A user interface system receives activity information relating at least to electronic device usage by a user. A mental state of the user is derived from this activity information, received during a preceding finite time period. Learning content is provided to a user based on learning goals and their associated difficulty levels, based on whether or not those goals have been met and also based on the mental state of the user. In this way, suitable learning content is selected based on the mental state of the user before the commencement of delivery of the learning content.