Silent reading rate and memory span

This paper reports two experiments concerned with the form of the linear function relating memory span to pronunciation rate. Experiment 1 asked whether the intercept of the equation is attributable to an interaction between modality, word-length, and serial position. The results lead us to reject this possibility. Experiment 2 examined the shape of the span function for visual presentation of lists read aloud or silently. The results show that the intercept of the span function disappears for silent presentation but not for aloud presentation. The results are discussed in terms of a balance between two opposing effects of word-length.     

A new model of verbal short-term memory

Two experiments tested a neo-Piagetian model of verbal short-term memory and compared it with the articulatory loop model. Experiment 1 (n = 113, age range 9-11) tested word span for 2-, 3-, and 4-syllable words, with both visual and auditory presentation. Experiment 2 (with the same participants) tested recall of visually presented supraspan lists. Measures of M capacity (as conceived in Pascual-Leone's neo-Piagetian theory) and articulation rate were also used. The proposed model can account for the effects of M capacity, word length, and presentation modality. The fit of this model to the data was acceptable, and parameter estimates were consistent across experiments. Furthermore, a correlation was found between M capacity and word span which resisted partialling out of age and articulation rate.     

Articulatory rehearsal and phonological storage in working memory

The theoretical distinction between an articulatory control process and a short-term phonological store was supported in five experiments on immediate serial recall. In Experiment 1, articulatory suppression during the presentation and recall of auditory material abolished the word length effect but not the phonemic similarity effect. In Experiment 2, the two latter effects were found to be independent with auditory presentation. In Experiment 3, the effects of irrelevant speech and word length were found to be independent with visual presentation. In Experiment 4, articulatory suppression during the presentation and recall of auditory material abolished the phonemic similarity effect with a slow presentation rate. Nevertheless, in Experiment 5, articulatory suppression with a conventional presentation rate did not reduce the effect of phonemic similarity, even when a 10-sec interval was interposed between presentation and recall. These results indicate that the encoding, maintenance, and retrieval of spoken material within the phonological store do not depend on a process of articulatory rehearsal.     

Taking the “text” out of context effects in repetition priming of word identification

Repetition priming of masked word identification is reduced when initial exposure to target words is in a text rather than in a word list. We demonstrate that there is nothing special about the text context that reduces priming. In Experiment 1, target words read in normal text or in rapid serial visual presentation (RSVP) text--either coherent or scrambled--produced similarly reduced priming, relative to the same words read aloud in a list. In Experiment 2, the delay was decreased between study and test for words presented in text, but they still displayed less priming than did words presented in a study list and tested after an equivalent delay. In Experiment 3, presenting study list words in RSVP to prevent reading each word aloud diminished priming to the same level as that in the text context. We conclude that presenting a target in context prevents it from being encoded and responded to as distinctively as when presented in isolation.     

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.     

Speech Intelligibility and Recall of Spoken Material Heard at Different Signal‐to‐noise Ratios and the Role Played by Working Memory Capacity

We studied speech intelligibility and memory performance for speech material heard under different signal‐to‐noise (S/N) ratios. Pre‐experimental measures of working memory capacity (WMC) were taken to explore individual susceptibility to the disruptive effects of noise. Thirty‐five participants first completed a WMC‐operation span task in quiet and later listened to spoken word lists containing 11 one‐syllable phonetically balanced words presented at four different S/N ratios (+12, +9, +6, and +3). Participants repeated each word aloud immediately after its presentation, to establish speech intelligibility and later on performed a free recall task for those words. The speech intelligibility function decreased linearly with increasing S/N levels for both the high‐WMC and low‐WMC groups. However, only the low‐WMC group had decreasing memory performance with increasing S/N levels. The memory of the high‐WMC individuals was not affected by increased S/N levels. Our results suggest that individual differences in WMC counteract some of the negative effects of speech noise. Copyright © 2012 John Wiley & Sons, Ltd.     

Frequency,not age of acquisition,affects Italian word naming

The purpose of this study was to evaluate the claim that age of acquisition (AoA) and word frequency effects are reduced or nonexistent in languages that have very regular letter-to-sound mappings, like Italian. The first two experiments (Exp. 1, Exp. 2) showed that frequency variables affect reading aloud and lexical decision in Italian. Variables interpretable as pertaining to a semantic component, including AoA, affected lexical decision but not reading aloud. In Experiments 3 and 4, a measure of frequency—child written word frequency (ChFreq)—and AoA were manipulated. Reading performance was affected by word frequency but not by AoA (Exp. 3), whereas lexical decision was affected by both variables (Exp. 4). In Experiments 5 and 6, ChFreq and AoA were manipulated orthogonally. Only frequency affected reading aloud, with no main effect or interaction involving AoA (Exp. 5). The effects of AoA and frequency interacted in Experiment 6 for lexical decision due to a larger effect of AoA for low frequency words than high frequency words. These results show that in languages with a transparent orthography word frequency may affect reading aloud in the absence of an effect of AoA because Italian readers employ lexical nonsemantic reading aloud. The effect of child written frequency points to the efficiency of the mappings between those orthographic and phonological word forms that were frequently encountered when learning to read.     

Effect of focus on verbal working memory: Critical role of the focus word in reading

The effect of focus on working memory was investigated with the reading span test (RST). In two experiments, the span scores and the number of intrusion errors were compared between the focused RST the and the nonfocused RST. Focus word was defined as the most important word for comprehending a sentence. For the focused RST, the target word to be maintained was the focus word for the sentence. In the nonfocused RST, however, the target word was not the focus word for the sentence. The results of both experiments showed that RST span scores were higher for the focused RST than for the nonfocused RST, and intrusion errors were found to increase for the nonfocused RST. In Experiment 2, the effect of focus was compared between high-span and low-span subjects. An effect of sentence length was also investigated. The result showed that low-span subjects were more affected than were high-span subjects by whether the word to be remembered was the focus word. The effect of sentence length was not confirmed. These findings suggest that the low-span subjects had deficits in their ability to establish and/or inhibit mental focus when faced with conflict situations in reading.     

The influence of lexical and conceptual constraints on reading mixed-language sentences: Evidence from eye fixations and naming times

In two experiments, we explored the degree to which sentence context effects operate at a lexical or conceptual level by examining the processing of mixed-language sentences by fluent Spanish-English bilinguals. In Experiment 1, subjects’ eye movements were monitored while they read English sentences in which sentence constraint, word frequency, and language of target word were manipulated. A frequency × constraint interaction was found when target words appeared in Spanish, but not in English. First fixation durations were longer for high-frequency Spanish words when these were embedded in high-constraint sentences than in low-constraint sentences. This result suggests that the conceptual restrictions produced by the sentence context were met, but that the lexical restrictions were not. The same result did not occur for low-frequency Spanish words, presumably because the slower access of low-frequency words provided more processing time for the resolution of this conflict. Similar results were found in Experiment 2 using rapid serial visual presentation when subjects named the target words aloud. It appears that sentence context effects are influenced by both semantic/conceptual and lexical information.     

Priming of new associations in reading time: What is learned?

The priming of new associations has been a controversial topic, with some studies finding significant effects but others failing to replicate these results. Three studies investigated the priming of new associations in a reading time task, presenting lists of word pairs that were read aloud as quickly as possible. In Experiment 1, significant priming of new associations was found after two study presentations, replicating similar results by Moscovitch, Winocur, and MacLachan (1986). In Experiment 2, reading time was facilitated for intact pairs when word positions remained constant relative to when word positions were reversed. This suggested that the associative priming effect was related to specific lower level features of the word pairs rather than to abstract associations. In Experiment 3, the insertion of the wordand between test words eliminated the pairing-specific effect, placing the locus of new association priming at the transition between words within pairs. These findings demonstrate that the knowledge that supports priming of new associations in the reading time task involves perceptual or articulatory information about the transitions between words rather than abstract associative knowledge.     

Production benefits both recollection and familiarity

In three experiments, we investigated the roles of recollection and familiarity in the production effect—the finding that words read aloud are remembered better than words read silently. Experiment 1, using the remember/know procedure, and Experiment 2, using the receiver operating characteristic procedure, converged in demonstrating that production enhanced both recollection and familiarity. Experiment 3 supported the role of recollection by demonstrating that specific episodic information—that is, whether a word had been studied aloud or silently—was stronger for items studied aloud. These findings fit with an explanation of the production effect as hinging on two factors: greater recollection of distinctive information from the study episode, and more familiarity due to greater attention allocated to the material studied aloud.     

Speech-like coding of pictures in short-term memory

Memory span for pictures of common objects and for the names of these objects was examined as a function of three speech-related variables. Both picture span and name span were found to be influenced by the phonological similarity (Experiment 1) and the length (Experiment 2) of the names, as well as by the subject’s engaging in “irrelevant” vocalization during item presentation (Experiment 3). Moreover, for each variable the effect was in the same direction and of comparable magnitude for the two types of items. Experiments 4-6 replicated these findings with the procedure modified such that the retention of order information was not required. It is concluded that under the present conditions, there is a substantial functional equivalence between short-term memory for readily nameable pictures and for words and that this equivalence may be thought of as due to mediation by a common, “speech-like” code.     

Group aggregates and individual reliability: The case of verbal short-term memory

Two experiments examined the generalizability of the effects of word length and phonological similarity with visual and auditory presentation in immediate verbal serial ordered recall. In Experiment 1, data were collected from 251 adult volunteers drawn from a broad cross-section of the normal population. Word length and phonological similarity in both presentation modes significantly influenced the group means. However, 43% of the subjects failed to show at least one of the effects, and the likelihood that effects appeared was highly correlated with verbal memory span. In Experiment 2, 40 subjects of the original sample were retested, 20 of whom had failed to show one or more effects in Experiment 1. Whether or not an effect had appeared for individual subjects on the first test session was a poor predictor of whether the effect would appear on retest. Finally, an analysis of subject reports demonstrated that the patterns of experimental data could be accounted for in part by the strategies that subjects reported using, and the effect of strategy was independent of the effect of span. The implications of these findings for theories of verbal short-term memory are discussed.     

Tracking the transition from sublexical to lexical processing: On the creation of orthographic and phonological lexical representations

Participants read aloud nonword letter strings, one at a time, which varied in the number of letters. The standard result is observed in two experiments; the time to begin reading aloud increases as letter length increases. This result is standardly understood as reflecting the operation of a serial, left-to-right translation of graphemes into phonemes. The novel result is that the effect of letter length is statistically eliminated by a small number of repetitions. This elimination suggests that these nonwords are no longer always being read aloud via a serial left-to-right sublexical process. Instead, the data are taken as evidence that new orthographic and phonological lexical entries have been created for these nonwords and are now read at least sometimes by recourse to the lexical route. Experiment 2 replicates the interaction between nonword letter length and repetition observed in Experiment 1 and also demonstrates that this interaction is not seen when participants merely classify the string as appearing in upper or lower case. Implications for existing dual-route models of reading aloud and Share's self-teaching hypothesis are discussed.     

Effects of level of processing and rehearsal on frequency judgments

The effects of attention during encoding and rehearsal after initial encoding on frequency estimates were investigated in three experiments. Varying the level of processing affected the linear increase in frequency estimates as a function of actual frequency, but varying processing after encoding with remember or forget cues had the greatest effects on the intercept of the function relating judged to actual frequency. Deeper levels of processing improved performance in a frequency discrimination task, whereas remember and forget cues had only very small effects on performance. Materials that are easy to rehearse were compared with materials that are difficult to rehearse in Experiment 2. The results were interpreted as evidence against a covert rehearsal explanation of slope effects in frequency estimation tasks because materials that are difficult to rehearse tended to produce larger interactions between remember versus forget cues and frequency than materials that are easier to rehearse. In Experiment 3, an arithmetic task that was performed during word encoding affected the slope of the function relating judged to actual frequency, but the same task performed immediately after word presentation had no effect on frequency estimates. It was concluded that frequency is not stored automatically because attention during the initial stages of encoding affects it; however, attention devoted to processing after initial encoding does not affect the rate with which subjective frequency increases with repetitions.     

Individual differences in word recognition latency

Previous studies of the effects of word characteristics on word recognition have used orthogonal combinations of word variables and have failed to consider individual differences. The present study examined word naming (Experiment 1) and lexical decision (Experiment 2) tasks using an unrestricted set of words and a correlational analysis. Individual differences were considered using a measure of the subjects’ knowledge of the English vocabulary. The results of Experiment 1 indicated that log (RT) for word naming is affected by word length, word frequency, and the number of syllables in the word; the results of Experiment 2 confirmed the effects of length and frequency but also showed that log (RT) is a function of the age at which the word is introduced to a child’s reading vocabulary. Subjects with a high vocabulary score were more rapid in Experiment 1 but were slower in Experiment 2, compared to subjects with a low vocabulary score. More importantly, high-vocabulary subjects, in both studies, were less affected by word length than the low-vocabulary subjects. The results suggest that subjects do differ in their reading strategy and that word length and word frequency may affect different stages in the word recognition process.     

What is in a tool concept? Dissociating manipulation knowledge from function knowledge

Research on patients with apraxia, a deficit in skilled action, has shown that the ability to use objects may be differentially impaired relative to knowledge about object function. Here we show, using a modified neuropsychological test, that similar dissociations can be observed in response times in healthy adults. Participants were asked to decide which two of three presented objects shared the same manipulation or the same function; triads were presented in picture and word format, and responses were made manually (button press) or with a basic-level naming response (verbally). For manual responses (Experiment 1), participants were slower to make manipulation judgments for word stimuli than for picture stimuli, while there was no difference between word and picture stimuli for function judgments. For verbal-naming responses (Experiment 2), participants were again slower for manipulation judgments over word stimuli, as compared with picture stimuli; however, and in contrast to Experiment 1, function judgments over word stimuli were faster than function judgments over picture stimuli. These data support the hypotheses that knowledge of object function and knowledge of object manipulation correspond to dissociable types of object knowledge and that simulation over motor information is not necessary in order to retrieve knowledge of object function.     

Age-of-acquisition affects word naming in Italian only when stress is irregular

In Italian, effects of age of acquisition (AoA) have been found in object naming, semantic categorization of words and lexical decision, but not in word naming (reading aloud). The lack of an AoA effect in Italian word naming is replicated in Experiment 1 which involved reading aloud two-syllable words which all have regular spelling-sound correspondences and regular stress patterns. Studies of English word naming have reported stronger effects of AoA for irregular or exception words than for words with regular, consistent spelling-sound correspondences. There are no grapheme-phoneme irregularities in Italian, but words containing three or more syllables can carry either regular stress on the penultimate syllable or irregular stress on the antepenultimate syllable. Experiment 2 found effects of AoA on reading three-syllable words for words with irregular stress. The results are interpreted in terms of the 'mapping hypothesis' of AoA, with effects arising as a result of a difficulty to generalize earlier-acquired patterns to irregular late-acquired words.     

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.     

Lateralization of lexical codes in auditory word recognition

Three experiments examined the lateralization of lexical codes in auditory word recognition. In Experiment 1 a word rhyming with a binaurally presented cue word was detected faster when the cue and target were spelled similarly than when they were spelled differently. This orthography effect was larger when the target was presented to the right ear than when it was presented to the left ear. Experiment 2 replicated the interaction between ear of presentation and orthography effect when the cue and target were spoken in different voices. In Experiment 3, subjects made lexical decisions to pairs of stimuli presented to the left or the right ear. Lexical decision times and the amount of facilitation which obtained when the target stimuli were semantically related words did not differ as a function of ear of presentation. The results suggest that the semantic, phonological, and orthographic codes for a word are represented in each hemisphere; however, orthographic and phonological representations are integrated only in the left hemisphere.