A variety of audio rates (from 48 kpbs MP3 to WAV, or lo-fi and hi-fi) were used to capture a rich tapestry of varying audio textures, as well as preserve recording space on the device. This contrast between rates can be seen as a parallel to the varying amount of mental attention that a student might give to a lesson, depending on how much she slept the previous night and other factors in her life, etc. More information is received on some days than is received on others, due to the faculties of the receiver. Therefore, the information recorded ultimately depends on the specifications, capabilities, and nuances of the instrument making the recording.