Robert Murphy, an online marketing representative in San Francisco, was invited to a business meeting with his boss and six colleagues a few weeks ago. He had attended previous meetings on the subject, and he prepared with additional research. He brought a thick sheaf of notes and contracts with him to the conference room.

So what did he contribute to the discussion? Absolutely nothing.

"I just sat there like a lump, fixated on the fact that I was quiet," said Murphy, 31.

Have you ever clammed up at a party or found yourself tongue-tied at a meeting for fear of saying something stupid—even though you consider yourself at least as smart as anyone else in the room?

Research from scientists at the Virginia Tech Carilion Research Institute offers an explanation of why many people become, in effect, less intelligent in small group settings.

If we think others in a group are smarter, we may become dumber, temporarily losing both our problem-solving ability and what the researchers call our "expression of IQ."

The clamming-up phenomenon seems to be more common in women and in people with higher IQs, according to the report, published in January in the journal Philosophical Transactions of the Royal Society B.

The Virginia Tech scientists used functional magnetic resonance imaging (fMRI) to study how the brain processes information about social status in a small group and how people's perception of their status affects their cognitive performance.

The researchers administered a standard intelligence test to 70 individuals and divided them into 14 groups of five. Then the groups repeated 92 test questions dealing with sequences and spatial problems.

Two subjects from each group answered the questions while having fMRI scans. After each question, the subjects saw how they ranked within the group and whether their ranking went up, down or stayed the same relative to the group.

Initially, all the brain scans showed spikes in activity in the amygdala, the part of the brain that registers fear and processes emotion. But after answering 10 or so questions, 13 subjects recovered and ended up with scores that were closer to their initial performance. Meanwhile, 14 didn't recover.

As they saw their rankings go down, they seemed to panic, and they answered more questions incorrectly.

"It was like the 'Survivor' show," said Read Montague, leader of the study, director of the Human Neuroimaging Laboratory and the Computational Psychiatry Unit at the Virginia Tech Carilion Research Institute and professor of neuroscience at University College London.

"Some people stayed stressed and freaked out the whole time, and some people habituated relatively quickly and started solving small problems," Montague said.

The researchers reported that 11 of the 14 "low performers" were female; 10 of the 13 "high performers" were men.

The low-performers were more attuned to group social dynamics, subconsciously worrying about their performance and evaluating themselves in relation to others, the researchers speculate.
Women often are more attentive to what others may be feeling or thinking, a sensitivity that likely has an evolutionary origin, Dr. Montague said.

"For the group to provide you with any extra stability or protection, you had to be sensitive to how the group was doing."

Two primary factors influence how we behave in a group: personality and position, said Michael Woodward, an organizational psychologist in New York and author of "The You Plan: A Five-Step Guide to Taking Charge of Your Career in the New Economy."

If you are quiet in a group setting, it doesn't necessarily mean you are shy, but it does mean you might be an introvert.

Introverts prefer to collect their thoughts before speaking and can be overwhelmed in a group, especially of extraverts, who tend to "think out loud" and process information by speaking.

But extraverts also may choke in group settings. Murphy, the online marketing representative, said he is typically confident and talkative in a group situation. "If I am comfortable in a setting, I can't get my mouth to shut up," he said.

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