In 1955, a black woman named Rosa Parks refused to give up her bus seat for a white man in Montgomery, Alabama. She was arrested and charged, and the events that followed made her a civil-rights icon.
Interestingly, though it's become the most famous, her case was neither unique nor the first. Many others had already been arrested for the same reason. So why did Parks's arrest spark a bus boycott that lasted over a year?
First of all, Rosa Parks was especially well-liked in the community and had an unusually broad array of friends. She belonged to many clubs and societies and was closely connected to people, from professors to field hands. For instance, she served as the secretary of the local NAACP chapter, was deeply involved in a youth organization at a Lutheran church close to where she lived, and spent her spare time providing poor families with dressmaking services, all while still finding time to make gown alterations for young debutantes from wealthy white families. She was so active in her community that her husband sometimes said she ate at potlucks more often than at home.
Parks had what is known in sociology studies as strong ties – first-hand relationships with plenty of people from across different social segments of her community. These ties not only bailed her out of jail; they spread the word of her arrest throughout Montgomery's social strata, thus sparking the bus boycott.
But her friends alone could not have sustained a lengthy boycott. Enter peer pressure. In addition to strong ties, social spheres also comprise weak ties, meaning acquaintances rather than friends. It is mostly via weak ties that peer pressure is exerted. When a person's larger network of friends and acquaintances supports a movement, it is harder to opt-out.
Eventually, the black community's commitment to the boycott began waning as city officials began introducing new carpooling rules to make life without buses increasingly difficult. The final component was added: a speech by Dr. Martin Luther King Jr. advocating nonviolence and asking participants to embrace and forgive their oppressors. People began to form new habits based on this message, such as independently organizing church meetings and peaceful protests. They moved a self-propelling force.
