Readers respond to an report on experiments that have shown a left-turn bias among humans It is not quite true to say that no one knows why people prefer to turn left and walk anticlockwise ( Report, 10 June ). Research by the French professor of physiology Raphaël Dubois in the 19th century revealed the existence of a phenomenon in the natural world that he called the “antikinetic gyratory movement”, caused by the rotation of the Earth on its axis. During the 1900 Universal Exhibition in Paris,