12.1 Wisdom of Crowds and Herd Thinking

Learning Goals

[Link to PlayPosit]

More details

After this lesson, students should

1. Not take for granted that consensus offers the best conclusions.
2. Take seriously (but not as absolute!) the consensus of a group which has reasoned about a question in a careful, appropriate way.
3. Take seriously (but not as absolute!) the average of a large group's independent estimates of a number, under appropriate conditions.

Definitions

• Wisdom of Crowds: Sometimes groups make better judgments than individuals. This happens when
  • Judgments are genuinely independent, preventing herd thinking.
  • Members of the group do not share the same biases.
  • There are enough people in the group to balance out random biases or fluctuations (analogous to the need for an adequate sample size).
  • 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
  • Judgments of individuals are influenced by the judgments of others, leading to groupthink and sometimes polarization.
  • Members of the group share biases, which can be exaggerated by discussion and cannot be decreased by averaging judgments.

Examples

• [item 1]

Common Misconceptions

• Mistaken quote

  Explanation.

Context

This lesson discusses when groups of people make better or worse judgments than individuals. It leads into the last part of the course, which revolves around group decision making, e.g. as a society.

Before

3.1 Systematic and Statistical Uncertainty

Individual judgments can deviate from the truth due to systematic bias and random fluctuation. Reducing shared bias and increasing sample size are ways to improve the effects of Wisdom of Crowds.

8.2 Heuristics and Biases II

Conformity to the group consensus, illustrated by the Asch experiment, and obedience to a perceived authority in a group, illustrated by the Milgram experiment, are psychological tendencies that affect group decision making.

10.1 Confirmation Bias

Confirmation bias can exacerbate other biases in group decision making, such as the motivation to make judgments that conform to the group consensus or agree with the opinion of the authority figure.

After

12.2 Denver Bullet Study

When making group decisions using the Denver Bullet Study method, it is important to survey each expert (on matters of fact) and each stakeholder (on matters of value) individually and independently so as to reduce "herd thinking" effects.

13.2 Deliberative Polling

In a somewhat opposite approach, deliberative polling encourages moderated discussion between all participants punctuated by dialogue with the relevant experts, before participants answer a poll to make informed decisions in society. Conformity with other participants as well as "obedience" to (in the sense of taking advice from) the expert panelists are essential features. The result tends to be a convergence of opinions towards moderation on divisive issues.

Recommended Outline

Before Class

• [Any essential logistical things that need to be done for this class]
• Prepare a seating chart.
• Review PlayPosit and discussion questions and ask faculty, Gabriel, or Emlen any questions you have.
• (Optional) Prepare a presentation.

During Class

• (5 min) Come up with some fun way to assign the roles of spokesperson and notetaker (e.g. earliest birthday in the year, lives furthest from campus). Remind them of the responsibilities of these roles.
• ([#] min) [Description of some module from #Lesson Content]
• (5 min) Collect questions for plenary.

After Class

• [Any essential logistical things that need to be done as followup for this class]
• Collect answers from notetakers for the forum / plenary.

Lesson Content

Questionnaire

[Brief description of and motivation for the activity]

Discussion Questions

1. Question 1
   1. Subquestion a

   2. Subquestion b
2. Consider the following passage from the Scientific American article "How Diversity Makes Us Smarter",[1]

Jury Composition and Deliberation

We use the composition and decision making process of juries as an example of a case where wisdom of crowds can be applied and misapplied.

Discussion Questions

1. ([x] min) How do the nuances of jury composition affect a jury’s likelihood of coming to a verdict? Does a 6 person jury where 1 person believes not guilty come to the same conclusion as a 12 person jury where 2 people believe not guilty? How does group decision-making psychology play out in these cases?
2. ([x] min) How might deliberation lead to fairer results or polarize group decision making?

Redesigning the System

1. ([x] min) Have a brief whole class discussion where you ask the students to consider what the flaws with the current jury system are and how it diverges from wisdom of crowds.
2. ([x] min) In small groups, ask the think through the following question.
   1. Considering mainly wisdom of crowds, how would you design a better jury system? Consider the whole process from selection of people (if you even have this?) to the final decision that’s made.
3. ([x] min) Bring the whole class back together to share their solutions.

Fermi Problem

As a final optional point, give the students an especially challenging Fermi problem to solve collectively. This is to emphasize that some problems do benefit from having deliberation at certain stages.

Step 1: The Tree

IKEA mainly produces two types of industrial bags. There are the blue bags that people can purchase and the yellow bags that are only used in the store. Besides the colors, these two types of bags are identical. As a group, figure out the quantities you need to estimate in order to determine the following:

1. How many blue (purchasable) bags does IKEA produce per year?
2. How many yellow (only for use in store) bags does IKEA produce per year?
3. Are there more blue or yellow IKEA bags?

Step 2: Estimates

Now, using wisdom of crowds, have every person in the group estimate each quantity independently. Average the final values together to get a result that's (hopefully) better than if the estimates were just determined individually.

Changemaker

"Members of a homogeneous group rest somewhat assured that they will agree with one another; that they will understand one another’s perspectives and beliefs; that they will be able to easily come to a consensus. But when members of a group notice that they are socially different from one another, they change their expectations. They anticipate differences of opinion and perspective. They assume they will need to work harder to come to a consensus. This logic helps to explain both the upside and the downside of social diversity: people work harder in diverse environments both cognitively and socially. They might not like it, but the hard work can lead to better outcomes."

How does homogeneity in groups contribute to herd thinking? What benefit does diversity therefore provide?

Collect Questions for Plenary

(5 min) Collect remaining questions from the students for faculty in plenary (can be questions for clarification, extension, discussion, etc.), and add [ here].