A new behavioral method for assessing relational reasoning: Transitive inference list task.

Nonverbal transitive inference (TI) is the ability to derive novel relationships among items based on their existing relationships (e.g., if B > C and C > D, then B > D). Interpreting nonverbal TI research has been challenging due to the difficulty of distinguishing genuinely inferential behavior from performance driven by differences in associative strength accumulated during training. To address these shortcomings, we developed a novel transitive inference list (TIL) task designed to minimize associative strength confounds and provide a clear behavioral signature of competing strategies. In the TIL task, participants learn three short sequences (A → B → C, C → D → E, and E → F → G) in a simultaneous chaining procedure requiring responses to all items in the correct order. Later, participants respond to within-list comparisons (e.g., BC) and a variety of between-list comparisons (e.g., BD, AF, and CF) that either align (consistent pairs) or conflict (conflicting pairs) with trained ordinal positions. Participants who were aware of the overlap between sequences showed evidence of integrating the training sequences into a single, unified list (i.e., A → … → G), correctly selecting the item higher in the integrated list even on conflicting between-list comparisons. Consistent with results from traditional TI and SC tasks, unaware participants did not form an integrated list, instead relying on sequence-specific ordinal positions to guide choice behavior. The TIL task therefore provides a powerful tool for studying inferential behavior that is particularly well suited for comparative research across species. (PsycInfo Database Record (c) 2026 APA, all rights reserved).