Editing Gambler's fallacy (section)

===Variations===
Some researchers believe that it is possible to define two types of gambler's fallacy: type&nbsp;one and type&nbsp;two. Type&nbsp;one is the classic gambler's fallacy, where individuals believe that a particular outcome is due after a long streak of another outcome. Type&nbsp;two gambler's fallacy, as defined by Gideon Keren and Charles Lewis, occurs when a gambler underestimates how many observations are needed to detect a favorable outcome, such as watching a roulette wheel for a length of time and then betting on the numbers that appear most often. For events with a high degree of randomness, detecting a bias that will lead to a favorable outcome takes an impractically large amount of time and is very difficult, if not impossible, to do.<ref name="KerenLewis1994">{{cite journal|last1=Keren|first1=Gideon|last2=Lewis|first2=Charles|title=The Two Fallacies of Gamblers: Type I and Type II|journal=Organizational Behavior and Human Decision Processes|volume=60|issue=1|year=1994|pages=75–89|issn=0749-5978|doi=10.1006/obhd.1994.1075}}</ref> The two types differ in that type&nbsp;one wrongly assumes that gambling conditions are fair and perfect, while type&nbsp;two assumes that the conditions are biased, and that this bias can be detected after a certain amount of time.

Another variety, known as the retrospective gambler's fallacy, occurs when individuals judge that a seemingly rare event must come from a longer sequence than a more common event does. The belief that an imaginary sequence of die rolls is more than three times as long when a set of three sixes is observed as opposed to when there are only two sixes. This effect can be observed in isolated instances, or even sequentially. Another example would involve hearing that a teenager has [[unprotected sex]] and becomes pregnant on a given night, and concluding that she has been engaging in unprotected sex for longer than if we hear she had unprotected sex but did not become pregnant, when the probability of becoming pregnant as a result of each intercourse is independent of the amount of prior intercourse.<ref>{{cite journal | last1 = Oppenheimer | first1 = D. M. | last2 = Monin | first2 = B. | year = 2009 | title = The retrospective gambler's fallacy: Unlikely events, constructing the past, and multiple universes | journal = Judgment and Decision Making | volume = 4 | issue = 5 | pages = 326–334 | doi = 10.1017/S1930297500001170 | s2cid = 18859806 | doi-access = free }}</ref>