The edge effect

At a conference last week, I had two posters next to each other. The next day, I scribbled this in my notes:

I think the difference in traffic was not due to any inherent difference in the poster, either scientifically or graphically, but was because of the room layout.

All the posters in the session were mounted on single poster boards. Every single mounting board had one had one edge along a wall (or, in the center, a curtained room divider). This meant that poster viewers couldn’t walk along a row of posters. They had to walk in towards the wall, surrounded by posters on either side, over and over again.

Remember that people read from left to right, so the starting point of a poster is on the left edge.

The poster marked “more traffic” above has its left edge away from the wall. As soon as people walked into that cul-de-sac, they first thing they will tend to read will be the “more traffic” poster.

The poster on the right (marked “less traffic”) has its left edge next to the wall. To get to the start of this poster, people have to make their way all to the end of the cul-de-sac. The path might be blocked with people reading the other poster, or people reading the end of the poster they want to start reading.

One poster had an unfair advantage in attracting attention over the other.

And the moral of the story is: Conference organizers, think about the patterns of foot traffic in the poster session! They influence what posters get viewed the most.