Paola Palladino

Working memory and updating processes in reading comprehension

In this study, we examine the relation between reading comprehension ability and success in working memory updating tasks. Groups of poor and good comprehenders, matched for logical reasoning ability, but different in reading comprehension ability, were administered various updating tasks in a series of experiments. In the first experiment, the participants were presented with lists of words, the length of which (4–10 words) was unknown beforehand, and were required to remember the last 4 words in each series. In this task, we found a decrease in performance that was related to longer series and poor reading ability. In the second experiment, we presented lists of nouns referring to items of different sizes, in a task that simulated the selection and updating of relevant information that occurs in the on-line comprehension process. The participants were required to remember a limited, predefined number of the smallest items presented. We found that poor comprehenders not only had a poorer memory, but also made a greater number of intrusion errors. In the third and fourth experiments, memory load (number of items to be selected) and suppression request (number of potentially relevant items) were manipulated within subjects. Increases in both memory load and suppression requests impaired performance. Furthermore, we found that poor comprehenders produced a greater number of intrusion errors, particularly when the suppression request was increased. Finally, in a fifth experiment, a request to specify the size of presented items was introduced. Poor comprehenders were able to select the appropriate items, although their recall was poorer. Altogether, the data show that working memory abilities, based on selecting and updating relevant information and avoiding intrusion errors, are related to reading comprehension.

Intrusion errors in working memory tasks: Are they related to reading comprehension ability?

Abstract The purpose of the present research was to investigate whether inefficient suppression mechanisms cause overload and interference in working memory and, consequently, influence reading comprehension. Two groups of children, matched for intelligence but differing in inferential comprehension ability, were compared on measures of short-term (passive storage) and working memory (maintenance and processing) and memory for relevant and irrelevant information after reading a passage. Poor comprehenders produced more intrusion errors in a working memory task and recalled more irrelevant information from the passage. The presence of irrelevant information in recall suggests that poor comprehenders are less efficient in reducing the activation (suppression) of information, which is no longer relevant. A year-long longitudinal study was conducted to investigate the influence of suppression efficiency in reading comprehension. Intrusion errors were shown to be a good predictor of comprehension performance 1 year later. Suppression mechanisms seem to play an important role in working memory by reducing interference and improving the processing and maintenance of relevant information in order to build a coherent representation during reading comprehension.

Decline in working memory updating through ageing: Intrusion error analyses

The present research examines the decline in working memory updating through age. Two experiments compared groups of participants in different age ranges (young‐old, 55–65 years, old, 66–75 years and old‐old, more than 75 years and, in Experiment 2 only, young, 20–30 years). Memory updating tasks were administered, which required participants to remember the smallest items in each list. To perform the task correctly, participants had to update information efficiently, reducing interference from items no longer relevant. Intrusion errors were computed and in the first experiment these were described as “intrusions of irrelevant items” (immediate exclusion) and “intrusions of once relevant items” (delayed exclusion). The oldest adults performed worse in memory updating and made a greater number of intrusion errors of once relevant information. In the second experiment results showed that increases in memory load (number of items that had to be remembered) and updating demand (number of potentially relevant items) impaired performance. The oldest adults had greater difficulty when the task demand was increased. Furthermore, they produced a higher number of intrusion errors, particularly when the updating demand was increased. It therefore appears that elderly people have specific difficulty in updating information in working memory by excluding irrelevant information.

What happens to information to be suppressed in working‐memory tasks? Short and long term effects

The study explored, from an individual differences point of view, what happens to information to be suppressed in a working–memory task at short and long term. In particular, it was examined whether control mechanisms of irrelevant information in working memory imply their complete elimination from working memory or just the modulation of their activation. To this end, we compared the fate of irrelevant information in groups of subjects with high and low reading comprehension (Experiments 1 and 2) and subjects with high and low working memory (Experiments 1, 2, 3, and 4). All the experiments presented a working–memory task devised by De Beni, Palladino, Pazzaglia, and Cornoldi (1998), which required participants to process lists of words, to tap when a word from a particular category was presented, and then to recall only the last items in each list. Results confirmed that participants with high reading comprehension also have higher working memory and make less intrusion errors due to irrelevant items that have to be processed but then discarded. Furthermore, it was found that participants with low working memory have slightly better implicit (Experiment 1) and explicit memory (Experiments 3 and 4) of highly activated irrelevant information. Nevertheless, in a long–term recognition test, participants with high and low reading comprehension/working memory presented a similar pattern of memory for different types of irrelevant information (Experiment 2), whereas in a short–term memory recognition test, low–span participants presented a facilitation effect in the time required for the recognition of highly activated irrelevant information (Experiment 4). It was concluded that efficient working–memory performance is related to the temporary reduction of activation of irrelevant information but does not imply its elimination from memory.

Reading Minds: The Relation between Children's Mental State Knowledge and Their Metaknowledge about Reading.

The relation between childrens mental state knowledge and metaknowledge about reading was examined in 2 studies. In Study 1, 196 children (mean age = 9 years) were tested for verbal ability (VA), metaknowledge about reading, and mental state words in a story task. In Study 2, the results of Study 1 were extended by using a cross-lagged design and by investigating older children (N = 71, mean ages = 10 years at Time 1 and 11 years at Time 2) for mental state knowledge, metaknowledge about reading, and VA. Results showed a significant relation between early cognitive (but not emotion) mental state knowledge and later metaknowledge about reading, controlling for VA. Results suggest close links between different aspects of childrens knowledge about the mind.

Do updating tasks involve updating? Evidence from comparisons with immediate serial recall

Updating tasks require participants to process a sequence of items, varying in length, and afterwards to remember only a fixed number of the elements of the sequence; the assumption being that participants actively update the to-be-recalled list as presentation progresses. However recent evidence has cast doubt on this assumption, and the present study examined the strategies that participants employ in such tasks by comparing the serial position curves found in verbal and visuo-spatial updating tasks with those seen in standard serial recall tasks. These comparisons showed that even when the same number of items are presented or recalled, participants perform less well in an updating than a serial recall context. In addition, while standard serial position effects were observed for serial recall, marked recency and reduced or absent primacy effects were seen in updating conditions. These findings suggest that participants do not typically adopt a strategy of actively updating the memory list in updating tasks, but instead tend to wait passively until the list ends before trying to recall the most recently presented items.

Working memory in aging: Maintenance and suppression

The present research is focused on a fine-grained analysis of memory decline with aging, and the role of suppression mechanisms in age-related memory decline. Three groups of participants (continuous age ranges; young-old: 55–65 years, old: 66–75 years, and old-old: more than 75 years) were administered Forward and Backward span test, and a Working Memory task with Categorization (WMC). This new task requires lists of five words to be processed in order to individuate animal nouns, and that the last word of each list be contemporarily maintained. The words incorrectly recalled as target items, but presented during the task (intrusion errors), were computed in order to analyze the efficiency of suppression mechanisms. The findings indicated a continuous decline in working memory measures, and an early decline in short-term memory (passive storage) measures (between 60’s and 70’s). An age-related increase in intrusion errors was observed; the intrusion index was inversely related to working memory performance but, according to the hypotheses, was not related to short-term memory measures. These results suggest that the stronger working memory effect observed through age might be due to the combined influence of a decline in the capacity of short-term memory, and a loss of efficiency in suppression mechanisms.

Prospective memory and working memory: Asymmetrical effects during frontal lobe TMS stimulation

The role of working memory (WM) for the realization of an intended action (prospective memory, PM) has been debated in recent neuropsychological literature. The present study aimed to assess whether WM and PM share resources or are, alternatively, two distinct mechanisms. A verbal task was used, which manipulated the cognitive demand of both WM and PM dimensions on an event-based prospective task. Transcranial magnetic stimulation (TMS) was also employed to clarify the causal contribution of frontal areas previously related to WM, to the PM process. The prospective task required the participant to respond whenever a word appeared which had been presented before the beginning of the task. Two ongoing tasks were administered: an updating WM task (in two conditions of medium and high WM demands) and a lexical decision task (representing a low WM demand). In the first two experiments, higher PM demand affected WM only at higher loads, but the PM load effect was independent of WM, showing asymmetrical behavioural effects. In the third experiment, single pulse TMS was applied to left and right dorsolateral prefrontal cortices. When applied to the experimental sites, stimulation increased error rates of the PM task, while the effect was only marginal in the WM task. The effect was bilateral, since there was no difference between left and right stimulation sites. These findings demonstrated, from both behavioural and neurofunctional perspectives, that WM and PM processes are not based on the same memory system, but PM may require WM resources at high demand.

Content–context binding in verbal working memory updating: On-line and off-line effects

The role of content-context binding in working memory updating has received only marginal interest, despite its undoubted relevance for the updating process. In the classical updating paradigm, the main focus has been on the process of discarding information when new information is presented. Its efficacy has been determined by measurement of the accuracy of recalled, updated information. In the current study we measured the working memory updating process directly, employing a dynamic memory task composed of alternating sequences of learning, active maintenance and updating phases. Binding was manipulated by changing the type of updating (total or partial) and the strength of the perceptual connection between items. The on-line updating process and the off-line efficacy were separately analysed. Both on-line and off-line measures indicated that partial updating conditions, where the operation of updating content-context binding was required, were more demanding than both total updating conditions and memory and maintenance phases. Our results suggest that working memory updating can be identified not only as a process of substitution of information, but also as inhibition of no longer relevant information and, above all, as a binding updating.

Phonological sensitivity and memory in children with a foreign language learning difficulty

The phonological processing and memory skills of 12- and 13-year-old Italian children with difficulty in learning English as a foreign language (foreign language learning difficulty, FLLD) were examined and compared with those of a control group matched for age and nonverbal intelligence. Three experiments were conducted. A dissociation between verbal and visuo-spatial working memory was observed when compared to the control group; children with FLLD showed a poorer performance in a phonological working memory task but performed to a comparable level in a visuo-spatial working memory task (Experiment 1). In Experiment 2 the word length and the response modality of an auditory word span task were manipulated in order to examine the efficiency of the phonological loop and the relevance of the spoken output. The FLLD group did not show sensitivity to the word length effect and showed no advantage in the picture pointing recall condition. In Experiment 3 children with FLLD were shown to be sensitive to phonological similarity but again they showed neither a word length effect nor a slower articulation speed. Furthermore, in all three experiments children with FLLD were shown to be less efficient in phonological sensitivity tasks and this deficit appeared to be independent of the phonological memory problem. All three experiments consistently showed that children with FLLD have an impairment in phonological memory and phonological processing, which appear to be independent from one other but both contribute to the childrens difficulty in learning a second language.