To an extent, it is rational to choose options that are more popular. There is a good possibility that your preferences will be similar to those of others, and for this reason, if there is no other information, one should generally pick the more popular option. However, people are sometimes willing to ignore other factors, and make choices based only on the choices of others. This effect gets stronger as the popularity of one choice increases. The bandwagon effect helps to explain social trends. It is also affects politics, as polls can create self-reinforcing cycles in which the top candidates gain advantage. The bandwagon effect can be very detrimental as well, with one notable example being the creation of market bubbles.
In a study in Germany, students were given information about two candidates running for mayor of a small town. They were then told that a candidate was leading in polls, losing in polls, or even with the other candidate. Students rated candidate’s competence and likelihood of winning higher if they were told that the candidate was winning.