Correlations can’t imply causation? Not so fast. A primer on causal networks

The old statistics axiom that correlation doesn’t imply causation is true, but causation can be drawn from more than one correlation. A clever and impressively efficient explainer, this short animation from MinutePhysics clears up a common maths misconception by showing how the concept of causal networks can be used to draw a straight line between correlations and causation via a process of elimination.

Ums, likes and y’knows get no respect – but they’re vital to conversation

If you’ve ever listened to a recording of yourself speaking, the frequency with which you used fillers such as ‘um’, ‘uh’, ‘like’ and ‘y’know’ might have grabbed your attention – and perhaps your scorn. Indeed, these verbal hesitations have been viewed as undesirable since the days of ancient Greece and, more recently, the American linguist Noam Chomsky characterised them as ‘errors’ irrelevant to language. But could there be more to these utterances than initially meets the ear? In this short animation from TED-Ed, Lorenzo García-Amaya, assistant professor of Spanish at the University of Michigan, reveals how ‘filled pauses’ can give conversation partners important context clues, communicate emphasis, help tether related thoughts together, and so much more.

The ‘dangerous nonsense’ of phrenology shows how pseudoscience takes hold

In the 19th century, the Viennese physiologist Franz Joseph Gall placed a formidable thumb on the scales of the ‘nature vs nurture’ debate when he proposed a simple – and, as we now know, false – solution to the age-old conundrum. Everything you need to know about someone’s character, he argued, could be predicted by the shape of different brain regions – and by extension, the contours of their head. That phrenology, as it became known, was built on conjecture rather than empiricism was clear to a great many scientists of the era. Still, it caught on in the public consciousness, and often with sinister consequences. This animation from BBC Reel provides a brief history of phrenology, shedding light on why facile solutions often gain traction over rigorous empiricism, and how pseudoscience can sometimes open gateways for the real thing.

A samurai rulebook offers guidance on how to kill enemies and refrain from gossip

From the 10th century till their abolition in the 1870s, samurai were a class of Japanese military nobility who inherited lives as warrior protectorates (bushi) for feudal lords, and had a notoriously strict and intricate honour code. This video from the YouTube channel Voices of the Past explores two scrolls from the famed samurai school Natori-Ryu’s 17th-century rulebook. The first scroll has codes of conduct for peacetime, with guidance ranging from the universal, such as the pitfalls of talking behind someone’s back, to the extremely samurai-specific, such as keeping a home garden that doesn’t leave you vulnerable to enemy attack. The second scroll lays out the rules of engagement in wartime and paints a much more violent portrait of samurai life, built around intricate rules for killing and being killed. These primary sources offer an intriguing window into the samurai value system, in which loss of reputation was considered a fate far worse than death.

A French resistance fighter reluctantly revisits her past in this Oscar-winning portrait

During the Nazi occupation of France, 14-year-old Colette Marin-Catherine joined the French resistance alongside her family. ‘We were playing cat and mouse. And playing with fire. Or rather, fire was playing with us,’ Marin-Catherine, now 92, recalls. Sadly, not everyone in her family would live to see France liberated. Her brother Jean-Pierre was just 17 when he was arrested for stockpiling weapons. He would die in the Mittelbau-Dora concentration camp in March 1945, just three weeks before the camp was liberated.

In this short documentary, Marin-Catherine faces her trauma with the support of a history student named Lucie Fouble – only 17 years old herself. For the first time in her life, and with Fouble ever by her side, Marin-Catherine travels from France to Germany to visit the camp where some 20,000 Nazi prisoners including her brother died. The US director Anthony Giacchino and the French producer Alice Doyard won the 2021 Academy Award for Best Documentary (Short Subject) for this poignant portrait of bravery and healing amid the long, painful echoes of the Second World War. An accomplished and moving piece of filmmaking, Colette is a reminder of the tremendous power of individual stories to humanise history.