Unit 8 · Detecting Reasoning Errors

Scrub Jays — Species Reasoning Error

Lesson 33 of 34

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Scrub jays move their buried nuts when watched — but only if they've stolen before. Logan says this means they can predict who'll steal. Kimberley says movers must have been stolen from. Both are wrong, but in completely different ways.

Chapters

0:00Introduction
0:22Question
1:18Strategy
2:00Step 1: Write the two facts as rules
2:34Step 2: Logan — reactive ≠ predictive
3:09Step 3: Kimberley — thief ≠ victim + answer
4:02Correct answer

Question

Scrub jays are a species of bird that will bury some of the nuts they collect in order to save some food for later.

Scientists studying the species made an interesting discovery:

  • Some scrub jays move nuts they bury if they see other scrub jays watching them bury the nuts the first time.
  • It is only those scrub jays who have previously stolen nuts from other scrub jays that move their nuts.

Logan: "That means a scrub jay must be able to predict which other scrub jays will steal its nuts."

Kimberley: "If a scrub jay moves a nut it has buried, you can be sure it has had its nuts stolen before."

If the information in the box is true, whose reasoning is correct?

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