The Heritage Foundation scholar who came under fire this week for a 2009 dissertation claiming Hispanic Americans lack "IQ parity with whites" has resigned from the conservative think tank. "He's no longer employed by Heritage," the group said Friday of Jason Richwine. Richwine's past Harvard University dissertation — in which he also wrote that Hispanic immigrants would have "low-IQ children" who would cause "more underclass behavior" and "less social trust" — had drawn ire after he co-authored Heritage's recent report on the costs of comprehensive immigration reform. The report, criticized by reformers in the GOP who said it failed to consider immigrants' contributions to the U.S. economy, had figured the cost of a "path to citizenship" at higher than $6 trillion. Heritage downplayed Richwine's involvement in the report earlier this week and distanced itself from Richwine's dissertation findings.