Paradigm constraints on moral decision-making dynamics

Investigating decision making with two-alternative forced choice (2AFC) tasks may artificially constrain decisions, especially in the moral domain where we may want to express nuance. We aimed at examining whether paradigm constraints—that is, binary (as in 2AFC tasks) versus continuous response mode—constrained early decision-making dynamics, as traceable in mouse movements. In the moral domain, long sentences are often used, and we therefore developed a new mouse-tracking design adapted to long-to-process stimuli while also introducing mouse-tracking-compatible continuous response scales. Two preregistered studies, with adapted (Study 1) and newly designed (Study 2) mouse-tracking paradigms tested how trajectories differed between response modes from an early stage onwards. Overall, findings provide evidence consistent with hypothesis, ruling out alternative explanations in terms of motor planning, hence questioning the prevalence of 2AFC tasks in decision-making research. Discussion further focuses on paradigmatic challenges addressed by the present research and basic contributions regarding the bidirectional influences between ongoing actions and decisions.