This video shows close observation and a subsequent switch in technique. Pal (out of sight in the first view) closely observes the demonstrator, then fetches a tube from the floor (out of sight), and then proceeds to suck the remainder of the juice in the bottle container. Pal had just performed the "dipping" technique prior to observing the alternate technique being demonstrated during the same trial.
Citation: Yamamoto S, Humle T, Tanaka M (2013) Basis for Cumulative Cultural Evolution in Chimpanzees: Social Learning of a More Efficient Tool-Use Technique. PLOS ONE 8(1): e55768. doi:10.1371/journal.pone.0055768.