"People look at the blood flow to one area and they say, ‘aha, this is the evil patch.' It's probably a lot more complex than that," Galetta told FoxNews.com.
"Certain areas are likely important for certain behaviors, certain attitudes. But it's probably not as simple as X marks the spot for a particular behavior."
Roth's study, according to Bild.de, was conducted for the German government on violent convicted offenders. He said the dark mass that he has identified appears in all CT scans of people with such records -- and taking it out ended their "evil" behavior.
Roth did not respond to FoxNews.com requests for more details on his study.
Terre Constantine, executive director of the Brain Research Foundation and the former director of the Jack Miller Center for Peripheral Neuropathy, expressed skepticism at the report, but agreed that brain abnormalities such as tumors can affect behavior.
"It absolutely can affect the brain and your personality and how you communicate. And it can make you aggressive -- not all tumors, of course: it depends where it is," Constantine told FoxNews.com.