Bugs or Features? Exploring Cognitive Biases, Fallacies, and Heuristics 

Department: Cognitive Science

Instructors: Adrian Seeley and Emma Duncan 
Instructors' Emails: adrian.marie.seeley@gmail.com and eduncan@ucsd.edu 
Prerequisites: None

Course Description

Linda* is 31 years old, single, outspoken, and very bright. She majored in philosophy. As a student, she was deeply concerned wit issues of discrimination and social justice, and also participated in antinuclear demonstrations.

Which alternative is more probable?

  1. Linda is a bank teller.
  2. Linda is a bank teller and is active in the feminist movement.

If you picked number 2, you’re not alone (and you’re wrong!). We tend to think we’re pretty good at making decisions—we know what we like, we can recognize when something’s a good deal or a scam, and if we take the time weigh our options we usually make the right choice. But things aren’t so simple. Many of the decisions we make every day don’t involve careful deliberation. Careful deliberation is hard! It takes a lot of focus and cognitive energy to juggle all of the variables involved in even a single choice. So, our minds resort to shortcuts to help us make quick decisions, often without us knowing how or why we decided the way we did. Most of the time these shortcuts work, but sometimes they steer us wrong. Knowing the shortcuts our brains take, usually without our permission, can help us understand why we consistently and predictably make certain mistakes, how we can make better choices, and how other people make decisions (which, by the way, is what marketing is all about).

This course will cover

  • Psychology
  • Some neuroscience
  • Persuasion techniques
  • Heuristics (shortcuts and rules of thumb)
  • Philosophy
  • Logical fallacies
  • Behavioral economics (how we choose things, how others can influence our decisions)
  • Marketing 

*(Kahneman and Tversky, “Extensional versus intuitive reasoning: The Conjunction Fallacy in Probability Judgment”, 1983.)

Course Goals / Learning Objectives

By the end of the program, students should have an appreciation for the many ways our mental shortcuts, fallacious reasoning, and other cognitive blunders impact the structure of our social institutions, as well as our ideas and behaviors, both as individuals and in groups.

A (non-exhaustive) list of (tentative) topics includes the following biases and fallacies:

  • Confirmation bias
  • Implicit biases (especially racial and gender)
  • Implicit Attitude Test (IAT)
  • Hindsight bias
  • Status quo bias
  • Base-rate fallacy
  • Correlation-causation fallacy
  • Logical Fallacies (e.g. ad hominem, slippery-slope, )
  • Diffusionof responsibility


The final grade for this course will be calculated as follows:

  • Participation (incl. group work, field-trips): 30%
  • Quizzes: 30%
  • Homework (in- or out-of-class assignments): 10%
  • Exams: 30%

Topical Outline

Week 1 - Intro, Cognition, Heuristics: “Who’s in Control, You or Your Brain?”


  • Introduction: How we think, for better or worse!
  • System 1 and System 2-thinking (Kahneman)
  • Systems conflicts: Conscious cognition automaticity: attention, performance, etc.


  • “Biases and Blunders” [excerpt from Nudge]
  • Daniel Kahneman’s: Thinking: Fast and Slow [excerpts]

Week 2 -Cognitive biases and logical fallacies: “Putting the ‘I’ in Irrationality!”


  • Quantification and numbers (including framing effects, probability judgments)
  • Overestimation and exaggeration
  • Practical impacts of biases: susceptibility to persuasion, misinformation, propaganda, fake news, future discounting,


  • Kahneman, Daniel, and Amos "Choices, values, and frames." American psychologist 39, no. 4 (1984): 341.
  • Rispo, Vito: “The Power of Framing Effects”
  • Tversky, Amos, and Daniel "The Framing of Decisions and the Psychology of Choice." SCIENCE 211 (1981): 30. pp. 453-458

Week 3 - Biases and Society: "Climbing Back up the Rabbit Hole"

We will explore the further implications of the mental shortcuts discussed in weeks 1 and 2. Emphasis will be placed on scientific methodology and publishing — the problems therein and the improvements already being made.


  • Publication biases among journals and some new safeguards in place to combat them
  • (Un)likely journals will publish negative results
  • failure to replicate
  • File-drawer problem
  • Researcher’s vulnerability to Confirmation bias
  • P-value fallacy
  • Education and hiring practices



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