Results and Interpretation of a Study of Effects of Poll Reports on Voter Preferences: The Mehrabian Polling Snowball Effect

Mehrabian, A. (1998). Effects of poll reports on voter preferences. Journal of Applied Social Psychology, 28, 2119-2130.

Results of two experimental studies described in this article constituted clear experimental demonstration of how polls influence voters. Findings showed that voters tended to vote for the candidate that they were told was leading in the polls. These poll-driven effects on votes were substantial.

Effects of polls on votes tended to be operative throughout a wide spectrum of voters. Voters with initial (i.e., pre-poll) preferences ranging from undecided to moderately strong were influenced by polling data. There was a limit on poll effects, however, as noted in Study Two: Polls failed to influence votes when voter preferences were very strong to begin with.

Additional findings of considerable interest showed that effects of polls were stronger for women than for men and also were stronger for more arousable (i.e., more emotional) and more submissive (or less dominant) persons. Especially noteworthy is my discussion of similarities and differences between the study methods and real-life political campaigns beginning with the middle paragraph on page 2128 ("Overall, results ...).

Here are some quotes from the article:

Overall, results obtained from both studies were consistent in showing the superior strength of the bandwagon or rally-around-the-winner effect .... [That is, polling data showing a candidate as leading will tend to influence voters to select that candidate. Thus,] it is important to consider cumulative effects of the bandwagon effect when it is combined with repeated and closely spaced reports of polling data. Assuming that the bandwagon effect is operative and one candidate is an initial favorite by a slim margin, reports of polls showing that candidate as the leader in the race will increase his or her favorable margin. Subsequent reports, based on more recent and stronger margins, will in turn progressively strengthen that candidate's lead. In short, the bandwagon effect, in combination with frequent poll reports, can create an unstable equilibrium (i.e., snowball) effect, and only highly dramatic and favorable (or unfavorable) disclosures or events may reverse that effect.... The 1996 campaign illustrates this phenomenon: Immediately following the nomination of Bob Dole as the Republican candidate, almost weekly poll reports showed Bill Clinton leading Bob Dole. Such frequent reports probably helped to consolidate and strengthen Bill Clinton's lead, helped him to overcome occasional negative publicity about his past record, and resulted in his strong showing on Election Eve.

This unstable equilibrium effect of polling described in the preceding paragraph, or The Mehrabian Polling Snowball Effect (MPSE) , helps identify a potential way in which political organizations can be tempted to influence voting by sponsoring biased "polling studies" and reports. Poll results can be slanted easily through selection of slightly skewed respondent samples or the actual wording of questions used in the polls. Frequent reporting of slanted and invalid poll results can help propel a candidate to the forefront and, in fact, increase his/her lead over time. Similar considerations would apply to major political issues (rather than candidates) is various political campaigns.

Accordingly voters need to be educated about the Polling Snowball Effect so they can be specially vigilant when they are repeatedly barraged by polling reports favoring one candidate (or poll results that suggest popularity of a particular campaign issue) during political campaigns. Voters, in particular, need to educate themselves about the political orientations of entities that repeatedly sponsor polling studies.

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