When we're blindfolded, we're doomed to walk in circles. The same thing happens when we drive and swim without the benefit of sight. Around and around we go. Robert Krulwich, the cohost of the excellent Radiolab show (iTunes - Feed - Site), breaks this all down with some intriguing animation. But let me add this little spoiler alert. What makes us spin in circles still defies scientific explanation. H/T to Mike in Cambridge.