No two cakes smell identical, yet we are still able to recognise the general aroma that promises pleasure. Ayse Yarali from the Leibniz Institute for Neurobiology, Germany, explains that this ability to generalise a previously learned link between a cue – such as an odour – and an experience – such as a pleasant taste or the attack of a predator – to a range of similar cues can help us to ensure that we repeatedly encounter pleasant situations while avoiding risky ones.