OBJECTIVES: Although there is consensus that sex hormones modulate memory, we have an incomplete understanding of their role in remembering and forgetting. Humans continuously update memory, forgetting old, out-of-date information and encoding new, more relevant information. Updating processes can be studied with the list method of directed forgetting.
METHODS: In the list method of directed forgetting task, subjects study two lists of items and, after study of list 1, are asked to either forget or remember the list for an upcoming memory test. Free testosterone level was quantified from saliva samples. Directed forgetting and saliva testosterone were evaluated in young men (aged between 18 and 28 years).
RESULTS: Following a forget cue, recall of list-1 items was reduced and recall of list-2 items was enhanced. However, only recall of list-2 items was associated with free testosterone level. Following a forget cue, participants with low testosterone levels showed higher recall of list-2 items than participants with high testosterone levels.
CONCLUSION: The selective association between testosterone level and list-2 recall is consistent with two-mechanism accounts of memory updating, where the forgetting effect is due to impaired retrieval and the enhancement effect to improved encoding. On the basis of this view, the present results indicate that low testosterone levels are associated with improved binding of the newly encoded memories to their context cue....