn’t pan out interest shifted to deaf sign language (also with mixed results)—I guess twin language will be the next thing.”
It’s not an easy scientific row to hoe. Twin languages come and go quickly as the children develop hearing their parents’ language much more than their twin language. They might keep speaking their twin language if they were very isolated, like two people in a Nell situation or that Russian family who lived alone for 40 years, but we’ll file that idea under “grossly unethically and probably illegal.” Not that it hasn’t been tried. Herodotus tells us of what is considered the first every psychological experiment, when Pharaoh Psammetichus I in the sixth century BCE wanted to know if the capacity for speech was innate to humans and beyond that, what language would that be. He ordered two infants to be raised by a shepherd hermit who was forbidden to speak in their presence. After two years the children began to speak; the word that they used most often was the Phrygian word for bread. Thus, Psammetichus concluded that the capacity for speech is innate, and that the natural language of human beings is Phrygian. Similar experiments were conducted by Holy Roman Emperor Frederick II in the 12th century CE who ordered children to be raised by caretakers forbidden to speak to them and 15th century James I of Scotland who ordered children raised exclusively by a deaf-mute woman, which was repeated by 16th century Mughal Indian Emperor Akbar, among others. I shouldn’t have to tell you that they were all based on dubious methodology and soaking in confirmation bias. A less-terrible test was done in the 20th century by British ethologist, or animal behavior scientist, William H. Thorpe, who raised birds in isolation to determine which songs are innate.
One of the best-known cases a negative impact from cryptophasia is the Kennedy sisters of San Diego, Grace and Virginia, of Poto and Cabengo, as they called each other. They created a media whirlwind in 1970s when it was reported that they only spoke their twin language, to the complete exclusion of English, at the rather advanced age of 6. “Twin Girls Invent Own Language,” “Gibberish-Talking Twins,” “Like a Martian” the headlines read. Here is a clip of the girls speaking and sadly this is the best audio quality I could find. Grace and Virginia had suffered apparent seizures as infants, leading their parents to conclude that the girls had been left mentally handicapped. Their parents opted to keep them inside and away from other children, leaving them mostly in the care of a laconic grandmother who often left them to their own devices. They seemed like the next big thing in language-creation studies, but on closer examination, it was discovered that, like most cryptophasics, the girls were just very badly, and very quickly, mispronouncing English and German, the languages spoken at home. Adding to their disappointment, when scientists tried to use the girls’ words to converse with them, the girls couldn’t stop laughing. Grace and Virginia were also cleared of their parents mis-labeling them as intellectually handicapped. Both were found to have relatively normal IQs, for as much good as IQ tests are, which is very little, but that’s another show. The girls eventually underwent speech therapy and learned regular English, though their language skills were a bit stunted, even into adulthood.
There was one particularly notable case of cryptophasia persisting well past pre-school years, that of June and Jennifer Gibbons. On April 11, 1963, the twins June and Jennifer Gibbons were born into from the Caribbean nation of Barbados, who immigrated to Haverfordwest, in Wales. For additional context, for fans of “Call The Midwife,” this is around that time, only even whiter than the east end of London. The Gibbons were the only black family in their neighborhood. The twins and their siblings grew up with constant racism and harassment. It was so bad and so constant that their teacher allowed them to leave 5 minutes early at the end of the school day, to get a head start home. This environment undoubtedly exacerbated the twins’ tendency to only talk to one another. When they did talk to someone else, their speech was rapid and staccato to the point of being almost unintelligible. Many people who are close will finish each other’s sentences, but Jenifer and June would even finish each other’s actions. They walked everywhere following each other in perfectly synchronized steps. These odd behaviors didn’t make school any easier, created a cycle of bullying and isolation. Their speech devolved to the point that only one member of their family, their younger sister Rose, could understand them. Imagine if the MicroMachine Man spoke in a mix of English and Barbadian slang; that was the Gibbons language. When they would speak to their family, that is. They became known as “The Silent Twins,” and sometimes even the “Zombies.”
Their concerned parents sent them to a string of therapists, but no one could reach them. Out of exasperation, their parents tried sending them to separate boarding schools, thinking that being apart would force each girl to interact with other people, independent of her twin. Instead, Jennifer and June went almost catatonic, refusing to respond to anyone and going rigid, “as stiff and heavy as a corpse.” Once that plan was scrapped after two years, the girls were reunited and immediately returned to their isolation, locked away in their room writing rather dark and sinister stories, some of which would actually be published. In 1982, June would publish “The Pepsi-Cola Addict,” a novel about a boy who was sent to reform school after having an affair with a teacher and is then subjected to unwanted sexual advances from a male guard. Jennifer wrote a novel, “Discomania,” that described the excessive violence that took place at a disco bar. They also played with dolls, creating elaborate fantasies around them and backstories that included the date and manner of each doll’s death. They spent the majority of their time in their room, taking meals left by the door and leaving notes for their parents.
June and Jennifer’s relationship was one of extremes. They could fought as intensely as they loved one another–Jennifer tried to strangle June with the cord from their radio and June tried to drown Jennifer in the nearby river–then they’d go back to laughing together. Jennifer wrote in her diary, “We have become fatal enemies in each other’s eyes. We feel the irritating deadly rays come out of our bodies, stinging each other’s skin. I say to myself, can I get rid of my own shadow, impossible or not possible? Without my shadow, would I die? Without my shadow, would I gain life, be free or left to die? Without my shadow, which I identify with a face of misery, deception, murder.”
Getting the girls to leave their room wasn’t necessarily an improvement. The teenage twins began drinking, smoking weed, and committing petty crimes like shoplifting. Not the type to do things by half-measure, they graduated to more serious acts, vandalizing a trade school and trying to set it on fire and successfully setting fire to a tractor store, causing hundreds of thousands in damage. This led to 19 year old Jennifer and June being send to Broadmoor Hospital in Berkshire, England, an institution with a reputation as a maximum security facility for the criminally insane. Shortly after arriving, the twins went unresponsive, but would react violently if anyone tried to seperate them. June went into a catatonic state and tried to commit suicide; Jennifer lashed out like a rabid animal. Even when they did communicate with staff, their speech was still their unique, indecipherable gobbledegook.
If you thought things weren’t going to get weirder, you haven’t been paying attention. Sometimes they would take turns eating, one twin gorging herself while the other refused to eat, then they would switch. Even when they were kept in different parts of the hospital, nurses and doctors would often enter their cells to find them both frozen into the same, sometimes bizarre, pose, despite the fact that they had had no contact with each other. They seemed to have an uncanny ability to know what the other was doing or feeling at any given time. June and Jennifer lived in Broadmoor hospital for 12 years. At some point during that time, they became convinced that they could not have a normal life as long as they were together. The solution needed to be permanent and complete. One of them had to die for the sake of the other. June expressed this in one entry, “We are both holding each other back….There is a murderous gleam in her eye. Dear Lord, I am scared of her. She is not normal. She is having a nervous breakdown. Someone is driving her insane. It is me.”
While at Broadmoor, the twins caught the attention of London Sunday Times reporter Marjorie Wallace, who would invest a great deal of time carefully forming a bond with the girls andi bringing the strange story to the public. There came a day in 1993 when the twins were to be transferred to a lower security facility closer to their family. On this day, Wallace claims, Jennifer prophetically told her, “I’m going to have to die. We’ve decided.” Jennifer seemed to be in a sort of trance on the way to the new facility, like she was asleep with her eyes open. Once they arrived, Jennifer crumbled to the ground. Despite all efforts to save her life, Jennifer Gibbons laid her head down in her sister’s lap and died at the age of 31. June would later claim that her sister’s last words to her had been, “At long last, we’re out.” Her cause of death was determined to be acute myocarditis, or inflammation of the heart, but she was relatively young, in good health, with no history of cardiac problems, and no drugs, alcohol, poisons or toxins were found in her system. Many people still believed that June somehow killed Jennifer to save herself. The Gibbons family blamed their incarceration at Broadmoor. June would say of her twin sister’s death, “I’m free at last, liberated, and at last Jennifer has given up her life for me.”
Marjorie Wallace wrote in her book “The Silent Twins,” “I’ve spent many years now wondering about the mystery of Jennifer’s death. Now, I don’t think there is really an explanation for that except Jennifer willing herself to die. After I learned about Jennifer’s death – it was about two or three days later – I went down to visit June. And I found her surprisingly intact, really, and very prepared to talk. She spoke very clearly about the conflict between her terrible grief at losing the person closest in her life and her – the freedom that Jennifer had given her. So there she was a few days later, both grieving and mourning, and at the same time, saying Jennifer gave up her life for me and now I have to go on and live for the both of us.”
In the days after Jennifer’s inexplicable death, June began to change, speaking to other people in a way they could understand. She was eventually released from psychiatric care and would go on to become a fairly normal, if quiet, member of society. Despite wanting to be a professional author when she was younger, June gave up writing after Jennifer’s death, saying in an interview, “I don’t see the point in writing books now. I can communicate by talking now, can’t I?” As for Jennifer, she is buried under a headstone that holds the haunting message: “We once were two/We two made one/We no more two/Through life be one/Rest in peace.”
And that… though we’ll finish up out story of the twin Jims. Their lives were so unbelievably similar, if you saw it in a movie, you’d throw your popcorn at the screen. Both Jims had married women named Linda, divorced them and married women named Betty. They each had sons that they named James Alan, though one was Alan and the other Allan. Both smoked, drove a Chevrolet, held security-based jobs, and even vacationed at the exact same Florida beach, though one assumes not at the same time. After being reunited at age 37, they took part in a study at University of Minnesota, which showed that their medical histories, personality tests, and even brain-wave tests were almost identical. Remember, you can always find… Thanks…