Scientists find that coin tosses aren't 50/50. Here's how you can get an advantage
The age-old method isn't as fair and practical as we originally thought.

Coin tosses aren't 50/50 like we've been led to believe
Settling things by coin toss has been around for centuries. The ancient Romans called it “‘Heads or Ships.” Britains of the Middle Ages knew it as “Cross or Pile.” Throughout history, this game of chance was believed to be a fair, unbiased way to settle a dispute, choose which team goes first in a sports game and make decisions.
And the thought behind this makes sense. After all, there are only two sides to a coin, making the odds for each outcome an even 50/50. It doesn’t get more even than that.
However, a team of scientists, led by former magician and American mathematician Persi Diaconis, have discovered that this age-old method isn’t as evenly split as we believed. And there's even a way to slightly cheat the odds to your advantage.Diaconis made a name for himself by studying (and debunking) randomness, one of his more famous feats being determining how many times a deck of cards must be shuffled in order to truly mix up the deck. Even as a teenager, he exposed how casino scammers would shave their dice to improve their chances against customers.
When it comes to coin games, Diaconis has long argued that while it’s “pretty close to fair,” it’s definitely not 50/50. Especially when a little wobble is introduced into the toss, which increases the chance that the coin will land on the same side it started.
A group of scientists set out to test Diaconis' findings and their study, currently in preprint, revealed that coins did indeed land on the same side they were tossed from around 51 percent of the time.
“According to the [Diaconis] model, precession causes the coin to spend more time in the air with the initial side facing up,” they wrote. “Consequently, the coin has a higher chance of landing on the same side as it started (i.e., ‘same-side bias’).”
If you bet a dollar on the outcome of a coin toss 1000 times, knowing the starting position of the coin toss would earn you 19$ on average. This is more than the casino advantage for 6deck blackjack against an optimal player (5$) but less than that for single-zero roulette (27$).
— František Bartoš (@BartosFra) October 9, 2023
The study recorded 350,757 coin flips, carried out by 48 people using 46 different currencies. In the end, there turned out to be a 50.8 percent chance of the coin showing up the same side it was tossed from.
They also found that some tossers showed a strong same-side bias while others had none at all, indicating that coin tosses may come down to the tosser, ever so slightly.
While this might not seem like a huge margin, the advantage becomes clear when you put into a betting scenario. "If you bet a dollar on the outcome of a coin toss (i.e., paying 1 dollar to enter, and winning either 0 or 2 dollars depending on the outcome) and repeat the bet 1,000 times, knowing the starting position of the coin toss would earn you 19 dollars on average,” the team explained.
"This is more than the casino advantage for 6 deck blackjack against an optimal-strategy player, where the casino would make 5 dollars on a comparable bet, but less than the casino advantage for single-zero roulette, where the casino would make 27 dollars on average."
You could also use physics to your advantage, not just probability. Diaconis also proved that the head side of a coin is a tiny bit heavier than its tails counterpart, causing it to land on tails more often. Especially when it comes to Lincoln Memorial pennies.
So next time you are fighting with a loved one over whose turn it is to do the dishes, you can still settle it with a coin toss. Just conceal the starting position first. Or take a peak a use this hard earned knowledge. No judgement.
There's a reason why some people can perfectly copy accents, and others can't
Turns out, there's a neurodivergent link.
A woman in black long sleeve shirt stands in front of mirror.
Have you ever had that friend who goes on vacation for four days to London and comes back with a full-on Queen's English posh accent? "Oooh I left my brolly in the loo," they say, and you respond, "But you're from Colorado!" Well, there are reasons they (and many of us) do that, and usually it's on a pretty subconscious level.
It's called "accent mirroring," and it's actually quite common with people who are neurodivergent, particularly those with ADHD (Attention Deficit Hyperactivity Disorder). According Neurolaunch, the self-described "Free Mental Health Library," "Accent mirroring, also known as accent adaptation or phonetic convergence, is the tendency to unconsciously adopt the accent or speech patterns of those around us. This linguistic chameleon effect is not unique to individuals with ADHD, but it appears to be more pronounced and frequent in this population."
Essentially, when people have conversations, we're constantly "scanning" for information—not just the words we're absorbing, but the inflection and tone. "When we hear an accent, our brains automatically analyze and categorize the phonetic features, prosody, and intonation patterns," writes Neurolaunch. For most, this does result in copying the accent of the person with whom we're speaking. But those with ADHD might be more sensitive to auditory cues. This, "coupled with a reduced ability to filter out or inhibit the impulse to mimic…could potentially explain the increased tendency for accent mirroring."
While the article explains further research is needed, they distinctly state that, "Accent mirroring in individuals with ADHD often manifests as an unconscious mimicry of accents in social situations. This can range from subtle shifts in pronunciation to more noticeable changes in intonation and speech rhythm. For example, a person with ADHD might find themselves unconsciously adopting a Southern drawl when conversing with someone from Texas, even if they’ve never lived in the South themselves."
People are having their say online. On the subreddit r/ADHDWomen, a thread began: "Taking on accents is an ADHD thing?" The OP shares, "My whole life, I've picked up accents. I, myself, never noticed, but everyone around me would be like, 'Why are you talking like that??' It could be after I watched a show or movie with an accent or after I've traveled somewhere with a different accent than my 'normal.'
They continue, "Apparently, I pick it up fast, but it fades out slowly. Today... I'm scrolling Instagram, I watch a reel from a comedian couple (Darcy and Jeremy. IYKYK) about how Darcy (ADHD) picks up accents everywhere they go. It's called ADHD Mirroring??? And it's another way of masking."
(The OP is referring to Darcy Michaels and his husband Jeremy Baer, who are both touring comedians based in Canada.)
Hundreds of people on the Reddit thread alone seem to relate. One comments, "Omfg I've done this my whole life; I'll even pick up on the pauses/spaces when I'm talking to someone who is ESL—but English is my first language lol."
Sometimes, it can be a real issue for those around the chameleon. "I accidentally mimicked a waitress's weird laugh one time. As soon as she was out of earshot, my family started to reprimand me, but I was already like 'oh my god I don’t know why I did that, I feel so bad.'"
Many commenters on TikTok were shocked to find out this can be a sign of ADHD. One jokes, "Omg, yes, at a store the cashier was talking to me and she was French. She's like 'Oh are you French too? No, I'm not lol. I'm very east coast Canada."
And some people just embrace it and make it work for them. "I mirror their words or phrase! I’m 30. I realized I start calling everyone sweetie cause my manager does & I work at coffee shop."