| Decades of research have demonstrated that episodic memory is vulnerable to significant semantic distortion (Gallo, 2006). Recent findings suggest that short-term memory is susceptible to similar distortions of meaning. The present investigations explore the cognitive and neural mechanisms of memory distortions that emerge within a few seconds of encoding. Findings demonstrate false recall and recognition of unstudied lure items only 3--4 seconds following encoding of a short, 4-item memory set, and show that correct rejections of lures are associated with considerable semantic interference (SI). An fMRI investigation of these effects suggests a distinction between the left mid-ventrolateral prefrontal cortex (L VLPFC), which shows increased activity changes associated with increased SI, and the right posterior parietal cortex (R PPC) which shows increased activity associated with declines in SI. An investigation of interactions between SI and proactive interference (PI) in short-term memory shows that vulnerability to PI is mediated by the semantic relationship between recently studied items and current memoranda. Taken together, findings are consistent with unitary, activation-based models of memory (Nairne, 2002), and reveal the considerable vulnerability of verbatim memory processes, even over very short retention intervals. |
