Progesterone and mental imagery interactively predict emotional memories

Different lines of research suggest that the consolidation of emotional memories is influenced by (a) endogenous levels of sex hormones, and (b) individual differences in the capacity to use vivid mental imagery. No studies to date have investigated how these factors may interact to influence declarative emotional memories. This study examined the interacting influence of progesterone and mental imagery strength on emotional memory consolidation. Twenty-four men, 20 women from the low progesterone (follicular) menstrual phase, and 20 women from the high progesterone (mid-luteal) phase of the cycle were assessed using an objective performance-based measure of mental imagery strength, and then shown a series of aversive and neutral images. Half of the images were accompanied by instructions to process sensory features, and the remaining half to process the conceptual characteristics of the images. Two days later, all participants returned for a surprise free recall memory test. The interaction of progesterone and mental imagery strength significantly predicted recall of visually processed, but not verbally processed, negative images. These data suggest that mental imagery strength may be one mechanism underlying the documented association between endogenous progesterone and enhanced emotional memory performance in the literature.