Presentation on theme: "Schemas and Heuristics"— Presentation transcript:
1Schemas and Heuristics “Please your majesty,” said the knave, “I didn’t write it and they can’t prove I did; there’s no name signed at the end.”“If you didn’t sign it,” said the King, “that only makes matters much worse. You must have meant some mischief, or else you’d have signed your name like an honest man.” –Lewis CarrollAlice’s Adventures in Wonderland
2Quote illustrates how beliefs might persevere, even in the face of contradictory evidence (the perseverance effect discussed last time)We’ll continue talking about schemas and mental shortcuts today
3Sometimes schemas can get us into trouble Confirmation biases: Tendencies to interpret, seek, and create information that verifies our preexisting beliefs or schemas.Examples of confirmation biasesBelief perseverance: The tendency to maintain beliefs, even after they have been discredited.
4Perseverance Effect Ross et al. (1975) IV: Success, failure, or average feedback about ability to detect “real” or “fake” suicide notesIntervention: E explained feedback was randomly assigned (discredited belief)DV: Estimated how well would actually do at taskResults: Beliefs persevered. Estimates closely matched false feedback Ps had received.Why? May think of reasons to support…takes on life of its own.
5Confirmation biasOur expectations also can influence how we go about obtaining new information about another person.Imagine that you are going to meet a friend of a friend. Your friend tells you that his friend, Dana, is very outgoing and friendly, the life of the party. When you meet Dana and are getting acquainted, will that information influence what you say and do? Some work suggests that it will.
6Confirming Prior Expectations Snyder & Swann, 1978IV: Expectations about person to be interviewed: introverted vs. extravertedDV: Selection of interview questions. Slanted toward extraverted (How do you liven things up at a party?), introverted (Have you ever felt left out of some social group?), or neutral.Results: Ps asked loaded questions that confirmed their prior expectations
7On being sane in insane places David Rosenhan+7 colleagues gained admission to mental hospitals“heard voices,” false name, all else trueExample of confirmation biasStayed in hospital average of 19 daysMost needed outside help to get out
10How might this apply to a clinician’s diagnosis? Clinicians might look for information that confirms their diagnosis and ignore information that might disconfirm it. (Example: “On being sane in insane places” Rosenhan)
11Confirmation Bias in the Clinic Once we have a hypothesis, it’s easy to look for confirming evidence.True for clinicians, psychiatrists, etc.True in other contextsCourtroom: Lawyer or witness makes inappropriate statement. Judge tells jury, “Disregard the evidence.”
12Self-fulfilling Prophecy One person’s expectations can affect the behavior of another person.Self-fulfilling prophecy: The process whereby (1) people have an expectation about another person, which (2) influences how they act toward that person, which (3) leads the other person to behave in a way that confirms people’s original expectations.
13ExampleI expect that the students in the front row are especially smart.I may give them more attention, nod, smile, and notice when they ask questions.As a consequence, students in the front row might pay closer attention, ask more questions, etc., thereby confirming my expectation.
15Limits of Self-fulfilling prophecies Self-fulfilling prophecies areMORE likely to occur when the interviewer is distracted (tired, under time constraints, etc.)LESS likely to occur when the interviewer is motivated to be accurate
16HeuristicsSpecific processing rules (or rules of thumb)
17Mental Shortcuts or Heuristics Judgmental heuristics: Mental shortcuts (rules of thumb) people use to make judgments quickly and efficientlyResearch on heuristics arose in response to a view of humans as rational, thoughtful decision-makers.Economists’ modelsTversky & KahnemanNisbett & Ross
18We will discuss a few specific heuristics (but there are many)
19What is the difference between a schema and a heuristic? organized set of knowledge in a given domain (knowledge structure)influences processingEx: Rude person – related traits, expected behaviors, expectations about own reactions, etc.Mental shortcutSpecific processing ruleNot necessarily tied to a particular schemaNot a “knowledge structure”Ex: If an item is expensive, it must be good quality.
21Representativeness heuristic The tendency to assume, despite compelling odds to the contrary, that someone belongs to a group because he/she resembles a typical member of that group.
22Base-rate information Are there more salespeople or librarians in the population?If knew that sample = 100 people and 70 were salespeople and 30 librarians, what would you have guessed?Representativeness heuristic can lead us to discount important base-rate information (i.e., info about the frequency of members of different categories in the population)
23Availability Heuristic The tendency to perceive events that are easy to remember as more frequent and more likely to happen than events than are more difficult to recall.
24Which of the following are more frequent causes of death in the U.S.? Homicide vs. diabetes?Flood vs. infectious hepatitisTornados or asthma?
25People often give too much weight to vivid, memorable information. Hamill, Nisbett, & Wilson (1980)IV: Type of informationVivid, concrete atypical + statisticalVivid, concrete typical + statisticalControl group (no information)DV: Positivity/negativity of attitudes toward welfare recipients in generalResults: Participants who read the vivid stories with either the “atypical” or “typical” label, expressed more UNFAVORABLE attitudes toward welfare mothers in general than those in the control group.
26Counterfactual Thinking We mentally change some aspect of the past as a way of imagining what might have been.
27Study of Counterfactual Thinking (Medvec, Madey, & Gilovich, 1995) Videotaped 41 athletes in the 1992 summer Olympic Games who had won a silver or bronze metal.Quasi-IV: Athlete won silver OR bronze medalDV: Judges’ ratings of participants’ emotional state from “agony” to “ecstasy.” (Judges unaware of participant’s award status.)Results: Bronze medallists were rated as happier than the silver medalists.Why?
28Automatic ThinkingMost biases/heuristics operate automatically (i.e., without conscious awareness)Some are highly automatic (e.g., availability), whereas others (e.g., counterfactual thinking) appear to have both automatic and more controlled components
30Controlled ThinkingThought suppression: the attempt to avoid thinking about something we would just as soon forgetHave you ever told yourself, “I just won’t think about [dessert, my ex, money…]”What happens?
31Example of Thought Suppression & Ironic Processing Homer Simpson tries to not drink beer.(video clip)
32Ironic processing & Thought Suppression Monitoring process (automatic): Search for evidence that unwanted thought is about to pop into consciousness.Operating process (controlled): Attempt to distract self from detected unwanted thought.Problem: If under cognitive load (tired, hungry, stressed, under time pressure), operating process breaks down.Ironic because when we try to STOP thinking about something, it keeps popping into our mind (if we are under cognitive load)
33How can we be better thinkers? Given that humans make a lot of errors in reasoning, what can we do to improve our thinking?TAKE STATISTICS!Nisbett and colleagues found that students who had formal training in statistics (psychology and medicine grad students) performed better on a test of reasoning than grad students in disciplines (chemistry, law) requiring less training in stats (see p. 89 of your text)
34ConclusionsSchemas and judgmental heuristics help us make sense of the worldThey increase our efficiency and speedThey often operate automatically, without conscious awarenessBut, they can sometimes lead to serious errors in judgment!