  The set of polarizing force-identification (PFI) questions in the FCI
consists of six items all basically asking only one question: the set of forces
acting on a given body. Although it may sound trivial, these questions are
among the most challenging in the FCI. In this work involving 163 students, we
investigate the correlation between student performance on the set of PFI
questions and the Cognitive Reflection Test. We find that for both scores in
the FCI as a whole and in the PFI questions, the range of values of the Pearson
coefficient at 95\% confidence interval, is suggestive that cognitive
reflection may be one of the contributing factors in the student performance in
the FCI. This is consistent with the idea that high level of cognitive
reflection may help in eliminating seemingly valid choices (misconceptions) in
the FCI that are intuitive from everyday experience or "common sense" but
otherwise misleading. The ability to activate System 2 in Dual Process Theory,
whether from System 1 or right after reading a physics problem, may contribute
in narrowing down the set of prospective valid answers in a given physics
problem. Complementary to cognitive reflection are other factors associated
with deep understanding of physics whose effects are expected to become more
evident with the level of difficulty of a set of physics problems. Given two
students with the same level of cognitive reflection, the one with deeper
understanding of physics is more likely to get the correct answer. In our
analysis, the range of correlation coefficient for the set of PFI questions is
downshifted with respect to that for the FCI as a whole. This may be attributed
to the more challenging nature of the latter compared to a significant fraction
of the remaining questions in the former.
