The present study is based on a large cross‐cultural study, which showed that a systemizing cognition type has a high impact on motivation to learn science, while the impact of gender is only indirect thorough systemizing. The present study uses the same structural equation model as in the cross‐cultural study and separately tests it for physics, chemistry, and biology. The model was confirmed for physics and chemistry, but not for biology. This is interpreted as empirical evidence for a cognitive difference between the learning of hard sciences (like physics and chemistry) and life sciences (like biology) that reflects an epistemological difference between ordered (linear) and complex (non‐linear) systems. It is concluded that a more prominent inclusion of complex issues into science teaching could motivate low and average systemizers, independent of their gender, for science learning, that is, could be a key to science for all. Thus, there is a mutual benefit between important 21st century's issues of science teaching and the need to foster students’ motivation to learn science. © 2017 Wiley Periodicals, Inc. J Res Sci Teach 9999:XX–XX, 2017