8/9/2019 Deductive Reasoning vs Inductive Reasoning Reseach

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Deductive reasoning is a basic form of valid reasoning. Deductive reasoning, or

deduction, starts out with a general statement, or hypothesis, and examines the

possibilities to reach a specific, logical conclusion. The scientific method uses deduction

to test hypotheses and theories.

In deductive reasoning, if something is true of a class of things in general, it is also true

for all members of that class. For example, "All men are mortal. arold is a man.

Therefore, arold is mortal." For deductive reasoning to be sound, the hypothesis must

be correct. It is assumed that the premises, "All men are mortal" and "arold is a man"

are true. Therefore, the conclusion is logical and true.

It!s possible to come to a logical conclusion even if the generaliation is not true. If the

generaliation is wrong, the conclusion may be logical, but it may also be untrue. For

example, the argument, "All bald men are grandfathers. arold is bald. Therefore,arold is a grandfather," is valid logically but it is untrue because the original statement

is false.

Inductive reasoning

Inductive reasoning is the opposite of deductive reasoning. Inductive reasoning ma#es

broad generaliations from specific observations. $ven if all of the premises are true in

a statement, inductive reasoning allows for the conclusion to be false. ere%s an

example& "arold is a grandfather. arold is bald. Therefore, all grandfathers are bald."

The conclusion does not follow logically from the statements.

Inductive reasoning has its place in the scientific method. 'cientists use it to

form hypotheses and theories. Deductive reasoning allows them to apply the theories to

specific situations.

Inductive Reasoning

Inductive reasoning is the more common way that scientists conduct experiments. 'cientists have an

idea of something to study more in depth. Then they go and collect data through experiments,

observations or surveys. (ith all of the data in hand, they analye it to draw out conclusions.

Inductive reasoning is about collecting data and seeing what patterns or meaning can be extracted. A

researcher, let!s say you in this example, was ta#ing a test and noticed that this fly #ept buing around.

It bued around your head and it was distracting you. 'o you wonder if noise distraction has any effect

on test ta#ing. )ou will then set up an experiment involving *++ people ta#ing a test with some

noisema#er in the bac#ground. The people will be divided into five groups of +, and each group will

have a different level of noise, from -uiet to obnoxiously loud.

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 After all five groups have completed the tests you will compare their different scores to see if there was

a difference. If the scores typically grew steadily worse as the noise increased, then you could draw a

conclusion that as distractions increase, test scores will generally decrease. If, on the other hand, the

maority of their scores increased with the noise, then you would ma#e the correlation that as distraction

increases, test scores will generally increase. To reiterate, inductive reasoning draws conclusions from

evidence.

Deductive Reasoning

Deductive reasoning and methodology is not as common as inductive reasoning with psychological

scientists. Deductive reasoning usually happens when a researcher observes something and believes it

to be a common response. The researcher would then develop a theory or conclusion and then wor# to

find evidence that supports or dismisses it. The reason this type of reasoning is not as commonly used

as inductive reasoning is the ris# of only loo#ing for research that supports your conclusion. It!s all

scientific, but it has a higher probability of going awry.

Deductive reasoning wor#s from the more general to the more specific.

'ometimes this is informally called a "top/down" approach. (e might

begin with thin#ing up a theory about our topic of interest. (e then

narrow that down into more specifichypotheses that we can test. (e

narrow down even further when we collect observations to address the

hypotheses. This ultimately leads us to be able to test the hypotheses

with specific data // a confirmation 0or not1 of our original theories.

Inductive reasoning wor#s the other way, moving from specific

observations to broader generaliations and theories. Informally, we

sometimes call this a "bottom up" approach 0please note that it!s "bottom

up" and not  "bottomsup" which is the #ind of thing the bartender says to

customers when he!s trying to close for the night21. In inductive

reasoning, we begin with specific observations and measures, begin to

detect patterns and regularities, formulate some tentative hypotheses

that we can explore, and finally end up developing some general

conclusions or theories.

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These two methods of

reasoning have a very

different "feel" to them

when you!re conducting

research. Inductive

reasoning, by its very

nature, is more open/

ended and exploratory,

especially at the beginning. Deductive reasoning is more narrow in

nature and is concerned with testing or confirming hypotheses. $ven

though a particular study may loo# li#e it!s purely deductive 0e.g., an

experiment designed to test the hypothesied effects of some treatment

on some outcome1, most social research involves both inductive and

deductive reasoning processes at some time in the proect. In fact, it

doesn!t ta#e a roc#et scientist to see that we could assemble the two

graphs above into a single circular one that continually cycles from

theories down to observations and bac# up again to theories. $ven in the

most constrained experiment, the researchers may observe patterns in

the data that lead them to develop new theories.