When Less Is Less: Solving Multiple Simple Problems Is Not Complex Problem Solving-A comment on Greiff et al. (2015)

In this commentary, we critically review the study of Greiff, Stadler, Sonnleitner, Wolff, and Martin, "Sometimes less is more: Comparing the validity of complex problem solving measures" (Intelligence, 2015, 50, 100-113). The main conclusion of Greiff et al. that the "multiple complex systems" (MCS) approach to measuring complex problem-solving ability possesses superior validity compared to classical microworld scenarios ("less is more") seems to be an overgeneralization based on inappropriate analysis and selective interpretation of results. In its original form, MCS is a useful tool for investigating specific aspects of problem solving within dynamic systems. However, its value as an instrument for the assessment of complex problem solving ability remains limited.