The streetlight effect, or the drunkard's search principle, is a type of

observational bias Observation is the active acquisition of information from a primary source. In living beings, observation employs the senses. In science, observation can also involve the perception and recording of data via the use of scientific instruments. Th ...

that occurs when people only search for something where it is easiest to look. Both names refer to a well-known joke: The anecdote is attributed to

Nasreddin Nasreddin () or Nasreddin Hodja (other variants include: Mullah Nasreddin Hooja, Nasruddin Hodja, Mullah Nasruddin, Mullah Nasriddin, Khoja Nasriddin) (1208-1285) is a character in the folklore of the Muslim world from Arabia to Central As ...

. According to

Idries Shah Idries Shah (; hi, इदरीस शाह, ps, ادريس شاه, ur, ; 16 June 1924 – 23 November 1996), also known as Idris Shah, né Sayed Idries el-Hashimi (Arabic: سيد إدريس هاشمي) and by the pen name Ark ...

, this tale is used by many Sufis, commenting upon people who seek exotic sources for enlightenment. Outside of the Nasreddin corpus, the anecdote goes back at least to the 1920s, and has been used metaphorically in the

social science Social science is one of the branches of science, devoted to the study of societies and the relationships among individuals within those societies. The term was formerly used to refer to the field of sociology, the original "science of soc ...

s since at least 1964, when

Abraham Kaplan Abraham Kaplan (June 11, 1918 – June 19, 1993) was an American philosopher, known best for being the first philosopher to systematically examine the behavioral sciences in his book ''The Conduct of Inquiry'' (1964). His thinking was influence ...

referred to it as "the principle of the drunkard's search".

Noam Chomsky Avram Noam Chomsky (born December 7, 1928) is an American public intellectual: a linguist, philosopher, cognitive scientist, historian, social critic, and political activist. Sometimes called "the father of modern linguistics", Chomsky is ...

, for instance, uses the tale as a picture of how science operates: "Science is a bit like the joke about the drunk who is looking under a lamppost for a key that he has lost on the other side of the street, because that's where the light is. It has no other choice."

See also

References

Further reading