Automatic Logical Inferences In Visual Scene Processing

The human capacity for logic is responsible for some of our grandest achievements; without it, formal mathematics, economic systems, and architectural marvels would be elusive. Yet logical cognition is not limited to rarefied intellectual challenges—it also arises in everyday contexts, such as inferring that a glass on a table must be yours because your friend is holding theirs. Previous work shows that a primitive logical operation—disjunctive syllogism (p OR q; NOT p; therefore, Q)—is deployed by infants to infer the identities of objects (Cesana-Arlotti et al., 2018). This raises an intriguing question: Do such logical inferences arise automatically in adults, and even impact processing of visual scenes? Experiment 1 showed adults events wherein an ambiguous object was ‘scooped’ by a cup from a two-item set (snake and ball). Upon seeing one of the objects outside the cup (snake), adults responded slower when the revealed object’s identity violated their logical prediction (snake) than when it was consistent (ball). The effect persisted over 40 trials, even though the revealed identity was random—suggesting that adults were executing this inference automatically. Put differently, they ‘couldn’t help’ but infer the hidden object’s identity, even when they knew they shouldn’t. Experiment 2 tested whether this effect resulted from one item’s appearance priming the other. We devised scenes with a third item in the cup, preventing logical inferences about the cup’s contents. A Bayes Factor analysis found strong evidence for the null hypothesis of no response time differences, confirming that logical inference drives the Experiment 1 effect. These findings open avenues in both logical cognition and scene processing. First, our results suggest that logical inferences may be spontaneously deployed to resolve visually uncertain events. Additionally, methods from vision science may serve as a previously unexplored tool for uncovering the nature of our mind's fundamental logical capacities.