工作记忆中汉语反词长效应机制

工作记忆中的反词长效应(reverse word-length effect)指在对长词和短词混合的词表进行即时序列回忆时, 独立长词回忆成绩优于独立短词的现象。以汉字词语为材料通过3个实验探讨反词长效应的机制。实验1采用纯粹词表和长短词混合词表, 既得到纯粹词词长效应, 也得到独立词反词长效应。实验2削弱了长短词之间的词长差异, 结果独立词反词长效应消失, 且独立词回忆成绩优于纯粹词。实验3设计了视觉延迟条件, 得到与实验1类似的结果, 只是独立词反词长效应有所削弱。三个实验的结果并不一致, 无法用现有的语音回路理论或SIMPLE理论进行很好地解释, 理论的整合与创新显得非常重要。因此, 提出多重编码以既相互竞争又相互补充方式进行平行加工的观点进行更完整地解释。     

Abolishing the word-length effect

The authors report 2 experiments that compare the recall of long and short words in pure and mixed lists. In pure lists, long words were much more poorly remembered than short words. In mixed lists, this word-length effect was abolished and both the long and short words were recalled as well as short words in pure lists. These findings contradict current models that seek to explain the word-length effect in terms of item-based effects such as difficulty in assembling items, or in terms of list-based accounts of rehearsal speed. An alternative explanation, drawing on ideas of item complexity and item distinctiveness, is proposed.     

汉语中词长效应的初步实验研究

该文以回忆出一个词表的序列呈现顺序的正确率为指标考察汉语中的词长效应(Word-Length Effect)。实验材料为汉语中不同音节数目的词语。实验结果发现,在纯词表中,存在显著的词长效应。但是在混合词表中(包括长短词交替词表以及随机词表),词长效应会消失。研究结果支持词长效应的基于词表的解释,同时,项目的特异性也具有一定的作用。     

Proactive interference plays a role in the word-length effect

The word-length effect is the advantage that lists of short words show over lists of long words in immediate recall. Typically, the word-length effect is used as strong support for decay-based theories of immediate retention. However, the present two experiments show that the traditional word-length effect emerges only after several trials in an experimental session, a result reminiscent of earlier findings in distractor-based short-term forgetting experiments. These results suggest that any complete account of the word-length effect will need to consider a role for proactive interference.     

The Word-length Effect and Disyllabic Words

Three experiments compared immediate serial recall of disyllabic words that differed on spoken duration. Two sets of long- and short-duration words were selected, in each case maximizing duration differences but matching for frequency, familiarity, phonological similarity, and number of phonemes, and controlling for semantic associations. Serial recall measures were obtained using auditory and visual presentation and spoken and picture-pointing recall. In Experiments 1a and 1b, using the first set of items, long words were better recalled than short words. In Experiments 2a and 2b, using the second set of items, no difference was found between long and short disyllabic words. Experiment 3 confirmed the large advantage for short-duration words in the word set originally selected by Baddeley, Thomson, and Buchanan (1975). These findings suggest that there is no reliable advantage for short-duration disyllables in span tasks, and that previous accounts of a word-length effect in disyllables are based on accidental differences between list items. The failure to find an effect of word duration casts doubt on theories that propose that the capacity of memory span is determined by the duration of list items or the decay rate of phonological information in short-term memory.     

The syllable-based word length effect and stimulus set specificity

The word length effect is the finding that a list of items that take less time to pronounce is better recalled on an immediate serial recall test than an otherwise equivalent list of items that take more time to pronounce. Contrary to the predictions of all major models of the word length effect, Hulme, Suprenant, Bireta, Stuart, and Neath (2004) found that short and long items presented within the same list were recalled equally as well as short items presented in lists of just short items. Different results were reported by Cowan, Baddeley, Elliot, and Norris (2003), who found that mixed lists were recalled worse than pure short lists, but better than pure long lists. The experiments reported here suggest that the different empirical findings are due to properties of the stimulus sets used: one stimulus set produces results that replicate Cowan et al., whereas all other sets tested so far yield results that replicate Hulme et al.     

THERE ARE TWO WORD-LENGTH EFFECTS IN VERBAL SHORT-TERM MEMORY:

Abstract— In the word-length effect (WLE), lists of shorter words are better recalled than lists of longer words This effect a fundamental to decay-based theories of verbal short-term memory, such as the phonological loop theory (Baddeley, 1986) The WLE has been attributed to the time taken to articulate words, not their structure, a critical point in the debate between decay and interference theories However, this article, we show that the traditional WLE comprises two opposed effects an advantage for words spoken more quickly (short words in terms of duration) and an advantage for words with more elements (long words in terms of complexity) We also report two interactions a disadvantage for a midlist change in duration and an advantage for a midlist change in complexity These results contradict simple decay- based theories and establish the importance of interference in short- term memory We discuss whether decay is also required     

The time-based word length effect and stimulus set specificity

The word length effect is the finding that short items are remembered better than long items on immediate serial recall tests. The time-based word length effect refers to this finding when the lists comprise items that vary only in pronunciation time. Three experiments compared recall of three different sets of disyllabic words that differed systematically only in spoken duration. One set showed a word length effect, one set showed no effect of word length, and the third showed a reverse word length effect, with long words recalled better than short. A new fourth set of words was created, and it also failed to yield a time-based word length effect. Because all four experiments used the same methodology and varied only the stimulus sets, it is argued that the time-based word length effect is not robust and as such poses problems for models based on the phonological loop.     

Word frequency effects in immediate serial recall of pure and mixed lists: tests of the associative link hypothesis.

In immediate serial recall, high-frequency words are better recalled than low-frequency words. Recently, it has been suggested that high-frequency words are better recalled because of their better long-term associative links, and not because of the intrinsic properties of their long-term representations. In the experiment reported here, recall performance was compared for pure lists of high- and low-frequency words, and for mixed lists composed of either one low- and five high-frequency words or the reverse. The usual advantage of high-frequency words was found with pure lists and this advantage was reduced, but still significant with mixed lists composed of five low-frequency words. However, the low-frequency word included in a high-frequency list was recalled just as well as high-frequency words. Results are challenging for the associative link hypothesis and are best interpreted within an item-based reconstruction hypothesis, along with a distinctiveness account.     

Encoding and retrieval processes in the memory for conceptually distinctive events

Memory for conceptually isolated (distinctive) words was investigated in two experiments. In Experiment 1, recognition of distinctive targets was compared with recognition of targets from homogeneous lists and with recognition of background information. Distinctive targets were better recognized than the same words presented in homogeneous lists. No effects of distinctiveness on the recognition accuracy of background items were observed. These results fail to support the hypothesis that distinctive information receives extra resources during encoding at the expense of surrounding background information. In Experiment 2 the effects of distinctiveness on recall were evaluated. Distinctive targets were more likely to be recalled than targets from homogeneous lists. However, unlike the effects found in recognition, background items were more poorly recalled from lists containing distinctive targets than from homogeneous lists. Organizational processes in recall were also evaluated. There was greater subjective organization for target and background items from lists containing distinctive targets than from lists containing nondistinctive targets. These results were discussed in terms of encoding and retrieval explanations of the effects of distinctiveness.     

Effects of word frequency on individual-item and serial order retention: Tests of the order-encoding view

The order-encoding view of the word frequency effect proposes that low-frequency (LF) items attract more attention to the encoding of individual-item information than do high-frequency (HF) items, but at the expense of order encoding (DeLosh & McDaniel, 1996). When combined with the assumption that free recall of unrelated words is organized according to their original order of presentation, this view explains the finding that HF words are better recalled than LF words in pure lists but that, in mixed lists, recall is better for LF words. The present study confirmed that in mixed lists, order memory becomes equivalent for HF and LF words and that the predicted pattern of order memory and recall holds fo r incidental order-encoding conditions, for longerlists than those used inprevious experiments, and for lists with minimal interitem associativity. Moreover, recall from HF lists declined, but recall from LF lists improved, in related-word lists, relative to unrelated-word lists, reversing the usual pure-list free recall advantage for HF words. These results were uniquely predicted by the order-encoding account and favor this view over accessibility, interitem association, and cuing effectiveness explanations of the word frequency effect.     

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.     

Retroactive interference in short-term memory and the word-length effect

Two experiments investigated the possibility that the word-length effect in short-term memory (STM) is a consequence of long words generating a greater level of retroactive interference than shorter words. In Experiment 1, six-word lists were auditorily presented under articulatory suppression for immediate serial reconstruction of only the first three words. These three words were always drawn from a single set of middle-length words, whereas the last three positions were occupied by either short or long interfering words. The results showed worse memory performance when the to-be-remembered words were followed by long words. In Experiment 2, a recent-probes task was used, in which recent negative probes matched a target word in trial n-2. The results showed lower levels of proactive interference when trial n-1 involved long words instead of short words, suggesting that long words displaced previous STM content to a greater extent. By two different experimental approaches, therefore, this study shows that long words produce more retroactive interference than short words, supporting an interference-based account for the word-length effect.     

When does length cause the word length effect?

The word length effect, the finding that lists of short words are better recalled than lists of long words, has been termed one of the benchmark findings that any theory of immediate memory must account for. Indeed, the effect led directly to the development of working memory and the phonological loop, and it is viewed as the best remaining evidence for time-based decay. However, previous studies investigating this effect have confounded length with orthographic neighborhood size. In the present study, Experiments 1A and 1B revealed typical effects of length when short and long words were equated on all relevant dimensions previously identified in the literature except for neighborhood size. In Experiment 2, consonant-vowel-consonant (CVC) words with a large orthographic neighborhood were better recalled than were CVC words with a small orthographic neighborhood. In Experiments 3 and 4, using two different sets of stimuli, we showed that when short (1-syllable) and long (3-syllable) items were equated for neighborhood size, the word length effect disappeared. Experiment 5 replicated this with spoken recall. We suggest that the word length effect may be better explained by the differences in linguistic and lexical properties of short and long words rather than by length per se. These results add to the growing literature showing problems for theories of memory that include decay offset by rehearsal as a central feature.     

The Effect of Word Length on Immediate Serial Recall Depends on Phonological Complexity, Not Articulatory Duration

Immediate recall for sequences of short words is better than for sequences of long words. This word-length effect has been thought to depend on the spoken duration of the words (Baddeley, Thomson, & Buchanan, 1975) or their phonological complexity (Caplan, Rochon, & Waters, 1992). In Finnish both vowel and consonant quantity distinguish between words. Long phonemes behave like phoneme repetitions. In Experiment 1, subjects were presented with auditory lists of three kinds of pseudowords based on Finnish phonotactics: short CVCV-structures (e.g. / tepa/ ), long two-syllable items with long phonemes (e.g. / te: p: a / ), and long three-syllable items with CVCVCV structures (e.g. / tepalo / ). Although both kinds of long stimuli (of identical spoken length) took longer to read, only three-syllable items were more difficult to remember than the short stimuli. Experiment 2 contrasted the effect of number of syllables with number of different phonemes. The long two-syllable items were replaced by two-syllable items of equal spoken duration but containing six different phonemes (e.g. / tiempa / ). These two-syllable items were as difficult to recall as were the three-syllable items. Experiment 3 controlled for the possibility that long stimuli might be rehearsed in a shorter form. It is concluded that aspects of phonological complexity are critical for word-length effects. Implications of this finding for working memory theory are discussed, and future work based on multi-layered phonological representations is proposed.     

Beyond the articulatory loop: A semantic contribution to serial order recall of subspan lists

In two experiments, serial order recall of short lists of content and function words under quiet and articulatory suppression conditions was examined in order to assess the hypotheses that (1) semantic attributes of words contribute to short-term-memory performance, and (2) do soindependently of effects attributable to the articulatory loop component. In Experiment 1, content words were better recalled than function words; both word types were equally impaired by suppression. This provides support for the notion that semantic coding makes an independent contribution to span performance. This word-class effect disappeared in Experiment 2, when content and function words were matched for imageability. These data suggest that at least some aspects of meaning contribute to serial order recall performance for short lists, independently of the articulatory loop.     

The bizarre mnemonic

Summary Five experiments measured effects of bizarre contexts on the free recall of noun triplets after brief retention intervals. More triplets were remembered from bizarre than from common contexts in short mixed lists (12 sentences) when the sentences were presented at a controlled (10 seconds/sentence) rate, regardless of incidental task (rating images for bizarreness, vividness, or memorability). The average number of words/sentence recalled, however, tended to be higher for common than for bizarre contexts. No memory benefit from bizarreness was found for pure lists nor for lists containing more than six triplets in bizarre contexts. The bizarreness effect was less when the subject controlled the rate of presentation. A sixth experiment, which tested recall after immediate and two-day retention intervals, found that the Bizarre/Common Context by Pure/Mixed List interaction increased over longer retention intervals.     

List composition and the word length effect in immediate recall: A comparison of localist and globalist assumptions

Lists of short words usually are recalled better than lists of longer words in immediate recall tasks. Such word length effects might be explained by localist accounts, in which the length of each word in a list affects the recall of that word only, or by globalist accounts, in which the lengths of at least some words affect the recall of other words (e.g., Baddeley, 1986). In a recent localist account, Neath and Nairne (1995) proposed that the recall of each word depends on the likelihood that features within the word are contaminated within the memory representation. We tested this by presenting not only homogeneous lists of short and long words, but also mixed lists, and by including articulatory suppression on some trials. The short-word advantage depended on the composition of the list, ruling out a strictly localist approach. There appear to be several globalist influences on recall, including distinctiveness factors as well as phonological storage and articulation.     

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.     

Word frequency and the mixed-list paradox in immediate and delayed serial recall

In free recall tasks, when low- and high-frequency items are mixed within the to-be-remembered lists, the usual recall advantage found for high-frequency words is eliminated or reversed. Recently, this mixedlist paradox has also been demonstrated for short-term serial recall (Hulme, Stuart, Brown, & Morin, 2003). Although a number of theoretical interpretations of this mixed-list paradox have been proposed, researchers have also suggested that it could simply be a result of participant-controlled strategies (M. J. Watkins, LeCompte, & Kim, 2000). The present study was designed to assess whether this explanation could be applied to immediate and delayed serial recall. The results showed that high-frequency words were recalled better than low-frequency words in pure lists, but that this effect was eliminated in mixed lists, whether they were given under intentional or incidental learning conditions. This pattern suggests that the mixed-list paradox cannot be explained by participant-controlled strategies.