Psychology/PPE 153
Judgments and Decisions, Fall 2010

MWF 11-12, Stiteler B26

baron picture
Professor Jonathan Baron (
For appointments, check my schedule and send me email.
Office: C7 Solomon Psychology Lab Building

Teaching assistants: Pavel Atanasov (
Office hours: Wed 3-5
Office: C7, C16, or C36 Solomon (for office hours only)


One semester of statistics or microeconomics.

Requirements that this course meets

This course counts toward the psychology major and is an option to meet a requirement for the PPE major. I do emphasize applications to public policy, as well as medical decision making.

It meets the quantitative data analysis requirement of the College. Please consider other ways of meeting that requirement.

It is an option for the consumer psychology minor, but Psych 153 does not emphasize applications to consumer psychology.

Overview and policies

This course addresses the ideal standards of judgment and decision making, and the ways in which people fall short according to these standards. Understanding of the ideals and our limitations can help improve judgments and decisions in such fields as medicine, law, and public policy.

This syllabus will be revised often. Use the reload button on your browser to make sure you have the latest version.

Email, appointments, mailing list

I check my email several times per day. I try to answer all questions, as does the TA. To make an appointment with me, check my schedule in my web page and then send me an email message saying when you want to meet and (in at least one sentence) what it is about.

Assignments may be submitted through the web (with special forms provided for each one), or pdf if they contain figures.

The course has a mailing list, for which you can sign up, if you are not already signed up. The list has archives so that you can see what you missed or lost.

Exams, assignments, and grades There are some assignments (which are graded). You may submit drafts of the last assignment for comments, at any time during the term, up to a week before the due date. (No exceptions for any reason.) Otherwise, do not do any other assignments until told that they are ready.

The midterm and final will consist of short essay questions, and short-answer questions. They will cover topics covered in class. Exams are open-book, typed, time- and page-limited, and submitted by web form. The midterm and final will be designed for two hours of work (including both writing and looking things up). The starting time is somewhat flexible. I can instruct the computer to send you the exam at a particular time. If you leave campus before the final exam, you can do it remotely. I will send exams to your Penn email address.

Grades will be based on a weighted sum of all work. Approximate weights (in percent of grade) were (last time the course was taught): assignments 45% (the last assignment being the biggest part of this), midterm 25%, final 30%. Each score will be standardized and multiplied by its weight, and then the weighted scores will be added up. Lateness will be penalized.

I will follow the rules of the University and the College of Arts and Sciences, including rules about incompletes and the Code of Academic Integrity. In particular, you may study together, but you cannot hand in identical text for any exams or assignments.

Schedule (subject to revision on short notice)

The letter T stands for Thinking and deciding. It is available at the Penn Book Center (not the Penn Bookstore). Other reading is listed with each topic.

Links for the names of topic go to slides that I may present in class. You should be able to print these if you want to, before class. But please wait until the last minute to do that, as I am constantly revising. To print the slides using Firefox without wasting paper, use the menus: "View / Use Style / print," then "File / Print." The slides are not intended as a complete outline of what I plan to cover.

9/8 9/10 Introduction: T1-3.

9/13 9/15 Irrational belief persistence: T9.
Sunstein. Why groups go to extremes.

9/17 9/20 Correlation and contingency: T8.
Class activity on contingency judgment.

9/22 9/24 9/27 Probability: T5, Clinical trials, Strogatz on Bayes's theorem,
Class activity and homework on personal probability estimation.

9/29 10/1 Probability and calibration: T6
  Dick Cavett on coincidences
Class activity on coincidences.

Assignment 1, first part due by the end of 10/2

10/4 Hypothesis testing: T7, Intelligent design

10/6 Logic: T4.

Assignment 1, second part due at the end of 10/7.

Assignment 2 due at the end of 10/14.

10/8 10/13 10/15 Utility: T10.

10/18 (P.A.) 10/20 Decisions under uncertainty: T11

10/22 Midterm exam (default time, 11-1)

10/25 10/27 Reference dependence in choice: T12, Tritch, T. (2007). Helping people help themselves.
Thaler, R. H., Sunstein, C. R., & Balz, J. P. (2010). Choice architecture.

Assignment 3, first part, due at the end of 10/30

10/29 11/1 11/3 11/5 Utility measurement and decision analysis: T13, T14,
Cost-benefit analysis in health care
Singer, P. (2009). Why we must ration health care
Keeney, R. L. (1992). Value-focused thinking: A path to creative decisionmaking. Cambridge, MA: Harvard University Press, pp. 3-87, 147-148 (possibly in Rosengarten), or
Keeney, R. L. (2002). Common mistakes in making value trade-offs. Operations Research, 50 (6), 935-945.
Mullin, B., Mullin, M., and Mullin, R. (2008). Mhairi’s Dilemma: A study of decision analysis at work (pdf version).

Assignment 3, second part, due at the end of 11/3

11/8 Judgment: T15.
Class activities on judging the mean, making predictions.

11/10 11/12 11/15 11/17 11/19 Moral thinking, utilitarianism, and fairness: T16, T17, Million-dollar Murray (Gladwell), Conflict among abortion opponents, Bailout (Collins)
Class activity on fairness vs. efficiency

Assignment 4 due at the end of 11/23

11/22 Negotiations
Class activity on negotiation.

11/24 11/29 12/1 (P.A.) 12/3 social dilemmas, and voting: T18,
G. Hardin (1968), The tragedy of the commons. (Science, 162, 1243-1248).
Approval voting (Wikipedia)
Edlin et al.: Vote for charity's sake

12/6 Intertemporal choice: T19

12/8 12/10 Risk: T20 Airport security follies, The odds of airborne terror (Nate Silver)

Final draft of Assignment 5 at the end of 12/9

12/16 Final exam: 12-2 (by email, like the midterm, with some time flexibility)


Assignment 4: Decision analysis

Carry out a multi-attribute analysis of a public-policy decision or some non-trivial decision that you might face. (Be imaginative if you wish. You might, for example, be president of a country some day.) Make sure that the decision has at least three options and at least three attributes. Repeated decisions such as what to have for lunch are more difficult than they seem, because the real options are policies.

This is not a paper. You don't need to go on at great length describing the decision in words. Just include the minimum to make it clear what the decision is about, and what the attributes are, if that is not clear from their names.

You will benefit most if you think about fundamental values in Keeney's sense. So, if you make up an initial list of things that you care about (or should care about, in the case of a public-policy decision), ask yourself why you care about each one. You may find that there is some deeper goal that motivates it. Keeney gives several other helpful suggestions to discover fundamental values. For example, one decision you might face is choosing a career. Many of the things that people say when asked for their values about this are superficial, e.g., that they want their career to be ``interesting.'' What is interesting to you may depend on your other fundamental values about what you want your life to mean, what you want to use it for. The values in the birth-control example below resulted from application of Keeney's method by several students in a former class.

You should hand in something like one of the examples we discussed in class. Do not worry about the precision of assigning values to intermediate cases. Do worry about assigning weights. You should explain how you did that for one attribute (relative to the most important one). Make sure you do the reading before you do this.

The weights are determined first by picking the most important attribute range and then comparing other ranges to that. You can pick the most important range in two ways. Ask yourself which is more important, the difference between the top and bottom of one range (as you have defined the top and bottom) or the difference between the top and bottom of another. (Alternatively, you could make up a hypothetical decision, e.g., between two option that are identical except that one is best on attribute A and worst on B and the other is the opposite.)

The simplest way to determine weights is by direct judgment. How big is the difference between the top and bottom of the smaller range, compared to the difference between the top and bottom of the larger range (or vice versa)? (See the text for other methods.) Make sure to explain how you have done this for one attribute. If you did what I just said, say that you did this, using one example.

In addition, you should carry out and explain at least one test of consistency. A test involves estimating one of the weights in two different ways and explaining how you resolved any disagreement that you found. One way is to make judgments relative to some attribute other than the largest and then check ratio consistency: if the weight of attribute B relative to A is .6 and the weight of C relative to A is .3, then the weight of C relative to B should be .5.

Here is a form for submitting the assignment.

Assignment 5: Discussion paper.

Write a short (absolute maximum 200 lines, 70 characters per line; minimum 25 lines) reflective discussion of some topic from the course. (Here is a form.) This should require no additional research, although you should of course acknowledge any sources that you use because you already know them (including course reading). Do not feel obliged to fill up the 200 lines; 125 should suffice if you write succinctly.

One possible format for this paper is a philosophical discussion of some question from the course, such as whether self-deception is rational (but probably not that one). Try to avoid questions that have completely trivial answers and questions so big that a book would be required to answer them. Avoid mere recapitulation of arguments in the reading as well as unsympathetic attacks on it. Avoid one-sided presentations that ignore the arguments of the other side. Feel free to ask if a topic is appropriate. A good model to follow is the discussion of self-deception on pp. 71-73 of the text, especially the discussion of whether self-deception can be rational. Feel free to skip ahead in the reading if you wish to hand in the paper early. If you choose this kind of topic, make sure to consider (and rebut, or take into account) objections to arguments you make.

Another possible format is something more like a research proposal. Take a result from the course, propose alternative explanations of it, and suggest ways of distinguishing them.

Grading of this assignment: If a paper does a good job summarizing the course, it is a B (8/12). It must say something beyond the course to get an A (11/12). But it must also consider obvious counter-arguments; failure to do that could drag it down, even below B. If I'm blown away by the writing, I give a higher grade, even A+ (12). If the writing is so incoherent that I cannot understand the ideas, I lower the grade. If 2 or more big problems are present (nothing original, one sided, badly written), the paper can get a C (5) or D (2). F (0) is reserved for papers that have nothing to do with the course, or are not submitted.

Last modified 02/16/14

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