I was so very sad to see that there were no supplementary materials included with the paper. No awesome videos of chimps spitting water into a tube to share with you.
So I sent an email to Dr. Claudio Tennie, the lead author of the paper, and postdoc at the Max Planck Institute for Evolutionary Anthropology in Leipzig, inquiring as to the possible existence of a video. It seems that there aren't any available. But, he gave me a link to an awesome video already on youtube of an orangutan doing the exact same task!
Check it out:
Tennie, C., Call, J., & Tomasello, M. (2010). Evidence for Emulation in Chimpanzees in Social Settings Using the Floating Peanut Task PLoS ONE, 5 (5). DOI: 10.1371/journal.pone.0010544
I like how it looked like the other chimp pointed into the tube: "Dude, spit it in here"... and then pushed him back down to get more water when the first time wasn't enough. Was he just being helpful, or did he think the other chimp was going to share the peanut with him when he got it? lol
Oops - orangutans, not chimps :)
I wouldn't read too much into that...not clear what was going on, but it's hard to see. The other monkey is the subordinate one, and likely wouldn't have expected to participate in snacktime anyway.
There was a National Geographic show a while back called "Ape Genius" which shows a chimpanzee doing this puzzle. It was a great show overall, I highly recommend finding it.
Here is the chimpanzee version:
...and here is the link to the (earlier) orangutan study - which fits the posted video:
Mendes et al. 2007 "Raising the level: orangutans use water as a tool" Biol. Lett. vol. 3 no. 5 453-455
I fear that I have human friends that would take much longer in figuring this out...
It reminds me very much of the crow trials (back in 2008 and surely more since) in which corvids use pebbles to raise water levels (fetching out mealworms rather than peanuts, of course).