If you are trying to persuade someone on a topic that you are knowledgeable about, convey your expertise up front. People who try to make a decision while listening to expert advice often stop analyzing and simply accept the recommendation.

People often seek expertise when they are unsure what to do or what to buy, particularly when there is risk involved, such as when they want to invest during a recession. But psychologists were not sure whether hearing external advice while making a decision affects a person’s thought process. So Jan Engelmann and others at Emory University wanted to find out.

In their experiment, participants were wired to an MRI scanner so that the psychologists could study the brain activity during the decision-making process. Participants were asked to make financial decisions, choosing between an investment with a guaranteed return and one that contained a risk of losing money. Sometimes, participants had to decide on their own; other times, they received an expert economist’s advice while they were deciding. They were free to follow or ignore the expert’s advice.

Writing in the research journal PloS ONE, Engelmann and his team said the expert’s financial advice, which was provided when participants were uncertain what to do, “had a significant impact on both behavior and brain responses.” In the participants who decided on their own, regions of the brain were activitated on the MRI scanner, indicating they were evaluating the situation. But in others, the expert’s advice switched off the brain’s evaluation mechanism, indicating that the person had “offloaded” the decision-making to the economist.

Monica Capra and Gregory Berns, two of the researchers, said the experiment showed that the brain relinquishes responsibility when a trusted authority provides expertise.

In the article, the research team said that when a person ignores the advice of an expert while making a decision, it may lead to increased mental conflict and make the choice appear more risky. “Following the expert’s advice can be considered a much safer option involving less emotional and cognitive conflict.”

So if someone asks you for your opinion regarding a topic on which you have extensive knowledge, tactfully mention your expertise before you give your opinion. For example, you might begin by saying, “having served on a task force that studied this for three years, I’m intimately familiar with the issue.” And then go on to provide your viewpoint.

Ken O’Quinn conducts writing and managerial communication workshops for corporations. A former Associated Press writer, he is the author of Perfect Phrases for Business and is a contributing author of Focus on Them, about leadership.