But I already know how to wiggle my ears. . .
One of the most important aspects of good musicianship is having a "good ear". This includes skills such as sight-singing, aural recognition, and the ability to "play by ear." Sight-singing is the ability to sing a written melody without having heard it. It is the most frequently practiced case of the broader ability to hear all aspects of music in one's head while reading a written piece of music. The ability to recognize musical elements, such as melodic intervals or chords, by ear is aural recognition. A person skilled in aural recognition can write down music which he or she hears. Playing by ear is the ability to play or sing a piece of music which one has heard without ever seeing it written down.
All of these abilities are complementary, and a person who practices one is likely to improve in the other areas as well. For instance, someone who is good at sight-singing written music probably also has the ability to write down melodies which he or she hears. The activity of working to improve one's ear is called ear training.
Big Ears is designed to help you improve aural recognition skills, specifically interval recognition. An interval is the difference in pitch between two tones. It's easy for most people to hear the difference between a high note and a low note, but it takes practice to be able to determine exactly how much higher one note is than another. Read the instructions to find out how to use Big Ears as your ear training partner.