The mitigating effect of repeated memory reactivations on forgetting

Memory reactivation is a process whereby cueing or recalling a long-term memory makes it enter a new active and labile state. Substantial evidence suggests that during this state the memory can be updated (e.g., adding information) and can become more vulnerable to disruption (e.g., brain insult). Memory reactivations can also prevent memory decay or forgetting. However, it is unclear whether cueing recall of a feature or component of the memory can benefit retention similarly to promoting recall of the entire memory. We examined this possibility by having participants view a series of neutral images and then randomly assigning them to one of four reactivation groups: control (no reactivation), distractor (reactivation of experimental procedures), component (image category reactivation), and descriptive (effortful description of the images). The experiment also included three retention intervals: 1 h, 9 days, and 28 days. Importantly, the participants received three reactivations equally spaced within their respective retention interval. At the end of the interval, all the participants were given an in-lab free-recall test in which they were asked to write down each image they remembered with as many details as possible. The data revealed that both the participants in the descriptive reactivation and component reactivation groups remembered significantly more than the participants in the control groups, with the effect being most pronounced in the 28-day retention interval condition. These findings suggest that memory reactivation, even component reactivation of a memory, makes memories more resistant to decay. Memory: Improving memory with “Partial Recall” No need for total recall, remembering a part can strengthen the whole. When Hugo Lehmann and colleagues at Trent University asked volunteers how many previously seen images contained a simple feature (e.g., living object), forgetting was reduced compared to volunteers who only viewed the images. Furthermore, this benefit was akin to that of volunteers who were asked to described the images in full detail. In both cases, the reduction in forgetting was achieved with only three recall opportunities and persisted for at least 28 days, including improvements in quality and quantity. Thus, our most lasting and vivid long-term memories should be amongst those that we reactivate from time-to-time, whether in whole or in part. This may also account for why some memories are less vulnerable than others to neurod