When an expert speaks does your ability to think for yourself literally shut down?

Yes. “Fascinatingly, the fMRI showed that in the face of “expert” advice (even though it actually wasn’t particularly good advice), the parts of the volunteers’ brains involved in considering alternatives became almost completely inactive.”

Via Brandwashed: Tricks Companies Use to Manipulate Our Minds and Persuade Us to Buy:

In a 2009 study, Emory University School of Medicine scientists led by Gregory Berns, MD, a professor of neuroeconomics and psychiatry at Emory, found that people will actually stop thinking for themselves when a person they perceive as an expert offers them advice or direction. In the study, experimenters asked volunteers to make a decision about their finances. In one trial, volunteers were asked to make decisions on their own. In another, they received conservative advice guaranteed to minimize their gains from a financial “expert.” Then the researchers scanned their brains.

Fascinatingly, the fMRI showed that in the face of “expert” advice (even though it actually wasn’t particularly good advice), the parts of the volunteers’ brains involved in considering alternatives became almost completely inactive. It seems that receiving “expert” advice shuts down the areas of our brains that are responsible for decision-making processes, especially when the situation involves risk (interestingly, the areas of the brain responsible for skepticism and vigilance also become less active when a person is engaged in prayer). “The brain activation results suggest that the offloading of decision-making was driven by trust in the expert,” according to C. Monica Capra, PhD, a coauthor of the study. Added Berns, “This study indicates that the brain relinquishes responsibility when a trusted authority provides expertise. “The problem with this tendency is that it can work to a person’s detriment if the trusted source turns out to be incompetent or corrupt.”