Advancing investigations into the effects of sweet and bitter tastes on agreeableness and hostility

In the studies to date that have examined the effect of taste on social affect, sweet taste has been reported to increase agreeableness (Meier et al., 2012), and bitter taste has been reported to increase hostility (Sagioglou & Greitemeyer, 2014). However, no study to date has examined changes to both agreeableness and hostility after tasting sweet and bitter substances, nor how the order of self-reporting these feelings, or individual differences in taste sensitivity, may influence the results. Our pre-registered study addressed these questions in 99 female undergraduates. Participants were randomly assigned to taste one of six sweet, bitter and neutral tastants, including those used in prior research on this topic, and then immediately completed the agreeableness and hostility scales used in past research, the order of which was counterbalanced across participants. Participants then evaluated all six tastants on various hedonic scales, and a 6-n-propylthiouracil (PROP) test of taste sensitivity was administered. Statistical analyses did not reveal any association between sweet, or any tastant and agreeableness scores. Hostility ratings were increased after participants tasted bitter, but only when this scale was administered before the agreeableness scale. Sensitivity to PROP did not moderate any of the findings. Based on prior work on self-affirmation and affect (e.g., Lindsay & Creswell, 2014), our results suggest that priming a prosocial self-schema (e.g., agreeableness) can eliminate the hostility induced by bitter taste. However, other explanations are possible and future work should investigate factors including measures of personality states vs. traits, and the timing between tasting and affect assessments.