Are additives unnatural? Generality and mechanisms of additivity dominance

Naturalness is important and valued by most lay Western individuals. Yet, little is known about the lay meaning of “natural”. We examine the phenomenon of additivity dominance: adding something to a natural product (additive) reduces naturalness more than removing an equivalent entity (“subtractive”). We demonstrate additivity dominance for the first time using equivalent adding and subtracting procedures. We find that adding something reduces naturalness more than removing the same thing (e.g., adding pulp to orange juice reduces naturalness more than removing pulp from orange juice; Study 1); an organism with a gene added is less natural than one with a gene removed (Study 2); and framing a product as an additive (versus as a subtractive) reduces naturalness (Study 3). We begin to examine accounts of additivity dominance. We find that it is not due to the connotations of the word “additive” (Study 4). However, data are consistent with an extra processing account -where additives involve more processing (extracting and adding) than subtractives (only removing)-and with a contagion account - where adding is more contaminating than removing (Study 5).