Conditional reasoning – a logical determination of whether the evidence supports,
refutes, or is irrelevant to the stated relationship.
     -standard form: if P, then Q
     -4 typical combinations
     1. if P, then Q
         P
         therefore, Q
     modus ponens

     2. if P, then Q
         not P
         no valid conclusion
     invalid inference

     3. if P, then Q
         Q
         no valid conclusion
     invalid inference

     4. if P, then Q
         not Q
         therefore, not P
     modus tollens

Modus ponens and modus tollens are valid inferences.  However, people don’t always
use them correctly.
 -Wason 4 card task

However, the Wason card task also shows that conditional reasoning is difficult, and might
not be the best model of how people reason.  People tend to show the confirmation bias and
only turn over the card/ask the person that confirms the rule.  In other words, the modus
ponens task is much easier than the modus tollens task.  A different theory of human reasoning
involves pragmatic reasoning schemas.
 
 

Decision Making

algorithms vs. heuristics
algorithm –

heuristic –

We often make decisions by using heuristics.  Daniel Kahneman (Nobel Prize for economics, 2002)
and Amos Tversky have done the most research on the heuristics we often use to make judgments
and decisions.

1. representativeness heuristic – the estimate of the probability of an event is determined by one
of two features: how similar the event is to the population of events it came from or whether the event
seems similar to the process that produced it

 gambler's fallacy
 

base rate neglect and stereotyping, conjunction fallacy

2. availability heuristic – estimates are influenced by the ease with which relevant examples can be
remembered.  How available the information is influences how easily it is recalled.

saliency and vividness

    a. anchoring and adjustment heuristic – we make estimates based on numbers in a question. 
        We tend to anchor our responses to a particular number or other figure in a question.

Naturalistic decision making: Discussion of Klein (1999): selections from Sources of
power: How people make decisions.