The patent, spotted by Fast Company, suggests Apple could rely on a mix of physiological, behavioural and spatial-temporal characteristics – such as location, date, day, time and data consumed – to work out how someone is feeling.

Initially, data would be used to establish a baseline mood profile for a user, after which, the patent states: “The user’s current mood can then be inferred by applying one or more mood rules to compare current mood-associated data to at least one baseline mood profile for the user.”