Why Aren't Students Studying?

According to recent research by UCSB economists Philip Babcock and Mindy Marks, the amount of time spent by college students studying has dropped:

1961: 24 hours/week

2009: 14 hours/week

Moreover, the total time spend on school (attending classes + studying) has likewise diminished:

1961: 40 hours/week

2009: 27 hours/week

What's gong on here?

As every college counsellor tells students, they should expect to be responsible for studying 3 hours for every hour in class. At many schools, students are considered full-time with as few as 12 units/week, which translates roughly (not counting labs) as 12 classroom hours per week. At 12 hours/week, the 3x multiple works out to only 36 hours. Added to 12 hours, this means a total time spend on school of only 48 hours/week.

This squares with my experiencing teaching undergraduates. Assign reading, and 90% will not do it. Test on this required reading, and still 90% will not do it. I get the sense, while grading midterms, that the majority of the class has spend less than one hour preparing for the exam. There are good students, students who diligently study, even in freshmen classes. But they are quite the rarity.

It seems to be the diminished number of hours actually spent studying may have a lot to do with declining academic standards, which are hidden only the band-aid of grade inflation. There is something seriously wrong going on here.