would have been more fun if they collected objective measures of smell and  loyalty

> These participants reported their ideals when single and then, after they started a new romantic relationship (several months later), they completed measures about their current romantic partner.[^1]

[^1]: https://www.researchgate.net/publication/382253515_A_Worldwide_Test_of_the_Predictive_Validity_of_Ideal_Partner_Preference_Matching

k00b

How did they measure the "revealed rank" of smell?  That implies they went and measured the actual smell of peoples' partners, then compared it to how much they said they value smell.