This study (http://www.sciencemag.org/cgi/content/abstract/256/5056/545) appeared in the prestigious journal Science in the early 90's and is now taken as fact by media and members of the public. My opinion is that the experiment found something significant but did not have proper controls. The results have not been replicated. Most octopuses are solitary, not group living animals - chances to learn through observation are not common. Running a controlled experiment with cuttlefish, which do live in groups, also failed to produce evidence of observational learning. I believe that the results of the initial study are real but are not best explained by observational learning. At the very least, we should not accept or perpetuate that observational learning is an undisputed fact.