Link to source: http://timvangelder.com/2010/10/20/how-are-critical-thinking-skills-acquired-five-perspectives/
Previous LW discussion of argument mapping: Argument Maps Improve Critical Thinking, Debate tools: an experience report

How are critical thinking skills acquired? Five perspectives: Tim van Gelder discusses acquisition of critical thinking skills, suggesting several theories of skill acquisition that don't work, and one with which he and hundreds of his students have had significant success.

In our work in the Reason Project at the University of Melbourne we refined the Practice perspective into what we called the Quality (or Deliberate) Practice Hypothesis.   This was based on the foundational work of Ericsson and others who have shown that skill acquisition in general depends on extensive quality practice.  We conjectured that this would also be true of critical thinking; i.e. critical thinking skills would be (best) acquired by doing lots and lots of good-quality practice on a wide range of real (or realistic) critical thinking problems.   To improve the quality of practice we developed a training program based around the use of argument mapping, resulting in what has been called the LAMP (Lots of Argument Mapping) approach.   In a series of rigorous (or rather, as-rigorous-as-possible-under-the-circumstances) studies involving pre-, post- and follow-up testing using a variety of tests, and setting our results in the context of a meta-analysis of hundreds of other studies of critical thinking gains, we were able to establish that critical thinking skills gains could be dramatically accelerated, with students reliably improving 7-8 times faster, over one semester, than they would otherwise have done just as university students.   (For some of the detail on the Quality Practice hypothesis and our studies, see this paper, and this chapter.)

LW has been introduced to argument mapping before.