Brain Snacks #135: Plug Socket, Riveted Trousers and Chimps Memory
The Small Connector That Made Electricity Safe at Home, How a Mining Problem Created the Most Iconic Jeans and Chimpanzees Incredible Memory
Welcome to this week's edition of Brain Snacks. I share three short, exciting stories every Sunday to inspire your week.
School is closed for August, so my son spent the week at his grandparents’. He’s loving it, and they’re loving it too. Four is such a great age: a mix of becoming a wonderful companion and not much trouble.
I hope you enjoy this week’s snacks.
Brain Snack #1: Plug Socket
Early home electricity was dangerous and awkward. In the late 19th century, lamps and appliances were often hardwired into walls or screwed into light sockets. Moving your toaster meant rewiring it. The detachable plug socket that we all are familiar today was actually an innovation that come later and really helped making electricity safe and portable.
The first known versions appeared in Britain in the 1880s, when inventor Thomas Tayler Smith patented a two-pin plug and matching wall socket. His design allowed appliances to be connected and disconnected without touching live wires, a leap forward in safety. In 1904, Harvey Hubbell II patented the first detachable plug in the United States. His design initially screwed into light bulb sockets, since dedicated wall outlets were rare, but the principle was the same: portable, safe access to power.
Over the next decades, the plug evolved from Hubbell’s round prongs into the flat blades that became the U.S. standard by the 1910s. Around the world, other nations developed their own standards, resulting in the confusing patchwork of plug shapes travelers still face today. Grounded three-prong designs emerged in the 1930s, and innovations like fused plugs and child-proof shutters followed in different countries.
Today, the plug is invisible to most of us until we travel abroad and can’t fit it into the wall. Yet it was this small connector, refined over decades, that turned home electricity from a risky luxury into an everyday essential. The next time you charge your phone or brew coffee, remember: the outlet beside you is the descendant of an idea sparked nearly 140 years ago in Britain.
Go deeper: The history of the plug socket - Retrotouch
Brain Snack #2: Riveted Trousers
If you had to pick one piece of clothing that is the most famous worldwide, you would probably choose a pair of jeans. The name itself comes from Gênes, the French word for Genoa, Italy, where a sturdy cotton cloth was once woven for sailors’ trousers. But despite “jean” being a fabric type, most modern jeans are actually made from denim. Their revolution began in the late 19th century as a way to provide better clothing for miners.
In the early 1870s, Jacob Davis was a busy tailor in Reno, Nevada, working mostly for the miners of the region. The trousers of the time were already made from denim, a tough fabric, but they kept breaking at weak points like pocket corners and fly seams. His solution was simple but revolutionary: reinforce those stress points with small copper rivets, the kind used on horse harnesses.
The pants lasted, and word spread quickly. Davis wanted to protect his idea but didn’t have the money for a patent. He turned to his fabric supplier: Levi Strauss, a San Francisco merchant already known for selling sturdy, indigo-dyed denim. Strauss saw the potential, and on May 20, 1873, the two men received a patent that protected riveted jeans under Levi’s name until 1890, cementing its reputation as the jeans brand.
Jeans remained primarily utilitarian during the early 20th century, worn mostly by laborers and even banned in some schools for their rugged image. But in the 1950s, Hollywood brought them into the spotlight, helped by icons like James Dean and Marlon Brando, making them popular with the youth. From there, they slipped seamlessly from workwear to everyday fashion.
Go deeper: The Origin of Blue Jeans - The Smithsonian Magazine
Brain Snack #3: Chimps Memory
Working memory, the brain’s mental sticky note, lets us briefly hold and juggle information, like a phone number we’re dialing or the positions of chess pieces mid-game. Most adult humans can track about seven items at once before details start to slip. In 2007, a group of chimpanzees in Japan proved just how far behind we might be.
The star of the experiment was Ayumu, a then-7-year-old male chimp who seemed to treat the task like a game. His photographic precision left researchers stunned: he could recall the exact location of all nine numbers after seeing them for just 650 milliseconds, less than the blink of an eye. Humans given the same test, with months of practice, still lagged far behind.
Why the edge? One theory points to an evolutionary trade-off. Humans may have sacrificed some working memory capacity in exchange for advanced language and abstract reasoning. In the wild, a chimpanzee’s survival hinges on razor-sharp spatial and short-term recall: remembering where ripe fruit is hidden in dense foliage or the exact location of rival group members. For humans, whose lives became less dependent on immediate recall, that capacity may have quietly eroded over millennia.
Today, Ayumu’s performance is a humbling reminder: our species isn’t the undisputed champion of every mental arena. While we’ve built rockets and written novels, some of our closest relatives still beat us in pure, fleeting recall.
Go deeper: Chimps Have Better Short-term Memory Than Humans - LiveScience