Tim wrote a great post last week on being responsible for getting your ideas to spread. This is important because a lot of us spend time working on a good idea and then take very little time working out the best way to get people to listen. I’m often guilty of this too and its a big trap for technical specialists who get wrapped up in the idea to the point where they believe that it should be obvious to everyone.

I’m reading Daniel Kahneman’s “Thinking Fast and Slow” at the moment and it’s a real jewel-box of information on what pschychological science has taught us about decision making and rationality. Kahneman has revolutionised economics and business theory by introducing the inherrent biasses and limitations to challenge our assumptions of rational behaviour. No matter how smart you think you are, our brains are wired up with a surprising capacity to be tricked.

The main idea in his book is that we have two thinking systems. System one is intuitive and fast. It runs in our minds most of the time without much effort but is affected by emotions. On the other hand system two is more critical and logical. Engaging system 2 requires more deliberation and effort. Sometimes system 1 tries to do work that should be done by system 2 and that’s when we get problems. Kahneman uses the following example:

A bat and a ball cost $1.10 in total. The bat costs $1 more than the ball. How much does the ball cost?

The answer that I thought of when reading the book was ten cents. That’s obvious isn’t it? Well the correct answer is 5 cents. I felt a bit stupid until Kahneman explained that this question tricks about half of Ivy League undergrads as well. The deception works because it invites system 1 to jump to the first answer with a simple question and some round numbers. Most of us only engage system 2 after we find out we are wrong.

One part of Kahneman’s book discusses the psychology of credibility. In essence, if you want people to listen and believe you then it’s important to find ways to engage system 1 and keep system 2 quiet. Experiments have found that people in a state of cognitive ease, where they don’t need to strain to take in ideas and information, have a quiet system 2. If you want to fire-up system 2 to get a more critical and sceptical response to what you are saying then the best way to do that is to impose cognitive strain.

Busy slides with many complex diagrams, long paragraphs on the slide and hard-to-read fonts are all presentation faults that will activiate system 2 and make you less credible. If you are hard to hear or speak in long and convoluted sentences you will be judged as being less credible as well. Sure, you might have the facts right but that is not how the mind works.

Have a look at this presentation by Seth Godin. Is he credible or not? Have a look at his slides.

On the other hand, system 1 engages quickly with familiarity and repetition. We feel at ease with familiar concepts when a I good speaker gives us something that we can relate to or when there is a repetition of themes. My favourite speech of all time does this superbly (and apparently Martin Luther King wrote it in one night).

Credibility is in the eye of the beholder. Understanding how people form perceptions of what to believe can go a long way to help you spread ideas.