This study examined whether odors possess intrinsic memorability and tested how perceived pleasantness and intensity influence recognition accuracy and confidence. Nineteen adults incidentally encoded six of twelve intensity‑matched monomolecular odorants and later completed a yes-no recognition test containing all twelve odors. Corrected recognition scores and confidence ratings were analyzed at both participant and odor levels. Memorability varied markedly across odors: some were reliably recognized (corrected recognition ≈ 0.90), whereas others were near chance or negative, indicating stimulus‑specific mnemonic strength. Perceived pleasantness did not predict recognition accuracy or confidence, and a one‑way ANOVA showed no accuracy differences across rounded pleasantness categories. In contrast, perceived intensity correlated positively with confidence and showed a weak, nonsignificant trend with accuracy. Confidence and corrected recognition were themselves positively related. These results indicate that (i) odor memorability is largely stimulus‑driven and consistent across individuals, and (ii) subjective intensity, rather than hedonic valence, enhances metacognitive certainty with minimal impact on objective accuracy. Future work should use larger samples, broader hedonic ranges, and neuroimaging to test whether stimulus‑level mnemonic differences map onto distinct activation patterns in olfactory and limbic regions and to assess potential sex‑specific effects.
Jianing Zhang (Fri,) studied this question.