Memory from nonsense syllables to novels: A survey of retention.

Memory has been the subject of scientific study for nearly 150 years. Because a broad range of studies have been done, we can now assess how effective memory is for a range of materials, from simple nonsense syllables to complex materials such as novels. Moreover, we can assess memory effectiveness for a variety of durations, anywhere from a few seconds up to decades later. Our aim here is to assess a range of factors that contribute to the patterns of retention and forgetting under various circumstances. This was done by taking a meta-analytic approach that assesses performance across a broad assortment of studies. Specifically, we assessed memory across 256 papers, involving 916 data sets (e.g., experiments and conditions). The results revealed that exponential-power, logarithmic, and linear functions best captured the widest range of data compared with power and hyperbolic-power functions. Given previous research on this topic, it was surprising that the power function was not the best-fitting function most often. Contrary to what would be expected, a substantial amount of data also revealed either stable memory over time or improvement. These findings can be used to improve our ability to model and predict the amount of information retained in memory. In addition, this analysis of a large set of memory data provides a foundation for expanding behavioral and neuroimaging research to better target areas of study that can inform the effectiveness of memory.

A new look at memory retention and forgetting.

The forgetting curve is one of the most well known and established findings in memory research. Knowing the pattern of memory change over time can provide insight into underlying cognitive mechanisms. The default understanding is that forgetting follows a continuous, negatively accelerating function, such as a power function. We show that this understanding is incorrect. We first consider whether forgetting rates vary across different intervals of time reported in the literature. We found that there were different patterns of forgetting across different time periods. Next, we consider evidence that complex memories, such as those derived from event cognition, show different patterns, such as linear forgetting. Based on these findings, we argue that forgetting cannot be adequately explained by a single continuous function. As an alternative, we propose a Memory Phases Framework, through which the progress of memory can be divided into phases that parallel changes associated with neurological memory consolidation. These phases include (a) Working Memory (WM) during the first minute of retention, (b) Early Long-Term Memory (e-LTM) during the 12 hr following encoding, (c) a period of Transitional Long-Term Memory (t-LTM) during the following week or so, and (d) Long-Lasting Memory (LLM) memory beyond this. These findings are of significance for any field of study where being able to predict retention and forgetting is important, such as training, eyewitness memory, or clinical treatment. They are also important for evaluating behavioral or neuroscientific manipulations targeting memories over longer periods of time when different processes may be involved. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

A novel study: hypermnesia for books read years ago.

Memory can increase across repeated tests without any further study, a finding known as hypermnesia (e.g., Erdelyi, M. H., & Kleinbard, J. (1978). Has Ebbinghaus decayed with time? The growth of recall (hypermnesia) over days. Journal of Experimental Psychology: Human Learning and Memory, 4(4), 275-289). This study is the first to examine hypermnesia in a recognition test over long delays between learning and test. The current experiment examined hypermnesia for popular novels across retention spans of up to 10 years. Participants took two tests separated by 24 hours on a novel they had previously read. The tests had identical questions presented in a different order. We found hypermnesia across the recognition tests, which was due to within-test memory improvements. Hypermnesia decreased as a function of retention time due to increased item losses at longer delays. We propose a guessing hypothesis to account for this result and suggest that increased item losses are in part due to greater instability of memory at longer intervals.

A novel study: long-lasting event memory.

The current study reports two experiments that assessed memory for complex sets of information (i.e., four novels) over the course of several years. This was done to explore several issues, including (a) the content and durability of memory, (b) causal connectivity among the described events, (c) serial position within the novel, (d) pattern of retention and forgetting, and (e) interest in the novel. This study revealed that people remember events read in a novel for long periods of time with a shallow rate of forgetting. We also found that they remembered information better when it was presented earlier on in the novel, was more causally connected to other events in the novel, and was transitional in the character or story plot. Consistent with prior research, reported level of interest was not related to later memory. Because we experience events through different learning modalities (e.g., novels, film, autobiographical experience) which are likely remembered similarly, this research broadens our understanding of how people remember the events they learn about through different means.