Increased negative emotional responses in PROP supertasters

Based on animal data it has been suggested that an increased sensitivity to bitter tastes is linked with increased emotional reactivity. The present study examined for the first time in humans whether the intensity of experimentally induced negative emotional responses is related to sensitivity to the bitter tasting compound PROP (6-n-propylthiouracil). Normal-weight participants (61 men, 57 women) with a mean age of 24 years were classified into PROP non-tasters (n = 54), medium tasters (n = 25), or supertasters (n = 39), and were shown two film clips to induce negative emotional response patterns: one pattern predominated by anger and tension, and another predominated by sadness and depressed mood. A third film clip was emotionally neutral. Before and after film clip viewing, self-rated emotional responses were obtained. PROP supertasters showed more intense responses than non-tasters or medium tasters after the anger-inducing film clip (increased anger, tension, sadness and fear as well as decreased mood and joy). Significant correlations were found between emotional responses and a continuos measure of PROP sensitivity. Group differences and correlations could not be attributed to personality measures, trait affectivity, or gender. For emotional responses after the sadness-inducing film clip, no differences between taster groups could be detected. PROP sensitivity appears to be related to arousability of emotions, in particular those emotions that are associated with an increased readiness to respond actively to stimuli from the environment, e.g. anger, disgust and fear.