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.

Event model retrieval and daily interference.

The differential fan effect was used to assess the influence of periods of daily, generalised interference. Experiment 1 replicated the differential forgetting effect as a control for the other experiments. Experiment 2 involved fact learning in either the morning or the evening with a 12-hr testing delay. It might be expected that experiencing more generalised interference during the retention interval would impair memory, but no differences in response times were observed, and only very small differences in the error rates were observed. Experiment 3 replicated Experiment 2 but with a 24-hr delay. In this way, the influence on memory of the proximity of daily, generalised inference to the learning experience could be assessed. Although one might expect worse memory when more interference occurred closer to the learning phase, no clear differences were observed. This is consistent with the idea that event model memory is relatively stable soon after encoding.

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).

Degree of learning and linear forgetting.

The aim of this study was to assess whether the degree of learning influences the observation of memory retention and forgetting that follows a linear pattern. According to our retention accuracy from fragmented traces (RAFT) model, one factor that should increase the likelihood of this is when there is greater learning of the material. Higher levels of learning can increase the number of trace components, making it more likely that reconstruction or partial retrieval can lead to an accurate response on a memory test. Here, we report three new experiments, as well as re-analyses of existing data from the literature, to show that increasing the level of learning in some ways can lead to increases in the likelihood of observing linear forgetting. For Experiment 1, people learned materials to different levels. This learning involved cued recall testing during memorisation. Linear forgetting was observed with increased learning. For Experiment 2, learning did not involve cued recall testing. Linear forgetting was not observed. Although our aim was not to test theories of retrieval practice, for Experiment 3, we showed that when people engage in this process, the pattern of retention and forgetting becomes more linear. Overall, these data are consistent with the RAFT theory and support mechanisms that it suggests can lead to the observation of linear forgetting.

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.

Spoken narrative comprehension for young adult listeners: effects of competing voices and noise.

OBJECTIVE: To examine the influence of competing voices or noise on the comprehension of spoken narratives for young adults. DESIGN: First, an intelligibility assessment of the target narratives was conducted to establish a signal-to-noise ratio ensuring accurate initial speech recognition. Then, narrative comprehension for two target types (fixed and varied target talker) was measured in four listening conditions (quiet, one-talker speech, speech babble, speech-shaped noise). After hearing target narratives in each listening condition, participants completed a visual recognition memory task that assessed the comprehension of the narrative materials at three levels of representation (surface form, propositional, event model). STUDY SAMPLE: Seventy adults (18-32 years of age). RESULTS: Narrative comprehension results revealed a main effect of listening condition at the event model level, indicating poorer narrative memory of described situations for all noise conditions compared to quiet. Increased positive responses to thematically consistent but situationally "wrong" memory probes drove this effect. No other significant effects were observed. CONCLUSION: Despite near-perfect speech recognition, background noise negatively influenced aspects of spoken narrative comprehension and memory. Specifically, noise did not disrupt memory for what was said (surface form and propositional memory), but only memory for what was talked about (event model memory).

Encoding and referent event influence on retrospective memory.

Previous work from our lab has shown that event structure can influence memory performance. Our work in prospective memory has shown that, consistent with an event model view, performance is better when multiple encoding events refer to a common retrieval event. The aim of this study was to assess the generality of this influence of event model structure on memory by using two retrospective memory tasks. This was done using lists of sentences (Experiment 1) and narrative texts (Experiment 2). The results of these retrospective memory tasks replicated that of the prospective memory task and are most consistent with an event cognition account. These results also suggest that encoding and referent event structures may affect some levels of representation (e.g., the surface form) more than others (e.g., the textbase and event model). Overall, we demonstrate that event structure has principled influences on memory apart from the nature of the materials or the task. Moreover, we discuss how these findings are inconsistent with more traditional theories of memory processing, such as associative interference and spreading activation accounts.

Failure to accept retractions: A contribution to the continued influence effect.

Previous research has shown that when information about a narrative event is retracted, people continue to use that information even though it has been explicitly identified as incorrect. Not only can this occur for implicitly inferred information, but also when the change is stated explicitly. The current study explored whether this effect reflects, at least in part, an unwillingness of some readers to accept changes to their understanding. Experiment 1 assessed this using a continued influence effect paradigm with an additional probe asking whether participants believed the explicitly stated change. Most did not. Those that did accept it showed evidence of a reduced use of the incorrect information, while those that did not accept it performed similarly to those who received no correction (control). Experiment 2 included an additional explicit instruction that participants could say "don't know" if they were unsure of how to respond. The pattern of results was largely the same as for Experiment 1. Experiment 3 modified the alternative account to increase plausibility, and added two additional stories/question sets to ensure effects were not limited to one set of materials. A greater number of participants found the retractions believable than in Experiments 1 and 2. Nonetheless, a similar pattern of results was found. Overall, these findings suggest that at least some of the evidence for the continued use of retracted information may be due to some people not accepting the retraction, even in the absence of external motivation to disregard it.

Location-based prospective memory.

This study explores location-based prospective memory. People often have to remember to do things when in a particular location, such as buying tissues the next time they are in the supermarket. For event cognition theory, location is important for structuring events. However, because event cognition has not been used to examine prospective memory, the question remains of how multiple events will influence prospective memory performance. In our experiments, people delivered messages from store to store in a virtual shopping mall as an ongoing task. The prospective tasks were to do certain activities in certain stores. For Experiment 1, each trial involved one prospective memory task to be done in a single location at one of three delays. The virtual environment and location cues were effective for prospective memory, and performance was unaffected by delay. For Experiment 2, each trial involved two prospective memory tasks, given in either one or two instruction locations, and to be done in either one or two store locations. There was improved performance when people received instructions from two locations and did both tasks in one location relative to other combinations. This demonstrates that location-based event structure influences how well people perform on prospective memory tasks.

Observer memories may not be for everyone.

Six studies explored the preponderance of people who experience third-person perspective observer memories during autobiographical memory retrieval. The concept of first-person field versus observer memories has been extensively used in the areas of cognitive, social, and clinical psychology. An implicit assumption is the idea that most people use both of these perspectives. What varies are the circumstances that bias people to use one perspective over another for a given autobiographical memory. We challenge that assumption across six studies by showing that, while there are some people who report to regularly have observer memories, there are also those that report to rarely or never have them. These reports were found to be related to levels of reported dissociative experiences. We discuss how this difference in the experience of observer memories may also reflect other innate characteristics, and may correspond to predispositions for various pathologies, including depression, social phobia, and post-traumatic stress disorder.

Walking through doorways causes forgetting: recall.

The aim of the current study was to explore how the location updating effect is affected when people are tested using recall rather than recognition, which is what has been done in prior work. Differences in the memory processes involved with these two tasks lead to predictions for two different patterns of data. In Experiment 1, memory was tested by having participants recall the single object they were carrying or had just put down, whereas in Experiment 2, people sometimes needed to recall both objects. It was found that, unlike recognition test performance, a similar location updating effect was found for both Associated (what was currently being carried) and Dissociated (what was recently set down) objects. Moreover, when both objects were correctly recalled, there was a bias to remember them in the order that they were encountered. Finally, if only one object was correctly recalled, it was the Associated object that was currently being carried. Overall, these results are consistent with the Event Horizon Model of event cognition.

Driven to distraction: A lack of change gives rise to mind wandering.

How does the dynamic structure of the external world direct attention? We examined the relationship between event structure and attention to test the hypothesis that narrative shifts (both theoretical and perceived) negatively predict attentional lapses. Self-caught instances of mind wandering were collected while 108 participants watched a 32.5 min film called The Red Balloon. We used theoretical codings of situational change and human perceptions of event boundaries to predict mind wandering in 5-s intervals. Our findings suggest a temporal alignment between the structural dynamics of the film and mind wandering reports. Specifically, the number of situational changes and likelihood of perceiving event boundaries in the prior 0-15 s interval negatively predicted mind wandering net of low-level audiovisual features. Thus, mind wandering is less likely to occur when there is more event change, suggesting that narrative shifts keep attention from drifting inwards.

Event Boundaries in Memory and Cognition.

Research on event cognition is rapidly developing and is revealing fundamental aspects of human cognition. In this paper, we review recent and current work that is driving this field forward. We first outline the Event Horizon Model, which broadly describes the impact of event boundaries on cognition and memory. Then, we address recent work on event segmentation, the role of event cognition in working memory and long-term memory, including event model updating, and long term retention. Throughout we also consider how event cognition varies across individuals and groups of people and consider the neural mechanisms involved.

Compression of environmental representations following interactions with objects.

Previous work reveals that interacting with all objects in an environment can compress spatial memory for the entire group of objects. To assess the scope and magnitude of this effect, we tested whether interacting with a subset of objects compresses spatial memory for all objects in an environment. Participants inspected objects in one or two unmarked regions of space, then recalled the distances between pairs of objects from memory. One group of participants picked up objects in both regions, a second group picked up objects in one region and passively viewed objects in the other region, and a third group passively viewed objects in both regions. When participants manually interacted with objects, they recalled shorter object-pair distances throughout the environment. The magnitude of this effect was the same, regardless of whether participants interacted with all objects in the environment or just a subset of them. Together, these findings suggest that interacting with objects can compress environmental representations in memory, even when observers interact with a relatively small subset of objects.

Narrative event boundaries, reading times, and expectation.

During text comprehension, readers create mental representations of the described events, called situation models. When new information is encountered, these models must be updated or new ones created. Consistent with the event indexing model, previous studies have shown that when readers encounter an event shift, reading times often increase. However, such increases are not consistently observed. This paper addresses this inconsistency by examining the extent to which reading-time differences observed at event shifts reflect an unexpectedness in the narrative rather than processes involved in model updating. In two reassessments of prior work, event shifts known to increase reading time were rated as less expected, and expectedness ratings significantly predicted reading time. In three new experiments, participants read stories in which an event shift was or was not foreshadowed, thereby influencing expectedness of the shift. Experiment 1 revealed that readers do not expect event shifts, but foreshadowing eliminates this. Experiment 2 showed that foreshadowing does not affect identification of event shifts. Finally, Experiment 3 found that, although reading times increased when an event shift was not foreshadowed, they were not different from controls when it was. Moreover, responses to memory probes were slower following an event shift regardless of foreshadowing, suggesting that situation model updating had taken place. Overall, the results support the idea that previously observed reading time increases at event shifts reflect, at least in part, a reader's unexpected encounter with a shift rather than an increase in processing effort required to update a situation model.

Predicting Individual Action Switching in Covert and Continuous Interactive Tasks Using the Fluid Events Model.

The Fluid Events Model is aimed at predicting changes in the actions people take on a moment-by-moment basis. In contrast with other research on action selection, this work does not investigate why some course of action was selected, but rather the likelihood of discontinuing the current course of action and selecting another in the near future. This is done using both task-based and experience-based factors. Prior work evaluated this model in the context of trial-by-trial, independent, interactive events, such as choosing how to copy a figure of a line drawing. In this paper, we extend this model to more covert event experiences, such as reading narratives, as well as to continuous interactive events, such as playing a video game. To this end, the model was applied to existing data sets of reading time and event segmentation for written and picture stories. It was also applied to existing data sets of performance in a strategy board game, an aerial combat game, and a first person shooter game in which a participant's current state was dependent on prior events. The results revealed that the model predicted behavior changes well, taking into account both the theoretically defined structure of the described events, as well as a person's prior experience. Thus, theories of event cognition can benefit from efforts that take into account not only how events in the world are structured, but also how people experience those events.

Event boundaries and memory improvement.

The structure of events can influence later memory for information that is embedded in them, with evidence indicating that event boundaries can both impair and enhance memory. The current study explored whether the presence of event boundaries during encoding can structure information to improve memory. In Experiment 1, memory for a list of words was tested in which event structure was manipulated by having participants walk through a doorway, or not, halfway through the word list. In Experiment 2, memory for lists of words was tested in which event structure was manipulated using computer windows. Finally, in Experiments 3 and 4, event structure was manipulated by having event shifts described in narrative texts. The consistent finding across all of these methods and materials was that memory was better when the information was distributed across two events rather than combined into a single event. Moreover, Experiment 4 demonstrated that increasing the number of event boundaries from one to two increased the memory benefit. These results are interpreted in the context of the Event Horizon Model of event cognition.

Walking through doorways causes forgetting: Event structure or updating disruption?

According to event cognition theory, people segment experience into separate event models. One consequence of this segmentation is that when people transport objects from one location to another, memory is worse than if people move across a large location. In two experiments participants navigated through a virtual environment, and recognition memory was tested in either the presence or the absence of a location shift for objects that were recently interacted with (i.e., just picked up or set down). Of particular concern here is whether this location updating effect is due to (a) differences in retention intervals as a result of the navigation process, (b) a temporary disruption in cognitive processing that may occur as a result of the updating processes, or (c) a need to manage multiple event models, as has been suggested in prior research. Experiment 1 explored whether retention interval is driving this effect by recording travel times from the acquisition of an object and the probe time. The results revealed that travel times were similar, thereby rejecting a retention interval explanation. Experiment 2 explored whether a temporary disruption in processing is producing the effect by introducing a 3-second delay prior to the presentation of a memory probe. The pattern of results was not affected by adding a delay, thereby rejecting a temporary disruption account. These results are interpreted in the context of the event horizon model, which suggests that when there are multiple event models that contain common elements there is interference at retrieval, which compromises performance.