Impaired working memory updating affects memory for emotional and non-emotional materials the same way: evidence from post-traumatic stress disorder (PTSD)

Abstract

Due to the limited capacity of working memory (WM), efficient suppression of no longer relevant memory contents (inhibition) and revising the current contents of the memory (updating) are crucial factors in memorizing. However, not every individual is able to do so; among them are post-traumatic stress disorder (PTSD) patients who seem to have trouble forgetting trauma-related materials, making their memory overloaded with irrelevant information. The present study assumes that the inability to forget in PTSD patients is due to the impaired updating function of WM and, therefore, suggests that these individuals have inferior WM function for both emotional and unemotional materials. A sample of 30 male veterans with PTSD and 30 healthy individuals (mean age = 46.62, SD = 5.23) participated in the study completing PTSD Checklist, Digit Span Task, and a computerized n-back task. Results revealed that although PTSD subjects showed a generally inferior WM compared with normal individuals; however, their WM performance for emotional and non-emotional stimuli was not significantly different. Supporting the main hypothesis of the study, the findings suggest that a dysfunctional updating function of WM underlies both forgetting and memorizing which affects memory for both emotional and non-emotional material similarly.