The Scientific Case for Rehearsals

By Heather Baldwin

You’ve heard for years about the importance of practicing your presentation to dispel presentation jitters. Now there’s new clinical research that shows there’s a physical reason why rehearsing works so well and why those hours of out-loud practice can make you a more confident presenter. That’s good news because if a public-speaking phobia is physical, it means there’s something you can do to fight it, that it’s something you can change, says David Weiner., author of several psychology bestsellers, including the new Reality Check: What Your Mind Knows But Isn’t Telling You (Prometheus Books, 2005).

The research shows there’s two important reasons why practice makes perfect. The first is that when you practice anything – be it a sales presentation or Beethoven’s "Moonlight" sonata – you essentially carve a path for it in your brain. Without practice, your brain can take any of tens or hundreds of paths to reach its final destination. To understand this concept, think about the letter P. If you were wired like a computer, your brain would take the same single line every time to get to that P. But the human brain isn’t wired like a computer so instead it takes any of about 30 or 40 different pathways to get there, explains Weiner. The result is that the thought of the letter P is the same, but each time you think of it the pathway your brain uses to get to that thought can be different.

Practice reduces the number of potential pathways. In other words, by repeating your presentation again and again you’ll start using about 8 to 10 pathways, says Weiner. "The brain will know what you want it to do," he says, "so you’ll become more precise."

As you get more precise, you’ll become more confident and optimistic – at which time your serotonin levels will increase. Which brings us to the second key point, which is the existence of an area of the brain called the Estria Terminalus. For years, says Weiner, scientists thought all phobia-related senses originated in the Amygdala, an area of the brain that mediates the feelings of fear, rage and anger. In the past year, however, researchers found that the Estria Terminalus mediates anxiety and worry. These two areas – the Amygdala and the Estria Terminalus – were essential for survival 50,000 years ago when fear and anxiety often kept our ancestors alive. Today, however, they generate false alarms, creating excess and sometimes paralyzing fear in non-life-or-death situations such as sales presentations.

The key to suppressing these two areas of the brain is serotonin. Serotonin, Weiner explains, stimulates the Nucleus Accumbens, which controls confidence, happiness and joy – and in turn trumps the Amygdala and the Estria Terminalus. "There’s a battle always going on between the old brain and the new brain," says Weiner. Serotonin is the weapon that lets you win that war. Confidence, which can be gained only through practice and the corresponding reduction of brain pathways, is the tool that produces serotonin.

So even if practice doesn’t make you perfect, scientists can now prove that it will make you a whole lot less nervous. Now you have no excuse not to carve out some rehearsal time before your presentations.

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