The earliest studies of political behavior in Western Europe and North America established gender as one of the standard variables routinely used to explain levels of electoral turnout, party membership, and protest activism, alongside the most powerful predictors of age and education. Based on a seven-nation comparative study of different dimensions of political participation conducted during the 1970s, ranging from voting turnout to party membership, contact activity, and community organizing, Verba, Nie, and Kim concluded: “In all societies for which we have data, sex is related to political activity; men are more active than women.” During the same era, Barnes and colleagues (1979) found that women were also less engaged in unconventional forms of participation, such as strikes and demonstrations. The literature suggested that the well-established gender gap in many common forms of political participation remained evident during the 1980s and early 1990s in many countries around the world – even in the United States and Western Europe, where women have been enfranchised with full citizenship rights for decades. Nevertheless, given all the other substantial changes in women's and men's lives that have already been documented, we would expect to find evidence that some of these gender differences have gradually diminished or even disappeared over time, with women becoming more active, especially among the younger generations in affluent modern societies.