A lamp for generating flickering at a selectable frequency corresponding to a desired human brainwave state comprises a base supporting a light source, a shade having a plurality of regularly circumferentially spaced apertures defined therein and a drive mechanism for rotating the shade about the light source. At least one speed control is coupled to the drive mechanism for controlling the rotational speed of the shade. Rotation of the shade while the light source is emitting light produces flickering for an observer looking at the lamp from a fixed position, and the speed control can be used to select a rotational speed of the shade to produce flickering at a frequency corresponding to a pre-selected human brainwave state.