REIT correlation with equity why, investment, following, opposite

stockjaguar

Quoting from Schweser:
“Finally, in the case of REITs, the returns are more correlated with equity while other types of real estate investment are less correlated with equity..”
I googled the topic, and I got the following link - if you read through, the statement basically states the opposite, namely that correlation is low. Now, is that because there is a mistake in the Schweser text, or because the correlation has changed throughout the years. If the latter, then why might this be the case?
http://seekingalpha.com/article/57005-keep-an-eye-on-reits-correlation-with-equities
Thanks everybody
A.J.