Key graf:<p>What makes people capable of this kind of activism? The Stanford sociologist Doug McAdam compared the Freedom Summer dropouts with the participants who stayed, and discovered that the key difference wasn’t, as might be expected, ideological fervor. "All of the applicants--participants and withdrawals alike--emerge as highly committed, articulate supporters of the goals and values of the summer program," he concluded. What mattered more was an applicant’s degree of personal connection to the civil-rights movement. All the volunteers were required to provide a list of personal contacts--the people they wanted kept apprised of their activities--and participants were far more likely than dropouts to have close friends who were also going to Mississippi. High-risk activism, McAdam concluded, is a "strong-tie" phenomenon.