WITHDRAWN: Four studies Yield limited evidence for prepared (disgust) learning via evaluative conditioning.

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Four studies yield limited evidence for prepared (disgust) learning via evaluative conditioning.

Prepared learning accounts suggest that specialized learning mechanisms increase the retention of associations linked to ancestrally-prevalent threats. Few studies have investigated specialized aversion learning for pathogen threats. In four pre-registered studies (N's = 515, 495, 164, 175), we employed an evaluative conditioning procedure to test whether foods (versus non-foods) are more readily associated with negative content associated with pathogens than negative content not associated with pathogens. Participants saw negatively valenced (either pathogen-relevant or -irrelevant), neutral or positively-valenced stimuli paired with meats and plants (in Studies 1 and 2) and with meats and abstract shapes (in Studies 3 and 4). They then evaluated each stimulus explicitly via self-reports (Studies 1-4) and implicitly via an Affect Misattribution Procedure (Studies 3 and 4). Linear mixed models revealed general evaluative conditioning effects, but inconsistent evidence for specialized (implicit or explicit) learning for a food-pathogen association. However, results from a mega-analysis across studies revealed stronger conditioning effects for meats paired with pathogen-relevant negative stimuli than pathogen-irrelevant negative stimuli.

The multidimensional nature of food neophobia.

People vary in their willingness to try new foods. This variation, which is most frequently measured using the Food Neophobia Scale (FNS; Pliner & Hobden, 1992), has been interpreted as unidimensional. In four studies (N's = 210, 306, 160, and 161), we 1) demonstrate that food neophobia varies across meat and plant dimensions, 2) explore the validity of a measure of meat and plant neophobia, and 3) test whether these food neophobia dimensions predict decisions to eat a novel food item (i.e., a snack bar that contains insects). Mixed-effects model across the four studies indicated that the two dimensions differentially relate to a number of variables, including disgust sensitivity, animal empathy, and masculinity. Women scored higher on meat neophobia than men, but the sexes did not differ on plant neophobia. Only meat neophobia uniquely predicted eating a novel insect-based snack bar. Overall, these results extend knowledge regarding orientations toward novel foods.

Why do people vary in disgust?

People vary in the degree to which they experience disgust toward-and, consequently, avoid-cues to pathogens. Prodigious work has measured this variation and observed that it relates to, among other things, personality, psychopathological tendencies, and moral and political sentiments. Less work has sought to generate hypotheses aimed at explaining why this variation exists in the first place, and even less work has evaluated how well data support these hypotheses. In this paper, we present and review the evidence supporting three such proposals. First, researchers have suggested that variability reflects a general tendency to experience anxiety or emotional distress. Second, researchers have suggested that variability arises from parental modelling, with offspring calibrating their pathogen avoidance based on their parents' reactions to pathogen cues. Third, researchers have suggested that individuals calibrate their disgust sensitivity to the parasite stress of the ecology in which they develop. We conclude that none of these hypotheses is supported by existing data, and we propose directions for future research aimed at better understanding this variation.This article is part of the Theo Murphy meeting issue 'Evolution of pathogen and parasite avoidance behaviours'.