the positive effect of wealth is only seen in high income families.
extreme income inequality reduces human capital of a large portion of the working population and encourages rent seeking activities by elites. it also reduces the trust and effectiveness of government.
it also reduces real GDP growth, contributes to more economic bubble/burst cycles and causes slow recovery from recessions (see ILO Global Wage Reports from 2008 and 2010 and the FRB for reports).
In the OECD and especially the US and UK there is a significant influence of the household income and educational attainment of any children.
www.oecd.org/dataoecd/2/7/45002641.pdf
In a recent report on social justice in the OECD the US ranked #27 out of #31 countries.
http://www.sgi-network.org/pdf/SGI11...stice_OECD.pdf
The US is losing it's educational advantage over other countries as they are catching up. a large majority of the highly educated workforce in the US is with the babyboomers who will be retiring in the next couple of decades.
Education at a Glance 2011 OECD Indicators
http://www.oecd.org/dataoecd/7/32/48685294.pdf
"Overall, the U.S. comes out as an average performer in reading (rank 14 in OECD) and science (rank 17) but the U.S. drops below the OECD average in mathematics (rank 25). Also, there is a very wide gap between the top 10% and the bottom 10% of 15-year olds in the U.S, similar to that observed between top and bottom performing PISA countries."
PISA 2009 Results
http://www.oecd.org/dataoecd/32/50/46623978.pdf