The model estimates that events that occur between the ages of 14 and 24 are the most important in determining an individual's political attitudes, though those attitudes continue to change after age 24. A separate model developed by Professor Dan Hopkins found that the political affiliation of a given individual was strongly affected by the popularity of presidents when that individual turned 18 years old. Osborne et al. use the theory to partially explain the decline of the Democratic Party and the New Deal coalition in the South. According to their theory, the events of the civil rights movement were extremely unpopular among white Southerners and the support of national Democratic leadership for the civil rights movement alienated white Southerners from the party. While older Southern voters resisted changes to their political affiliations and attitudes, younger voters moved to the Republican Party. As, older, Democratic voters died out, the Republican Party became the dominant party in the South. The impressionable years hypothesis has also been explored in other countries. A 2002 study by James Tilley found that individuals in the United Kingdom who came of age during the 1920s, 1950s, and 1980s tended to more strongly support the Conservative Party, which was dominant during those decades. A 2004 study in Algeria found that most generations were not strongly affected by the circumstances of their youth, with some exceptions regarding certain attitudes in certain generations.