What happens when two people are walking together, talking, and each is content to go where the other is headed.
If one person moves slightly off course, the other interprets this as a change in heading and so also changes heading. The first person then interprets this as a change in heading.
This results in taking an effectivly random path, while maintaining object avoidance.

It will normally end with one person looking up and saying "What the hell are we doing in the fine arts department?!", and the other person replying "But I was following you!".