????事實簡單明了，甚至讓人有些不解：相較于男性，女性上大學的比例更高，而且一旦進入大學校園，她們中途輟學的可能性也更低。美國學士學位持有者中，女大學畢業生現在占據了約60%的比重。

????這是否意味著男生不如女生那般勤勉，求學的決心沒有女生大呢？

????未必如此。相反，這種性別差異的根源似乎在一定程度上與金錢有關：如今，完成一個本科學位越來越需要金錢作為后盾，男性不太愿意背負沉重的債務負擔。一旦大學生所欠的助學貸款達到12,500美元，相較于女性，男性“更容易望而卻步”，而且認為離開學校、開始全職工作才是明智之舉。

????這個發現出自一篇刊發在最近一期《性別與社會》（Gender & Society）雜志上的研究論文：《性別、債務與大學生輟學現象》（Gender, Debt, and Dropping Out of College）。在勞工統計局（the Bureau of Labor Statistics）的資助下，三位來自美國的俄亥俄州立大學（Ohio State University）和太平洋路德大學（Pacific Lutheran University）的教授對1997年至2011年全美青年縱向研究的數據（其中包括對大約9,000名20多歲的青年人的采訪紀要）進行了分析。

????事實證明，勞動力市場長期存在的薪酬差距是激勵女性完成學業的重要因素之一。就短期而言，男性初入職場的薪水并不會因為輟學而減少。另一方面，女性一旦輟學，她們的薪酬馬上就會一落千丈，因為女輟學生剛開始工作時的平均年薪要比男輟學生低6,500美元。

????“女輟學生顯然要面臨更糟糕的就業前景，”作者寫道。“她們更有可能從事薪酬較低的服務類工作，而中途輟學的男生則更有機會在制造業、建筑業和交通運輸業中找到薪酬較高的工作。”

????的確如此，但希望適齡子女讀完大學的家長們或許想強調研究人員更深一層的發現：男輟學生的薪水優勢往往曇花一現。這項研究指出，雖然畢業前離開大學的男生“剛開始不會面臨多大的工資損失，但這種損失隨后就會顯現出來，而且還會與日俱增。邁入中年時，一年下來，擁有學位的男性要比上過大學但沒有獲得學位的男性平均多掙2萬美元。”

????能夠掙錢時不愿背負債務這一事實或許有助于解釋為什么輟學的男生更多，但考上大學的男生比例少于女生這種現象又該如何解釋呢？在一本名為《女性的崛起：受教育程度日益加劇的性別差異及其對美國校園的影響》（The Rise of Women: The Growing Gender Gap in Education and What It Means for American Schools）一書中，哥倫比亞大學（Columbia University）社會學教授托馬斯?迪普雷特和俄亥俄州立大學社會學教授克勞迪婭?布赫曼試圖解釋這個棘手的問題，并給出了不同于傳統看法的答案。

????男孩的成績之所以比女孩差，他們之所以不太喜歡上學，并不是因為女孩天生就比男孩刻苦，也不是因為學校的環境對男孩不夠“有利”——他們寫道。正相反，“我們的研究顯示，男孩在學校表現不佳更多的是與社會對‘陽剛之氣’所確立的規范有關。相較于其他男生，喜歡參加音樂、藝術、戲劇和外語這類課外文化活動的男生更熱衷于學校生活，成績也更好。但這些活動時常受到貶低，說什么缺乏男子氣概。”

????The facts are plain, if puzzling: Not only do women enter college at higher rates than men, but they're less likely to drop out once they get there. Female grads now account for about 60% of U.S. bachelor's degree holders.

????Does that mean men are less studious or committed than women are?

????Not necessarily. Instead, it seems the gender gap's roots are partly financial: Men are less willing to take on the heavy debt loads that are increasingly required to complete a college degree. When they reach the point of owing $12,500 in school loans, men "are more likely to be discouraged" than women -- and to decide it makes sense to leave school and start working full-time.

????That's according to a new study, "Gender, Debt, and Dropping Out of College," published in a recent issue of the journal Gender & Society. The researchers, three professors from Ohio State University and Pacific Lutheran University, analyzed data from a national longitudinal study of youth from 1997 to 2011, funded by the Bureau of Labor Statistics, that included interviews with about 9,000 men and women in their 20s.

????It turns out that persistent wage gaps in the labor market play a big part in motivating women to finish school. In the short term, men who drop out face no financial penalty in their entry-level salaries. Women, on the other hand, pay a steep price right away for dropping out, since female dropouts earn entry-level pay that averages $6,500 a year lower than what their male counterparts earn.

????"Female dropouts simply face worse job prospects," the authors observe. "They are more likely to be employed in lower-paying service work, while men who drop out have more opportunities in higher-paying jobs in manufacturing, construction, and transportation."

????True, but parents of college-age kids may want to emphasize one further finding: Male dropouts' earnings advantages are short-lived. While men who leave college before graduating "don't face a wage penalty early on, the penalty accumulates later," the study notes. "By middle age, men with a college degree earn $20,000 a year more, on average, than men with some college but no degree."

????An unwillingness to pile on debt when they could be making money may explain why more men quit school, but what accounts for the fact that fewer men start college in the first place? In a new book called The Rise of Women: The Growing Gender Gap in Education and What It Means for American Schools, Thomas A. DiPrete and Claudia Buchmann, sociology professors at Columbia and Ohio State, respectively, tackle that thorny question -- and come up with answers that challenge conventional wisdom.

????Boys get lower grades than girls, and report liking school less, not because girls are naturally more studious or because schools aren't "boy-friendly" enough, they write. Rather, "our research shows that boys' underperformance in school has more to do with society's norms about masculinity … Boys involved in extracurricular cultural activities such as music, art, drama, and foreign languages report higher levels of school engagement and get better grades than other boys. But these activities are often denigrated as un-masculine."