Heuristic literacy--an individual's capacity to use heuristic vocabulary in discourse and to apply the selected heuristics to solution of routine and non-routine mathematical tasks--was indirectly promoted in a controlled five-month classroom experiment with Israeli 8th grade students (N = 92). The experiment achieved a moderate mean effect size, which is in line with some previous research on heuristics. The novel result of the study is that those students of the experimental group who were below sample average at the beginning of the experiment benefited from the heuristically-oriented intervention significantly more than the rest of the students. It is argued here that this is, in part, due to communicational aspects of the intervention. (Contains 3 tables and 2 figures.)