Decisions among shifting choice alternatives reveal option-general representations of evidence.

Dynamic models of choice typically describe the decision-making process in terms of the degree or balance of support for available response options. However, these alternative-specific representations of support are liable to fail when the available options change during the course of a decision. We suggest that people may use alternative-general representations, where stimulus feature information-rather than option-specific support-is accumulated over time and mapped onto support for available options as they appear. We tested alternative-specific and alternative-general models of choice in two perceptual experiments where the available options could change during a trial. In the first study, we showed that changing the choice options partway through a trial resulted in no substantial difference in performance relative to a condition where the final options were always onscreen. This was supported by a quantitative model comparison that strongly favored an alternative-general (geometric) model over two alternative-specific models (diffusion and racing accumulator models). In the second study, the stimulus primed specific unavailable responses to test whether irrelevant support for unavailable options was integrated into the decision process. This study elicited a pattern of accuracy that could not have occurred unless participants accumulated support for options that were not yet available. Together, these experiments and modeling results indicate that the majority of participants rely on alternative-general representations of evidence during dynamic decisions among options that can change over time. Future work on decision behavior and its neural antecedents should explore the predictions of these alternative-general theories of choice. (PsycInfo Database Record (c) 2025 APA, all rights reserved).