I've been discussing this on another thread and you'll have to forgive me for not reading the 4 pages here yet. However, if the arguments here are the same as in the other thread the following synopsis covers the issues nicely.
I was looking for PET scans done on great apes and found this wonderful synopsis. If you are the least bit interested in this topic, read the whole thing. It discusses why the conclusions Piggy makes in the OP are based on early research and fail to consider what has been learned since. And I have much respect for Piggy's opinions. But in this case, it's also a good lesson that being skeptical means waiting for research to be completed before concluding future research will not yield anything else.
I do believe I did indeed have this right all along. The naysayers seem to have reached their conclusions based on early returns. Early conclusions were premature. You really have to test your hypothesis thoroughly before tossing it out.