I really enjoy reading about neuroscience. I know, super nerdy. But there is something fascinating to me about understanding the inner workings of the human brain.

Lately, I’ve been reading Daniel Kahneman’s New York Times Bestseller, Thinking, Fast and Slow. Packed with scientific research and fascinating studies, this book is changing the way I think about how I think. And most interestingly, it’s helping me understand why public speaking can be so difficult even though we engage in conversations every single day.

Today I’ll unpack some of what Kahneman says, specifically as it relates to delivering presentations. This should help us understand the neuroscience behind why public speaking can be so challenging.

The 2 Brain Systems

So we basically have two brain systems. Kahneman has chosen to call them System 1 and System 2. He says, “System 1 operates automatically and quickly, with little or no effort and no sense of voluntary control.” On the other hand, “System 2 allocates attention to the effortful mental activities that demand it, including complex computations. The operations of System 2 are often associated with the subjective experience of agency, choice, and concentration.” So System 1 is impulsive, quick, and easy, while System 2 is logical, slow, and difficult.

To understand these two systems, think about the difference between driving to a familiar place at a time of day when there isn’t much traffic. You’ll likely slip into autopilot at times, not even consciously thinking about where to turn or how much farther you have to go. System 1 will get you there without much help from System 2.

Now think about navigating to somewhere you’ve never been during a busy time of day. You’ll likely have to carefully follow instructions, paying attention to road signs, other cars, speed limits, and distances. This takes conscious thought. You have to engage System 2. So neuroscience explains why the types and amounts of mental energy we expend can be very different given different contexts.

Conversation vs. Public Speaking

The difference between conversation and public speaking is much like the example of navigating somewhere familiar versus somewhere new. Conversation is a System 1 brain activity for the most part. And here’s how we know that. Researcher Eckhard Hess studied the relationship between pupil size and mental effort. He found that our pupils dilate with difficult mental tasks. Conducting similar studies, Kahneman stumbled upon something interesting. While watching a participant talk with someone in between their research studies, he was surprised to see no change in her pupils. He noted that “the mundane conversation apparently demanded little or no effort.” This means conversation is not very mentally taxing on us. Granted, there are exceptions, but generally, we engage in conversation on autopilot, using System 1.

However, public speaking is more of a System 2 activity. It requires conscious thought. You have to make choices about what to say and how to say it, mainly because you are being watched. And studies have shown that trying to impress others, which most of us do when we stand in front of an audience, is a mentally challenging task. This speaks to why so many people try to avoid public speaking: it is tough. It takes literal brain energy to engage in this System 2 activity.

The Good News

But Kahneman doesn’t leave us without hope. Here’s the good news: “As you become skilled in a task, its demand for energy diminishes. Studies of the brain have shown that the pattern of activity associated with an action changes as skill increases, with fewer brain regions involved.”

None of us will probably be able to deliver a speech fully on autopilot. And that’s probably a good thing. However, we can continue to get better at it. We can practice and learn from feedback and improve. And as neuroscience has proven, as we build skill, we’ll decrease mental energy. In other words, when we get better, it gets easier.

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