It takes for granted that yawns have no cause other than the one it cites. It supports its conclusion by appealing solely to opinion in a matter that is largely factual. It attempts to support its conclusion solely by restating that conclusion in other words. It makes a sweeping generalization about yawning based on evidence drawn from a limited number of atypical cases.
Most people believe that yawning is most powerfully triggered by seeing someone else yawn. This belief about yawning is widespread not only today, but also has been commonplace in many parts of the world in the past, if we are to believe historians of popular culture. Thus, seeing someone else yawn must be the most irresistible cause of yawning.
The argument is most vulnerable to which one of the following criticisms?