Recency and suffix effects with immediate recall of olfactory stimuli

In contrast to our understanding of the immediate recall of auditory and visual material, little is known about the corresponding characteristics of short-term olfactory memory. The current study investigated the pattern of immediate serial recall and the associated suffix effect using olfactory stimuli. Subjects were trained initially to identify and name correctly nine different odours. Experiment 1 established an immediate correct recall span of approximately six items. In Experiment 2 participants recalled serially span equivalent lists which were followed by a visual, auditory, or olfactory suffix. Primacy was evident in the recall curves for all three suffix conditions. Recency, in contrast, was evident in the auditory and visual suffix conditions only; there was a strong suffix effect in the olfactory suffix condition. Experiment 3 replicated this pattern of effects using seven-item lists, and demonstrated that the magnitude of the recency and suffix effects obtained in the olfactory modality can equate to that obtained in the auditory modality. It is concluded that the pattern of recency and suffix effects in the olfactory modality is reliable, and poses difficulties for those theories that rely on the presence of a primary linguistic code, sound, or changing state as determinants of these effects in serial recall.     

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.     

Recency and suffix effects with immediate recall of olfactory stimuli

In contrast to our understanding of the immediate recall of auditory and visual material, little is known about the corresponding characteristics of short-term olfactory memory. The current study investigated the pattern of immediate serial recall and the associated suffix effect using olfactory stimuli. Subjects were trained initially to identify and name correctly nine different odours. Experiment 1 established an immediate correct recall span of approximately six items. In Experiment 2 participants recalled serially span equivalent lists which were followed by a visual, auditory, or olfactory suffix. Primacy was evident in the recall curves for all three suffix conditions. Recency, in contrast, was evident in the auditory and visual suffix conditions only; there was a strong suffix effect in the olfactory suffix condition. Experiment 3 replicated this pattern of effects using seven-item lists, and demonstrated that the magnitude of the recency and suffix effects obtained in the olfactory modality can equate to that obtained in the auditory modality. It is concluded that the pattern of recency and suffix effects in the olfactory modality is reliable, and poses difficulties for those theories that rely on the presence of a primary linguistic code, sound, or changing state as determinants of these effects in serial recall.     

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.     

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.     

Can the irrelevant speech effect turn into a stimulus suffix effect?

The irrelevant sound effect (ISE) and the stimulus suffix effect (SSE) are two qualitatively different phenomena, although in both paradigms irrelevant auditory material is played while a verbal serial recall task is being performed. Jones, Macken, and Nicholls (2004) have proposed the effect of irrelevant speech on auditory serial recall to switch from an ISE to an SSE mechanism, if the auditory-perceptive similarity of relevant and irrelevant material is maximized. The experiment reported here (n = 36) tested this hypothesis by exploring auditory serial recall performance both under irrelevant speech and under speech suffix conditions. These speech materials were spoken either by the same voice as the auditory items to be recalled or by a different voice. The experimental conditions were such that the likelihood of obtaining an SSE was maximized. The results, however, show that irrelevant speech—in contrast to speech suffixes—affects auditory serial recall independently of its perceptive similarity to the items to be recalled and thus in terms of an ISE mechanism that crucially extends to recency. The ISE thus cannot turn into an SSE.     

前分类声音存储器对声调和情绪韵律的加工

采用系列位置回忆任务, 探讨作为声调语言的汉语普通话中声调及情绪信息是否具有近因及后缀效应, 从而揭示同为超音段信息的声调和情绪韵律在前分类声音存储器(Precategorical Acoustic Storage, PAS)中是否具有单独的表征, 及该表征可能受到哪些因素的影响。实验一和二分别考察了声调是否具有近因和后缀效应, 实验三和四分别考察了情绪信息是否具有近因和后缀效应。实验结果发现两者均在PAS存储器中有单独的表征, 但这种表征会受到一些因素的影响, 且受影响的方式不一样。研究结果表明作为超音段信息的声调和情绪信息在表征上的不稳定性和脆弱性, 及在短时记忆加工过程中的特殊性。     

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.     

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.     

Short-lived auditory memory for pitch

The effect of a stimulus suffix on immediate serial recall of lists of tones was assessed with 50- and 350-msec complex tones. Although recency effects were not found under the control conditions, the addition of a stimulus suffix significantly degraded recall at the final serial position for both stimulus durations. The implications of these results for models of auditory memory and speech perception are discussed.     

Non-Modality Specific Speech Coding: The Processing Of Lip-Read Information

Two experiments investigated the nature of the code in which lip-read speech is processed. In Experiment 1 subjects repeated words, presented with lip-read and masked auditory components out of synchrony by 600 ms. In one condition the lip-read input preceded the auditory input, and in the second condition the auditory input preceded the lip-read input. Direction of the modality lead did not affect the accuracy of report. Unlike auditory/graphic letter matching (Wood, 1974), the processing code used to match lip-read and auditory stimuli is insensitive to the temporal ordering of the input modalities. In Experiment 2, subjects were presented with two types of lists of colour names: in one list some words were heard, and some read; the other list consisted of heard and lip-read words. When asked to recall words from only one type of input presentation, subjects confused lip-read and heard words more frequently than they confused heard and read words. The results indicate that lip-read and heard speech share a common, non-modality specific, processing stage that excludes graphically presented phonological information.     

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 recall of two-voice lists: Implications for theories of auditory recency and suffix effects

Substantial recency effects are found in immediate serial recall of auditory items. These recency effects are greatly reduced when an irrelevant auditory stimulus (a stimulus suffix) is presented. A number of accounts that have been proposed to explain these phenomena assume that auditory items are susceptible to masking or overwriting in memory. Later items overwrite earlier items, leading to an advantage for the last item, unless it is masked by a suffix. This assumption is called into question by evidence that presenting list items in two voices has no beneficial effect in immediate serial recall. In addition, it is shown that suffix effects on both terminal and preterminal list items are influenced by the physical similarity of the suffix to the terminal item and not by the physical similarity of the suffix to preterminal items.     

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.     

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 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.     

Recency and suffix effects in pictures as a function of recall method

Two studies compared recency and suffix effects in pictures. In Experiment 1, which used strict serial recall, the recall curve for the control condition fell sharply until the final position when it exhibited a small but significant amount of recency. No suffix effects were present. In Experiment 2, a modified free recall condition exhibited a U-shaped serial position curve and significant recency. Picture and graphic suffixes led to small, reliable end-of-sequence suffix effects, but spoken suffixes did not. Thus pictures appear to lead to recency and suffix effects similar to those produced by static visual alphanumeric stimuli when strict serial recall is used. With a modified free recall procedure, recency is enhanced and suffix effects appear. The implications of the results with pictures and of differences between the two recall procedures are discussed with respect to literature in the area on pictures (Cohen, 1972) and American Sign Language (Krakow & Hanson, 1985; Shand & Klima, 1981). Additionally, some new methods of defining and analyzing recency, which are also applicable to primacy, are proposed and used in the paper to bring out more clearly the effects present.     

Modalities of memory: Is reading lips like hearing voices?

Functional similarities in verbal memory performance across presentation modalities (written, heard, lipread) are often taken to point to a common underlying representational form upon which the modalities converge. We show here instead that the pattern of performance depends critically on presentation modality and different mechanisms give rise to superficially similar effects across modalities. Lipread recency is underpinned by different mechanisms to auditory recency, and while the effect of an auditory suffix on an auditory list is due to the perceptual grouping of the suffix with the list, the corresponding effect with lipread speech is due to misidentification of the lexical content of the lipread suffix. Further, while a lipread suffix does not disrupt auditory recency, an auditory suffix does disrupt recency for lipread lists. However, this effect is due to attentional capture ensuing from the presentation of an unexpected auditory event, and is evident both with verbal and nonverbal auditory suffixes. These findings add to a growing body of evidence that short-term verbal memory performance is determined by modality-specific perceptual and motor processes, rather than by the storage and manipulation of phonological representations.     

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.     

Enhanced recency effects with changing-state and primary-linguistic stimuli

A number of explanations for the modality effect in immediate serial recall have been proposed. The auditory advantage for recall of recency items has been explained in terms of (1) the contributions of precategorical acoustic storage (PAS), (2) an advantage of changing-state over static stimuli, and (3) an advantage of primary-linguistic coding. Four experiments were conducted to evaluate these hypotheses. In the first, subjects viewed seven consecutive rectangles of different colors on a computer monitor. A small recency effect was obtained when the task was to recall the colors of the rectangles in order, with the size of the effect being independent of whether the rectangles remained stationary on the screen or moved in one of four directions. However, when the task was to recall the direction of movement of the rectangles, a larger recency effect was found. This pattern of results was interpreted as suggesting that recency effects are enhanced by changing-state stimulus information, but only when the changing-state information serves to identify the stimulus. Experiments 2 and 3 provided converging evidence by demonstrating an analogous recency advantage for changing-state visual stimuli that were somewhat different from those of Experiment 1. Experiment 4 demonstrated recency effects with synthesized speech stimuli that were substantially greater than were those found with the changing-state visual stimuli of the first three experiments. Implications of the results for the PAS, changing-state, and primary-linguistic hypotheses, as well as temporal-distinctiveness theories of recency, are discussed.