I’ve made a few posts on here about pain and the perception of pain. The gate theory of pain suggests that perception of pain can be influenced by external influences like distraction. Could smell have a similar effect on the perception of pain? Well a new study would have us believe that it can, especially if it’s a sweet smell.
The research conducted by Prescott and Wilkie (2007) aimed to see if participants could hold their hand in a vat of cold water for longer depending on the type of smells presented at the same time:
The mechanism underlying reported analgesic effects of odors in humans is unclear, although odor hedonics has been implicated. We tested whether odors that are sweet smelling through prior association with tasted sweetness might influence pain by activating the same analgesic mechanisms as sweet tastes. Inhalation of a sweet-smelling odor during a cold-pressor test increased tolerance for pain compared with inhalation of pleasant and unpleasant low-sweetness odors and no odor. There were no significant differences in pain ratings among the odor conditions. These results suggest that smelled sweetness can produce a naturally occurring conditioned increase in pain tolerance. [abstract]
The results showed that those participants who were presented with the sweet smelling odors were able to keep their hands in the water for over twice as long as the other participants (for a much more detailed discussion of the study see Mixing Memory).
So, how can smells actually effect our perceptions of pain?
This experiment obviously doesn’t test any causal hypotheses, but Prescott and Wilkie suggest that because the sweetness of smells is largely learned, through associations with sweet tastes, the analgesic effects of sweet smells are likely the result of learned associations as well. Sweet tastes have been show to increase pain tolerance, and by association, sweet smells come to do so as well. [quote]
A really interesting study which again shows that the mind can have a massive effect over our perceptions of pain.
- Prescott, J., & Wilkie, J. (2007). Pain tolerance selectively increased by sweet-smelling odor. Psychological Science, 18(4), 308-311.
- Mixing Memory: Do Sweet Smells Make Pain More Tolerable?