Question: Who was a member of an international organization that was formed in 1957?

Context paragraphs:
International Organization for Biological Control: The International Organization for Biological and Integrated Control of Noxious Animals and Plants is usually referred to as the International Organization for Biological Control or IOBC.  It is a professional organization affiliated with the International Union of Biological Sciences (IUBS) and aims to be an effective advocate for biological control, integrated pest management (IPM) and integrated production (IP).

Bureau of International Organization Affairs: The Bureau of International Organization Affairs (IO) is a bureau in the United States Department of State that creates and executes U.S. policy in the United Nations and other international organizations.  It is headed by the Assistant Secretary of State for International Organization Affairs.

Situationist International: The Situationist International (SI) was an international organization of social revolutionaries made up of avant-garde artists, intellectuals, and political theorists, prominent in Europe from its formation in 1957 to its dissolution in 1972.

Mister International: Mister International is an annual male beauty pageant founded in 2006.  It is owned and organized by the Mister International Organization which also organizes the annual Mister Singapore pageant.  Along with its rival contest, Mister World, this pageant is one of the two largest male beauty pageants in the world in terms of the number of national-level competitions.  Since the first edition, 76 countries have sent their representative to this pageant, with an annual average of 31 contestants.  Mister International Organization licenses local organizations that wish to select the Mister International contestant for their country, and approves the selection method for national contestants.

International Journal of Psychophysiology: The International Journal of Psychophysiology is a peer-reviewed official journal of the International Organization of Psychophysiology The subjects covered by the journal includes sensation and perception, evolution and development of behaviour, interhemispheric relations, learning and memory, sleep, stress, motivation and emotion, aggression and defence, information processing, psychopharmacology and psychophysiological disorders.  It is currently published by the International Organization of Psychophysiology, Elsevier and edited by Michael J. Larson (Brigham Young University).

Ninety-Nines: The Ninety-Nines: International Organization of Women Pilots, also known as 99s, is an international organization for female pilots that provides professional opportunities to women in aviation.  The organization was founded on November 2, 1929, at Curtiss Field, Valley Stream, New York, by 26 licensed women pilots for the mutual support and advancement of women pilots.  Amelia Earhart had called for a meeting of female pilots in 1929 following the Women's Air Derby.  All 117 women pilots licensed at the time were invited, and the group is named for the 99 of them who attended the meeting or expressed an interest in forming a group.

The Movement of the Free Spirit: The Movement of the Free Spirit: General Considerations and Firsthand Testimony Concerning Some Brief Flowerings of Life in the Middle Ages, the Renaissance and, Incidentally, Our Own Time (French: "Le mouvement du Libre-Esprit" ) is a 1986 book by former Situationist International (SI) member Raoul Vaneigem published in English in 1998 by Zone Books.

Bureau for United Nations Affairs: The Bureau for United Nations Affairs is a former name of the Bureau of International Organization Affairs, a division of the United States Department of State.  The Bureau was established on June 24, 1949, but its name was changed to the Bureau for United Nations Affairs four months later.  In 1954 the bureau's name was changed back to the Bureau of International Organization Affairs.  Richard J. Kerry, the father of US Senator John Kerry, worked for the bureau.  Today, the division of the State Department that handles relations with the United Nations is the Bureau of International Organization Affairs.

International Organization for Migration: The International Organization for Migration (IOM) is an intergovernmental organization that provides services and advice concerning migration to governments and migrants, including internally displaced persons, refugees, and migrant workers.  As of September 2016, it became a related organization of the United Nations.  It was initially established in 1951 as the Intergovernmental Committee for European Migration (ICEM) to help resettle people displaced by World War II.  As of June 2016, the International Organization for Migration has 166 member states and 8 observer states.

International Organization: International Organization is a quarterly peer-reviewed academic journal that covers the entire field of international affairs.  It was established in 1947 and is published by Cambridge University Press on behalf of the International Organization Foundation.  The editor-in-chief is Jon Pevehouse (University of Wisconsin–Madison).

Supporting paragraphs: The Movement of the Free Spirit Situationist International
Answer: Raoul Vaneigem