Precategorical acoustic storage and postcategorical lexical storage

A variety of experimental findings have indicated that a system of precategorical acoustic storage is responsible for the recency effect obtained in the immediate serial recall of sequences of digits, consonants, or syllables. This study investigated whether such findings could be generalized to the recall of sequences of words. Experiment 1 showed that phonemic similarity among a sequence of words failed to reduce the modality effect or the recency effect. Experiment 2 demonstrated that this finding was not attributable to a failure to control the phonemic properties of the stimulus material. Experiment 3 showed that the stimulus suffix effect obtained with sequences of words was not affected by the acoustic similarity between the list items and the stimulus suffix. Finally, Experiment 4 demonstrated that phonemic similarity among a sequence of words failed to reduce the stimulus suffix effect. These results were explained by extending the original model of short-term memory to incorporate a system of postcategorical lexical storage.     

The stimulus suffix effect as a memory coding phenomenon

Two short-term memory experiments examined the nature of the stimulus suffix effect on auditory linguistic and nonlinguistic stimulus lists. In Experiment 1, where subjects recalled eight-item digit lists, it was found that a silently articulated digit suffix had the same effect on recall for the last list item as a spoken digit suffix. In Experiment 2, subjects recalled lists of sounds made by inanimate objects either by listing the names of the objects or by ordering a set of drawings of the objects. Auditory suffixes, either another object sound or the spoken name of an object, produced a suffix effect under both recall conditions, but a visually presented picture also produced a suffix effect when subjects recalled using pictures. The results were most adequately explained by a levels-of-processing memory coding hypothesis.     

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。     

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.     

Manipulations of irrelevant information: Suffix effects with articulatory suppression and irrelevant speech

Numerous studies have demonstrated impaired recall when the to-be-remembered information is accompanied or followed by irrelevant information. However, no current theory of immediate memory explains all three common methods of manipulating irrelevant information: requiring concurrent articulation, presenting irrelevant speech, and adding a stimulus suffix. Five experiments combined these manipulations to determine how they interact and which theoretical framework most accurately and completely accounts for the data. In Experiments 1 and 2, a list of auditory items was followed by an irrelevant speech sound (the suffix) while subjects engaged in articulatory suppression. Although articulatory suppression reduced overall recall compared to a control condition, comparable suffix effects were seen in both conditions. Experiments 3 and 4 found reliable suffix effects when list presentation was accompanied by irrelevant speech. Experiment 5 found a suffix effect even when the irrelevant speech was composed of a set of different items. Implications for working memory, pre-categorical acoustic store, the changing-state hypothesis, and the feature model are discussed.     

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.     

Echoic memory and voice quality: Recency recall is not enhanced by varying presentation voice

Three experiments explored the effects on immediate recall of varying voice of presentation. Experiment 1 showed that the free-recall recency effect was not enhanced by presenting list words alternately in a male and a female voice. Experiment 2 replicated this result and also showed that recall of a given recency item from such a list was no more probable when the subjects were informed immediately following presentation that they need not recall the words presented in the other voice. Experiment 3 replicated previous findings of a reduction in the “suffix effect” when presentation voice is changed for the suffix item. The relation of this result to those of Experiments 1 and 2 is discussed.     

Exploring the suffix effect in serial visuospatial short-term memory

The suffix effect—the loss of recency induced by a redundant end-of-list item—was studied in a visuospatial serial recall task involving the memory for the position of dots on a screen. A visuospatial suffix markedly impaired recall of the last to-be-remembered dot. The impact on recall was roughly of equal magnitude whether the suffix shared attributes with the to-be-remembered dots (Experiment 1) or was visually distinct (Experiments 2 and 3). Although the presence of a tone suffix also impaired serial memory for the last items in the sequence, the impact of a visuospatial suffix was more marked, implying a specific as well as a possible general effect of suffix in the visuospatial domain (Experiment 4). The suffix effect seems not to be a phenomenon confined to verbal material but rather a universal phenomenon possibly related to grouping.     

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 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.     

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.     

Voice change in the stimulus suffix effect: Are the effects structural or strategic?

The literature on the stimulus suffix effect shows that if the suffix is presented in a voice different from that in which the list items are presented, there is less of a decrement in list recall than if the suffix is presented in the same voice. This experiment attempted to answer the question of whether this variable diminishes the suffix effect because of attentional factors or because of structural properties of echoic memory. Subjects received lists of digits in a male voice and either a tone, same-voice suffix, or different-voice suffix. Subjects received either the same suffix for all lists or two different suffixes. Those subjects given two suffixes and those given two tones were either forced to discriminate between them or had no discrimination requirement. The results demonstrated that voice change has both attentions] and structural consequences on the suffix effect, with the attentional factors being confined to the preterminal positions and the structural factors being confined to the last position or two.     

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.     

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.     

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.     

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.     

Stimulus redundancy and immediate recall

This study examined immediate recall in two stimulus prefix and two stimulus suffix conditions and in a condition that combined a prefix and suffix. Suffixes and the combination of a prefix with a suffix interfered more with recall overall than did prefixes. Performance in each of the conditions that included a prefix was significantly better overall than in appropriate control conditions, in which interference was augmented by a redundant element in recall. It was suggested that prefixes and suffixes lie operationally on a continuum and that their effects result from the subject's inability to dissociate the redundant element from the memory series. However, the location of redundancy imposes different processing requirements that differentially influence recall.     

Tactual and visual alphanumeric suffix effects

Two experiments tested the effects of suffixes on the recall of tactual and visual sequences of alphabetic characters presented at 19 letters per min. Scoring techniques allowed for the differentiation of losses of item and order information. In Experiment I performance decrements were found for both modalities, which were mainly caused by item loss at the more recent part of the serial position curve in the suffix conditions. In Experiment II, these effects were replicated and a non-alphabetic suffix led to greater decrements for both modalities than an alphabetical suffix. While a suffix effect based on the loss of item information is consistent with a sensory trace interpretation of the suffix effect, the presence of a visual suffix effect with slow stimulus presentation is not. Additionally, the greater effect of the non-alphanumeric suffix challenges attentional interpretations. Some possible explanations are proposed.     

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.     

Differential effects of repetition on pre- and postcategorical memory traces

The effect of list repetition on immediate recall for aurally presented nine-letter lists was studied under two conditions. In the first, a redundant stimulus item was presented as the tenth item in each list, while the suffix was not included in a control condition. As in previous research (Crowder & Morton, 1969), the stimulus suffix selectively interfered with recall at the terminal presentation serial positions, indicating the presence of precategorical acoustic storage. Repetition had a nonselective effect on performance. This result and an analysis of acoustic errors support the inference that qualitative differences in the memory code may lead to differences in other functional properties of the memory trace, such as responsiveness to repetition.