Absence of a cross-modal “suffix effect” in short-term memory

Three experiments are reported involving the presentation of lists of either letters or digits for immediate serial recall. The main variable was the presence or absence of a suffix-prefix, an item (tick or cross) occurring at the end of the list which had to be copied before recall of the stimulus list. With auditory stimuli and an auditory suffix-prefix there was a large and selective increase in the number of errors on the last few serial positions—the typical “suffix effect”. The suffix effect was not found with auditory stimuli and a visual suffix-prefix nor with a visual stimulus and an auditory suffix-prefix. These results are interpreted as supporting a model for short-term memory proposed by Crowder and Morton (1969) in which it is suggested that with serial recall information concerning the final items following auditory presentation has a different, precategorical, origin from that concerning other items.     

Time of day and processing strategy in free recall

Consistent effects of time of day have been observed in digit span/sequence performance, and in the immediate memory for information presented in prose. However, studies using syntactically unstructured word lists have yielded inconsistent results. Three experiments were conducted that examined the free recall of 15 word lists. In all three, immediate recall from the pre-recency positions was found to be superior in the morning to the afternoon. This superiority disappeared after a 20-min delay (Experiment 1) and under articulatory suppression (Experiment III), but was unaffected by a manipulation that equated recall order (Experiment II). Immediate recall from the recency positions showed a W-shaped trend over the day (Experiment I) that might account for the inconsistencies previously reported. It is suggested that the changes in recall from the pre-recency positions may reflect a decrease in maintenance, and increase in elaboration, over the day. Such a change in processing strategy could itself reflect an increase in attentional selectivity associated with the changes in basal arousal level commonly held to occur over the day.     

The word-length effect in probed and serial recall

The word-length effect in immediate serial recall has been explained as the possible consequence of rehearsal processes or of output processes. In the first experiment adult subjects heard lists of five long or short words while engaging in articulatory suppression during presentation. Full serial recall or probed recall for a single item followed the list either immediately or after a 5-second delay to encourage rehearsal. The word-length effect was not influenced by recall delay, but was much smaller in probed than in serial recall. Examination of the serial position curves suggested that this might be due to a recency component operating in probed recall. Experiment 2 confirmed a word-length-insensitive recency effect in probed recall and showed that this was resistant to an auditory suffix, unlike the small recency effect found in serial recall. Experiment 3 used visual presentation without concurrent articulation. Under these conditions there was no recency effect for either recall method, but the word-length effect was again much smaller in probed than in serial recall. This was confirmed in Experiment 4, in which the presentation of serial and probed recall was randomized across trials, showing that the differences between recall methods could not be due to encoding strategies. We conclude that for visual presentation, at least part of the word-length effect originates in output processes. For auditory presentation the position is less clear, as serial and probed recall appear to draw on different resources. The nature of the output processes that may give rise to word-length effects is discussed.     

Ineffectiveness of visual distinctiveness in enhancing immediate recall

Glenberg (1984) and others have theorized that greater recency effects are obtained with auditory as opposed to visual presentation because of greater temporal distinctiveness of items in auditory sequences. We tested a number of ways of enhancing visual distinctiveness, including the use of color, spatial location, and minimized visual interference. None of the seven experiments provided any evidence of improved recall from enhanced visual distinctiveness. In particular, no increase in recency effects was obtained with increased distinctiveness. Additional analyses of pairwise dependency in recall across serial positions also failed to show any evidence of the near-independence of recall of the terminal item that characterizes recall of auditory sequences. Visual-perceptual distinctiveness does not get mapped in any simple way onto memorial distinctiveness in an immediate-serial-recall task.     

Recency effects in delayed recall of mouthed stimuli

Auditory presentation leads to greater recency effects in recall than does visual presentation. This phenomenon (the modality effect) is found in both free and serial recall and in both immediate and delayed recall. Silent mouthing of visually presented stimuli also leads to enhanced recency effects in immediate serial recall. Two experiments reported here extend the generality of the mouthing effect by demonstrating that enhanced recency effects of mouthed stimuli occur in delayed serial and free recall. These results are inconsistent with theories that attribute the modality effect to a purely auditory sensory memory.     

Enumeration produces poor primacy for tactile presentation relative to visual and auditory presentation as the only modality effect

Methodological biases may help explain the modality effect, which is superior recall of auditory recency (end of list) items relative to visual recency items. In 1985 Nairne and McNabb used a counting procedure to reduce methodological biases, and they produced modality-like effects, such that recall of tactile recency items was superior to recall of visual recency items. The present study extended Nairne and McNabb's counting procedure and controlled several variables which may have enhanced recall of tactile end items or disrupted recall of visual end items in their study. Although the results of the present study indicated general serial position effects across tactile, visual, and auditory presentation modalities, the tactile condition showed lower recall for the initial items in the presentation list than the other two conditions. Moreover, recall of the final list item did not differ across the three presentation modalities; modality effects were not found. These results did not replicate the findings of Nairne and McNabb, or much of the past research showing superior recall of auditory recency items. Implications of these findings are discussed.     

Recency and suffix effects in serial recall of musical stimuli

Auditory presentation of verbal items leads to larger recency effects in recall than visual presentation. This enhanced recency can be eliminated if a stimulus suffix (an irrelevant sound) follows the last item. Four experiments tested the hypothesis that recency and suffix effects in serial recall result from a speech-specific process. It was demonstrated that serial recall of musical notes played on a piano exhibited substantial recency effects. These recency effects were reduced when the list items were followed by either a piano chord or the word start. However, a white-noise suffix had no effect on recency. This pattern of data is consistent with current work on auditory perception and places constraints on theories of recency and suffix effects.     

Mechanisms of aural encoding: VII. Differences in consonant and vowel recall in a Peterson and Peterson short-term memory paradigm

Ss either saw or heard lists of three syllables which differed by their initial consonant phoneme or their final vowel phoneme. After 5 or 15 sec of mental arithmetic, Ss were required to recall the syllables. Following auditory presentation, vowels were recalled more accurately than consonants in all serial positions and at both delays. In addition, spoken consonants and vowels showed primacy and recency effects. Following visual presentation, consonants and vowels were recalled with equal accuracy at both delays, and no recency effects were observed. These data suggest that superior recall of vowels over consonants results from differential decay of these stimuli in an acoustic storage. These data are consistent with previous experiments showing that, during serial recall, the final vowels in a sequence are recalled more accurately than the final consonants.     

Recency and the modality effect in immediate ordered recall

In immediate ordered recall, recency is the improved recall of the last item of a presentation, and the modality effect is the advantage for an acoustic presentation over a subvocalized visual presentation, primarily occurring at the last serial position. Experiment 1 tested grouped presentations. There was a modality effect for the first item of the last group, even though that item was at the third-to-last or fourth-to-last serial position. In Experiment 2, for vocalized presentations of syllables ending in a, recency was larger for staccato speech than legato speech; for subvocalized presentations, there was a substantial recency for the legato style. In Experiment 3, recency was larger for a set of syllables ending in ATE than for a set of syllables ending in AME. These results suggest that recency cannot be explained by the existence of a fixed-capacity store, auxiliary to the auditory short-term store, that retains only some types of presentations. It is suggested instead that recency might reflect an auxiliary method of using the information in the auditory short-term store.     

Adding sound to lipread lists: The effects on serial recall of adding an auditory pulse train and a pure tone to silently lipread lists

These investigations examined subjects’ serial recall of lipread digit lists accompanied by an auditory pulse train. The pulse train indicated the pitch of voiced speech (buzz-speech) of the seen speaker as she was speaking. As a purely auditory signal, it could not support item identification. Such buzz-speech recall was compared with silent lipread list recall and with the recall of buzz-speech lists to which a pure tone had been added (buzz-and-beep lists). No significant difference in overall accuracy of recall emerged for the three types of lipread list; however, there were significant differences in the shape of the serial recall function for the three list types. Recency characterized the silent and the buzz-speech lists, and these lists differed in their varying susceptibilities to a range of speechlike suffixes. By contrast, adding a pure tone to a buzz-speech list (buzz-and-beep) produced little recency and no further recall loss as a function of suffix type. We discuss these effects with reference to the contrast betweensensory-similarity and speechlikeness accounts of auditory recency and suffix effects. Sensory similarity accounts cannot capture the effects reported here, but processing in a speech mode (buzz-and-beep) need not always lead to recency effects like those resulting from clearly heard or lipread lists.     

Primacy and recency effects in immediate free recall of sequences of spatial positions

This study evaluated the serial position curve based on free recall of spatial position sequences. To evaluate the memory processes underlying spatial recall, some manipulations were introduced by varying the length of spatial sequences (Exp. 1) and modifying the presentation rate of individual positions (Exp. 2). A primacy effect emerged for all sequence lengths, while a recency effect was evident only in the longer sequences. Moreover, slowing the presentation rate increased the magnitude of the primacy effect and abolished the recency effect. The main novelty of the present results is represented by the finding that better recall of early items in a sequence of spatial positions does not depend on the task requirement of an ordered recall but it can also be observed in a free recall paradigm.     

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.     

Explanations of grouping in immediate ordered recall

This article is about grouping in immediate ordered recall. The following findings are reported: (1) grouping a presentation improves recall, even when steps are taken to prevent rehearsal; (2) grouping primarily improves recall of the items adjoining the grouping, creating primacy and recency within groups; and (3) this primacy and recency are found even when single, isolated errors in recall are considered. These results suggest that the effects of grouping cannot be fully explained by rehearsal, chunking, or the number of directions in which an item can be transposed. It is suggested instead that (1) the auditory short-term store contains an unparsed and uncategorized representation that must be parsed and categorized just prior to recall, in a process of recovery; (2) items adjoining the boundary of a presentation are more easily recovered; and (3) grouping creates a boundary within the presentation. To support this explanation, a final experiment demonstrates an interaction between type of stimuli and serial position, with grouping most improving recall of adjoining phonemes.     

Is there a modality effect? Evidence for visual recency and suffix effects

In Experiment 1, four groups of 16 subjects performed ordered recall of six-syllable lists in both suffix and nonsuffix conditions. Sequential presentation of the lists varied for each group. In the auditory presentation, the syllables were delivered from one location only and were read aloud by the subjects. For the visual, spatially nondistributed presentation, the syllables appeared in one location only and were read silently. For visual, spatially distributed presentations, the syllables were spread out either vertically or horizontally and were read silently. Very robust recency and suffix effects were found in the auditory presentation, as well as in visual, spatially distributed presentations. In Experiment 2, 16 subjects performed ordered recall of visually presented lists with the items spread out vertically and conflicting spatial and temporal orders. A reliable recency effect was found for the final block of trials. In Experiment 3, 16 subjects performed ordered recall in the same conditions as in Experiment 2, except that they were instructed to recall the temporal order in which the spatial positions would be filled in. A bow-shaped curve and a strong recency effect were obtained.     

Serial-position effects on a free-recall task in bilinguals

In this study, we examined mechanisms that underlie free-recall performance in bilinguals' first language (L1) and second language (L2) through the prism of serial-position effects. On free-recall tasks, a typical pattern of performance follows a U-shaped serial-position curve, where items from the beginning of the list (the primacy effect) and items from the end of the list (the recency effect) are recalled with higher accuracy than items from the middle of the list. The present study contrasted serial-position effects on the free-recall task in Korean-English bilinguals' L1 vs. L2 and examined the relationship between an independent working memory (WM) measure and serial-position effects in bilinguals' two languages. Results revealed stronger pre-recency (primacy and middle) effects in L1 than in L2, but similar recency effects in the two languages. A close association was observed between WM and recall performance in the pre-recency region in the L1 but not in the L2. Together, these findings suggest that linguistic knowledge constrains free-recall performance in bilinguals, but only in the pre-recency region.     

Further evidence of interference between lipreading and auditory recency

In both free and backward recall, it is shown that auditory but not visual recency is greatly disrupted when subjects have to lipread, rather than read, a series of numbers in a distractor task interpolated between list presentation and recall. This selective interference effect extends the generality of a finding reported by Spoehr and Corin (1978) and adds to an accumulating body of evidence that seems inconsistent with acoustic or echoic memory interpretations of the enhanced recency recall typically observed in comparing auditory with visual presentation. Alternative interpretations are briefly considered.     

Levels of Processing and Retrieval: Recency Effects After Incidental Learning in A Reaction Time Task

In their development of the levels-of-processing approach to memory Craik and Jacoby (1975) proposed a dual-process theory of retrieval which involves both the scanning of recent episodic memory and a process of reconstruction in semantic memory. The theory predicts that a depth of processing effect will emerge only when the latter retrieval process is employed. Two experiments tested this prediction under the “conveyor-belt” assumption that scanning will be adopted for recent items while earlier items must be retrieved by reconstruction. An incidental-learning paradigm was employed, in which subjects performed an orienting reaction-time task on a sequence of word-pairs. Each word-pair was judged at either a semantic, phonemic or (in Experiment I) orthographic level of coding. In the first experiment half the subjects subsequently attempted free recall while half performed a recognition task; in the second experiment subjects were cued for recall in the last six serial positions, followed by free recall of the remaining items. A consistent “levels” effect emerged in both recall and recognition and this was particularly clearly observed in recency positions. A significant difference also emerged between positive and negative judgements. Although it is argued that these effects might emerge even in scanning it is concluded that these experiments provide no support for the proposal of two distinct retrieval modes.     

Contextual variability and serial position effects in free recall.

In immediate free recall, words recalled successively tend to come from nearby serial positions. M. J. Kahana (1996) documented this effect and showed that this tendency, which the authors refer to as the lag recency effect, is well described by a variant of the search of associative memory (SAM) model (J. G. W. Raaijmakers & R. M. Shiffrin, 1980, 1981). In 2 experiments, participants performed immediate, delayed, and continuous distractor free recall under conditions designed to minimize rehearsal. The lag recency effect, previously observed in immediate free recall, was also observed in delayed and continuous distractor free recall. Although two-store memory models, such as SAM, readily account for the end-of-list recency effect in immediate free recall, and its attenuation in delayed free recall, these models fail to account for the long-term recency effect. By means of analytic simulations, the authors show that both the end of list recency effect and the lag recency effect, across all distractor conditions, can be explained by a single-store model in which context, retrieved with each recalled item, serves as a cue for subsequent recalls.     

The effects of recoding and presentation format on recency and suffix effects

The primary linguistic theory of Shand and Klima (1981) hypothesizes that stimuli that cannot be directly processed without recoding are not in the primary linguistic mode of the subject and thus should lead to lesser recency and associated suffix effects. In three experiments, different normal hearing subjects learned to pair American Sign Language (ASL) stimuli, visual "quasivocables" (QVs), word-like letter strings, and auditory QVs with common English words. In the first experiment, the subjects were given sequences of ASL or QV stimuli and required to recall the associated words in strict serial order. In two other experiments involving auditory and visual presentation, respectively, subjects who had never been given paired associate training were required to recall the English words that had previously been associated with the ASL and QV stimuli, in a standard suffix paradigm. The results showed recency and suffix effects to be present only with auditorily presented QVs and words. Contrary to the predictions of the primary linguistic hypothesis, greater recency and larger suffix effects were present with the auditory QVs than with the auditory words, although the QVs were not primary linguistic and the task involved forced recoding. Previous results showing recency with ASL stimuli in normal subjects were not replicated. It is concluded that recency and suffix effects are not related either to the primary linguistic mode of the subject or to stimulus recoding, as we and Shand and Klima have defined them.     

The influence of word frequency on recency effects in directed free recall

Leading theoretical explanations of recency effects are designed to explain the reported absence of a word frequency effect on recall of words from recency serial positions. The present study used a directed free-recall procedure (J. J. Dalezman, 1976) and manipulated the frequency composition of the word lists (pure and mixed). Overall, with pure lists, a greater proportion of high-frequency (HF) words were recalled than low-frequency (LF) words, and with mixed lists, a greater proportion of LF words were recalled than HF words. Of importance, this recall advantage for one frequency over the other as a function of list composition was evident across the last three serial positions, indicating an influence of word frequency on recency effects that is dependent on the frequency composition of the lists. These results challenge one of the major assumptions on which several theories of recency effects have been based.