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This is subtle but important distinction. It is absolutely possible to do a confirming experiment that can give misleading results. There is a nice explanation in the wikipedia article under "Confirmation Bias". http://en.wikipedia.org/wiki/Confirmation_bias A striking example is the (2,4,6) test. From wikipedia: "Wason's research on hypothesis-testing
The term "confirmation bias" was coined by English psychologist Peter Wason.[66] For an experiment published in 1960, he challenged participants to identify a rule applying to triples of numbers. At the outset, they were told that (2,4,6) fits the rule. Participants could generate their own triples and the experimenter told them whether or not each triple conformed to the rule.[67][68]
While the actual rule was simply "any ascending sequence", the participants had a great deal of difficulty in finding it, often announcing rules that were far more specific, such as "the middle number is the average of the first and last".[67] The participants seemed to test only positive examples—triples that obeyed their hypothesized rule. For example, if they thought the rule was, "Each number is two greater than its predecessor", they would offer a triple that fit this rule, such as (11,13,15) rather than a triple that violates it, such as (11,12,19).[69]
Wason accepted falsificationism, according to which a scientific test of a hypothesis is a serious attempt to falsify it. He interpreted his results as showing a preference for confirmation over falsification, hence the term "confirmation bias".[Note 4][70] Wason also used confirmation bias to explain the results of his selection task experiment.[71] In this task, participants are given partial information about a set of objects, and have to specify what further information they would need to tell whether or not a conditional rule ("If A, then B") applies. It has been found repeatedly that people perform badly on various forms of this test, in most cases ignoring information that could potentially refute the rule." |