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

Effect of Foreign Accent on Immediate Serial Recall

Abstract. This study disentangled factors contributing to impaired memory for foreign-accented words – misperception and disruption of encoding. When native English and Cantonese-accented words were presented auditorily for serial recall (Experiment 1), intrusion errors for accented words were higher across all serial positions (SPs). Participants made more intrusion errors during auditory presentation than visual and auditory presentation, and more errors for accented words than native words. Lengthening the interstimulus intervals in Experiment 2 reduced intrusion, repetition, order, and omission errors in the middle and late SPs during accented word recall, suggesting that extra time is required for identification and encoding of accented words into memory. Analyses of the intrusions showed that a majority of them were misperceptions and sounded similar to the stimulus words. These findings suggest that effortful perceptual processing of accented speech can induce perceptual difficulty and interfere with downstream memory processes by exhausting the shared pool of working memory.

Two systems of maintenance in verbal working memory: evidence from the word length effect

The extended time-based resource-sharing (TBRS) model suggested a working memory architecture in which an executive loop and a phonological loop could both support the maintenance of verbal information. The consequence of such a framework is that phonological effects known to impact the maintenance of verbal information, like the word length effect (WLE), should depend on the use of the phonological loop, but should disappear under the maintenance by the executive loop. In two previous studies, introducing concurrent articulation in complex span tasks barely affected WLE, contradicting the prediction from the TBRS model. The present study re-evaluated the WLE in a complex span task while controlling for time parameters and the amount of concurrent articulation. Specifically, we used a computer-paced span task in which participants remembered lists of either short or long words while concurrently either articulating or making a location judgment. Whereas the WLE appeared when participants remained silent, concurrent articulation eliminated the effect. Introducing a concurrent attention demand reduced recall, but did not affect WLE, and did not interact with concurrent articulation. These results support the existence of two systems of maintenance for verbal information.

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.

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.

Backward recall and the word length effect

The word length effect, the finding that words that have fewer syllables are recalled better than otherwise comparable words that have more syllables, is one of the benchmark effects that must be accounted for in any model of serial recall, and simulation models of immediate memory rely heavily on the finding. However, previous research has shown that the effect disappears when participants are asked to recall the items in strict backward order. The present 2 experiments replicate and extend that finding by manipulating the participant's foreknowledge of recall direction (Experiment 1) and by giving the participant repeated practice with one direction by blocking recall direction (Experiment 2). In both experiments, a word length effect obtained with forward but not backward recall. The results are problematic for all models that currently have an a priori explanation for word length effects. The finding can be accounted for but is not predicted by Scale-Independent Memory, Perception, and Learning (SIMPLE), a model in which item and order information are differentially attended to in the 2 recall directions.

Strong and long: Effects of word length on phonological binding in verbal short-term memory

This study examined the effects of item length on the contribution of linguistic knowledge to immediate serial recall (ISR). Long words are typically recalled more poorly than short words, reflecting the greater demands that they place on phonological encoding, rehearsal, and production. However, reverse word length effects—that is, better recall of long than short words—can also occur in situations in which phonological maintenance is difficult, suggesting that long words derive greater support from long-term lexical knowledge. In this study, long and short words and nonwords (containing one vs. three syllables) were presented for immediate serial recall in (a) pure lists and (b) unpredictable mixed lists of words and nonwords. The mixed-list paradigm is known to disrupt the phonological stability of words, encouraging their phonemes to recombine with the elements of other list items. In this situation, standard length effects were seen for nonwords, while length effects for words were absent or reversed. A detailed error analysis revealed that long words were more robust to the mixed-list manipulation than short words: Their phonemes were less likely to be omitted and to recombine with phonemes from other list items. These findings support an interactive view of short-term memory, in which long words derive greater benefits from lexical knowledge than short words—especially when their phonological integrity is challenged by the inclusion of nonwords in mixed lists.

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.

Eye Movements and Serial Memory for Visual-Spatial Information

Abstract. This research investigated the nature of encoding and its contribution to serial recall for visual-spatial information. In order to do so, we examined the relationship between fixation duration and recall performance. Using the dot task - a series of seven dots spatially distributed on a monitor screen is presented sequentially for immediate recall - performance and eye-tracking data were recorded during the presentation of the to-be-remembered items. When participants were free to move their eyes at their will, both fixation durations and probability of correct recall decreased as a function of serial position. Furthermore, imposing constant durations of fixation across all serial positions had a beneficial impact (though relatively small) on item but not order recall. Great care was taken to isolate the effect of fixation duration from that of presentation duration. Although eye movement at encoding contributes to immediate memory, it is not decisive in shaping serial recall performance. Our results also provide further evidence that the distinction between item and order information, well-established in the verbal domain, extends to visual-spatial information.

The roles of semantic similarity and proactive interference in the word length effect

We examined the influence of semantic similarity and proactive interference (PI) on the word length effect (WLE) in immediate serial recall. Word length was manipulated by comparing memory for monosyllabic versus multisyllabic words. PI effects were evaluated by manipulating semantic similarity in the to-be-remembered lists and examining its impact on the WLE's magnitude across eight-trial blocks. Words were sampled from a single semantic category across the entire block, from a single category within the list, or from different categories. Robust WLEs were observed in single-category blocks and when words were from different categories. However, when all the within-list words were from the same semantic category, the WLE was sharply attenuated. Except for the within-list semantic similarity condition, there was a buildup in PI levels in the form of protrusion errors across trials. However, the magnitude of the WLE did not increase with the PI buildup, suggesting that it was not affected by PI across trials.

The distinctiveness of the word-length effect

The authors report 2 experiments that compare the serial recall of pure lists of long words, pure lists of short words, and lists of long or short words containing just a single isolated word of a different length. In both experiments for pure lists, there was a substantial recall advantage for short words; the isolated words were recalled better than other words in the same list, and there was a reverse word-length effect: Isolated long words were recalled better than isolated short words. These results contradict models that seek to explain the word-length effect in terms of list-based accounts of rehearsal speed or in terms of item-based effects (such as difficulty of assembling items).