The distinctive power of odors in evoking memories explained by their emotional characteristics: New insights into episodic memory

Odors are often considered to be particularly powerful at evoking memories. We hypothesized that the emotional relevance of olfactory stimuli grants them privileged access to memory traces. Using a virtual-reality protocol, we examined the influence of emotional characteristics of different sensory cues on episodic retrieval, predicting stronger effects for odors, than for music or faces. This approach allowed us to disentangle, within episodic memory, cue recognition from associative retrieval, and to assess how pleasantness, emotional intensity, and reward value modulate these processes. Our findings reveal that episodic memory retrieval depends on a complex interaction between both the sensory modality and the emotional characteristics of the cues. Music recognition was almost perfect and specifically favored by both music reward value and emotional intensity. Critically, only odors reliably supported the retrieval of associated contextual details, underscoring their privileged role in associative memory. The subjective reward value of odors emerged as the strongest and most consistent predictor of successful retrieval. Cue pleasantness had a modality unspecific effect, with both cue unpleasantness and pleasantness (vs neutral) enhancing the whole episodic memory process across modalities. These results suggest that reward-related processes, rather than general valence, underpin the distinctive power of olfaction on episodic memory, positioning it as a privileged and unique gateway into autobiographical memories.