21 <strong>Topic XXI. Wisdom of Crowds vs. Herd Thinking<…
Topic XXI. Wisdom of Crowds vs. Herd Thinking
- Addressing the Question: How should we use science to make better decisions?
- Wisdom of Crowds
- Herd Thinking
- Explore ways that groups fall short of their optimal reasoning ability. There are better and worse ways to aggregate a group’s knowledge.
- Sometimes groups of people reach better conclusions than people working independently, and sometimes they reach worse conclusions. There are features of group reasoning that can help, and features of group reasoning that can hurt. Here we explore how to avoid the pitfalls of group reasoning and to maximize the benefits.
- Exemplary Quotes
- "We can get a pretty good estimate of the weight of this turkey by asking everyone in the family to write their guess privately on a piece of paper, and then averaging the answers."
- Cautionary Quotes: Mistakes, Misconceptions, & Misunderstandings
- "We can be pretty confident we are right, because all five members of our family agree that vaccines cause autism. Since all five of us think so, we must be right."
- A. ATTITUDES
- Not take for granted that consensus offers the best conclusions.
- Take seriously (but not as absolute!) the consensus of a group which has reasoned about a question in a careful, appropriate way.
- Take seriously (but not as absolute!) the average of a large group's independent estimates of a number, under appropriate conditions.
- B. CONCEPT ACQUISITION
- Wisdom of Crowds: Sometimes groups make better judgments than individuals. This happens when:
- a. Judgments are genuinely independent, preventing herd thinking.
- b. Members of the group do not share the same biases.
- c. There are enough people in the group to balance out random biases or fluctuations (analogous to the need for an adequate sample size).
- d. Works especially well when estimating a quantity, where errors may be large but are not systematic.
- Herd Thinking: Sometimes groups make worse judgments than individuals. This happens when:
- a. Judgments of individuals are influenced by the judgments of others, leading to groupthink and sometimes polarization.
- b. Members of the group share biases, which can be exaggerated by discussion and cannot be decreased by averaging judgments.
- The enterprise of science is essentially social, and advances in part because scientists look actively for what other scientists might have gotten wrong. This process, including peer review, enables science to iteratively improve.
- C. CONCEPT APPLICATION
- Recognize when groups are likely to make good decisions.
- Recognize when groups are likely to make poor decisions.
- Structure group decision-making processes so as to maximize the benefits and minimize the dangers.
- Identify features of existing group decision-making practices which we could improve.
- Suggested Readings & Reading Questions
- Clicker Questions
- Discussion Questions
- Can you think of a group you've worked with that engaged in groupthink/herd thinking? What happened?
- Each person think of the best-functioning group they've worked with. What made that group stand out?
- Class Exercises
- Students answer typical wisdom-of-crowd estimate questions using their clickers—but they can update their estimates as they see the histogram with the other students’ guesses. Afterwards, it is shown that the accuracy of the class’ mean estimate actually got worse as they continued to update their estimate—showing (if it works) that wisdom of crowd works best if the inputs are independent.
- One way to gather data about how people might respond to a product or idea is to conduct a “focus group,” in which several participants share their impressions in a group conversation. Based on the reading, why is or isn’t this a good way to obtain reliable information?