Does length or neighborhood size cause the word length effect?

Jalbert, Neath, Bireta, and Surprenant (2011) suggested that past demonstrations of the word length effect, the finding that words with fewer syllables are recalled better than words with more syllables, included a confound: The short words had more orthographic neighbors than the long words. The experiments reported here test two predictions that would follow if neighborhood size is a more important factor than word length. In Experiment 1, we found that concurrent articulation removed the effect of neighborhood size, just as it removes the effect of word length. Experiment 2 demonstrated that this pattern is also found with nonwords. For Experiment 3, we factorially manipulated length and neighborhood size, and found only effects of the latter. These results are problematic for any theory of memory that includes decay offset by rehearsal, but they are consistent with accounts that include a redintegrative stage that is susceptible to disruption by noise. The results also confirm the importance of lexical and linguistic factors on memory tasks thought to tap short-term memory.     

Articulatory and Phonological Determinants of Word Length Effects in Span Tasks

Several previous studies have shown that memory span is greater for short words than for long words. This effect is claimed to occur even when the short and long words are matched for the number of syllables and phonemes and so to provide evidence for subvocal articulation as being one mechanism that underlies memory span (Baddeley, Thomson, & Buchanan, 1975). The three experiments reported in this paper further investigate the articulatory determinants of word length effects on span tasks. Experiment 1 replicated Baddeley et al.'s finding of an effect of word length on auditory and visual span when the stimuli consist of words that differ in terms of the number of syllables. Experiments 2 and 3 showed that the effects of word length are eliminated when the words in the span task are matched for the number of syllables and phonemes but differ with respect to the duration and/or complexity of their articulatory gestures. These results indicate that it is the phonological structure of a word and not features of its actual articulation that determines the magnitude of the word length effect in span tasks.     

Reading aloud polysyllabic words and nonwords: The syllabic length effect reexamined

Two experiments were run in order to reinvestigate the role of the number of syllables in naming. Experiment 1 (word naming) showed that effects of number of syllables on naming latency were observed for very low-frequency words but not for high-frequency words (thus replicating Jared & Seidenberg’s, 1990, finding). In Experiment 2 (nonword naming), syllabic length effects were also obtained for nonwords. Control experiments found no effect on the latency of delayed naming of the same words and nonwords. These results suggest that naming does require syllabic decomposition, at least for very low-frequency words and nonwords in French. In particular, these data are compatible with any model of reading that postulates that reading aloud depends on the activity of two procedures: (1) a procedure that operates in parallel across a letter string (and does not generate a strong syllabic length effect) and that is the predominant process in generating responses to high-frequency words, and (2) another procedure that operates serially across a letter string (and generates a strong syllabic length effect) and that is the predominant process in generating responses to very low-frequency words and nonwords. These results are discussed in the context of the multiple-trace memory model for polysyllabic word naming (Ans, Carbonnel, & Valdois, 1998).     

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.     

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。     

Word length and age influences on forward and backward immediate serial recall

The present research is aimed at understanding the processes involved in short-term memory and how they interact with age. Specifically, word length effects were examined under forward serial recall, backward serial recall, and item recognition tasks, with performance being interpreted within an item-order theoretical framework. The interaction of age, word length, and direction of recall was examined in two experiments, the first of which confirmed that the word length was present with forward recall and absent with backward recall. In addition, age effects were stronger in backward recall than in forward recall. In the second experiment, an item-order trade-off methodology was utilized with backward recall. When order memory was required, there was no word length effect and strong age effects. When memory was tested via an item recognition test, there was a reverse word length effect and no age effect. While word length effects can be interpreted within the item-order framework, age effects cannot.     

Overt language production plays a key role in the Hebb repetition effect

When asked to recall verbatim a short list of items, performance is very limited. However, if the list of items is repeated across trials, recall performance improves. This phenomenon, known as the Hebb repetition effect (Hebb, 1961; Brain Mechanisms and Learning: A Symposium, pp. 37–51), is considered a laboratory analogue of language learning. In effect, learning a new word implies the maintenance of a series of smaller units, such as phonemes or syllables, in the correct order for a short amount of time before producing them. The sequence of smaller units is typically presented more than once. In the present study, we investigated the role of overt language production in language learning by manipulating recall direction. If the learning of a repeated list of items relies on overt language production processes, changing list production order by manipulating recall direction should impact the learning of the list. In Experiment 1, one list was repeated every third trial, and recall direction of the repeated list changed on the ninth repetition. In Experiment 1a, the repeated list changed from a forward to a backward order recall, where participants had to recall the items in reverse presentation order. In Experiment 1b, the repeated list changed from a backward to a forward order recall. Results showed a cost in recall performance for the repeated list when recall direction switched from forward to backward recall, whereas it was unaffected by the change from backward to forward recall. In Experiment 2, we increased the number of trials before introducing the change from a backward to a forward order recall. Results showed a decrement in recall performance for the repeated list following the change in recall direction, suggesting that language production processes play a role in the Hebb repetition effect.     

Examining the relationship between free recall and immediate serial recall: Similar patterns of rehearsal and similar effects of word length,presentation rate,and articulatory suppression

In five experiments, rehearsal and recall phenomena were examined using the free recall and immediate serial recall (ISR) tasks. In Experiment 1, participants were presented with lists of eight words, were precued or postcued to respond using free recall or ISR, and rehearsed out loud during presentation. The patterns of rehearsal were similar in all the conditions, and there was little difference between recall in the precued and postcued conditions. In Experiment 2, both free recall and ISR were sensitive to word length and presentation rate and showed similar patterns of rehearsal. In Experiment 3, both tasks were sensitive to word length and articulatory suppression. The word length effects generalized to 6-item (Experiment 4) and 12-item (Experiment 5) lists. These findings suggest that the two tasks are underpinned by highly similar rehearsal and recall processes.     

Short-term memory in autism spectrum disorder

Three experiments examined verbal short-term memory in comparison and autism spectrum disorder (ASD) participants. Experiment 1 involved forward and backward digit recall. Experiment 2 used a standard immediate serial recall task where, contrary to the digit-span task, items (words) were not repeated from list to list. Hence, this task called more heavily on item memory. Experiment 3 tested short-term order memory with an order recognition test: Each word list was repeated with or without the position of 2 adjacent items swapped. The ASD group showed poorer performance in all 3 experiments. Experiments 1 and 2 showed that group differences were due to memory for the order of the items, not to memory for the items themselves. Confirming these findings, the results of Experiment 3 showed that the ASD group had more difficulty detecting a change in the temporal sequence of the items.     

Revisiting backward recall and benchmark memory effects: a reply to Bireta et al. (2010)

When participants are asked to recall lists of items in the reverse order, known as backward recall, several benchmark memory phenomena, such as the word length effect, are abolished (Bireta et al. Memory & Cognition 38:279–291, 2010). Bireta et al. (Memory & Cognition 38:279–291, 2010) suggested that in backward recall, reliance on order retention is increased at the expense of item retention, leading to the abolition of item-based phenomena. In a subsequent study, however, Guérard and Saint-Aubin (in press) showed that four lexical factors known to modulate item retention were unaffected by recall direction. In a series of five experiments, we examined the source of the discrepancy between the two studies. We revisited the effects of phonological similarity, word length, articulatory suppression, and irrelevant speech, using open and closed pools of words in backward and forward recall. The results are unequivocal in showing that none of these effects are influenced by recall direction, suggesting that Bireta et al.’s (Memory & Cognition 38:279–291, 2010) results are the consequence of their particular stimuli.     

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.     

Syllabic length effects in visual word recognition and naming

Two experiments investigated the role of the number of syllables in visual word recognition and naming. Experiment 1 (word and nonword naming) showed that effects of number of syllables on naming latencies were observed for nonwords and very low-frequency words but not for high-frequency words. In Experiment 2 (lexical decision), syllabic length effects were also obtained for very low-frequency words but not for high-frequency words and nonwords. These results suggest that visual word recognition and naming do require syllabic decomposition, at least for very low-frequency words in French. These data are compatible with the multiple-trace memory model for polysyllabic word reading [Psychol. Rev. 105 (1998) 678]. In this model, reading depends on the activity of two procedures: (1) a global procedure that operates in parallel across a letter string (and does not generate a strong syllabic length effect) and that is the predominant process in generating responses to high-frequency words, and (2) an analytic procedure that operates serially across a letter string (and generates a strong syllabic length effect) and that is the predominant process in generating responses to very low-frequency words. A modified version of the dual route cascaded model [Psychol. Rev. 108 (1) (2001) 204] can also explain the present results, provided that syllabic units are included in this model. However, the Parallel Distributed Processing model [Psychol. Rev. 96 (1989) 523; J. Exp. Psychol.: Human Perception Perform. 16 (1990) 92] has difficulties to account for these results.     

An auditory repetition deficit under low memory load

Previous studies of the auditory analogue of repetition blindness have led to different conclusions regarding the nature of the effect (e.g., N. Kanwisher & M. C. Potter, 1989; M. Miller & D. MacKay, 1994). In the present study, recall accuracy for repeated elements was examined with lists of 2 or 3 items presented dichotically under high temporal pressure. When this procedure was used, a repetition deficit in recall was obtained for both vowels (Experiment 1) and consonant-vowel syllables (Experiment 2). Further experiments demonstrated that this deficit decreases as the stimulus onset asynchrony between the 2 critical elements increases (Experiment 3) and showed that the effect also occurs for words and not just nonsense syllables (Experiment 4). In all 4 experiments, estimations of guessing biases showed that responses to unrepeated lists were not artificially favored over responses to repeated lists.     

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.     

An item/order trade‐off explanation of word length and generation effects

The item‐order hypothesis suggests that under certain conditions increased item processing can lead to deficits in order processing, and that this produces a dissociation in performance between item and order tasks. The generation effect is one such example. The word length effect is seen as another instance where this trade‐off might be observed. The following experiments compare word length and generation effects under serial recall and single item recognition conditions. Short words are better recalled than long words on the serial recall task but long words were better recognised than short words. The results are consistent with the item‐order approach and support a novel explanation for the word length effect.     

An item/order trade-off explanation of word length and generation effects

The item-order hypothesis suggests that under certain conditions increased item processing can lead to deficits in order processing, and that this produces a dissociation in performance between item and order tasks. The generation effect is one such example. The word length effect is seen as another instance where this trade-off might be observed. The following experiments compare word length and generation effects under serial recall and single item recognition conditions. Short words are better recalled than long words on the serial recall task but long words were better recognised than short words. The results are consistent with the item-order approach and support a novel explanation for the word length effect.     

Backward recall and benchmark effects of working memory

Working memory was designed to explain four benchmark memory effects: the word length effect, the irrelevant speech effect, the acoustic confusion effect, and the concurrent articulation effect. However, almost all research thus far has used tests that emphasize forward recall. In four experiments, we examine whether each effect is observable when the items are recalled in reverse order. Subjects did not know which recall direction would be required until the time of test, ensuring that encoding processes would be identical for both recall directions. Contrary to predictions of both the primacy model and the feature model, the benchmark memory effect was either absent or greatly attenuated with backward recall, despite being present with forward recall. Direction of recall had no effect on the more difficult conditions (e.g., long words, similar-sounding items, items presented with irrelevant speech, and items studied with concurrent articulation). Several factors not considered by the primacy and feature models are noted, and a possible explanation within the framework of the SIMPLE model is briefly presented.     

Cues to speech segmentation: Evidence from juncture misperceptions and word spotting

The question of whether Dutch listeners rely on the rhythmic characteristics of their native language to segment speech was investigated in three experiments. In Experiment 1, listeners were induced to make missegmentations of continuous speech. The results showed that word boundaries were inserted before strong syllables and deleted before weak syllables. In Experiment 2, listeners were required to spot real CVC or CVCC words (C = consonant, V = vowel) embedded in bisyllabic nonsense strings. For CVCC words, fewer errors were made when the second syllable of the nonsense string was weak rather than strong, whereas for CVC words the effect was reversed. Experiment 3 ruled out an acoustic explanation for this effect. It is argued that these results are in line with an account in which both metrical segmentation and lexical competition play a role.     

Testing the associative-link hypothesis in immediate serial recall: Evidence from word frequency and word imageability effects

Two immediate serial recall experiments were conducted to test the associative-link hypothesis (Stuart & Hulme, 2000). We manipulated interitem association by varying the intralist latent semantic analysis (LSA) cosines in our 7-item study word lists, each of which consists of high- or low-frequency words in Experiment 1 and high- or low-imageability words in Experiment 2. Whether item recall performance was scored by a serial-recall or free-recall criterion, we found main effects of interitem association, word imageability, and word frequency. The effect of interitem association also interacted with the word frequency effect, but not with the word imageability effect. The LSA-cosinexword frequency interaction occurred in the recency, but not primacy, portion of the serial position curve. The present findings set explanatory boundaries for the associative-link hypothesis and we argue that both item- and associative-based mechanisms are necessary to account for the word frequency effect in immediate serial recall.     

How implicitly activated and explicitly acquired knowledge contribute to the effectiveness of retrieval cues

The extralist cued recall task simulates everyday reminding because a memory is encoded on the fly and retrieved later by an unexpected cue. Target words are studied individually, and recall is cued by associatively related words having preexisting forward links to them. In Experiments 1 and 2, forward cue-to-target and backward target-to-cue strengths were varied over an extended range in order to determine how these two sources of strength are related and which source has a greater effect. Forward and backward strengths had additive effects on recall, with forward strength having a consistently larger effect. The PIER2 model accurately predicted these findings, but a plausible generation-recognition version of the model, called PIER.GR, could not. In Experiment 3, forward and backward strengths, level of processing, and study time were varied in order to determine how preexisting lexical knowledge is related to knowledge acquired during the study episode. The main finding indicates that preexisting knowledge and episodic knowledge have additive effects on extralist cued recall. PIER2 can explain these findings because it assumes that these sources of strength contribute independently to recall, whereas the eSAM model cannot explain the findings because it assumes that the sources of strength are multiplicatively related.