Semantic congruency facilitates the retrieval of visual associations to odors and decreases retroactive memory interference.

Odors are often considered to be powerful memory cues, yet early olfactory paired-associate (PA) studies suggested that they are less effective than other sensory cues and particularly prone to proactive interference (PI). Research with other modalities indicates semantic similarity increases retroactive interference (RI). Two experiments compared olfactory PA memory to verbal and auditory PA memory, focusing on the role of semantic congruency. In Experiment 1, a mixed design tested the efficiency of odors as a PA cue under semantically congruent versus incongruent conditions. One hundred one participants were randomly assigned to 4 groups, each experiencing one of the following cross-modal pairs: olfactory-visual and verbal-visual (as a control group for olfactory-visual), auditory-visual, and verbal-visual (as a control group for auditory-visual). Replicating prior work, odors were less effective than verbal or auditory cues. However, semantic congruency enhanced performance across modalities, with a greater effect for olfactory PAs. Experiment 2 employed a mixed design to assess PI and RI in olfactory versus verbal PA memory. Thirty-eight participants were randomly assigned to one of two cross-modal pair groups (olfactory-visual and verbal-visual). RI was more pronounced than PI for both modalities, with RI levels increasing when the second pair of associations was semantically congruent, but the first was not. Semantic congruency consistently enhanced olfactory retrieval cues, supporting its role in mitigating interference effects. These findings demonstrate that while odors are less effective associative cues than verbal or auditory stimuli, semantic congruency significantly improves their utility, highlighting the nuanced interplay between modality and memory processes.