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The Single Lesson Plan


  1. To link Thinking Errors with logical fallacies and biases and an understanding of how Thinking Errors can apply to every facet of everyday thought.
  2. To impress how important it is to have a clear view of reality.


The children in the lesson should all have a working knowledge of the Thinking Errors and how to recognize when somebody commits one.


Some sort of presentation method (PowerPoint, an overhead projector, etc.), a deck of 25 Zener cards, paper and pencils, a fake horoscope for each child, and a bag of candy (for reinforcement)


The single Kids Thinking Critically lesson takes about two hours to teach. It attempts to explain how Thinking Errors with which the kids are already familiar are not just personal issues, but can all be generalized to lead to false beliefs and bad decisions about just about anything. It starts with a “psychic” experiment which provides an interactive “hook” as well as a solid referent to show how Thinking Errors apply to things other than self-image and interpersonal interactions.

The children are taken through the Thinking Errors and are shown how each relies on ignoring evidence to reach an inaccurate belief or conclusion. The importance of following where the evidence leads is then impressed with examples from real life. Finally, they are shown, through simple optical illusions, how fallible human perception is, and reminded to question their perceptions and assumptions to make sure their beliefs accord with reality.


  • Review, if necessary, all of the Thinking Errors
  • Run a simple “psychic” test with the Zener cards
    • Pick a volunteer to be the “psychic” and one to be the recorder
      • The “psychic” tries to divine the contents of each card
      • The recorder checks each card once it has been named and records whether the “psychic” was right or wrong
    • The instructor will act as the facilitator
      • Deal the cards, one-by-one, facedown on a table so the psychic can attempt to divine them
      • Hand the cards to the recorder to check
      • Explains each step along the way
        • The cards are shuffled to randomize them
        • The psychic does not see any of the cards as they are laid out–this is to keep him or her blind and stave off cheating
        • The facilitator does not see the cards because he or she might give unconscious signals to the “psychic” through facial or body language–this ensures a double-blind procedure
        • The recorder is the only one to see the cards so neither “psychic” or facilitator can be biased
    • When the deck is finished, take the results from the recorder, figure the percent of “hits” and “misses,” and display them for the class
  • Begin a brief word about probability
    • About 20% hits is to be expected
    • Most people don’t understand probability and think 20% is either “success” or “failure”
  • Magnification and catastrophization
    • People exaggerate the importance of small numbers
    • More than one (or a few) points of data is necessary for a good conclusion
  • Emotional reasoning
    • People’s fear can lead them to faulty interpretations of statistics
      • The “evening news effect:” disasters (like plane crashes) are very rare, but people think they happen all the time based on the media’s reporting of exceptional, frightening events
  • Disqualifying the positive and mental filter
    • Both rely on cherry-picking the evidence–refer back to the experiment
      • Disqualifying the positive would be finding reasons the “hits” don’t count
      • Mental filter would be focusing so hard on the “misses” that one doesn’t see the whole picture
      • Reminder: just counting the “hits” and ignoring the “misses” is just as wrong
  • All-or-nothing thinking
    • A 20% “hit” rate in the experiment is neither a total “failure” or a total “success;” 20% of the cards were guessed right, so it was a 20% success
    • Name all-or-nothing thinking: the “false dilemma” or “false dichotomy,” because only two options are given when more are present
    • Use an example from TV advertising: a certain product that claims to be necessary for weight loss, or a cleaning product that claims to be necessary for a nice house
    • Provide strategies for fixing black-and-white thought
      • Find the grey area in between the extremes
      • Find options other than those presented
      • Reject the dilemma as irrational
  • The role of evidence
    • All Thinking Errors rely on ignoring some form of evidence
    • Give examples of people who ignored evidence, i.e. the story of “The Emperor’s New Clothes,” where people ignored the evidence that the Emperor was naked, or stories of Wild West hucksters who exploited people’s sicknesses for a quick buck
  • Thinking Errors and evidence
    • Ask the children to think about what evidence each Thinking Error ignores
      • Catastrophization ignores a lack of positive evidence
      • Emotional reasoning uses emotions as a substitute for evidence
      • Disqualifying the positive ignores positive evidence
      • All-or-nothing thinking ignores alternative solutions or ideas
    • Quickly go over the Thinking Errors not yet mentioned in the context of ignoring evidence
      • Mind Reading makes assertions with no evidence at all
      • Should statements are assertions made before the evidence comes in
      • Labeling and overgeneralization are conclusions made to sum up an entire person or thing based on only a single piece of evidence
      • Minimization downplays important evidence
      • The fortune-telling error assumes the future can only go one way without any evidence to back the prediction up
  • Evidence and real life
    • A single instance is not enough data to draw a conclusion
      • One failure does not make someone a bad person
      • One mean joke does not make someone a jerk
      • Even one experiment is not enough to form a solid conclusion!
    • A large amount of evidence is needed before someone draws conclusions about anything
    • Jumping to conclusions is an easy way out, but it’s better to say “I don’t know yet”
  • Horoscope activity
    • Bring out the fake horoscopes and hand one to each child
    • Tell them they were ordered from a famous astrologer
    • Explain they are to read them silently to themselves
    • Ask them to consider how accurately they are described by their horoscopes
    • When they are all done reading, go around the room and have each child rate his or her horoscope for accuracy (with a good fake horoscope, chances are most will rate it highly)
    • Reveal to them that they all got the same horoscope
    • Ask them to reread them more critically, without the preconceived notion that they are accurate
    • They didn’t see all the evidence because they were seeing what they wanted to see
  • Confirmation bias
    • Explain the meaning of “bias”
    • Confirmation bias: seeing only things that confirm your preconceived notions and biases
    • At work in many Thinking Errors
  • The “How” and “Why” of Thinking Errors
    • How: cherry-picking evidence and ignoring evidence
    • Why: to continue believing something you already believe, to avoid changing your mind, to believe what you want to believe instead of what really is
  • The fallout of poor thinking
    • Thinking Errors can affect them personally through creating negative thoughts and a negative worldview
    • They can also affect them outside their heads by leading to false or inaccurate beliefs or bad (even dangerous) decisions
  • Becoming a doctor
    • Choose a volunteer “patient”
    • Explain that they have terminal cancer
    • Tell them they’re afraid of standard treatments like chemotherapy, surgery, or radiation
    • Present them with a non-frightening miracle cure: a piece of candy that will cure all their ills
    • Ask them to consider what might happen if someone’s fear causes him to ignore the evidence for effective treatments and instead pick a less frightening one with no evidence to back it up
    • Generalize the concept: how else can a choice made against the evidence cause harm?
  • Question yourself
    • Thinking Errors can color their entire world inaccurately
    • They must always begin by questioning their own perceptions of events
    • Perception is fallible
      • Show them a few optical illusions like the Muller-Lyer illusion
      • Speak briefly about how human perception can be deceived and mistaken
      • They must look for reliable evidence instead of always unquestioningly trusting their initial perceptions
    • Examine your biases
      • Why do they hold their personal biases?
      • Is it wishful thinking? Fear? Are they just plain made up?
      • Are their biases justified by the evidence?
  • Conclusion
    • Thinking Errors can be committed in just about every sphere of life
    • It is extremely important to follow the evidence


Given the single-shot nature of this lesson, it is difficult to get a solid assessment. Afterwards, the kids can be asked what they thought of the lesson and if they learned anything new from it. I have found that subsequently presenting them with irrational statements based on the Thinking Errors in the context of normal conversation can be a good way to judge if they retained the information. If they call you out on your Thinking Error, they’re learning. If they do not, you have a great teachable moment on your hands.

Formal assessment can be accomplished through the development of simple worksheets presenting short narratives and asking what Thinking Errors are being committed by the people in the stories, and what evidence they are ignoring and should be factoring into their belief or decision-making process.

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