Most modern research on gangs has focused on the thesis of class struggle following the work of Walter B. Miller and Irving Spergel. In this body of work The Gaylords are cited as the prime example of an American gang that is neither Black nor Hispanic. Some researchers have focused on ethnic factors. Frederic Thrasher, who was a pioneer of gang research, identified "demoralization" as a standard characteristic of gangs. John Hagedorn has argued that this is one of three concepts that shed light on patterns of organization in oppressed racial, religious and ethnic groups (the other two are Manuel Castells' theory of "resistance identity and Derrick Bell's work on the permanence of racism).