In 1939, A research team began secretly stealing identical twins.
• The kids knew nothing.
• The adoptive parents knew nothing.
• Some were blocks apart. Some were in the same classroom.
Over 50 years later... The patterns they witnessed blew me away🧵
The mastermind?
Dr. Peter Neubauer, a child psychiatrist who fled Nazi Austria.
Ironically, he would go on to conduct one of the most ethically questionable studies in American history.
His goal?
End the nature vs. nurture debate once and for all.
The Louise Wise Adoption Agency in New York was his partner in crime.
When twins came in for adoption, they secretly separated them.
One twin would go to a wealthy family.
The other to a working-class home.
The perfect "scientific experiment"...
The deception was elaborate:
• Parents were told they were part of a "child development study"
• Researchers visited homes regularly for "routine checkups"
• Children were filmed, tested, and monitored
• But no one knew about their twin
The truth stayed buried for decades.
Then in 1980, 19-year-old twins met by chance.
Paula Bernstein sat down at a deli in Manhattan when customers started calling her "Elyse."
She had no idea who Elyse was.
Until she came face to face with her identical twin sister she never knew existed...
The twins were stunned:
• Same laugh
• Same expressions
• Same mannerisms
• Same interests
Despite never meeting for 19 years.
But this wasn't just coincidence. It was by design.
And they weren't alone...
As news spread, more twins came forward.
Doug Rausch and Howard Burack
Michele Mordkoff and Allison Kanter
Ellen Carbone and Melanie Mertzel
All separated at birth.
All living parallel lives.
All victims of a secret experiment.
This is Doug and Howard: ↓
The researchers tracked everything:
• IQ tests
• Personality assessments
• Medical examinations
• School performance
• Family dynamics
5 researchers visited each child multiple times a year for over a decade.
All while keeping their true purpose hidden.
The study's findings?
Locked away at Yale University until 2065.
Dr. Neubauer never published his research.
Before his death in 2008, he said:
"I don't know if I could do it again... I don't think I could."
Yet he never apologized to the families.
Why 2065?
To protect the "privacy" of the researchers.
The same researchers who had no problem violating the privacy of dozens of families and separating twins at birth.
The irony is chilling.
Some twins eventually gained partial access to their files:
They discovered researchers had:
• Filmed their childhood
• Recorded their voices
• Documented every detail
• Known about their twin all along
While they grew up feeling "something was missing"
But here's what legitimate twin research actually shows...
Dr. Nancy Siegel at California State University Fullerton has spent 30+ years studying twins ethically.
With full consent and transparency.
Her findings changed everything we thought we knew about human nature...
By comparing how similar identical twins are versus fraternal twins, researchers can measure genetic influence on any trait.
At the Minnesota Study of Twins Raised Apart, Dr. Siegel studied hundreds of twins separated at birth.
These twins shared only genes, not environment.
Any similarities between them had to come from genetics.
The results shocked everyone.
Physical traits like height and weight?
80% genetic.
General intelligence?
70% genetic.
But here's where it gets wild: Even personality traits, job satisfaction, and brain wave patterns showed strong genetic influence.
The most surprising findings from the last 20 years:
• Religiosity (how much you invest in religious activities)
• Political attitudes
• Social attitudes
All have genetic components.
Things we assumed were purely learned are partially inherited.
This blew apart decades of psychology textbooks.
The most mind-bending cases are identical twins raised apart who show bizarre similarities:
• Both scatter love letters around the house to their wives
• Both bite their nails down to the nub
• Both describe mixed headaches "as if someone is beating on their head with a hammer"
Same exact phrases. No contact for decades.
But here's the crucial part most people miss:
Genes don't work like destiny.
They work like probability.
Dr. Siegel calls this the difference between "deterministic" and "probabilistic."
Having a gene for X doesn't guarantee X will happen.
Even identical twins can show different gene expression.
Same DNA, different outcomes.
This can happen even in the womb when environmental differences trigger different genetic switches in each twin.
Some identical twins look slightly different despite sharing 100% of their genes.
The beauty of legitimate twin research is it respects human dignity.
Dr. Siegel studied fraternal twins too - they serve as the "natural control group."
This ethical approach gives us the same insights without exploitation.
For me, this connects to everything I believe about human potential.
Yes, we have genetic predispositions.
But we also have incredible power to shape our development through our chosen environments.
That's why education and learning matter so much.
If this thread moved you, follow me @ToanTruongGTX for more mind-bending stories about psychology and human nature.
I dig deep into fascinating historical stories that changed how we understand ourselves.
I am the writer behind @geniusgtx, @geniusbusiness_, @mentalities_… and the "thread guy" behind many of your favorite creators.
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