Are there reliable qualitative individual differences in cognition? Probably not

Rouder and Haaf (2021, this issue) propose a focus shift toward qualitative individual differences in cognition and present a research toolkit for doing so. In this invited commentary, I will argue that the observation of qualitative individual differences may be no more than an indicator that more theoretical and empirical work needs to be done to identify the mechanisms and abilities underlying these individual differences in directionality. I will then move on to discuss how the toolkit can be used though to investigate one of the currently most central current topics in cognitive differential psychology, that is, the question over the existence of true quantitative individual differences in attentional control experimental effects. I conclude that, while highly valuable, no toolkit can save us from facing the challenging theoretical and conceptual questions in this area.