Fig. 2.

An illustration of the presentation of a background sequence (B) and an inserted target sound (T) during one trial. Each letter represents one warble element, and the number in subscript indicates the order of each element in the sequence. In this example, the background warble stream was played in its natural sequence, and a target sound was inserted between the 17th and the 18th element in the sequence. The background sequence was played continuously except during reinforcement (food reward on “hit” or blackout on “false alarm”)