The processes of pattern separation and pattern completion are very important in the correct discrimination of similar memories. Much research has been conducted on these processes, but there are some gaps that need to be addressed. First, there is some debate as to whether false alarms to lure items come about because of a failure to accurately encode a memory or a failure to retrieve a memory. Second, much of the research on pattern separation and pattern completion in humans is done with visual stimuli and contributions of stimulus modality to these processes are not well understood as a result.Study 1 consisted of three experiments conducted using a combination of eye tracking and functional magnetic resonance imaging (fMRI) methods. Analyses of eye tracking data in the experiments examined the contribution of fixation counts at encoding and retrieval, as well as target-lure similarity level, to accuracy on lure trials. Task designs were altered across studies to attempt to replicate specific research previously conducted with a specific answer period, as well as generalize the findings to a broader body of research that allows participants to answer while the stimulus is presented. The three experiments showed mixed support for the contribution of fixation counts at encoding and retrieval to the accurate discrimination of similar lures. Target- lure similarity, however, was a robust predictor of accuracy for all three experiments.Prior research examining activity in the hippocampus demonstrates a reduction of fMRI activity to repetitions of a stimulus. Greater activity is also observed in the dentate gyrus/CA3 (DG/CA3) subregions for correct rejections of lure items compared to lure false alarms. There should be a greater reduction in the DG/CA3 as a function of encoding for lure false alarms than for lure correct rejections if memory encoding drives the activity differences between these outcomes. The fMRI data showed a marked reduction of activity in the left hippocampus to repetition trials as a function of encoding trial fixation count. There was no significant difference between activity as a function of encoding fixation count in the DG/CA3 for lure correct rejections and lure false alarms. There was also no difference in activity for the CA1 either. Overall, the results of the eye tracking and fMRI data give support for the contribution of pattern completion to false alarms to lure stimuli rather than poor encoding.Study 2 examined the contribution of sensory modality to accurate discriminations of lure stimuli. A behavioral task was developed to directly compare discrimination of similar lures on visual and auditory stimuli. Participants were significantly more accurate and more confident of their responses when discriminating visual stimuli as compared to discriminating auditory stimuli.

No / In a memory survey, adult respondents recalled, dated, and described two earliest positive and negative memories that they were highly confident were memories. They then answered a series of questions that focused on memory details such as clothing, duration, weather, and so on. Few differences were found between positive and negative memories, which on average had 4/5 details and dated to the age of 6/6.5 years. Memory for details about activity, location, and who was present was good; memory for all other details was poorer or at floor. Taken together, these findings indicate that (full) earliest memories may be considerably later than previously thought and that they rarely contain the sort of specific details targeted by professional investigators. The resulting normative profile of memory details reported here can be used to evaluate overly specific childhood autobiographical memories and to identify memory details with a low probability of recall.

The effectiveness of memory specificity training (MeST) was compared with standard cognitive processing therapy (CPT) in treatment of individuals with posttraumatic stress disorder. Eighteen adults aged 18-36 were randomly assigned to the MeST intervention (n = 9) or to the active control group (n = 9) of CPT. Both treatments were administered in group format across 6 weeks. MeST consisted of 6 weekly sessions, while CPT consisted of 12 biweekly sessions. The trial was undertaken in the Psychology Clinic of the University of North Texas, with randomization to conditions accomplished via computer random number generator. The primary outcome measure was change in PTSD symptoms post-treatment from baseline. Sixteen individuals (13 women and 3 men; MeST n = 8 and CPT n = 8) completed treatment and their data was analyzed. MeST significantly decreased PTSD symptomology at post-treatment and these results were maintained at 3 months post-treatment. MeST was found to be as effective as the established CPT intervention at reducing PTSD symptomology. Both MeST and CPT significantly increased participants' ability to specify memories upon retrieval at post-treatment, with results maintained at follow-up. There were no significant effects of MeST or CPT in ability to increase overall controlled cognitive processing at post-treatment or follow-up. No individual in either group reported any adverse effects during treatment or at 3 months follow-up. MeST appears to hold promise as an efficacious treatment option for PTSD. MeST was as effective as CPT in reducing symptoms of PTSD, but required only half the number of treatment sessions to accomplish these gains. Replication of these findings in larger samples is encouraged.