A McCain ad released today features a former Clinton delegate telling fellow Hillary supporters that she plans to vote for John McCain and it's okay for them to do so too.

Strategically, the TV spot looks to break what communication researchers call the "spiral of silence" phenomena, the tendency for a person to be less likely to voice an opinion on a topic if the individual feels that they are in the minority, for fear of reprisal or isolation from that majority. Derived in part from the classic Asch and Milgram conformity experiments, the theory holds that when individuals form an opinion and/or decide to voice that opinion, they scan their environment for what might be the majority position and often conform their opinion to that position.

Yet the problem is that most people are not very good at accurately figuring out what majority opinion might be. And often times, news coverage and media presentations shape or skew that perception.

In this particular McCain ad, the strategy is to communicate to Hillary supporters that others like them are shifting their allegiances to McCain, shaping the perception among this reference group of what might be the majority norm. If the Obama team is not able to send a very strong and concentrated rival message of common unity during this convention week, look for this advertising strategy to be very effective.