How the mind sees these Wason selection tasks



Wason selection task with a descriptive rule.


The structure of the task in logical terms is shown in blue.


David planted a lovely garden with flowers of every color.  He has not been able to enjoy it, though, because deer from the forest nearby have been nibbling on his plants, killing some of them. 


He would like to keep the deer out of his garden.  His grandmother said that in the old days, she kept deer away by spraying an herbal tea -- lacana -- in her garden. She said:


"If you spray lacana tea on your flowers, deer will stay out of your yard."

"If P happens, then Q happens"


This sounded dubious.  So David convinced some of his neighbors to spray their flowers with lacana tea, to see what would happen.  You are interested in seeing whether any of the results of this experiment violate Grandma's rule.


The cards below represent four yards near David's house.  Each card represents one yard.  One side of the card tells whether or not lacana tea was sprayed on the flowers in a yard, and the other side tells whether or not deer stayed out of that yard.


Which of the following cards would you definitely need to turn over to see if what happened in any of these yards violated Grandma's rule:


"If you spray lacana tea on your flowers, deer will stay out of your yard."


Don't turn over any more cards than are absolutely necessary.

 

 

sprayed with lacana tea

P

 

 

not sprayed with lacana tea

not-P

 

 

deer stayed away

Q

 

 

deer did not stay away

not-Q


The logically correct answer is:

P = sprayed with lacana tea

and

not-Q = deer did not stay away

 

NOTE for logic jocks: you might wonder whether people reason logically, but are interpreting this rule as a biconditional.  The answer is "no".  If people were interpreting it as a biconditional and then reasoning logically, they should choose all four cards.  They don't -- choosing all four is a very rare response.  The most common response is to choose P alone, or P&Q.



 

Wason selection task with a Social Contract rule


The mind translates social contracts into representations of benefits and requirements, and it inserts concepts such as "entitled to" and "obligated to".  In blue, we show how the mind "sees" this particular social contract.


Teenagers who don’t have their own cars usually end up borrowing their parents’ cars.  In return for the privilege of  borrowing the car, the Goldstein’s have givein their kids the rule,


“If you borrow my car, then you have to fill up the tank with gas.”

"If you take the benefit, then you are obligated to satisfy the requirement."


Of course, teenagers are sometimes careless and irresponsible.  You are interested in seeing whether any of the Goldstein teenagers broke this rule.


These cares represent four of the Goldstein teenagers.  Each card represents one teenager.  One side of the card tells whether or not a teenager has borrowed the parents’ car on a particular day, and the other side tells whether or not that teenager filled up the tank with gas on that day.


Which of the following cards would you definitely need to turn over to see if any of these teenagers are breaking their parents’ rule:


“If you borrow my car, then you have to fill up the tank with gas.”


Don’t turn over any more cards than are absolutely necessary.


  
borrowed car

took the benefit

 


did not borrow car

did not take the benefit

 


 
filled up tank with gas

satisfied the requirement

 

 
did not fill up tank with gas

did not satisfy the requirement


The correct cheater detection answer is:

Took the benefit = borrowed the car ( = P)

and

Did not satisfy the requirement

= did not fill up the tank with gas ( = not-Q)


Notice that for this particular social contract (a standard one), the correct cheater detection answer happens to be the logically correct answer, P & not-Q.


But if the rule had been phrased in switched form:

“If you fill up the tank with gas, then you can* borrow my car" ”

"If you satisfy the requirement, then you are entitled to take the benefit"

looking to see if the teenagers had cheated would result in choosing the exact same cards, only now they correspond to a logically INCORRECT answer, Q & not-P

Took the benefit = borrowed the car ( = Q)

and

Did not satisfy the requirement

= did not fill up the tank with gas ( = not-P)

 

*note: one does not need to put the word "can" (meaning "entitled to") into the rule.  People "read it in" to social contracts, even if it is not explicitly stated.  The same is true of the word "must" (meaning "obligated to")




Wason selection task with a Precautionary rule


The mind translates precautionary rules into representations of hazards and precautions. In contrast to social contracts, precautionary rules do not involve notions of entitlement -- nor do they involve "obligation".  The must in a precautionary problem is prudential -- if you want to be safe, this is what you must do...   The hazard management reasoning system is looking for cases where someone is in danger.

 


To see how the mind "sees" a precautionary problem


Biology labs often study diseases by studying the viruses that cause disease.  Of course, anyone who gets the virus on their skin can get quite sick.  Paragon, Inc. is a drug company that studies diseases.  Some of their labs study viruses, others are just chemical labs where they invent new drugs.  Paragon has a safety rule,


“If you work in the lab with viruses, then wear rubber gloves.”

"If you are engaging in a hazardous activity, then take the proper precaution."


You want to see whether anyone ever breaks this safety rule.


The cards below represent four people who work for Paragon.  Each card represents one person.  One side of the card tells whether that person works in the lab with viruses and the other side tells whether that person is wearing rubber gloves.


Which of the following cards would you definitely need to turn over to see if any of these people are breaking the safety rule:


“If you work in the lab with viruses, then wear rubber gloves.”


Do not turn over any more cards than are absolutely necessary.


 
works in the lab with viruses

enaged in hazardous activity

 

 
does not work in the lab with viruses

not engaged in hazardous activity

 

 
wearing rubber gloves

 

is taking the precaution

 

 
not wearing rubber gloves

 

is not taking the precaution