Clustering-Illusion

The clustering illusion (of English. Cluster " cluster ") is the natural human tendency to see patterns even where they do not exist. Since the Ramsey theory ( a branch of mathematics of ) According to a complete mathematical disorder is impossible in a physical system, the clustering illusion can also be described as the human capacity to attribute certain patterns that occur inevitably in sufficiently large amounts of data meanings.

For example, keep most people the sequence " OXXXOXXXOXXOOOXOOXXOO " ( Gilovich, 1993) for non- random, when in fact it has many features that one would expect in a true random data stream, approximately the same frequency of the two events and the fact that the number which directly adjoins the same symbols for each of the two symbols is the same. Apparently, the viewer of such sequences expect a greater variety, as it corresponds to the statistical prediction. In fact, in short trials seemingly non-random series are quite likely.

Another example are the questions of the SAT (an important multiple-choice entrance test for U.S. students). They are chosen by the test developers aware that no longer exist the same series answers because the student population according to experience such series as unlikely. The specimens could feel compelled to wrong answers, just to avoid a series.

Whether a record contains patterns or not, can often be determined with statistical analysis tools or even computer-based cryptanalysis. For example, the sequence " XXOXOXOOOXOXOOOXOX " contains a recognizable pattern: the position of the X corresponds to the prime numbers from 2 and the O the non-primes. Computer programs for data compression are suitable to detect in the data pattern, and be replaced by alternative links, of which the proper algorithm can recover the original data. Large amounts of data that contain non-random clusters, can be compressed usually good. Data without real clusters or patterns, however, are rather poorly or not compressible.

The clustering illusion is an essential element of a well-known study by Thomas Gilovich, Robert Vallone, and Amos Tversky. Their conclusion exposed the hot hand as purely coincidental - denotes an expression of the basketball, the alleged winning streaks of the launcher.

As mistake the clustering illusion may end at logical reasoning in a target error. It may also be the cause of the gambler's fallacy. See also representativeness heuristic.