Rhythm pattern skills are associated with slower brain rhythms (seconds), while beat-keeping skills are associated with faster brain rhythms (milliseconds and microseconds).

Rhythm was defined as "durational patterns that consist of sounds and silences," she said. The indri's singing sounds like lower and higher howling pitches that pierce through the air.

Rhythm pattern skills are associated with slower brain rhythms (seconds), while beat-keeping skills are associated with faster brain rhythms (milliseconds and microseconds).