Evidence for similar principles in episodic and semantic memory: The presidential serial position function

When people recall a list of items that they have just experienced (an episodic memory task), the resulting serial position function looks strikingly similar to that observed when people are asked to recall the presidents of the United States (a semantic memory task). Despite the similarity in appearance, there is disagreement about whether the two functions arise from the same processes. A local distinctiveness model of memory, SIMPLE, successfully fit the presidential data using two underlying dimensions: one corresponding to item (or presidential) distinctiveness and the other to order (or positional) distinctiveness. According to the model, presidential primacy and recency are due to the same mechanisms that give rise to primacy and recency effects in both shortand long-term episodic memory. All of these primacy and recency effects reflect the relative distinctiveness principle (Surprenant & Neath, 2009): Items will be well remembered to the extent that they are more distinct than competing items at the time of retrieval.     

Distinctiveness and serial position functions in implicit memory

Serial position functions, with their characteristic primacy and recency effects, are ubiquitous in episodic memory tasks, and have also been observed in tasks tapping semantic memory. However, only one experiment, [Raanaas, R. K., & Magnussen, S. (2006a). Serial position effects in implicit memory. European Journal of Cognitive Psychology, 18, 398–414. doi:10.1080/09541440500162065], has demonstrated primacy and recency effects in implicit memory using an indirect memory test. In Experiment 1, we replicate this finding and in Experiment 2, we confirm a prediction that holds only if the serial position function observed in Experiment 1 was a “real” serial position function. These results confirm the presence of serial position functions in implicit memory and also support a general prediction of the relative distinctiveness principle that serial position functions should obtain whenever a set of items are ordered along a relevant dimension.     

Serial position effects in semantic memory: reconstructing the order of verses of hymns

Serial position effects (primacy and recency) have been consistently demonstrated in both short- and long-term episodic memory tasks. The search for corresponding effects in semantic memory tasks (e.g., reconstructing the order of U.S. presidents) has been confounded by factors such as differential exposure to stimuli. In the present study, the stimuli were six-verse hymns that would have been sung from the first to the last verse by churchgoers on numerous occasions. Participants were presented with the verses of each hymn in random order and were required to reconstruct the correct order. Primacy and recency effects were significantly more evident for churchgoers than for nonchurchgoers. Moreover, error gradients were steeper than chance for churchgoers but not for nonchurchgoers; in other words, churchgoers' errors were more likely to be close to the correct position than further away. These findings provide the first unequivocal demonstration of serial position effects in semantic memory.     

Auditory and visual serial position functions obey different laws

Rhesus monkeys were tested in serial probe recognition tasks with either travel slide pictures or natural sounds. Tests with four-item lists produced serial position functions that were essentially opposite in shape for the two modalities and changed in opposite ways with retention interval. For visual memory, the primacy effect grew and the recency effect dissipated with retention interval. Capuchin monkeys, humans, and pigeons showed similar results. For auditory memory with rhesus monkeys, the recency effect grew and the primacy effect dissipated with retention interval. These results taken together, along with results from rehearsal tests of monkeys and humans, implicate two passive memory processes with different time courses. Interference among items within auditory lists was manipulated by varying the time between items and categories of items. Interference across lists was manipulated by varying the item pool size and, hence, item repetitions. Changes in the auditory serial position functions indicated that proactive and retroactive interference may have been instrumental in these dynamically changing serial position functions. Implications for theories and models of memory are discussed.     

Metacognition and learning about primacy and recency effects in free recall: The utilization of intrinsic and extrinsic cues when making judgments of learning

Although memory researchers know about primacy and recency effects, it is unclear whether students are aware of these effects and incorporate them when making judgments of learning (JOLs). The present research examined how participants use serial position information (extrinsic cues) when making JOLs after studying each item and showed that participants rely on the intrinsic qualities of the items and underestimate primacy and recency effects. However, when participants made JOLs prior to studying each item and engaged in multiple study-test sessions, their JOLs accurately reflected recall, as well as when serial position information was explicitly provided during the study phase. The findings are interpreted in a cue utilization framework and suggest that under certain conditions, participants can predict primacy and recency effects.     

Inter- and intra-individual variation in immediate free recall: an examination of serial position functions and recall initiation strategies

Serial position functions in immediate free recall have been historically noted for their bowed shape, where items presented at the beginning (primacy) and end (recency) of a list are better remembered than those presented in the middle. While extensive work has examined these effects, researchers typically ignore the systematic differences among individuals that likely contribute, but are lost when using an aggregate function. In the current study, inter- and intra-individual differences in serial position functions and differences in recall strategies were examined. Participants performed a free recall task on multiple lists. Three groups of participants were derived based on the relative profiles in their serial position functions. These groups differed in the extent that they output mainly primacy items, recency items, or both primacy and recency items. Performance on immediate free recall and on cognitive ability tasks was compared between these three groups. Systematic inter- and intra-individual variation in recall strategies led to differential profiles of performance in immediate free recall, which was also related to the additional cognitive ability measures. Performance on a task can be due to the utilisation of a variety of control processes that emphasise various components of that task over other components.     

Amnesia,rehearsal, and temporal distinctiveness models of recall

Classical amnesia involves selective memory impairment for temporally distant items in free recall (impaired primacy) together with relative preservation of memory for recency items. This abnormal serial position curve is traditionally taken as evidence for a distinction between different memory processes, with amnesia being associated with selectively impaired long-term memory. However recent accounts of normal serial position curves have emphasized the importance of rehearsal processes in giving rise to primacy effects and have suggested that a single temporal distinctiveness mechanism can account for both primacy and recency effects when rehearsal is considered. Here we explore the pattern of strategic rehearsal in a patient with very severe amnesia. When the patient’s rehearsal pattern is taken into account, a temporal distinctiveness model can account for the serial position curve in both amnesic and control free recall. The results are taken as consistent with temporal distinctiveness models of free recall, and they motivate an emphasis on rehearsal patterns in understanding amnesic deficits in free recall.     

Auditory List Memory in Rhesus Monkeys

Auditory memory of 2 rhesus monkeys was tested in a serial probe recognition task. Lists of four environmental or natural sounds were followed by a retention interval and a test. The test matched one of the list items on half of the trials. The retention interval was varied across sessions. Six experiments showed similar results and changes in the serial position function. At short retention intervals, there was good memory for first list items (primacy effect) and poor memory for last list items. At intermediate retention intervals, memory improved for last list items (recency effect). At long retention intervals (20 s and 30 s), the recency effect was strong, and the primacy effect had dissipated. These auditory primacy and recency effects and their changes with retention interval were opposite to those for visual memory. Implications for processes and mechanisms of memory are discussed.     

Do updating tasks involve updating? Evidence from comparisons with immediate serial recall

Updating tasks require participants to process a sequence of items, varying in length, and afterwards to remember only a fixed number of the elements of the sequence; the assumption being that participants actively update the to-be-recalled list as presentation progresses. However recent evidence has cast doubt on this assumption, and the present study examined the strategies that participants employ in such tasks by comparing the serial position curves found in verbal and visuo-spatial updating tasks with those seen in standard serial recall tasks. These comparisons showed that even when the same number of items are presented or recalled, participants perform less well in an updating than a serial recall context. In addition, while standard serial position effects were observed for serial recall, marked recency and reduced or absent primacy effects were seen in updating conditions. These findings suggest that participants do not typically adopt a strategy of actively updating the memory list in updating tasks, but instead tend to wait passively until the list ends before trying to recall the most recently presented items.     

Do updating tasks involve updating? Evidence from comparisons with immediate serial recall

Updating tasks require participants to process a sequence of items, varying in length, and afterwards to remember only a fixed number of the elements of the sequence; the assumption being that participants actively update the to-be-recalled list as presentation progresses. However recent evidence has cast doubt on this assumption, and the present study examined the strategies that participants employ in such tasks by comparing the serial position curves found in verbal and visuo-spatial updating tasks with those seen in standard serial recall tasks. These comparisons showed that even when the same number of items are presented or recalled, participants perform less well in an updating than a serial recall context. In addition, while standard serial position effects were observed for serial recall, marked recency and reduced or absent primacy effects were seen in updating conditions. These findings suggest that participants do not typically adopt a strategy of actively updating the memory list in updating tasks, but instead tend to wait passively until the list ends before trying to recall the most recently presented items.     

Serial position phenomena: Training and retrieval effects

With successive free recall lists primacy items are usually among the first to be reported on the initial list. Recency items will then take over and be first reported on later lists. This retrieval shift was studied under varied list conditions designed to counteract ordinary position effects, and proved to be a stable and resistent effect. One experiment had subjects practice on five different free recall lists over three trials, and the results agreed with the hypothesis that primacy reduction is caused by proactive interference rather than by the primacy to recency report shift. Experiments of the usual one-session laboratory type have consistently failed to show practice effects on serial lists with incompatible spatial and temporal order cues. In a case study of five subjects examined over a period of three months only slight improvement on single-trial lists was observed. However, when naive subjects were given four successive trials with the same type of cue-conflict list, prominent practice effects were easily demonstrated. Observations confirmed the assumption that repeated presentations of items located in middle list positions may counteract the privilege of primacy and recency positions. When repetitions were made within contracting and expanding lists, the results proved that active anchoring, making itself visible as primacy effects, is feasible with contracting lists but difficult with expanding lists. Active performance of list learning strategies generally results in primacy effects; whereas passive shortcut procedures, in learning and retrieval of information, produce recency effects. Predominant recency effects are symptoms of difficult task situations only partially mastered by the learner; primacy effects point to more successful elaboration. Overall, serial position effects do not seem to be due to structural memory stores so much as to the working of cognitive strategy factors. A problem-solving theory was presented as an alternative to information-processing models of serial learning and memory.     

Presence and absence of serial position effects in short-term memory

The nature of serial position effects was examined with a method based on pooled observations. With standard list presentation procedures, primacy and recency effects in short and long-term memory were observed. When learning operations were directed away from end positions, by changes in presentation rate, by within-list repetitions, by focusing instructions, and by differential grouping of list items, the usual serial position pattern was found to be affected in several ways, primacy and recency effects often being absent. Attempts to create anchor points and to ascribe serial positions verbally, were generally found to favour recency over primacy effects. Taken as a whole, the results, all of them based on recall of lits given a single presentation, indicated that position phenomena are more easily influenced by functional than by structural factors. The findings were explained in terms of a two-stage conception of serial learning, doing without specific storage assumptions.     

Semantic cuing and the scale insensitivity of recency and contiguity

In recalling a set of previously experienced events, people exhibit striking effects of recency, contiguity, and similarity: Recent items tend to be recalled best and first, and items that were studied in neighboring positions or that are similar to one another in some other way tend to evoke one another during recall. Effects of recency and contiguity have most often been investigated in tasks that require people to recall random word lists. Similarity effects have most often been studied in tasks that require people to recall categorized word lists. Here we examine recency and contiguity effects in lists composed of items drawn from 3 distinct taxonomic categories and in which items from a given category are temporally separated from one another by items from other categories, all of which are tested for recall. We find evidence for long-term recency and for long-range contiguity, bolstering support for temporally sensitive models of memory and highlighting the importance of understanding the interaction between temporal and semantic information during memory search.     

Serial recall of colors: Two models of memory for serial order applied to continuous visual stimuli

This study investigated the effects of serial position and temporal distinctiveness on serial recall of simple visual stimuli. Participants observed lists of five colors presented at varying, unpredictably ordered interitem intervals, and their task was to reproduce the colors in their order of presentation by selecting colors on a continuous-response scale. To control for the possibility of verbal labeling, articulatory suppression was required in one of two experimental sessions. The predictions were derived through simulation from two computational models of serial recall: SIMPLE represents the class of temporal-distinctiveness models, whereas SOB-CS represents event-based models. According to temporal-distinctiveness models, items that are temporally isolated within a list are recalled more accurately than items that are temporally crowded. In contrast, event-based models assume that the time intervals between items do not affect recall performance per se, although free time following an item can improve memory for that item because of extended time for the encoding. The experimental and the simulated data were fit to an interference measurement model to measure the tendency to confuse items with other items nearby on the list—the locality constraint—in people as well as in the models. The continuous-reproduction performance showed a pronounced primacy effect with no recency, as well as some evidence for transpositions obeying the locality constraint. Though not entirely conclusive, this evidence favors event-based models over a role for temporal distinctiveness. There was also a strong detrimental effect of articulatory suppression, suggesting that verbal codes can be used to support serial-order memory of simple visual stimuli.     

Temporal-spatial memory: retrieval of spatial information does not reduce recency

Factors influencing the shape of serial position curves in non-verbal serial short-term memory were examined, using a task testing memory for the position of dots. Similar recency slopes were found when both position and order were recalled (Experiment 1A) and when order only was required (Experiment 1B). This observation was confirmed and tested further in conditions requiring the same encoding but different amounts of spatial information at retrieval (Experiment 2). However, Experiment 2 also revealed an effect of spatial information retrieval on the overall level of memory for recency items. Overall, the results indicate that spatial items produce bow-shaped serial positions curves in tasks requiring the maintenance of order information and that recency is affected by the demand on spatial information retrieval in terms of the overall level of performance but not in terms of the recency slope. These findings are contrary to what is found in the literature on serial verbal recall when both item and order information are required.     

Serial position effects in visual short-term memory for words and abstract spatial patterns

Two experiments tested the effects of list postion, and retention-interval in recognition for two distinct stimulus categories in young adults. Stimulus categories were spatial abstract patterns and words presented on a computer screen. At short delay intervals recency effects predominates and at longer delay intervals a primacy effect predominates in both experiments, indicating similar basic memory processes producing the serial position functions for the two different categories of visual stimuli, but as length of retention-interval increases, memory for first list items improves for words and remains constant for abstract patterns. Recency functions are similar for both stimulus categories tested.     

Examining the relationship between free recall and immediate serial recall: The serial nature of recall and the effect of test expectancy

In two experiments, we examined the relationship between free recall and immediate serial recall (ISR), using a within-subjects (Experiment 1) and a between-subjects (Experiment 2) design. In both experiments, participants read aloud lists of eight words and were precued or postcued to respond using free recall or ISR. The serial position curves were U-shaped for free recall and showed extended primacy effects with little or no recency for ISR, and there was little or no difference between recall for the precued and the postcued conditions. Critically, analyses of the output order showed that although the participants started their recall from different list positions in the two tasks, the degree to which subsequent recall was serial in a forward order was strikingly similar. We argue that recalling in a serial forward order is a general characteristic of memory and that performance on ISR and free recall is underpinned by common memory mechanisms.     

系列包含的项目数、项目之间的间隔时间与系列位置效应

以中国汉字为材料,考察系列包含的项目数、项目之间的时间间隔与系列位置曲线不同部分记忆性质分化的关系。结果表明,(1)提取过程的重要性。(2)在包含11个项目、并且项目之间的时间间隔为400毫秒的系列中,系列位置曲线的首因部分表现为联想记忆的性质,是依赖于线索的提取;近因部分表现为绝对记忆的性质,是依赖于记忆痕迹的提取。(3)系列位置曲线不同部分记忆性质的分化,于系列包含的项目数和项目之间的间隔时间有关,结果体现出这两个因素的交互作用。     

Memory for lists of spatial events in the rat

Three experiments are reported in which rats were presented with lists of spatial events or responses in distinct visual contexts, and retention subsequently was measured for the events occuring at each serial position. In Experiments 1 and 2, lists contained different numbers of forced choices on successively presented T-mazes, and memory for each serial position was tested on each trial. In Experiment 3, lists were made up of different numbers of forced entries into randomly ordered arms on the eight-arm radial maze, and memory for one serial position was probed on each trial. All three experiments yielded serial position curves which demonstrated recency effects but no primacy effects. Comparisons of retention for different list lengths within each experiment indicated that retention of shorter lists was equivalent to retention of the final items of longer lists and superior to retention of the initial items on longer lists. This pattern of results indicated that there was no evidence of proactive inhibition in the serial position curves. Analysis of input and output interference effects and the results of control tests suggested that both retroactive inhibition and time-based forgetting processes were responsible for recency effects.     

Primacy and recency effects in nonhuman primates.

The reports of primacy and recency memory effects in nonhuman primates have been criticized because they have all used an initiating response. That is, the presentation of the to-be-remembered list of items was always contingent on a response being initiated by the nonhuman primate. It has been argued that this initiating response improves performance for early items in the list, resulting in the occurrence of the primacy effect, independent of any memory processing mechanism. This criticism was addressed in the present study by not using an initiating response prior to the presentation of the list. Nevertheless, both a primacy and a recency effect were observed in all 6 rhesus monkeys evaluated using a serial probe recognition task. Thus, the results are similar to those for humans, in that both primacy and recency effects can be obtained in nonhuman primates. A brief literature review is included, and it is proposed that the primacy and recency effects observed in humans, nonhuman primates, and infraprimates can be explained within the context of the configural-association theory.