Semantic content of visual stimuli has a greater impact on associative equivalence learning than stimulus modality.

Introduction: Associative equivalence learning, the ability to form connections between different stimuli based on shared outcomes, plays a fundamental role in human cognition. In this study, we investigated how stimulus modality (visual vs. audiovisual) and the semantic content of the visual stimuli affect performance in associative equivalence learning. Methods: We applied four tests (FaceFish, Polygon, SoundFace, and SoundPolygon) based on the Rutgers Acquired Equivalence Test, in a sample of 117 healthy adult participants. The tests differed in modality and semantic content of visual stimuli. All tests were divided into an acquisition phase, where participants learned associations based on shared outcomes, and a test phase, where they retrieved the learned associations and applied the acquired equivalence to new stimulus pairs. Results: Our results revealed that visual semantic content had a stronger and more consistent effect on performance than stimulus modality, particularly in the acquisition phase. Audiovisual presentation offered some facilitative effects (lower error ratios), especially when combined with visual stimuli with higher semantic content, but did not compensate for the limitations of simplified stimuli. Discussion: These findings support the critical role of visual stimulus features in shaping learning efficiency and suggest that the benefits of multisensory input may depend on the semantic content of visual stimuli. The results also validate previous findings obtained from smaller samples and highlight directions for future research, including developmental, multisensory, and neurophysiological investigations of associative learning.