Field‐testing olfactory ability to understand human olfactory ecology

Abstract

Objectives: We know little about human olfactory ability in natural settings because current knowledge derives from lab-based studies using nonrepresentative samples of convenience. The primary objective was to use a validated lab tool, the five-item odor identification test, to assess variation in olfactory ability in different environments. Methods: Using the five-item test, we conducted two repeated measures experiments that assessed participant ability to correctly identify an odor source in different odor environments. We also examined consistency in odor labelling due to documented potential bias from idiosyncrasies in odor terms. Results: We found no variation in olfactory ability due to environment, but this may be due to methodological biases. First, subjective bias results from idiosyncratic differences in participant labelling and researcher coding of answer correctness. Second, better ability to learn odors may provide an advantage to women. Third, reducing positive female learning bias by analyzing consistency in response (regardless of correct odor source identification) results in no sex differences but fails to assess the functional aspect of olfactory ability (naming the correct odor source). Fourth, functional olfactory ability is significantly better in women, especially in food-rich odor environments. Conclusions: Environment was not a significant factor in olfactory ability in this study but that result may be confounded by methodological biases. We do not recommend odor identification as a field tool. Functional olfactory ability exhibits a sex-based pattern but consistency in recognizing the same odor does not. Food-rich odors may enhance olfactory ability in females. We discuss evolutionary and ecological implications of superior female functional olfactory ability relative to food foraging activity.

Smells, Well-being, and the Built Environment

“…It has been shown that odors affect eating behavior and seem to determine appetite and food choices, and thereby health (Hoover et al, 2020). In a recent study by Hedblom et al (2019), implemented in a multisensory VR environment, the researchers found that a high rating of forest smell (olfactory stimuli: fir and mushroom) and park environment (olfactory stimuli: grass) resulted in a lower psychological stress response compared to an urban environment with olfactory stimuli of gunpowder and diesel.…”

Smell throughout the life course

“…This tendency for females to be better at detecting and naming odorants seems to be maintained through adulthood and might have an evolutionary relevance, for instance, in increasing foraging efficiency, and protecting young children from harm by food or environmental toxicity. 104,107,116 Nevertheless, these findings may be an artifact of the propensity for females to generally have better verbal skills than males, and to be correspondingly better at naming odors when answering questionnaires, without necessarily being better at detecting them. 116,117…”

“…104,107,116 Nevertheless, these findings may be an artifact of the propensity for females to generally have better verbal skills than males, and to be correspondingly better at naming odors when answering questionnaires, without necessarily being better at detecting them. 116,117…”

“…Moreover, the generalization of field-based methods will further help capture the breath of variation existing in human olfactory sensitivity. For example, Hoover et al 116 tested the ability of participants to identify an odor source in different environmental conditions.…”