thinking and reasoning 6 Flashcards
what is reasoning ?
-philosphers and psychologists have long been concerned with the nature of human thinking
- recently developed following the cogntive revolution
-Reasoning, decision making and problem solving= separate areas
- the study of reasoning has altered the ways in which logic is considered as a part of thinking
what did johnson- laird and byrne suggest?
deductive reasoning was central to activities such as: Formulating plans, determine the consequences ofhypotheses, to interpret and formulate instructions, topursue arguments and negotiations
an important distinction can be made between deduction and induction
what is inductive reasoning?
it increases semantic information
often yields plausible conditions, but they are not necessarily true
more from our thinking than is actually presented to us
The burglary was committed at 8 - 8.30
Adam was seen running from the house at 8.15
We may conclude that Adam was involved in theburglary - but it is notnecessarilythe case
We add our knowledge of burglaries to the informationpresented
what is deductive reasoning?
reasoning where conclusions are necessarily true
always truth perserving
does not involve use of any additional knowledge but requires only info presented in premises
making the implicit become explicit
not adding anything from our ‘world knowledge’
info to draw conc was already present
judge validity of a conc or to draw their own conc
what is a syllogism?
consists of two premises and a conc and uses quantity terms like: all, some, none
valid argument form- truth preserving- if premises are true then the conclusion will also be true
- e.g. all artists are beekeepers- all beekeepers are chemists- therefore all artists are chemists
what is the distinction between truth and validity?
validity refers to the form of the argument rather than the content of it
All A are B
Some B are C
Some A are C
This argument is invalid (the ‘A’s that are ‘B’s may be totally separate from the ‘B’s that are C’s)
Part of the problemseems to arise from theassumptionthat All Aare B means that AllBareA
If this happens thenreasoning might beaccurate but on thewrong material
what is a belief bias?
One notable aspect about human reasoning is that weareseducedby the believability of conclusions ratherthan their validity
evans, bartson and pollard show clear evidence of belief bias
what is propositional reasoning?
- a formal system of logic
- symbols are used in place of sentences- p and q
- conc are reached via the application of ‘logical operators’ or connectives and the rules of logic
- logical operators= not, and, or, if, then, if and only then
what is conditional reasoning?
one aspect of propositional reasoning
reasoning after the operator- if.. then
the meaning of words used in logic is often different from their meaning in natural everyday usage
difference= things are only ever true or false in propositional logic- there is no inbetween
the differences may have an effect on how people reason and why people often make errors in reasoning
what are inferences in conditional reasoning?
- 4 inferences traditionally associated with conditionals
ideas from logic tell us whether these inferences are valid or not
we use formal logic to assess whether p’s reasoning is accurate or not
logic is the normative system psychologists use
what is modus ponens?
If p then q
p
Therefore, q
valid inference form- truth preserving- always yield true conc from true premises
what is modus tollens?
If p then q
not-q
Therefore, not-p
valid- truth preserving
valid inferences
- Modus tollens= harder- a series of rules must be applied, the longer the derivation, the more likely that errors will occur – complex ideas like making assumptions and testing them via mental proofs- there is no single rule for modus tollens = difficulty
what is affirming the consequent?
Formally we could express this as
If p then q
q
Therefore, p
not valid form
what is denial of the antecedent?
If p then q
not-p
Therefore, not-q
not valid
what is assessing human performance?
when assessing human performance we can use:
- generation tasks
- evaluation tasks
- some form of logical problem
Boole (1854) stated that the the laws of logic are the laws of thought
what is reasoning performance?
Evans, Newstead and Byrne (1993) reviewed many studies and reported similar endorsement rates
what is theories of reasoning ?
-Any proposed theory of reasoning will need to be able to account for the pattern of performance that has been observed
We have seen that in the psychology of reasoning there are a number of factors that a theory must be able to account for:
Competence
Errors (biases)
A number of studies show an effect of content
what are abstract rule theories?
numerous versions of mental logic and they are not all the same.
people are rational- we have some rules of logic or specialised processes for logical thinking
we make mistakes because because we misunderstand or misrepresent the task (Henle, 1962) we lack the necessary rules of logic resource limitations.
what is Braine’s abstract rule theory?
- comprehension component
- first stage- the premises must be converted into a mental reoresentation that can be held in working memory
-application of rule schemas - incompatibility rules
-check for inconsistent or contradictory reasoning
what are issues with the theory?
- incomplete- states little about comprehension component, predictions are not always clear
- Context and content have a dramatic effect on reasoning, and this is difficult to reconcile with a theory that proposes abstract, content free rules of reasoning, this includes belief bias
- ignores individual differences
-Propositional reasoning is only one type of reasoning - it isunclear whether abstract rules can account for other types
-There is ultimately no compelling evidence that people use any type of logic when attempting to solve deductive problems
-Numerous alternative explanations – mental models, information gain, pragmatic reasoning schemas
