Cognitive Biases, Reasoning, and Truth

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Review

Cognitive Bias v. Fallacy

Types of Biases

Truth and Knowledge

For next time:Comprehensive Chapter 1 exercises due:

(1-3): 1, 4, 6; (1-5): 2, 5, 8; (1-6): 3, 4, 8; (1-7): 4, 5, 7; (1-9): all of it

Review

Claims have propositional structure. They are declarative. Sentences that are claims can be true or false

Imperative sentences are not claims. Imperative sentences state commands.

Interrogative sentences ask questions. Questions are not claims but questions raise issues

There are many different kinds of claims: objective, subjective, factual, evaluative, and policy

Factual, evaluative, and policy claims can be either objective or subjective

Review

Arguments can only be composed of claims Arguments have two essential parts: premises and

conclusion Claims that are premises function as evidence/support that

is meant to make the concluding claim more likely to be true

Premises must therefore be relevant to the conclusion True premises are cogent premises

Fake Quiz

Which of the following is a subjective policy claim?:

Rocky road is the best ice cream flavor We must allow the Bush-era tax cuts to expire If some neutrinos can travel faster than light then

we can probably build a time machine in the distant future

Should we reform our health care policy to give everyone universal access?

Fake Quiz

Which of the following is an argument? Why? (a) If there is smoke then there is fire. There is

smoke. Therefore there is fire (b) The price of gold has been going up over the last

10 years. It has risen about 600% during that time period.

(c) I am better at playing checkers than I am at chess but I am not very good at either game to be honest.

Cognitive Bias v. Fallacies

A cognitive bias is sometimes confused with another form of mistaken reasoning known as a fallacy

Cognitive biases affect belief formation in non-rational ways and are almost always non-conscious (we are not aware that we are subject to the biases)

A fallacy is a mistake in reasoning which can be explained by cognitive biases

Personal attacks are a kind of fallacy (ad hominem) that we might resort to if we run out of good reasons or if we are subject to one of several cognitive biases

Common Cognitive Biases

Belief Bias: We are far more likely to agree that an argument is

good when we already agree with the conclusion This is a bias because we are being persuaded that

an argument is good by something other than the relevance and truth of an argument's premises.

1. All Dogs are animals

2. Some animals are German Shepherds

3.Therefore some dogs are German Shepherds

Belief Bias

1. All Dogs are animals

2. Some animals are German Shepherds

3.Therefore some dogs are German Shepherds

This is a bad argument. Why? The fact that some animals are German Shepherds is not relevant evidence for believing that some dogs are German Shepherds.

All As are Bs

Some Bs are Cs

Can we conclude that ANY As are Bs?

Some animals reproduce asexually....

Availability Heuristic

Many cognitive biases have to do with how we judge the frequency or likelihood of things.

For example: Quick! Are there more words (in English) that begin

with the letters r or k or are there more words where r or k are the 3rd letter in a word?

What do you think?

Availability Heuristic

There are 3 times as many words (in English) that have r or k as the 3rd letter than there are that begin with r or k

Is this surprising? The availabiliy heuristic tells us that we judge the

probabilities of an event by how easy it is for us to recall instances of that event

In this case it is easy for us to remember words that begin with r or k so we judge that there are probably more of them.

Availability Heuristic

The availability heuristic affects how we perceive many different aspects of our day to day lives

The media tend to focus their reports on extraordinary, rare, and negative events (violent crimes, thefts, corruption, etc)

Because these events are easy to remember we tend to think our cities are far more dangerous or corrupt than they actually are

Multiple exposures to the same commercials also trigger the availability heuristic

Framing Effects

Our judgments about how likely or desirable something is depend strongly on how information is presented to us

For example: Consider the different frames (and their effects on perceived attractiveness) of the following:

1. Wealthiest 5% of the population

2. Job Creators

3. The rich

These three terms all describe the same population but people prefer taxing 'the rich' more than the 'wealthiest 5%' and they do not at all prefer taxing 'job creators'

Anchoring and Framing Effects

Framing effects can also be used to trigger a cognitive bias called anchoring

Anchoring occurs when we focus on one (mostly irrelevant) factor to judge the relative probability or value of something

Ex- What percentage, above or below 10%, of African nations are members of the United Nations?

Take a guess

Anchoring

What percentage, above or below 10%, of African nations are members of the United Nations?

When phrased this way the average answer is about 25%

However, the average guess is 45% when phrased as “What percentage, above or below 60%, of African nations are members of the United Nations?”

The question doesn't change the information we already know (even though it might be very little) but the frame changes the numbers we anchor on and thus dramatically changes our judgments of likelihood

The Bandwagon Effect

Later in the quarter we will study a fallacy called the Bandwagon fallacy. The bandwagon fallacy is so convincing because of the cognitive bias (confusingly) called the Bandwagon Effect

The bandwagon effect relates to our preferences We tend to align our preferences with the preferences of the

majority We shift our preferences from one product (MySpace) to

another (Facebook) more rapidly depending whether we think that others are doing the same

The Bandwagon Effect

The bandwagon effect plays a very large role in political elections

Voters tend to shift their votes to the perceived front-runner in an election

What matters here is that a candidate is perceived as a front-runner

Political polls showing that one or another candidate will win an election, for example, tend to dramatically sway undecided voters toward the perceived leader

This is why the framing and bandwagon effects are often used in political campaigns

Negativity Bias

The bandwagon effect tells us that we have an implicit bias to make our preferences match the preferences of perceived majority groups

This bias is magnified if the preferences of the perceived majority are negative

If we are presented with equally strong positive and negative information about something (a person, a policy, a film, etc) we overwhelmingly form a negative opinion of it

We subjectively weigh the negative information as far more important than the positive even if both are equally relevant

Negativity Bias: Examples

-Negativity bias (i.e. subjectively valuing negative information more than positive) manifests in several ways

-Loss Aversion: we weigh losses as more significant, more harmful, than gains of the same size

-ex: receiving $5 is rated as far less significant than losing $5

-Judgments of character: we weigh negative information about a person as revealing their true nature

-ex: If David was honest with us in three of our last four meetings and dishonest with us once we will tend to rate David as a dishonest person.

Negativity Bias

-Did you ever wonder why Political Campaign Advertisements are predominantly negative?

-Campaign managers know about the negativity bias, the availability heuristic, and the bandwagon effect.

-Negative Campaign Advertisements are designed to work around critical thinking by triggering these cognitive biases.

-Let's take a look at, and discuss, an example...

Self Assessment Biases

We are especially bad at making assessments of our own abilities

Overconfidence Effect: the harder and less familiar a task the higher our estimates are of how well we performed it

Better-than-Average: if asked to rate our performance relative to others on a task we are (almost all) likely to say we performed better than average even though this is impossible

-ex- Do you believe you are in the top 30% or lower 70% of students in your year (freshman, sophomore, etc)?

Self Assessment Biases

The Bias Blind Spot: we also have a bias about our perception of how likely we are to fall prey to our biases

Studies have shown that people who have the overconfidence and better-than-average effects explained to them will judge that they are not nearly as likely as others to succumb to these effects

This cognitive bias is known as the bias blind spot Do you think that your judgments are often biased in

these ways?

For next time

Comprehensive Chapter 1 exercises due Bring this to class Late homework will not be accepted without

good reason