Researchers have identified traces of plant poison from the South African plant gifbol on Stone Age arrowheads – the oldest known arrow poison in the world to date. The discovery, published in the scientific journal Science Advances, shows that 60,000 years ago, people in southern Africa had already developed advanced knowledge of toxic substances and how they could be used for hunting.

Imagine sitting across from someone describing two movies to you. You listen attentively, trying to decide which one interests you more — but during that time, without noticing, your face already reveals what you prefer. You smile slightly when they smile, raise your eyebrows when they surprise you, tense your muscles when they emphasize something. This phenomenon is called facial mimicry — and it turns out to be a better predictor of your choice than anything else.