Now let’s raise the ante by increasing the amount of text in each picture and text combination into four short bullets, as is often done in presentations.

Most people in Western cultures find it easier to take in the slide when the picture is on the left and the text is on the right. Do you?

The reason is that, in Western cultures, we are accustomed to reading from left to right. Therefore, when the pictures is on the left, your eyes start by taking it in with one swift scan, and then continue to the right to take in the text by traveling back and forth across each bullet line. In the reverse arrangement, where the text is on the left, your eyes start by making all those back and forth moves through the text, while aware that there is still another image, the picture on the right, remaining to be scanned.

This juxtaposition, although seemingly innocuous, when combined with other thoughtlessly-designed or crowded slides—not an uncommon occurrence in presentations today—can accumulate into a negative effect because it makes the audience work harder to take in the images. In one of last week’s posts in this series on presentation graphics, you read about Dr. Stephen Kosslyn, the Chairman of the Department of Psychology at Harvard University, whose scientific research found that, “showing people meaningful, content-based visuals, as opposed to text, lessens their cognitive exertion and improves overall experience.”

Follow the doctor’s orders. Make it easy on your audience and they will make it easy for you.

Tomorrow: Professor Lawrence Lessig’s unique presentation style.