The sources of visual recency: Movement and language in serial recall

Four experiments examine the importance of movement—the sequential ordering of stimulus features—in producing recency in the ordered serial recall of visual lists. The written recall of handsigns produced more recency when they were seen moving than still (Experiment I). Number lists presented as moving bar figures showed more recency than numbers which were displayed in the normal way with all features displayed simultaneously (Experiment II). The order in which features of abstract shapes are displayed can, itself, determine recency (Experiment III). However, a final experiment showed that still lip pictures of speech sounds generate more recency than letters representing those speech sounds. Therefore movement of stimulus features need not account for the extensive recency advantage in remembering lipread lists. The theoretical implications of these findings are discussed.     

Age dissociates recency and lag recency effects in free recall

The temporal relations among word-list items exert a powerful influence on episodic memory retrieval. Two experiments were conducted with younger and older adults in which the age-related recall deficit was examined by using a decomposition method to the serial position curve, partitioning performance into (a) the probability of first recall, illustrating the recency effect, and (b) the conditional response probability, illustrating the lag recency effect (M. W. Howard & M. J. Kahana, 1999). Although the older adults initiated recall in the same manner in both immediate and delayed free recall, temporal proximity of study items (contiguity) exerted a much weaker influence on recall transitions in older adults. This finding suggests that an associative deficit may be an important contributor to older adults' well-known impairment in free recall.     

Moving and memorizing: Motor planning modulates the recency effect in serial and free recall

Motor planning has generally been studied in situations where participants carry out physical actions without a particular purpose. Yet in everyday life physical actions are usually carried out for higher-order goals. We asked whether two previously discovered motor planning phenomena - the end-state comfort effect and motor hysteresis - would hold up if the actions were carried out in the service of higher-order goals. The higher-order goal we chose to study was memorization. By focusing on memorization, we asked not only how and whether motor planning is affected by the need to memorize, but also how memory performance might depend on the cognitive demands of motor planning. We asked university-student participants to retrieve cups from a column of drawers and memorize as many letters as possible from the inside of the cups. The drawers were opened either in a random order (Experiment 1) or in a regular order (Experiments 2 and 3). The end-state comfort effect and motor hysteresis were replicated in these conditions, indicating that the effects hold up when physical actions are carried out for the sake of a higher-order goal. Surprisingly, one of the most reliable effects in memory research was eliminated, namely, the tendency of recent items to be recalled better than earlier items - the recency effect. This outcome was not an artifact of memory being uniformly poor, because the tendency of initial items to be recalled better than later items - the primacy effect - was obtained. Elimination of the recency effect was not due to the requirement that participants recall items in their correct order, for the recency effect was also eliminated when the items could be recalled in any order (Experiment 3). These and other aspects of the results support recent claims for tighter links between perceptual-motor control and intellectual (symbolic) processing than have been assumed in the past.     

The basis and implications of the restoration of a recency effect in immediate serial recall

When a spoken presentation of a supra-span sequence of to-be-remembered (TBR) items is followed immediately by a similarly-spoken non-TBR item (stimulus suffix) the typical salience of the terminal item in recall is almost destroyed. However, Salter (1975) observed restoration of salience when pre-terminal and terminal TBR items differed in category membership. Five experiments are reported which aimed to clarify the basis and locus of Salter's effect. Survival of salience for the heterogeneous item was found under the following conditions: with the occurrence of the item unpredictable from trial-to-trial (Experiment I); with enforced processing of the suffix (Experiment II); with performance of a secondary task during list presentation (Experiment III); with the requirement to retain both the location and identity of the item (Experiment IV); and with the item as the terminal member of a non-suffixed visual list (Experiment V). It is argued that the effect has a postcategorical locus, and that its origin is not in better registration (mediated by selective attention), but, rather, in the enhancement of retrieval (mediated by access to distinctive information encoded during presentation). It is suggested that the latter hypothesis may have wide application in accounting for many kinds of salience.     

The effect of articulatory suppression and manual tapping on serial recall

Concurrent tasks, such as articulatory suppression and manual tapping, are used to understand the mechanisms underlying short-term memory by overloading domain-specific resources. The present study addresses the debate regarding the theoretical frameworks accounting for interference in serial recall by comparing the effects of both the modality of concurrent tasks (verbal vs. spatial) as well as the state of the tasks (steady vs. changing) in both verbal and spatial recall. The findings indicate that the verbal changing-state concurrent task significantly impaired digit recall, whereas the spatial changing-state concurrent task significantly impaired block recall. The theoretical implications are discussed in the context of a multimodal working memory model with domain-specific resources and a unitary approach to short-term memory.     

Modality dependency of loss of recency in free recall

Summary Four experiments were carried out in which the probability of free recall of words as a function of serial position within lists was examined. The lists were presented either auditorily or visually, with subjects either silent or engaged in irrelevant articulation, and with recall either immediate or after an auditory or visual intervening task. The results provide evidence for the presence of modality-specific capacity limitations in primary memory, and also indicate that forgetting may occur in a last-in, first-out manner.The authors thank Nancy Chenier for assistance with Experiment 4, and two anonymous reviewers for their helpful comments. Research has been supported by the SRC (MM) and MRC (GVJ). Requests for offprints should be sent to Maryanne Martin, University of Oxford, Department of Experimental Psychology, South Parks Road, Oxford OX1 3UD, England.     

Rehearsal in immediate serial recall

We report for the first time overt rehearsal data in immediate serial recall (ISR) undertaken at three presentation rates (1, 2.5, and 5 sec/word). Two groups of participants saw lists of six words for ISR and were required either to engage in overt rehearsal or to remain silent after reading aloud the word list during its presentation. Typical ISR serial position effects were obtained for both groups, and recall increased with slower rates. When participants rehearsed, they tended to do so in a cumulative forward order up to Serial Position 4, after which the amount of rehearsal decreased substantially. There were similarities between rehearsal and recall data: Both broke down toward the end of longer sequences, and there were strong positive correlations between the maximum sequence of participants' rehearsals and their ISR performance. We interpret these data as suggesting that similar mechanisms underpin both rehearsal and recall in ISR.     

Phonological similarity and enhanced auditory recency in longer-term free recall

The effect of phonological similarity amongst list items on the modality effect was investigated in free recall with distraction activity interpolated before and after each list word. In Experiment 1 the distractor activity involved counting backward silently mouthing each number, and the modality effect was drastically attenuated by high similarity. This outcome is comparable with that found in immediate recall, and it is consistent with an echoic memory interpretation. In Experiment 2 the same backward-counting task was performed with each number being vocalized, and the modality effect was unaffected by phonological similarity. This outcome leads to the stronger conclusion that, under those conditions at least, the modality effect cannot be echoic. Implications of these findings for general theoretical accounts of the modality effect are discussed.     

A context-based theory of recency and contiguity in free recall

The authors present a new model of free recall on the basis of M. W. Howard and M. J. Kahana's temporal context model and M. Usher and J. L. McClelland's leaky-accumulator decision model. In this model, contextual drift gives rise to both short-term and long-term recency effects, and contextual retrieval gives rise to short-term and long-term contiguity effects. Recall decisions are controlled by a race between competitive leaky accumulators. The model captures the dynamics of immediate, delayed, and continual distractor free recall, demonstrating that dissociations between short- and long-term recency can naturally arise from a model in which an internal contextual state is used as the sole cue for retrieval across time scales.     

Empirical and theoretical limits on lag recency in free recall

One widely accepted empirical regularity in free recall holds that when people successively transition from report of one list item to another, they prefer transitions across short lags (e.g., by reporting items from adjacent serial positions) to transitions involving large lags. This regularity has provided crucial support for the temporal context model (TCM), a model of the evolution of temporal context in episodic memory (Howard & Kahana, 2002a). We report a reanalysis of 14 data sets that shows that, contrary to the presumed preference for short lags, people often produce transitions with larger lags during recall. We show that these data cannot be accommodated by the TCM. We furthermore show that existing applications of the model have, for mathematical convenience, introduced assumptions that have circumvented its core principle of context evolution. When we instantiated the TCM as it was actually described, with a gradually evolving context, we found that its behavior qualitatively departed from that of the version currently implemented, but that the model was still unable to capture the nature of transitions in free recall. We conclude that the TCM requires further modification and development before it can explain the data that constitute its main source of support. Supplementary materials relevant to this article can be downloaded from the Psychonomic Society’s Norms, Stimuli, and Data Archive, www.psychonomic .org/archive.     

Proactive interference in immediate serial recall

Two experiments yielded significant inter-list proactive interference (PI) in immediate serial recall of nine-consonants lists. This argues against the assumption that intra-trial rehearsal is sufficiently powerful to prevent PI from occurring. In the first experiment PI proved to be more pronounced in the case of visually than of auditorily presented lists to the extent that the modality effect on the prerecent items could be completely attributed to PI. PI also enlarged the effect of output interference through reversed order recall. These findings were confirmed in the second experiment which also showed that the effect of PI persisted at a slower presentation rate, suggesting that the role of rehearsal in counteracting PI should not be overestimated. Implications of these results for current notions on short-term retention are discussed.     

Transposition asymmetry in immediate serial recall

When participants confuse the position of items in immediate serial recall, they tend to recall transposed items too early rather than too late. This asymmetry of transposition errors was observed in four experiments. It increased as a function of list length, but was independent of report order, output position, cueing condition, and recall mode. The transposition asymmetry is consistent with error patterns in free recall and in regular speech production where transpositions are usually forward-looking. The asymmetry of transposition errors is discussed in terms of models of serial memory.     

Transposition asymmetry in immediate serial recall

When participants confuse the position of items in immediate serial recall, they tend to recall transposed items too early rather than too late. This asymmetry of transposition errors was observed in four experiments. It increased as a function of list length, but was independent of report order, output position, cueing condition, and recall mode. The transposition asymmetry is consistent with error patterns in free recall and in regular speech production where transpositions are usually forward‐looking. The asymmetry of transposition errors is discussed in terms of models of serial memory.     

Output order in immediate serial recall

In two experiments, we examined the effect of output order in immediate serial recall (ISR). In Experiment 1, three groups of participants saw lists of eight words and wrote down the words in the rows corresponding to their serial positions in an eight-row response grid. One group was precued to respond in forward order, a second group was precued to respond in any order, and a third group was postcued for response order. There were significant effects of output order, but not of cue type. Relative to the forward output order, the free output order led to enhanced recency and diminished primacy, with superior performance for words output early in recall. These results were replicated in Experiment 2 using six-item lists, which further suggests that output order plays an important role in the primacy effect in ISR and that the recency items are most highly accessible at recall.     

Primacy and recency in primed free association and associative cued recall

Two experiments compared the serial positions of primed words in an implicit free association test with words recalled in a cued recall test. In both tests, weakly or strongly related word pairs were studied, and the first words of each pair formed the test cues. In the implicit test, weakly related words pairs showed primacy and extended recency effects but strongly related word pairs did not. In the explicit test, both weakly and strongly related word pairs showed primacy and extended recency effects. These functional dissociations between implicit and explicit memory tests indicate that strongly related word pairs are encoded together because they have unitized memory representations that function as integrated units without requiring any additional associative links to be made, but that an additional system or process is required to strengthen weakly related word pairs during encoding. In addition, a further additional system or process is accessed by explicit retrieval.     

Influences of environmental context on the recency effect in free recall

A total of 208 undergraduate participants incidentally encoded a list of seven pairs of familiar words in two experiments. A 30-sec calculation task was imposed before and after each pair was encoded. Participants received a free recall test 24 h (Experiment 1) or 10 min (Experiment 2) after the encoding session, under conditions in which the original environmental context was reinstated or not. The environmental context was manipulated in terms of the combination of the physical features of the room, the subsidiary task conducted, the experimenter (Experiment 1), or background music (Experiment 2). A recency effect appeared when the original environmental context was reinstated in both experiments, even though the IPI/RI ratio was too small to produce recency effects according to the ratio rule. The results imply that the environmental context should be taken into account for the recency effect.     

Overwriting of phonemic features in serial recall

We tested two explanations of the phonological similarity effect in verbal short‐term memory: The confusion hypothesis assumes that serial positions of similar items are confused. The overwriting hypothesis states that similar items share feature representations, which are overwritten. Participants memorised a phonologically dissimilar list of CVC‐trigrams (Experiment 1) or words (Experiment 2 and 3) for serial recall. In the retention interval they read aloud other items. The material of the distractor task jointly overlapped one item of the memory list. The recall of this item was impaired, and the effect was not based on intrusions from the distractor task alone. The results provide evidence for feature overwriting as one potential mechanism contributing to the phonological similarity effect.     

Inverting the modality effect in serial recall

Differences in recall ability between immediate serial recall of auditorily and visually presented verbal material have traditionally been considered restricted to the end of to-be-recalled lists, the recency section of the serial position curve (e.g., Crowder & Morton, 1969). Later studies showed that--under certain circumstances--differences in recall between the two modalities can be observed across the whole of the list (Frankish, 1985). However in all these studies the advantage observed is for recall of material presented in the auditorily modality. Six separate conditions across four experiments demonstrate that a visual advantage can be obtained with serial recall if participants are required to recall the list in two distinct sections using serial recall. Judged on a list-wide basis, the visual advantage is of equivalent size to the auditory advantage of the classical modality effect. The results demonstrate that differences in representation of auditory and visual verbal material in short-term memory persist beyond lexical and phonological categorization and are problematic for current theories of the modality effect.