Decision Making Strategies Decisions involving Uncertainty · Decision Making Strategies Single Feature Model Making a decision based on only a single feature or criteria. Additive

LP 7D DM strategies and why unwarrents beliefs persist 1 03/30/20

Decision Making Decision Making Strategies

• Single Feature Model

• Additive Model

• Elimination by Aspects Decisions involving Uncertainty

• Availability heuristics o Ego-centric bias (not in your textbook)

• Representative heuristic The persistence of unwarranted beliefs

• The belief-bias effect

• Confirmation bias

• Fallacy of positive instances

• The overestimation effect


Decision Making Strategies Single Feature Model Making a decision based on only a single feature or criteria. Additive Model From a list of important features of a decision, rate each feature on an arbitrary scale (the scale is arbitrary, but the ratings are not) and then add up the ratings of each feature for each alternative. Elimination by Aspects Evaluate your choices one characteristic at a time, eliminating the choices that do not meet a certain criteria. How would you use these strategies to decide among the following?

• Presidential candidates

• College to attend

• Jobs

• Boyfriend / girlfriend / partner


The persistence of unwarranted beliefs



The persistence of unwarranted beliefs The belief-bias effect The tendency for people to accept evidence that conforms to their belief, rejecting or ignoring any evidence that does not (page 264). Confirmation bias The strong tendency to search for information or evidence that confirms a belief, while making little or no effort to search for information that might disprove the belief (page 264). Fallacy of positive instances The tendency to remember uncommon events that seem to confirm our beliefs and to forget events that disconfirm our beliefs (page 265). The overestimation effect The tendency to overestimate the rarity of events.



There is a lot of similarity between confirmation bias and fallacy of positive instances. To distinguish between them, consider the following differences:

Belief-Bias Confirmation Bias Fallacy of Positive Instances There is a difference in evaluating information.

There is a difference in the search of information.

There is a difference in the information that is remembered.

Belief Confirmation bias Fallacy of positive instance

• Women are bad drivers

• Democrats push bad policies

• Republicans push bad policies

• More babies are born on the night of a full moon than any other night


The Belief-Bias

The belief bias is the tendency for a person (or group of people) to only accept the evidence that conforms to their belief and reject or ignore any evidence that is inconsistent with their belief.

Another way of looking at the belief-bias is that our beliefs influence how we evaluate evidence. Our standards for determining the quality of evidence is lower for consistent information and our standards for inconsistent information are higher.

When evidence that supports and does not support your belief is available to you,

• Evidence that is consistent is seen as more convincing and well done.

• Evidence that is inconsistent is explained away as irrelevant or ignored. The belief-bias can be more pronounced with strongly held beliefs.


The Belief-Bias Example 1: The Death Penalty A group of people who were for the death penalty and against the death penalty were presented with evidence that showed the effectiveness and the ineffectiveness of the death penalty. One would expect that when both groups saw the mixed evidence, their beliefs would become more moderate.

I support it I am against it However, the people who were for the death penalty became more convinced that their position was “right”, and those who were against the death penalty became more convinced that their position was “right”.


The Belief-Bias

I agree with the sentiment of teaching people how to question what they read. However, we tend to question claims that are contrary to our beliefs and not apply the same standards to our own beliefs. In addition, we tend to seek information that is consistent with our beliefs and ignore information that is inconsistent with our beliefs.


Confirmation bias

The strong tendency to search for information or evidence that confirms your belief, while making little or no effort to search for information that disconfirms your belief.

The confirmation bias can lead to incorrect beliefs, including illusory

correlations. It is also quite similar to the fallacy of positive instances—the tendency to remember information consistent with your belief.

• Assume you have the belief that women are bad drivers. To assess this belief, you think of all of the women who are bad drivers. What is wrong with this way of assessing this belief?

• When students take multiple choice tests, there is a tendency for students to think of all the reason why their choice is correct and not consider reasons why other choices may be correct.

• The internet, with all of its information will probably divide us, rather than bring us together. There is a tendency for people to look for information that is consistent with their beliefs, rather than information that is inconsistent with their beliefs.

• For example, Democrat leaning voters will visit Democrat leaning websites. Likewise, Republican leaning voters will visit Republican leaning websites.


In order to reduce the problem of the confirmation bias, we need to search for information that is inconsistent with our beliefs. This is something we normally don’t do because it challenges our beliefs and is uncomfortable (see negative reinforcement).


Fallacy of positive instances The tendency to remember uncommon events that seem to confirm our belief (and forget events that disconfirm our belief). Example:

(1) Every time I switch lines at the grocery store, the line I just left goes faster. There is a tendency to remember all of the times this occurs and forget the times your line goes faster.

(2) On multiple choice answer tests, many students believe that they should always keep the first answer they selected instead of thinking too much about the answer because they remember all of the times they changed the answer and got it wrong. What is wrong with this logic?

(3) There is a tendency to remember the number of times you were thinking of calling someone and they called (thus increasing one’s belief in E.S.P.) and forget the number of times you were thinking of calling someone and they didn’t call.



There is a lot of similarity between confirmation bias and fallacy of positive instances. To distinguish between them, consider the following differences:

Belief-Bias Confirmation Bias Fallacy of Positive Instances

There is a difference in evaluating information.

There is a difference in the search of information.

There is a difference in the information that is remembered.

The pitfalls in judgment and decision making are unconscious and automatic. Without being aware of these pitfalls,

(1) We continue to make them (2) We can’t take steps to minimize their effects. We won’t think

Scientists minimize (but not eliminate) some of these by having their work in the open and having their work available for peer review and critique.


What does this bias in assessing information mean? If you are willing to give evidence and people who believe the same thing as you the benefit of the doubt while you harshly criticize your opponents. It becomes difficult to have a constructive dialogue about the issue, such as in the example with the death penalty. How can this affect a person’s perception of the world around them?

The person views their belief as strongly supported by their experiences and the counter position as questionable.

What behaviors can this help explain?

This can help explain why people have very extreme beliefs (such as strong nationalist beliefs, extreme positions on religion, abortion, gun rights, and other “hot topics”) and are certain that their opponent is not correct. This can help explain why people can look at mixed evidence and become more convinced (and confident) that their view of the world is true.


In Chapter 12, Social Psychology, we will look at a similar process called the in-group bias, where you will give the benefit of the doubt to members of your own group, while using a different standard for out-groups.

Decision Making Strategies Decisions involving Uncertainty · Decision Making Strategies Single Feature Model Making a decision based on only a single feature or criteria. Additive

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