I haven't seen either talk, but I am really curious now about why TED would post Wilkinson's talk but not Hanauer's, if they both address the subject income inequality.

From reading the transcript of Hanauer's, Wilkinson's talk is just way better. He has A LOT of actual data, in fact the whole talk is data, data, data, on obesity, happiness, violence & homocide, lifespan, infant mortality, trust, teenage pregnancy, addiction, child wellbeing, mental illness, highschool dropout, social mobility; all on a country level and on a US state level. He also shows that inequality is the problem and that GNP per capita hardly matters ... while Hanauer's talk is 99% rhetoric. Even though the message is roughly the same, Wilkinson's talk definitely is a lot more objective rather than subjective political assertions, so it's a lot harder to argue that he's simply pushing a political agenda.

Is that an appeal to authority? Just because something is on TED, doesn't make it true.

I'm sure you could find studies that disagree with this.

That's not an appeal to authority. It's a link to information. If you manage to find any contradicting studies, please do post them here. That said, his data seems pretty solid, unless he's flat out lying (unlikely). Keep an open mind!