In The Chronicle of Higher Education, a recent article talked about a study that found cold-calling on undergraduate students increased the students' voluntary participation over the semester. The article referenced that like any other skill, students need practice – practice in the skill of class participation. The link to the article is here: Why Cold-Calling on Students Works. (Of course, the article also made a negative reference to the law school use of cold-calling and included a link to the well-known clip from Paperchase in which Kingsfield terrorizes Hart.)
For a more positive look at law school Socratic Method, see my post here: Turning the Socratic Method into a Positive Experience. (Amy Jarmon)