Apparatus for inducing sleep comprising: a. a display for providing a subject with a light stimulus b. a base unit on which said display is mounted such that the display is selectively positionable, in use, into a field of view of a subject c. input means for recording an active input provided by the subject in response to the stimulus d. processing means for processing said active input to determine a characteristic of said active input and e. a base unit housing one or more of said means, wherein the apparatus is capable of sequentially providing the subject with a plurality of stimuli, each next stimulus being based on a characteristic determined from the active input made in response to a previous stimulus, and wherein a position and/or brightness and/or a colour and/or a shape of the next stimulus on the display and/or a time interval between stimuli is based on the characteristic of the active input provided in response to a previous stimulus.
