Lecture4

Heuristics and Biases: Part IISeptember 18, 2003: 

Today’s Plan The other 2 of the 'Big 3' heuristics Availability Egocentrism Estimating risk Anchoring and Adjustment Relevance to social judgment Some new findings regarding how it works Information-seeking Confirmation bias Reducing bias? Heuristics and Biases: Part II September 18, 2003 Daniel Kahneman Amos Tversky REMINDER: Quiz #1 is one week from today!

Availability: 

Making judgments about the frequency or likelihood of an event based on the ease with which evidence or examples come to mind Actual frequency certainly influences how easily evidence comes to mind, but other factors play a role as well. Availability

Perseverance of belief:Availability of supporting information: 

Suicide notes study (Ross, Lepper, andamp; Hubbard, 1975) Perseverance of belief: Availability of supporting information

Credit for Intentions(Kruger & Gilovich, 2003): 

Credit for Intentions (Kruger andamp; Gilovich, 2003) I’m just a soul whose intentions are good, Oh Lord, please don’t let me be misunderstood ~The Animals Don’t let me be misunderstood, 1965

Credit for Intentions(Kruger & Gilovich, 2003): 

The 'Cold Pressors': Earn $50 for your favorite charity for every minute you can keep you hand in this cold (0 - 2 degrees C) water afterwards, compare performance to other study participants’: actual altruism altruistic intentions (i.e., how willing to do the task, how much you wanted to help) The 'Observers' Observe video of a cold pressor and make same ratings of performance Credit for Intentions (Kruger andamp; Gilovich, 2003) I’m just a soul whose intentions are good, Oh Lord, please don’t let me be misunderstood ~The Animals Don’t let me be misunderstood, 1965

Credit for intentions: 

Credit for intentions

Egocentrism:How much did we each contribute?: 

Egocentrism: How much did we each contribute? (Ross andamp; Sicoly, 1979) primarily wife primarily husband

Egocentrism:How much did we each contribute?: 

Egocentrism: How much did we each contribute? (Ross andamp; Sicoly, 1979) primarily wife primarily husband H W

Egocentrism:How much did we each contribute?: 

Egocentrism: How much did we each contribute? (Ross andamp; Sicoly, 1979) primarily wife primarily husband H W

Egocentrism:How much did we each contribute?: 

Egocentrism: How much did we each contribute? (Ross andamp; Sicoly, 1979) primarily wife primarily husband H W

Egocentrism:How much did we each contribute?: 

One’s own contributions are more 'available' than others’ are (Ross andamp; Sicoly, 1979): Selective encoding: attention and rehearsal Differential retrieval: 'How much did I contribute?' (keep this in mind when we get to information-seeking...) Informational disparities Motivational influences Egocentrism: How much did we each contribute?

Another influence on availability: Media Coverage and “bad news bias”: 

Plane crashes: It's 22 times safer flying in a commercial jet than traveling by car (comparing accident fatalities per million passenger-miles traveled in the U.S.) More than 3,000,000 people fly safely on commercial airliners world-wide each day. Stranger abductions: less than 1% of the 800,000 children abducted in 2001 were abducted by strangers 'It strikes at your fears. When you have children, you worry about them ... When are you ever safe? The media and people seem to get off on the fear. ... The media love to play with anything that gets people excited.' ~Will C. Kennedy Another influence on availability: Media Coverage and 'bad news bias'

Impact on risk assessment: 

Impact on risk assessment Which in each pair causes more deaths per year? Stomach Cancer vs. Motor Vehicle Accidents Tuberculosis vs. Fire and Flames

Slide14: 

Which causes more deaths per year? Impact on risk assessment (Russo andamp; Shoemaker, 1989)

Slide15: 

Big Heuristic #3: Anchoring and Adjustment

Anchoring and AdjustmentThe classic demonstration(Kahneman & Tversky, 1974): 

Step 1: Is the percentage of African nations in the UN greater or less than 65% [10%]? Step 2: What is your best estimate of the actual percentage of African nations in the UN? Anchoring effect: 10% anchor group, mean estimate: 25% 65% anchor group, mean estimate: 45% Anchoring and Adjustment The classic demonstration (Kahneman andamp; Tversky, 1974)

Anchoring and Adjustment: Relevance to social judgment: 

Fundamental attribution error (Quattrone, 1982) Hindsight bias (Fischoff, 1975) Language production and comprehension (Keysar andamp; Barr, 1995) Negotiations--e.g., Real estate evaluation (Northcraft andamp; Neale, 1987) Anchoring and Adjustment: Relevance to social judgment

Selective Accessibility Model(Mussweiler & Strack, 1997): 

Selective Accessibility Model (Mussweiler andamp; Strack, 1997) Thomas Mussweiler Fritz Strack

Selective Accessibility Model(Mussweiler & Strack, 1997): 

Anchoring effect involves 2 steps: Comparative (i.e., 'larger or smaller than X?') Absolute (i.e., what’s your best guess?) The effect of each step: Comparative: Recruit evidence that is consistent with anchor Absolute: Judgment biased by accessible information Selective Accessibility Model (Mussweiler andamp; Strack, 1997) Thomas Mussweiler Fritz Strack

Slide20: 

Is the average price of a new car greater or less than 40,000 [20,000] German marks? Lexical decision task: Expensive car words: Mercedes, BMW, Limousine Inexpensive car words: Golf, Opel, VW Non-words: namon, mumphel Dependent measure: (RT for target words) - (RT for control words) i.e., the more negative, the more facilitation Selective Accessibility Model

Slide21: 

Selective Accessibility Model: (RT for target words) - (RT for control words) i.e., the more negative, the more facilitation

Putting the adjustment back in “anchoring and adjustment”(Epley & Gilovich, 2001): 

Different kinds of anchors: Experimenter-provided (the classic demonstration): you consider the possibility that they’re correct Self-generated e.g., What’s the freezing point of vodka? Well, I know water freezes at 0 and it’s got to be lower than that... you know they’re wrong, but relevant to the judgment Does this make a difference? Putting the adjustment back in 'anchoring and adjustment' (Epley andamp; Gilovich, 2001)

Slide23: 

Two types of anchors: Experimenter-provided Self-generated Two types of head movements Nodding =andgt; acceptance Shaking =andgt; rejection Putting the adjustment back in 'anchoring and adjustment' (Epley andamp; Gilovich, 2001) What’s the freezing temperature of vodka? Anchor: water freezes at 0

Self-generated Anchors: 

Self-generated Anchors Estimates were further from anchor when shaking than when nodding (Epley andamp; Gilovich, 2001)

Self-generated vs. experimenter-generated anchors: 

Self-generated vs. experimenter-generated anchors Smaller numbers =andgt; less adjustment (Epley andamp; Gilovich, 2001)

What’s wrong?: 

How fast can you spot what is unusual about this paragraph? It looks so ordinary that you might think nothing was wrong with it at all and, in fact, nothing is. But it is atypical. Why? Study its various parts, think about tis curious wording, and you may hit upon a solution. But you must do it without aid; my plan is not to allow any scandalous misconduct in this psychological study. No doubt, if you work hard on this possibly frustrating task, its abnormality will soon dawn upon you. You cannot know until you try. But it is commonly a hard nut to crack. So, good luck! I trust a solution is conspicuous now. Was it dramatic and fair, although odd? What’s wrong?

Slide27: 

? When the bus is going forward, which direction is it going? A B

Slide28: 

How did today’s musical selections relate to the today’s lecture? Let Down by Radiohead Hollywood Freaks by Beck Please don’t let me be misunderstood by The Animals

Remember Triesman & Souther, 1985...: 

Remember Triesman andamp; Souther, 1985... O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

Slide30: 

We 'normally see things and not the holes between them' (Kurt Koffka) We are more sensitive to the presence (vs. absence) of features and objects, the occurrence (vs. non-occurrence) of events When evaluating evidence or seeking information regarding a hypothesis, people are often biased towards information regarding the presence of the feature in question

O-rings: 

Does temperature at launch cause O-ring damage? Look at cases where damage occurred: O-rings

O-rings: 

Does temperature at launch cause O-ring damage? Look at cases where damage occurred Don’t forget to look at cases where NO DAMAGE occurred! O-rings Damage No Damage

“Confirmation Bias”: 

Positive-test Strategy: Look for the presence of cases that confirm the hypothesis: e.g., When trying to determine if someone is an extravert, look for evidence of extraversion (Snyder andamp; Swann, 1978) Tends to lead to biased conclusions when stimuli are complex such that cases exist that fit the hypothesis, regardless of whether the hypothesis is actually true--e.g., horoscopes, palm reading, Murphy’s Law 'Confirmation Bias'

Judging Similarity(Tversky 1977): 

Either asked: How similar are X and Y? How different are X and Y? X and Y were either pairs of: familiar stimuli (e.g., Japan and China) unfamiliar stimuli (e.g., Paraguay and Ecuador) Judging Similarity (Tversky 1977)

Judging Similarity(Tversky 1977): 

Either asked: How similar are X and Y? How different are X and Y? X and Y were either pairs of: familiar stimuli (e.g., Japan and China) unfamiliar stimuli (e.g., Paraguay and Ecuador) Judging Similarity (Tversky 1977) Determines the hypothesis you test Determines the amount of information that you find

Slide36: 

(Incidentally: This adds to the argument that concepts cannot be structured purely on the basis of similarity) Judging Similarity (Tversky 1977) are MORE SIMILAR than Familiar Stimuli China and Japan Ecuador and Paraguay Unfamiliar Stimuli AND are MORE DIFFERENT than

Social Comparison and self-judgment: 

Comparing one’s self to others can lead both to: CONTRAST: your view of yourself becomes less similar to what the other person is like (e.g., feeling worse about your abilities comparing yourself to a super-star) ASSIMILATION: your view of yourself becomes more similar to what the other person is like (e.g., feeling better about your abilities comparing yourself to a super-star) What determines which effect will occur? Social Comparison and self-judgment

Slide38: 

Prime the process of looking for similarities or looking for differences Read a passage about a student who is adjusting well or adjusting poorly to university life Rate self on how well adjusting to university life Social Comparison and self-judgment

Slide39: 

Social Comparison and self-judgment

Reducing bias/Improvingeveryday reasoning: 

Exposure to the probabilistic sciences (e.g., psychology!) could help.... Test statistical and methodological reasoning of graduate students in : Psychology, Medicine, Chemistry, and Law No differences before graduate training After two years: 70% improvement for psychology students 25% improvement of medical students NO improvement for chemistry or law students Reducing bias/Improving everyday reasoning Lehman, Lempert, andamp; Nisbett (1988)

Slide41: 

'It appears that the probabilistic sciences of psychology and medicine teach their students to apply statistical and methodological rules to both scientific and everyday-life problems, whereas the nonprobabilistic science of chemistry and the nonscientific discipline of law do not affect their students in these respects (p. 438) ... the luxury of not being confronted with messy problems that contain substanital uncertainty and a tangled web of causes means that cehemistry does not teach some rules that are relevant to everyday life (p. 441).' Lehman, Lempert, andamp; Nisbett (1988) Reducing bias/Improving everyday reasoning

However...Some biases are easier to overcome than others:: 

When it is possible to identify the influence of biased processing on one’s judgments, AND one knows the appropriate alternate strategy to apply, bias may be reduced (e.g., applying statistical principles to everday reasoning) When bias is due to a deliberate strategy (e.g., adjusting from a self-generated anchor), investing effort to modify that strategy can be helpful. BUT, bias is often caused by 'unconscious' or 'uncontrollable' mental processes (e.g., priming effects with experimenter-generated anchors). In these cases, it may be extremely difficult to overcome the effects of bias. However... Some biases are easier to overcome than others: (Wilson andamp; Brekke, 1994)