The relationship between morningness-eveningness and naturalness bias.

The naturalness bias in which people perceive natural items to be safer, healthier, and better than synthetic alternatives has been found to be associated with numerous individual difference variables (e.g. connectedness to nature and religiosity). However, no research has examined the role of morningness-eveningness in influencing preferences for naturalness. Here, we propose that evening individuals may exhibit a weaker preference for naturalness compared to morning individuals due to their greater exposure to artificial lighting, technology, and stimuli. To systematically test our theoretical perspective, we conducted three complementary and high-powered studies. In an online survey (Study 1), student participants with a stronger evening orientation displayed a diminished preference for natural drugs compared to those with a morning orientation. Using a sample of community adults, Study 2 replicated the findings of Study 1 in a real-world, behavioral context. Study 3 examined the relationship between morningness-eveningness and preference for naturalness within the domain of beverages. The results revealed that individuals with an evening-orientation had decreased odds of selecting natural water without minerals. Taken together, the findings suggest that an individual's diurnal preference toward eveningness may have implications for their bias toward and perception of naturalness across various domains.