The aim of this task is determine a participant's ability to recognise chords of increasing complexity. As music often involves parallel events, it is important to be able to distinguish between harmonic contexts.

Initially, the chords have two notes and this increases to three and finally four notes. Each time a new chord size is introduced, only two specimens are used. Subsequent questions increase the number of specimens by one. The specimens vary in degrees of similarity; some have the same top and/or bottom tones as the test, others have notes chosen from completely different keys.