Assessment of odor evoked emotions using the EmojiGrid

We recently introduced the EmojiGrid as an intuitive graphical self-report tool to measure food-evoked valence and arousal. The EmojiGrid is Cartesian grid, labeled with facial icons (emoji) expressing different degrees of valence and arousal. The lack of verbal labels makes it a valuable, language-independent tool for cross-cultural research. Users can efficiently report their subjective ratings of both valence and arousal with a single click on the location of the grid that best represents their affective state after perceiving a given stimulus. The EmojiGrid has previously been validated for the assessment of emotions evoked by food images.

In this study we validated the EmojiGrid for the affective appraisal of odors. Observers (N=56, 24 males, mean age=24.3±4.6) smelled 40 randomly presented odors (27 food and 13 non-food smells), ranging from very unpleasant and arousing (e.g., feces, fish), via pleasant and calming (e.g., clove, cinnamon) to very pleasant and stimulating (e.g., peach, caramel). The odor samples consisted of felt pens, with tips that were impregnated with 4 mL of fluid odorant substance. Each pen was presented once, for about 5 seconds and about 2 cm below both nostrils. The participants sniffed following a verbal command. Immediately after sniffing the pen was removed, and participants were given at least 30 s to smell fresh air.

The participants reported their affective appraisal of each odor using the EmojiGrid. The resulting mean valence and arousal ratings closely agree with those from previous studies in the literature that were obtained with alternative rating tools. In addition, we find that the EmojiGrid yields the typical universal U-shaped relation between mean valence and arousal that is commonly observed for a wide range of affective sensory (visual, auditory, tactile, gustatory) stimuli.

We conclude that the EmojiGrid is also a valid affective self-report tool for the assessment of odor evoked emotions.