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A blind or blinded experiment is an experiment in which information about the test is kept from the participant until after the test.〔Oxford English Dictionary, 2nd ed.〕 Bias may be intentional or unconscious. If both tester and subject are blinded, the trial is a double-blind experiment. Blind testing is used wherever items are to be compared without influences from testers' preferences or expectations, for example in clinical trials to evaluate the effectiveness of medicinal drugs and procedures without placebo effect, nocebo effect, observer bias, or conscious deception; and comparative testing of commercial products to objectively assess user preferences without being influenced by branding and other properties not being tested. Blinding can be imposed on researchers, technicians, subjects, and funders. The opposite of a blind trial is an open trial. Blind experiments are an important tool of the scientific method, in many fields of research—medicine, psychology and the social sciences, natural sciences such as physics and biology, applied sciences such as market research, and many others. In some disciplines, such as medicinal drug testing, blind experiments are considered essential. In some cases, while blind experiments would be useful, they are impractical or unethical; an example is in the field of developmental psychology: although it would be informative to raise children under arbitrary experimental conditions, such as on a remote island with a fabricated enculturation, it is obviously a violation of ethics and human rights. The terms blind (adjective) or to blind (transitive verb) when used in this sense are figurative extensions of the literal idea of blindfolding someone. The terms masked or to mask may be used for the same concept; this is commonly the case in ophthalmology, where the word 'blind' is often used in the literal sense. ==History== The French Academy of Sciences originated the first recorded blind experiments in 1784: the Academy set up a commission to investigate the claims of animal magnetism proposed by Franz Mesmer. Headed by Benjamin Franklin and Antoine Lavoisier, the commission carried out experiments asking mesmerists to identify objects that had previously been filled with "vital fluid", including trees and flasks of water. The subjects were unable to do so. The commission went on to examine claims involving the curing of "mesmerized" patients. These patients showed signs of improved health, but the commission attributed this to the fact that these patients believed they would get better - the first scientific suggestion of the now well-known placebo effect. In 1799 the British chemist Humphry Davy performed another early blind experiment. In studying the effects of nitrous oxide (laughing gas) on human physiology, Davy deliberately did not tell his subjects what concentration of the gas they were breathing, or whether they were breathing ordinary air.〔〔http://www.pharmaclinicalresearch.com/〕 Blind experiments went on to be used outside of purely scientific settings. In 1817, a committee of scientists and musicians compared a Stradivarius violin to one with a guitar-like design made by the naval engineer François Chanot. A well-known violinist played each instrument while the committee listened in the next room to avoid prejudice.〔 〕 One of the first essays advocating a blinded approach to experiments in general came from Claude Bernard in the latter half of the 19th century, who recommended splitting any scientific experiment between the theorist who conceives the experiment and a naive (and preferably uneducated) observer who registers the results without foreknowledge of the theory or hypothesis being tested. This suggestion contrasted starkly with the prevalent Enlightenment-era attitude that scientific observation can only be objectively valid when undertaken by a well-educated, informed scientist.〔 〕 Double-blind methods came into especial prominence in the mid-20th century.〔 〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Blind experiment」の詳細全文を読む スポンサード リンク
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