By Jennifer Nicoll Victor, Ph.D., George Mason University
Individual and aggregate opinions play an important role in a representative democracy like the United States. Although the elected people enact laws on behalf of everyone else, they also need to have a way to understand what people in society think. There has been a fair amount of skepticism expressed within the media in recent years about the veracity of polling.
Definition of Public Opinion and When It’s Used
The political scientist V.O. Key once defined public opinion as “those opinions held by private persons which the government finds it prudent to heed”. Key is pointing out that in the absence of knowledge about what people think, it can be difficult for democratic governments to decide on policies.
But it’s not clear that democratic governments always need to know what people think. For example, one could imagine situations in which there is consensus or near unanimity about a topic. A non-controversial topic may have obvious policy implications, such that political elites have little doubt about what they should do.
One could also imagine other situations where topics are exceedingly complicated or of a sensitive nature, such that the public may not know or be able to understand everything about a policy.
In those cases, elected leaders are entrusted by the public to use the information at their disposal to make appropriate policy choices.
But there are many other instances where there are controversial or important topics, and it is unclear what the policy should be. Under those circumstances, it is incumbent upon the democratically-elected representatives to try to understand public opinion.
Learn more about the challenges of polling public opinion.
The Difference Between Individual and Aggregate Opinions
Understanding public opinion, however, isn’t that easy since there are different ways to investigate it. Individual public opinion means the attitudes held by a single person. When the attitudes of a bunch of individuals are summed up, it means aggregate public opinion. To explain this, imagine how this topic is approached in a classroom setting.
Think of a room full of people with someone posing a question. Then, people are selected randomly and assigned to one of two groups.
In Group A, people are not allowed to communicate with one another. They simply read the question, come up with a thoughtful guess, and write it down on a slip of paper (individual public opinion).
In Group B, people are asked to deliberate with one another about what they think the correct answer might be. Then they submit a single answer from their group (aggregate public opinion).
This is a transcript from the video series Understanding the US Government. Watch it now, on Wondrium.
The Condorcet Jury Theorem or the Wisdom of Crowds
A famous theorist known as the Marquis de Condorcet developed what is known today as the Condorcet Jury Theorem or, in other words, the ‘wisdom of crowds’.
In a group of informed people who make decisions independent of one another, as in Group A, the more people there are, the more likely they are to get it right when their decisions are aggregated together. But if some in the group are uninformed or make wild guesses, it will throw off the result.
In Group B, where communication is encouraged, if someone gives an extreme response, how seriously that suggestion is taken will depend a bit on the dynamics of the group. If most of the members of the group are well-informed, then an extreme response is likely to be marginalized, and the ability to deliberate will enhance their ability to find the correct answer.
But if a guess is abnormally high or low compared to other guesses, and it is delivered with great confidence and authority, it could persuade others to think that their guesses are wrong, and the outlandish guess is more likely to be correct.
Groupthink Versus Crowd Wisdom
Sometimes an erroneous idea can take hold in a group and spread like a virus. This phenomenon is sometimes called groupthink. Groupthink happens when a group of people develops an incorrect belief about something, and they inadvertently reinforce one another’s incorrect beliefs, solidifying each person’s misplaced confidence in that belief.
So, how is it possible to know if a group will benefit from the wisdom of crowds, or if it will be subject to the ills of groupthink? There are advantages and disadvantages in each scenario, but the key distinction that needs to be focused on is whether or not the individuals in the group make their choices independent of one another.
In the example, there is no deliberation in Group A. Everyone makes their own thoughtful guess, and there is an algorithm used to discern the group’s answer. In this case, individual errors should, more or less, cancel each other out.
Learn more about the pros and cons of organized interests.
Individual Public Opinion or Aggregate Public Opinion?
In Group A, the group average is expected to be near the correct answer and getting closer to the truth as the size of the group increases.
In Group B, however, there is the opportunity for people to change their minds in the face of deliberation from others. A lot of things might influence the choice of this group.
What if everyone in the group expresses an opinion, but the people in the group do not have equal power relative to one another?
People with less power or status may defer to those with greater power. People in the group might follow along with someone expressing confidence, even if that person is also just making a considered guess, like everyone else.
In Group B, it’s probable that the choices expressed by each individual will be influenced by someone else in the group. This sort of individual-level dependence creates the conditions for groupthink.
So, Group A is more likely to have a response closer to the correct answer than Group B is.
Common Questions about the Difference Between Individual and Aggregate Opinions
The political scientist V.O. Key once defined public opinion as “those opinions held by private persons which the government finds it prudent to heed”. Key is pointing out that in the absence of knowledge about what people think, it can be difficult for democratic governments to decide on policies.
Individual public opinion means the attitudes held by a single person, whereas when the attitudes of a group of individuals are summed up, this means aggregate public opinion.
Groupthink happens when a group of people develops an incorrect belief about something, and they inadvertently reinforce one another’s incorrect beliefs, solidifying each person’s misplaced confidence in that belief.
