Rethinking the nature of "logical" intuitions about deductive reasoning: Conflict detection and semantic cues

There is evidence that when people make illogical (heuristic) judgments, they are intuitively aware that their answer is incorrect. There are competing hypotheses about this intuition. De Neys (2023) claimed that people have intuitions that correspond to formal validity. Ghasemi et al. (2022) suggested that people use a simple matching heuristic unrelated to validity. In these studies, we examine reasoning with simple, concrete syllogisms of the form "All A are B, X are B." We examine the hypothesis that when given such inferences, people have a "logical" intuition that leads to an automatic search for potential alternatives (cases of C that are also B). Successful activation will cue for conclusion rejection; otherwise, the absence of alternatives cues for conclusion acceptance. In Study 1, we presented participants with syllogisms with concrete premises with believable or unbelievable conclusions, with major premises chosen to have relatively many alternatives. In Study 2, we presented concrete syllogisms with major premises chosen to have relatively few alternatives. In Study 3, we presented participants with major premises chosen to have an unfamiliar consequent. Consistent with the hypothesis, conflict detection indices in Study 1 show that intuitive judgments correspond to conclusion rejection, while the same indices in Studies 2 and 3 indicate intuitions corresponding to conclusion acceptance. Results cannot be explained by an intuition that corresponds to formal logical validity or one that uses matching. This suggests that there is a "logical" intuition that is developmentally appropriate and corresponds to an intuitive grasp of the importance of counterexamples. (PsycInfo Database Record (c) 2026 APA, all rights reserved).