Making perfume is an art that can be traced back to ancient Greece but now modern-day perfumiers are beginning to look beyond their noses to develop the scents most likely to appeal to us. They are, instead, turning to AI. Perfumes can now be designed to trigger emotional responses using ingredients known as neuroscents – odours shown by biometric measures to arouse different positive feelings such as calm, euphoria or sleepiness. Hugo Ferreira, a researcher at the Institute of Biophysics and Biomedical Engineering in Lisbon, is mapping brain activity and response to perfumes to build a database of neuroscents. He says the sense of smell is fascinating. "With sight and hearing, you can imagine the face of a loved one or favourite tune. It's hard to imagine a smell even though [it] can provoke a torrent of emotions and memories."