Guskey and Bailey (2001, p. 18)

"Around the middle school years and sometimes earlier, students' perceptions of grades begin to change.  Although the reasons for this change are uncertain, it seems likely due to teachers' shifting emphasis from the formative aspects of grades to their summative functions.  As a result, students no longer see grades as a source of feedback to guide improvements in their learning.  Instead, they regard grades as the major commodity teachers and schools have to offer in exchange for their performance.  This change brings a slow but steady shift in students' focus away from learning and toward what they must do to obtain the grade commodity."  
Take aways:

  1. Yet another reason not to grade formative assessments. 
  2. Who owns the grades in a classroom?  In my earlier years of teaching, I believe that I did.  Students could dig themselves into a hole, but it was difficult to fill it back in. 
  3. I tend to agree that the system creates grade craving for students.  Somewhere in school, students begin playing the "points game" and it becomes increasingly difficult, but not impossible, to undo this craving as a given student progresses through the K-12 system.