To prevent this streamline of students, many of them minorities, from entering the juvenile justice system, schools need to reevaluate their zero-tolerance policies by adding discretion and alternative forms of punishments.

*  Grades tend to diminish students’ interest in whatever they’re learning.  A “grading orientation” and a “learning orientation” have been shown to be inversely related and, as far as I can tell, every study that has ever investigated the impact on intrinsic motivation of receiving grades (or instructions that emphasize the importance of getting good grades) has found a negative effect. *  Grades create a preference for the easiest possible task.  Impress upon students that what they’re doing will count toward their grade, and their response will likely be to avoid taking any unnecessary intellectual risks.  They’ll choose a shorter book, or a project on a familiar topic, in order to minimize the chance of doing poorly — not because they’re “unmotivated” but because they’re rational.  They’re responding to adults who, by telling them the goal is to get a good mark, have sent the message that success matters more than learning. *  Grades tend to reduce the quality of students’ thinking.  They may skim books for what they’ll “need to know.” They’re less likely to wonder, say, “How can we be sure that’s true?” than to ask “Is this going to be on the test?”  In one experiment, students told they’d be graded on how well they learned a social studies lesson had more trouble understanding the main point of the text than did students who were told that no grades would be involved.  Even on a measure of rote recall, the graded group remembered fewer facts a week later (Grolnick and Ryan, 1987).