Pathogen Avoidance: We drink significantly less water when we believe it came from pathogen-prevalent environments (e.g., restrooms) and rated the water from pathogen-prevalent environments as lower in cleanliness, crispness, quality, and other characteristics when compared

Belief Influences Gustation: Evidence of a Psychophysical Pathogen Avoidance Mechanism. Carey J. Fitzgerald etal. Evolutionary Psychological Science, https://link.springer.com/article/10.1007%2Fs40806-017-0132-6

Abstract: Individuals often avoid pathogens by refraining from ingesting things that are associated with pathogen-prevalent stimuli. The present study examined whether individuals would be less likely to ingest water that is associated with pathogen-prevalent environments and whether individuals’ perceptions of water quality would decrease when they believed the water originated from a pathogen-prevalent environment, (even though the water actually did not originate from the indicated source). Across two experiments, undergraduates were asked to taste-test water they believed came from a variety of sources on their college campus. For each cup of water presented to participants, an image of its supposed water source (e.g., kitchen sink, drinking fountain, or bathroom sink) was also presented. Participants drank significantly less water when they believed it came from pathogen-prevalent environments (e.g., restrooms) and rated the water from pathogen-prevalent environments as lower in cleanliness, crispness, quality, and other characteristics when compared to water from environments not associated with pathogens (study 1). Similar results were also found after controlling for perceived cleanliness of the images of water sources (study 2). Ultimately, the results from both studies provide evidence that individuals’ beliefs can influence perception and behavior in a manner consistent with pathogen avoidance.