Bilingual working memory span is affected by language skill

A complex span procedure was used to study whether there is a measurable extra load on general working memory (WM) when a not fully automatised language has to be comprehended. Participants verified heard sentences in relation to simultaneously shown pictures and memorised the last word of each sentence. The sentences were presented in growing set sizes and recall of all the last words was required after each set. The largest number of sentences that could be processed in combination with successful recall of their last words determined the participant's WM span. Sentences were either in the participants' native language or a well-mastered second language, English. Participants were psychology and English students. WM span and decision accuracy were better for native-language than foreign-language sentences, especially for the psychology students. A second experiment ascertained that the difference between participant groups could not be explained by variables related to phonological shortterm memory or word processing. A third experiment controlled for systematic trade-off differences between languages and groups. We conclude that aspects of sentence comprehension in foreign language develop with practice so that they require less WM resources.     

The influence of contextual constraints on recall for words within sentences

Two experiments examined predictions of the relational-distinctive processing view to account for the influence of sentence constraints on memory of target words. In Experiment 1, congruous expected words were recalled better than incongruous words. Words appearing in high-constraint sentences were recalled better than words appearing in low-constraint sentences. In Experiment 2, word expectancy and sentence constraint interacted so that unexpected congruous words appearing in high-constraint sentences were recalled better than their expected counterparts, but this difference was not present for low-constraint sentences. A hybrid model including aspects of the featural restriction model of sentence constraint and the relational-distinctive processing view is proposed.     

Emotional memory for words: Separating content and context

We developed a technique to examine the effects of emotional content and context on verbal memory. Two sets of sentences were devised: in the first, each sentence was emotionally arousing due to the inclusion of an emotional “target” word. In the second set, “targets” were replaced with well-matched neutral words. Subjects read aloud a selection of emotional and neutral sentences, and were then surprised with memory tasks after a range of time delays. Emotional target words were remembered significantly better than neutral words in all experiments. Recognition of emotional words was relatively stable despite increasing delays between encoding and recognition testing, in contrast to memory for neutral words, which decayed over time. Memory for neutral non-target words was enhanced when words had been presented in an emotional context. The results confirm the phenomenon of emotional enhancement of memory at short and long delays and suggest that emotional context may be encoded independently of word meaning.     

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.     

The role of the verb in sentence memory

Investigators have frequently found that nouns are more important than verbs in the memory representation of sentences. This pattern of results is incompatible with recent theories of sentence memory that have emphasized the verb and with the results of sentence comprehension studies that have demonstrated the importance of the verb. The four experiments reported here were designed to reexamine the role of the verb in sentence memory. Linguistic variables other than sentence function were held constant in three studies. Verbs were recalled as well and were as effective retrieval cues as nouns in these experiments. The to-be-remembered sentences were presented in the context of paragraphs in the fourth experiment. This reduced the difference in level of recall between subjects, verbs, and objects. The conclusion was drawn that the verb is no less important than sentence nouns in the memory representation.     

Pictures,Words, and Sounds: From Which Format Are We Best Able to Reason?

The effect of presentation format on reasoning was studied with a sentence verification task. Background information was presented in single-format and combined conditions that included pictured, printed, or spoken versions of the stimulus items. In Experiment 1, a test sentence appeared together with the background at varied stimulus onset asynchronies, to study how format influences the acquisition of the stimulus information. In Experiments 2 and 3, however, the test sentence followed the presentation of the background, to test the effect of format on memory. Reaction time responses to the test sentences showed a consistent picture advantage. However, when participants responded to materials stored in memory, both pictured and spoken formats provided quicker responses in comparison to printed words, and the format difference was smaller than when materials were readily available on the screen. Multimedia presentations, when compared with single-format conditions, did not provide additional benefits.     

Pictures, words, and sounds: from which format are we best able to reason?

The effect of presentation format on reasoning was studied with a sentence verification task. Background information was presented in single-format and combined conditions that included pictured, printed, or spoken versions of the stimulus items. In Experiment 1, a test sentence appeared together with the background at varied stimulus onset asynchronies, to study how format influences the acquisition of the stimulus information. In Experiments 2 and 3, however, the test sentence followed the presentation of the background, to test the effect of format on memory. Reaction time responses to the test sentences showed a consistent picture advantage. However, when participants responded to materials stored in memory, both pictured and spoken formats provided quicker responses in comparison to printed words, and the format difference was smaller than when materials were readily available on the screen. Multimedia presentations, when compared with single-format conditions, did not provide additional benefits.     

Memory-load interference in syntactic processing

Participants remembered a short set of words while reading syntactically complex sentences (object–extracted clefts) and syntactically simpler sentences (subject–extracted clefts) in a memory–load study. The study also manipulated whether the words in the set and the words in the sentence were of matched or unmatched types (common nouns vs. proper names). Performance in sentence comprehension was worse for complex sentences than for simpler sentences, and this effect was greater when the type of words in the memory load matched the type of words in the sentence. These results indicate that syntactic processing is not modular, instead suggesting that it relies on working memory resources that are used for other nonsyntactic processes. Further, the results indicate that similarity–based interference is an important constraint on information processing that can be overcome to some degree during language comprehension by using the coherence of language to construct integrated representations of meaning.     

Active memory processes in visual sentence comprehension: Clause effects and pronominal reference

Two experiments were conducted to investigate active memory processes during reading. Subjects read two-clause sentences one word at a time at a self-paced rate. Following each sentence a probe word was presented; subjects were to decide if this word occurred in the sentence they had just read. The first experiment examined clausal effects during reading. Reaction times to items from the final clause were shorter than those to items from a previous clause even when the same number of words intervened. The second experiment used the clause effect to address the issue of proniminal reference. Results indicated that a pronoun in the final clause activated the meaning of its antecedent, thus demonstrating that the method is sensitive to both surface and meaning codes in active memory.     

The bizarreness effect and individual differences in imaging ability

The bizarreness effect refers to the superior performance in recall of bizarre sentences as compared to common sentences. The subjects studied each target word and in Exp. 1 rated its congruity with its sentence frame. In Exp. 2 they rated the vividness of the image for each sentence frame in which it was included. Four types of sentence frames were provided: bizarre image sentences, bizarre nonimage sentences, common image sentences, and common nonimage sentences. Good imagers and poor imagers were assessed on the Questionnaire Upon Mental Imagery. Both experiments showed that good imagers recalled target words in bizarre image sentences better than target words in common image sentences. A difference between the two sentence types was not observed for poor imagers. The differences between bizarre nonimage sentences and common nonimage sentences were not found for both type of imagers. The results were interpreted as showing that a difference in imaging ability was critical for the occurrence of a bizarreness effect.     

Functional structure in sentences: A performance analysis

Two experiments are reported which attempt to define the groupings of component words within sentences which subjects have committed to memory. The structural groupings are indexed by judgement latencies for pairs of words and these serve as the input matrix for a hierarchical clustering (HC) analysis. It is concluded that when subjects make judgements concerning the forward order of pairs of words, the latencies imply the presence of a hierarchical organization. Although the tree structures obtained do not follow in any detail the surface structures of the sentence types in either experiment, nonetheless when constituent analysis indicates no difference it is accompanied by identical performance structures, and when a surface distinction is called for, an appropriate difference is found in the tree diagrams produced by cluster analysis. Deep structure differences involving the rearrangement of component words are not found in the hierarchical structure subjects imposed. The pausing patterns followed by subjects when reading the sentences are shown to relate to the structural diagrams generated by the HC analysis.     

Similarity information versus relational information: differences in the time course of retrieval

Two experiments are reported that examine the time course of retrieval in a sentence matching procedure. Subjects learned lists of active and passive sentences and were tested with sentences in active or passive, correct or incorrect versions; for example, if "John hit Bill" was a studied sentence, "Bill hit John" would be an incorrect active test sentence. A response signal procedure was used so that accuracy could be measured as a function of time. The data show that sentences containing words from studied sentences are discriminable early in processing from sentences containing all new words, but discrimination of correct from incorrect versions of studied sentences occurs only later in processing (after 600-700 ms). These results demonstrate that different kinds of information are available at different points during the time course of retrieval and so suggest that modifications are required of models that provide only a unitary value for the amount of match between a test probe and information in memory. Early in processing, the growth of accuracy can be explained by a simple model that assumes independent contributions to total amount of match for each of the content words of a sentence, but this independent processing model cannot account for discrimination later in processing. Several, more general, memory models are examined with respect to their abilities to produce independent item information early in processing and relational information later in processing.     

The consequences of reduced memory span for the comprehension of semantic versus syntactic information

Aphasic patients with restricted memory spans were assessed on their comprehension of syntactically simple sentences varying in numbers of content words and on their comprehension of sentences matched in content words but varying in syntactic complexity. Three different presentation modes were used: unlimited visual presentation, limited visual presentation, and auditory presentation. The difference between performance in the unlimited and limited modes was used as a measure of the extent to which memory decrements caused comprehension failure. These difference scores were related to memory span in order to assess whether the memory involved in sentence processing overlaps that assessed by a memory span task. For the sentences varying in number of content words, performance was worse for the limited presentation modes than the unlimited mode, and the difference between unlimited and limited presentation modes was highly related to memory span. For the sentences varying in syntactic complexity, there was no clear reduction in performance for limited presentation modes, and the difference scores did not relate to memory span. The results support the view that the processing of sentences with many content words draws on the short-term memory capacity assessed by memory span, while the processing of syntactic complexity does not.     

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.     

The role of phonology in reading comprehension: Implications of the effects of homophones on processing sentences with referentially dependent categories

Two experiments investigated whether phonological representations are activated in the processing of anaphors in reading, and if they are, whether they play a role in the initial (first-pass) processing of the sentence or in review (second-pass) processes. Subjects made sentence acceptability judgements for sentences that contained either verb-gaps or indefinite and personal pronouns (overt anaphors). All sentences contained homophones. Half of the semantically unacceptable sentences were phonologically plausible if the homophones were inserted in the gap (e.g. The children sleighed in the winter, and the murderer in cold blood) or used as the referent of the pronoun (e.g. There is a sale on at the store and I have one at the boat). The other half of the semantically unacceptable sentences were phonologically implausible. In both experiments, half of the subjects saw the sentences under normal viewing conditions (whole sentence condition); for the other half of the subjects the words of each sentence were presented sequentially in the centre of the video screen at the rate of 250 msec/word (RSVP condition). A large proportion of the phonologically implausible sentences in the first experiment contained phrases in the second clause which resulted in semantic “oddities” (e.g. The children sleighed in the winter, and the murderer in the jar); the sentences in Experiment 2 did not contain such oddities. In Experiment 1 subjects made more errors on the phonologically plausible than implausible unacceptable sentences with both verb-gaps and pronouns in the whole sentence but not in the RSVP condition. There was no effect of phonological plausibility in Experiment 2. As the effect of phonological plausibility was only seen in the whole sentence condition, and only when the sentences contained semantic oddities, these data suggest that phonological information was not used in the first-pass analysis of the sentence, but rather when the subject re-read the sentence to find the referent.     

Varieties of frequency interference in children's recognition of sentence information

The memory of fourth-grade children (9 years, 10 months of age) for information contained in target sentences presented 24 hours earlier was tested by multiple-choice recognition items each consisting of a question about a target sentence followed by three response options. The options consisted of the correct word from the sentence, a new word, and an old, incorrect word that was contained in another sentence on the study trial. The results indicated that the amount of interference produced by old information depended upon the relationship between the sentence in which the old information occurred and the target sentence—being the least when the two were unrelated; the most when the two shared the same subject noun (which also occurred in the stem of the test item for the target sentence); and intermediate when the subjects of the two sentences were synonyms. The interference produced by these manipulations was moderated by instructional strategies and the distance between the target sentence and its variation. The experiment establishes the validity of contextual frequency accrual, a construct logically necessary in extending frequency theory to recognition of information contained in sentences.     

Reading between the lines: Event-related brain potentials during natural sentence processing

Event-related potentials (ERPs) were recorded from subjects as they silently read 160 different seven-word sentences, presented one word at a time. Each sentence was in itself a natural, meaningful phrase. Substantial intersubject variability was observed in the ERP waveshapes following the words. More than half of the subjects generated P3 components to word stimuli, but those who did showed similar responses to repeated control presentations of a single word. In addition, it was found that all but the first word in the sentence elicited an ERP with a significant left-greater-than-right asymmetry in the late positivity over temporo-parietal regions. The ERPs to the last words were associated with more late positivity than those to the preceding words. One quarter of the sentences, at random, ended with a word printed in a typeface that was different from that of the preceding words. This infrequent change in typeface elicited a complex ERP having three consistent late positive components.     

The retention of nouns,adjectives, and verbs of sentences

This research compared the retention of nouns, adjectives and verbs of sentences. A model of the structure underlying the retention of sentences and in which deep structure constituent propositions are hierarchically related, was used to make predictions concerning the retention of these word classes. The model was not supported by the data and it was determined that latencies to recognize the words of a previously presented sentence were the same for all classes of words. This result indicated that for recognition (but not necessarily for other memory tasks), each word of a sentence is seperately or equally accessible (as long as inter-word imagery is the same). However, a further experiment showed that, although word class is not a variable, the image-arousing capacity of a word is. Latencies and error rates were much lower for high-imagery words than for low-imagery ones. The findings on error rates in recognizing words were interesting and pointed to a different model where the meaning representations and syntatic functions of words have an active role in sentence retention.     

Changes in the semantic constraint of spreading activation of memory across three age groups

28 undergraduate, 34 sixth-grade, and 36 second-grade students studied target words embedded in interchangeable or noninterchangeable sentences, and then performed free recall tests. In an interchangeable sentence the word which was to be remembered and its associated word fitted sensibly, whereas in a noninterchangeable sentence the target word fitted sensibly but its word associate did not. Undergraduates recalled the target words in noninterchangeable sentences better than sixth or second graders for whom a difference was not observed (undergraduates > sixth graders = second graders). In interchangeable sentences undergraduates recalled more targets than sixth or second graders, and sixth graders recalled more than second graders (undergraduates > sixth graders > second graders). The results were interpreted as indicating changes across age groups in the semantic constraint of spreading activation of target words in memory.     

Articulatory suppression and phonological codes in reading for meaning

The aim of this study was to investigate whether the phonological code that causes errors in printed sentence comprehension is affected by concurrent articulation. Forty adult subjects made speeded judgements of the acceptability of printed sentences. The critical sentences were foils that were (1) orthographi-cally unacceptable but phonologically acceptable (e.g. The palace had a thrown room), and (2) spelling controls that were orthographically and phonologically unacceptable (The palace had a thorns room). Half the subjects performed this task in silence (without concurrently articulating) and showed a marked phonological effect such that false alarms to phonologically acceptable foils were more frequent than false alarms to their spelling controls. The remaining subjects who performed this task with concurrent articulatory suppression showed an increase in false alarm rates, but no effect of phonology. In a control experiment using the same subjects, memory span for visually presented long and short words was measured under conditions of silence or concurrent articulation. The word length effect (Baddeley, Thomson, & Buchanan, 1975) disappeared under suppression, indicating that the suppression manipulation was highly effective. Thus the phonological codes that are used both in sentence comprehension and memory span are highly susceptible to articulatory suppression. We discuss possible relationships between phonological codes that mediate lexical access and those that support short-term verbal memory.