Your Hot Sauce Expectations Affect How Spicy a Dip Tastes

Spiciness is subjective, according to a new study published in PLOS Biology.

In the novel experiment, participants underwent a brain MRI scan while being sprayed with water and low- and high-intensity hot sauces. During the ordeal, the participants were shown images of chili peppers that alternated between a “neutral” grey, a low-intensity blue and an “intense” red while being asked how spicy their mouths felt.

After analyzing the results, the researchers from the East China Normal University found that, at the sight of a red pepper, the brain scans of the participants who like hot sauce showed increased readiness for the incoming spice, while the participants who didn’t like hot sauce demonstrated a heightened pain response.  

Hot ones

To test how expectations affect people’s perceptions of pain, the researchers recruited 47 participants; 24 said they liked spicy sauces; 22 said they didn’t; 1 participant said their tastes weren’t inclined either way; their data were excluded from further analyses.

Each participant underwent two MRI scan experiences. In the first instance, neutral grey chili peppers were displayed six seconds before a spray – of either water, low-grade or high-grade hot sauce – was delivered into the participants’ mouths. The participants were then asked to rate the heat and flavor of each of the 30 sprays.

The second MRI scan followed the same routine, only the images of the peppers were colored either red or blue to indicate that the incoming spray was either high- or low-intensity. In reality, the 30 sprays were in a random order.

All participants received an additional spray of water between each “test squirt” to help return their spicy tongues back to baseline.

As expected, the participants who claimed to enjoy spicy sauces tended to report positive feelings when given the hotter sprays, while those who didn’t enjoy spice reported negative feelings.

The positive expectations of the pro-spice group also appeared to decrease the reported heat intensity of the sprays. During these moments, the participants’ dorsal anterior cingulate and dorsolateral prefrontal cortexes showed more activity, indicating raised pleasure.

The same was not true of the brains of the participants who didn’t enjoy spice. When presented with the red chili pepper cues, their brains showed an elevated neural pain signature.

“I was surprised by how strongly negative expectations amplified the brain’s pain response, even though the stimulus was the same,” Yi Luo, a psychology researcher at East China Normal University and lead author of the study, said in a statement. “This highlights how our anticipation of discomfort can significantly intensify the experience of pain.”

Few differences, qualitative or neural, were observed between the experiences of the pro-spice participants when they were sprayed with the top high-intensity hot sauces. Luo and her colleagues say these results suggest a sensory ceiling that prevents positive expectations from further altering sensory perceptions.

Nonetheless, the researchers say that, overall, their results suggest that the participants’ expectations of incoming spiciness were integrated with the actual sensory input to generate significant changes in their subjective taste experiences.

This conclusion is in-line with that of a recently published meta-analysis of placebo-related pain relief, which determined that placebo analgesia is associated with higher-level cognitive processes, and that distinct neural circuits are involved in its placebo effects.

According to Yi Luo, this burgeoning consensus on placebo-related pain relief could inform future therapeutics.

“I hope this encourages further exploration into how expectations shape our sensory experiences, potentially informing strategies for managing pain and enhancing therapeutic outcomes,” she said.

Reference: Luo Y, Lohrenz T, Lumpkin EA, et al. The expectations humans have of a pleasurable sensation asymmetrically shape neuronal responses and subjective experiences to hot sauce. PLOS Bio. 2024. doi: 10.1371/journal.pbio.3002818

This article is a rework of a press release issued by PLOS. Material has been edited for length and content.