1. Wason’s selection task
E K <- four cards
Each card in a deck of cards has a letter on one side and a number on the other
Claim: If there is an even number one side, then there is a vowel on the other side

2. problem and solution E K 4 7
If there is an even number on one side, then there is a vowel on the other side.
Determine which cards need to be turned over to verify that the rule or claim holds
answer: “4,” “K,” but not “E,” “7”
only ~10% of population gets the right answer

3. another selection problem
You serve drinks in a bar. Every patron of the bar has an age and a beverage.
beer water
If you are drinking alcohol, then you have to be at least 21 years of age.
Which patrons do you need to know more about to see if the law is being observed?
Answer: check out 16-year old and the beer drinker; leave others alone
most of the population gets the answer right

4. differences in problems
connection to everyday life
EK47 version has no connection to everyday life; whereas, the bar problem does
difference in content: abstract version (EK47) and the realistic version (bar version)

5. logical structure of bar problem
beer water
If someone is drinking alcohol, then they must be 21 years or older.
“p” = drinking alcohol
“q” = being 21 years or older
If p, then q

6. replace content with terms
beer water
If p, then q (p = drinking alcohol; q = 21 years or older)
16  “not q” beer  “p”
22  “q” water  “not p”

7. logical structure not q q p not p If p, then q
exactly the same logical structure with EK47 version

8. conditions of naturally good critically thinking skills
more likely when we have realistic content in the problem
explanation: minds have a natural ability to solve logic problems, but only in situations of realistic content
deontic content: situations involving social rules (laws, detecting cheaters, etc.)

9. Implicit statements
If Michael Jackson is a normal guy, then I’m a monkey’s uncle.
(I’m not a monkey’s uncle.)
(Michael Jackson is not a normal guy.)
Implicit = unstated (indicate implicit statements by using parentheses)

10. logical structure of implicit statements
If Michael Jackson is a normal guy, then I’m a monkey’s uncle.
If p, then q (p = MJ normal guy, q = monkey’s uncle)
not q (I’m not a monkey’s uncle.)
not p (MJ is not a normal guy.)
 denial of the consequent (modus tollens)

11. realistic vs. abstract versions
If p, then q <- alone, no particular implications
If MJ is a normal guy, then I’m a monkey’s uncle <- adding words, particular implication is that MJ is not a normal guy

12. logical operators If…then (conditional)
= if p, then q  under the condition that p is true, q is true
not (negation) “~”
= not p  p is not true
and (conjunction)
= p and q  both p and q are true

13. Disjunction OR (disjunction) = p or q  either p or q is true
logical operators allow you to combine information (premises) into logical statements

14. Interpretation of disjunction
p OR q  either p or q is true
but what about “I am male or female.”
 you are one or the other but not both (exclusive OR) excludes both (XOR)
what about “I am happy or smart.”
 you are one or the other or both
(inclusive OR) includes both

15. Interpretation of OR p or q
could mean, p is true or q is true but not both
alternatively, could mean, p is true or q is true or both
unless specifically stated, either interpretation is possible

16. Disjunctive Reasoning
doing reasoning or critical thinking involving the word “or”
Start paying attention to me or I’ll kick you out of the class. (p or q) disjunction
means, If you don’t pay attention to me, then I’ll kick you out of the class. (If p, then q) conditional