Scent-sational: How emotion correlates to liking

How emotion correlates to liking

The Question: Why is emotion important, and how do we assess it?
Noldus Consultants: Patrick Zimmerman, PhD and Leanne Loijens, PhD
Case study write up: Abbe Macbeth, PhD

Our client approached Noldus Consulting to develop a test for identifying “liking” of new odors that goes beyond traditional questionnaires. With these traditional methodologies, respondents sniff odors and rate how much they are “liked” after exposure1, potentially taking up to 5 seconds to get that response. Could we devise a non-cognitive, faster test to get at liking in a more immediate sense? How do we assess whether someone will like a novel odor without asking them outright?

The Noldus Method

We know that individual reactions to odors are processed in the emotional centers of our brain2, and bypass the “thinking” paths. Who hasn’t experienced a sudden memory, either positive or negative, when exposed to a smell from the past? Some odors make us immediately react, without us having to think about that reaction. How do we measure this immediate, emotional reaction to an odor? And how can our client make use of that reaction to innovate new odors for their products?

The answer is by applying FaceReader™, the leading software for facial emotion analysis. Facial emotional responses to odors occur quickly, within 400-1700ms after odor presentation3,4. This emotional reaction can be detected directly by measuring muscle activity (3left), or by assessing the emotions displayed on the face, via FaceReader™ (4right).

Previous studies using FaceReader indicate three important things regarding emotional reactions to odors:

  1. Exposure to pleasant odors results in lower displayed levels of both Disgust and Anger4
  2. Emotional reaction to odors occurs within 3s of exposure5, and is a better assessor of liking than traditional questionnaires6.
  3. Facial emotions correlate with purchase intent7, particularly the emotion of Happy

Furthermore, there are inherent issues with self-report that indicate a need to get away from solely using this type of testing. Moving to a more objective measurement of liking that can be captured in the moment instead of after testing adds a level of analysis that was not previously possible.

The Noldus Solution

Knowing this, we designed an odor test that allowed for comparing the emotional responses of female consumers to different potential odors.



  • The Findings and Recommendations

Using implicit measures, we were able to capture the specific emotional reactions displayed by female consumers, in real time, immediately, during odor exposure. Odors 3, 4, and 5 elicited the highest overall emotional response, had the highest relative intensity of happy, and resulted in the highest emotional index score, which is a measure of likability and positive association. Detecting liking via emotion during sniffing indicates the pleasurability of the odor during use, instead of relying upon past memory of the odor to determine likability.

  • The Outcome

Odors 3, 4, and 5 are found in best-selling products currently on the market from our client. Focusing on these odors to the exclusion of others tested was based in part due to our findings.


1Triscoli et al. (2014). Liking and wanting pleasant odors: different effects of repetitive exposure in men and women. Frontiers in Psychology, 5, 1-8.

2Fox, Kate (2010). The Smell Report: an overview of facts and findings. Social Issues Research Centre.

3Delplanque et al. (2009). Sequential unfolding of novelty and pleasantness appraisals of odors: Evidence from facial electromyography and autonomic reactions. Emotion, 9, 319-328.

4He et al. (2014). Dynamics of autonomic nervous system responses and facial expressions to odors. Frontiers in Psychology, 5, 104-111.

5de Wijk et al. (2014). ANS responses and facial expressions differentiate between the taste of commercial breakfast drinks. PLOS One, 9, 1-9.

6Greenwald et al. (2009). Understanding and using the Implicit Association Test: III. Meta-analysis of predictive validity. Journal of Personality and Social Psychology, 97, 17-41.

7Lewinski et al. (2014). Predicting advertising effectiveness by facial expressions in response to amusing persuasive stimuli. Journal of Neuroscience, Psychology, and Economics, 7, 1-14.



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