Mind wandering during hypertext reading: The impact of hyperlink structure on reading comprehension and attention.

Online reading is becoming more and more popular in learning and teaching environments. However, little is known about characteristics of hypertexts that influence on reading comprehension and attention. Some previous studies have suggested that attention failures also referred to as mind wandering (MW) occur whenever the available resources of the reader (e.g., working memory capacity; WMC) do not match the task demands (e.g., text difficulty). This study aims to investigate the effect of restructuring a linear text into different hypertext types by means of hyperlinks on MW in a cognitively demanding task like reading. We hypothesized that participants exposed to a difficult to read hypertext with networked structure engage more in task-unrelated thoughts (TUTs) compared to participants asked to read a difficult but hierarchically organized hypertext. 90 participants read either an easy or difficult version of the same unfamiliar hypertext with either a hierarchical or networked structure and with embedded thought probes. Reading comprehension and WMC measures followed. As expected, participants reading the difficult (to read) hypertext with networked link structure showed significantly more TUTs than participants reading the hierarchical link structure hypertext. In addition, readers with a low-WMC showed significantly more TUTs while reading a demanding hypertext regardless of its structure. These findings are in line with the view that mind wandering occurs if available resources do not match with task demands, and thus deepen assumptions about hyperlinks as new cohesive devices.

Concurrent prospective memory task increases mind wandering during online reading for difficult but not easy texts.

Many prior theories have tried to explain the relationship between attentional processes and mind wandering. The resource-demand matching view argues that a mismatch between task demands and resources led to more mind wandering. This study aims to test this view against competing models by inducing mind wandering through increasing the level of demands via adding a prospective memory task to cognitively demanding tasks like reading. We hypothesized that participants with a second task still in mind (unfinished group) engage more in task-unrelated thoughts (TUTs) and show less text comprehension compared to participants who think a second task is finished (finished group). Seventy-two participants had to study 24 items of a to-do list for a recall test. After a first cued recall of ten items, participants were either told that a second task was finished or that the recall was interrupted and continued later. All participants then started reading an easy or difficult version of the same unfamiliar hypertext, while being thought probed. Text comprehension measures followed. As expected, participants in the unfinished group showed significantly more TUTs than participants in the finished group when reading difficult texts, but, contrary to our assumptions, did not show better text comprehension measures when reading difficult text. Nevertheless, participants compensate for the influence of the second task by reading longer, which in turn has a positive effect on their reading knowledge. These findings support the resource-demand-matching model and thus strengthen assumptions about the processing of attention during reading.

In search for the most optimal EEG method: A practical evaluation of a water-based electrode EEG system.

The study assessed a mobile electroencephalography system with water-based electrodes for its applicability in cognitive and behavioural neuroscience. It was compared to a standard gel-based wired system. Electroencephalography was recorded on two occasions (first with gel-based, then water-based system) as participants completed the flanker task. Technical and practical considerations for the application of the water-based system are reported based on participant and experimenter experiences. Empirical comparisons focused on electroencephalography data noise levels, frequency power across four bands (theta, alpha, low beta and high beta) and event-related components (P300 and ERN). The water-based system registered more noise compared to the gel-based system which resulted in increased loss of data during artefact rejection. Signal-to-noise ratio was significantly lower for the water-based system in the parietal channels which affected the observed parietal beta power. It also led to a shift in topography of the maximal P300 activity from parietal to frontal regions. The water-based system may be prone to slow drift noise which may affect the reliability and consistency of low-frequency band analyses. Practical considerations for the use of water-based electrode electroencephalography systems are provided.

Error-Related Cognitive Control and Behavioral Adaptation Mechanisms in the Context of Motor Functioning and Anxiety.

Motor proficiency reflects the ability to perform precise and coordinated movements in different contexts. Previous research suggests that different profiles of motor proficiency may be associated with different cognitive functioning characteristics thus suggesting an interaction between cognitive and motor processes. The current study investigated this interaction in the general population of healthy adults with different profiles of motor proficiency by focusing on error-related cognitive control and behavioral adaptation mechanisms. In addition, the impact of these processes was assessed in terms of trait anxiety and worries. Forty healthy adults were divided into high and low motor proficiency groups based on an assessment of their motor skills. Using electroencephalography during a flanker task, error-related negativity (ERN) was measured as the neural indicator of cognitive control. Post-error slowing (PES) was measured to represent behavioral adaptation. Participants also completed an anxiety assessment questionnaire. Participants in the high motor proficiency group achieved better task accuracy and showed relatively enhanced cognitive control through increased ERN. Contrastingly, individuals in the lower motor proficiency group achieved poorer accuracy whilst showing some evidence of compensation through increased PES. Trait anxiety reflecting general worries was found to be correlated with motor functioning, but the study could not provide evidence that this was related to cognitive or behavioral control mechanisms. The interaction between cognitive and motor processes observed in this study is unique for healthy and sub-clinical populations and provides a baseline for the interpretation of similar investigations in individuals with motor disorders.

Motor and non-motor sequence prediction is equally affected in children with developmental coordination disorder.

Children with Developmental Coordination Disorder (DCD) are diagnosed based on motor difficulties. However, they also exhibit difficulties in several other cognitive domains, including visuospatial processing, executive functioning and attention. One account of the difficulties seen in DCD proposes an impairment in internal forward modelling, i.e., the ability to (i) detect regularities of a repetitive perceptual or motor pattern, (ii) predict future outcomes of motor actions, and (iii) adapt behaviour accordingly. Using electroencephalographic recordings, the present study aimed to delineate these different aspects of internal forward modelling across several domains. To this end, 24 children with DCD and 23 typically-developing children (aged 7-10 years) completed a serial prediction task in the visual, temporal, spatial and motor domains. This task required them to learn short sequences and to indicate whether a sequence was disrupted towards its end. Analyses revealed that, across all domains, children with DCD showed poorer discrimination between intact and disrupted sequences, accompanied by a delayed late parietal positivity elicited by disrupted sequences. These results indicate an impairment in explicit sequence discrimination in DCD across motor and cognitive domains. However, there is no evidence for an impairment in implicit performance on the visuomotor task in DCD. These results suggest an impairment of the updating of an internal forward model in DCD resulting in a blurred representation of that model and, consequently, in a reduced ability to detect regularities in the environment (e.g., sequences). Such a detailed understanding of internal forward modelling in DCD could help to explain the wide range of co-occurring difficulties experienced by those with a diagnosis of DCD.

Attention control processes that prioritise task execution may come at the expense of incidental memory encoding.

Attention underpins episodic memory encoding by gating information processing. However, it is unclear how different forms of attention affect encoding. Using fMRI, we implemented a novel task that separates top-down and bottom-up attention (TDA; BUA) to test how these forms of attention influence encoding. Twenty-seven subjects carried out a scanned incidental encoding task that required semantic categorisation of stimuli. Trials either required visual search (TDA) to locate a target, or the target blinked and captured attention (BUA). After a retention period, subjects performed a surprise recognition test. Univariate analyses showed that ventral visual regions and right hippocampus indexed encoding success. Psychophysiological interaction analyses showed that, during TDA, there was increased coupling between dorsal parietal cortex and fusiform gyrus with encoding failure, and between lateral occipital cortex and fusiform gyrus with encoding success. No significant connectivity modulations were observed during BUA. We propose that increased TDA to objects in space is mediated by parietal cortex and negatively impacts encoding. Also, increases in connectivity within ventral visual cortex index the integration of stimulus features, promoting encoding. Finally, the influences of attention on encoding likely depend on task demands: as cognitive control increases, task execution is emphasised at the expense of memory encoding.

Exploring the bilingual advantage: manipulations of similarity and second language immersion in a Stroop task.

To explain varying previous results as to whether bilinguals show an advantage over monolinguals in inhibitory control, two hypotheses have been suggested. The Bilingual Inhibitory Control Advantage (BICA) hypothesis proposes a bilingual advantage specific to the presence of conflict. In contrast, the Bilingual Executive Processing Advantage (BEPA) hypothesis proposes a global advantage in processing, across all contexts. The present research contrasts these hypotheses by investigating the effects of second language immersion and similarity of colour terms across languages on the bilingual Stroop task. Ten English and ten German native speakers, residing in Munich, Germany, completed a bilingual Stroop task using stimuli with colour terms which were similar or dissimilar between the two languages. Event-related potentials were recorded alongside behavioural data. Dissimilar stimuli showed greater costs, reflected by increased reaction times (RTs), more negative N400 amplitudes and more positive Late Positive Component (LPC) amplitudes, than similar stimuli. Participants who were immersed in a second language environment experienced greater costs, which were specific to conflict trials for RT and LPC measures, but occurred across all trial types during the N400 window. It was concluded that in contrast to previous research only supporting BEPA, there is also evidence for the BICA hypothesis.

Meditation experience predicts negative reinforcement learning and is associated with attenuated FRN amplitude.

Focused attention meditation (FAM) practices are cognitive control exercises where meditators learn to maintain focus and attention in the face of distracting stimuli. Previous studies have shown that FAM is both activating and causing plastic changes to the mesolimbic dopamine system and some of its target structures, particularly the anterior cingulate cortex (ACC) and striatum. Feedback-based learning also depends on these systems and is known to be modulated by tonic dopamine levels. Capitalizing on previous findings that FAM practices seem to cause dopamine release, the present study shows that FAM experience predicts learning from negative feedback on a probabilistic selection task. Furthermore, meditators exhibited attenuated feedback-related negativity (FRN) as compared with nonmeditators and this effect scales with meditation experience. Given that reinforcement learning and FRN are modulated by dopamine levels, a possible explanation for our findings is that FAM practice causes persistent increases in tonic dopamine levels which scale with amount of practice, thus altering feedback processing.

Potential for use of creatine supplementation following mild traumatic brain injury.

There is significant overlap between the neuropathology of mild traumatic brain injury (mTBI) and the cellular role of creatine, as well as evidence of neural creatine alterations after mTBI. Creatine supplementation has not been researched in mTBI, but shows some potential as a neuroprotective when administered prior to or after TBI. Consistent with creatine's cellular role, supplementation reduced neuronal damage, protected against the effects of cellular energy crisis and improved cognitive and somatic symptoms. A variety of factors influencing the efficacy of creatine supplementation are highlighted, as well as avenues for future research into the potential of supplementation as an intervention for mTBI. In particular, the slow neural uptake of creatine may mean that greater effects are achieved by pre-emptive supplementation in at-risk groups.

Recollection reduces unitised familiarity effect.

Two types of encoding tasks have been employed in previous research to investigate the beneficial effect of unitisation on familiarity-based associative recognition (unitised familiarity effect), namely the compound task and the interactive imagery task. Here we show how these two tasks could differentially engage subsequent recollection-based associative recognition and consequently lead to the turn-on or turn-off of the unitised familiarity effect. In the compound task, participants studied unrelated word pairs as newly learned compounds. In the interactive imagery task, participants studied the same word pairs as interactive images. An associative recognition task was used in combination with the Remember/Know procedure to measure recollection-based and familiarity-based associative recognition. The results showed that the unitised familiarity effect was present in the compound task but was absent in the interactive imagery task. A comparison of the compound and the interactive imagery task revealed a dramatic increase in recollection-based associative recognition for the interactive imagery task. These results suggest that unitisation could benefit familiarity-based associative recognition; however, this effect will be eliminated when the memory trace formed is easily accessed by strong recollection without the need for a familiarity assessment.

Learning context modulates the processing of expectancy violations.

The detection of unexpected or unfavorable events is crucial for successful behavioral adaptation. There is a family of ERP components, the so-called error negativities, that has been associated with these detection processes. In the current study, we explored the functional characteristics of one of these components, the N2b which reflects the detection of unexpected events in a stream of stimuli in our environment, in more detail. In a sequence learning task, we found that the same type of deviant event elicited an N2b only when it conveyed information about the to-be-learned sequence, but not when it was rendered learning-irrelevant by means of task instruction. This supports the view that deviant events generate an error negativity in a similar way as committed errors and negative feedback. It also demonstrates that error monitoring processes are very flexible and can be tailored to the specific demands of the task at hand, i.e., expectancy violations only activate the error system when the detected mismatch is classified as relevant for the specific goals in the current learning context. Additionally, a P3 to all deviant types was found reflecting a higher-order form of performance monitoring associated with evaluation of task-relevant events and updating of working memory contents.

Concurrence of rule- and similarity-based mechanisms in artificial grammar learning.

A current theoretical debate regards whether rule-based or similarity-based learning prevails during artificial grammar learning (AGL). Although the majority of findings are consistent with a similarity-based account of AGL it has been argued that these results were obtained only after limited exposure to study exemplars, and performance on subsequent grammaticality judgment tests has often been barely above chance level. In three experiments the conditions were investigated under which rule- and similarity-based learning could be applied. Participants were exposed to exemplars of an artificial grammar under different (implicit and explicit) learning instructions. The analysis of receiver operating characteristics (ROC) during a final grammaticality judgment test revealed that explicit but not implicit learning led to rule knowledge. It also demonstrated that this knowledge base is built up gradually while similarity knowledge governed the initial state of learning. Together these results indicate that rule- and similarity-based mechanisms concur during AGL. Moreover, it could be speculated that two different rule processes might operate in parallel; bottom-up learning via gradual rule extraction and top-down learning via rule testing. Crucially, the latter is facilitated by performance feedback that encourages explicit hypothesis testing.

Different aspects of performance feedback engage different brain areas: disentangling valence and expectancy in feedback processing.

Evaluating the positive and negative outcomes of our behaviour is important for action selection and learning. Such reinforcement learning has been shown to engage a specific neural circuitry including the mesencephalic dopamine system and its target areas, the striatum and medial frontal cortex, especially the anterior cingulate cortex (ACC). An intensively pursued debate regards the prevailing influence of feedback expectancy and feedback valence on the engagement of these two brain regions in reinforcement learning and their respective roles are far from being understood. To this end, we used a time estimation task with three different types of feedback that allows disentangling the effect of feedback valence and expectancy using functional magnetic resonance imaging (fMRI). Our results show greater ACC activation after unexpected positive and unexpected negative feedback than after expected feedback and by this sensitivity to unexpected events in general irrespective of their valence.

Is a novel conceptual unit more than the sum of its parts?: FMRI evidence from an associative recognition memory study.

Recollection, an effortful process relying on the integrity of a brain network including the hippocampus, is generally required to remember arbitrary associations whereas a simple familiarity signal arising in the perirhinal cortex is sufficient to recognize single items. However, the integration of separate items into a single configuration (unitization) leads to reduced involvement of recollection and greater reliance on familiarity. This seems to imply that unitized associations are processed similar to single items. Here, using functional magnetic resonance imaging, we investigated the effects of unitization as encoding strategy on retrieval processes in a between-group-design. A definition was provided that allows combining two unrelated words into a novel conceptual unit (e.g., milk taxi = a delivery service, which is directly dispatched from a farm). We compared this to an encoding strategy in which the words were studied as parts of a sentence. We included pairs in reversed order at test because reversing a unitized word pair is assumed to disrupt the unit while leaving item familiarity for the single constituents intact. This enabled us to compare recognition memory for novel units and single items. Sentence encoding led to a flexible recruitment of brain areas previously associated with recollection, irrespective of the order of the test pair. Unitization encoding reduced the involvement of the recollection network and specifically engaged regions within the parahippocampal cortex and the medial prefrontal cortex for novel units. In contrast, recognition of reversed pairs involved activation of BA 45 in the left inferior frontal gyrus. This possibly suggests that familiarity for novel units and single items are associated with different brain networks.

Memory function and the hippocampus.

There has been a long tradition in memory research of adopting the view of a vital role of the medial temporal lobe and especially the hippocampus in declarative memory. Despite the broad support for this notion, there is an ongoing debate about what computations are performed by the different substructures. The present chapter summarizes several accounts of hippocampal functions in terms of the cognitive processes subserved by these structures, the information processed, and the underlying neural operations. Firstly, the value of the distinction between recollection and familiarity for the understanding of the role the hippocampus plays in memory is discussed. Then multiple lines of evidence for the role of the hippocampus in memory are considered. Cumulating evidence suggests that the hippocampus fosters the binding of disparate cortical representations of items and their spatiotemporal context into a coherent representation by means of a sparse conjunctive neural coding. This association of item and context will then lead to the phenomenological experience of recollection. In contrast, surrounding cortical areas have broader neural coding that provide a scalar signal of the similarity between two inputs (e.g. between the encoding and the retrieval). By this they form the basis of a feeling of familiarity, but also might encode the commonalities between these different inputs. However, a more complete picture of the importance of the hippocampus for declarative memories can only be drawn when the interactions of the medial temporal lobe with other brain areas are also taken into account.

Selective transfer of visual working memory training on Chinese character learning.

Previous research has shown a systematic relationship between phonological working memory capacity and second language proficiency for alphabetic languages. However, little is known about the impact of working memory processes on second language learning in a non-alphabetic language such as Mandarin Chinese. Due to the greater complexity of the Chinese writing system we expect that visual working memory rather than phonological working memory exerts a unique influence on learning Chinese characters. This issue was explored in the present experiment by comparing visual working memory training with an active (auditory working memory training) control condition and a passive, no training control condition. Training induced modulations in language-related brain networks were additionally examined using functional magnetic resonance imaging in a pretest-training-posttest design. As revealed by pre- to posttest comparisons and analyses of individual differences in working memory training gains, visual working memory training led to positive transfer effects on visual Chinese vocabulary learning compared to both control conditions. In addition, we found sustained activation after visual working memory training in the (predominantly visual) left infero-temporal cortex that was associated with behavioral transfer. In the control conditions, activation either increased (active control condition) or decreased (passive control condition) without reliable behavioral transfer effects. This suggests that visual working memory training leads to more efficient processing and more refined responses in brain regions involved in visual processing. Furthermore, visual working memory training boosted additional activation in the precuneus, presumably reflecting mental image generation of the learned characters. We, therefore, suggest that the conjoint activity of the mid-fusiform gyrus and the precuneus after visual working memory training reflects an interaction of working memory and imagery processes with complex visual stimuli that fosters the coherent synthesis of a percept from a complex visual input in service of enhanced Chinese character learning.

ERPs show that classroom-instructed late second language learners rely on the same prosodic cues in syntactic parsing as native speakers.

The loss of brain plasticity after a 'critical period' in childhood has often been argued to prevent late language learners from using the same neurocognitive mechanisms as native speakers and, therefore, from attaining a high level of second language (L2) proficiency [7,11]. However, more recent behavioral and electrophysiological research has challenged this 'Critical Period Hypothesis', demonstrating that even late L2 learners can display native-like performance and brain activation patterns [17], especially after longer periods of immersion in an L2 environment. Here we use event-related potentials (ERPs) to show that native-like processing can also be observed in the largely under-researched domain of speech prosody - even when L2 learners are exposed to their second language almost exclusively in a classroom setting. Participants listened to spoken sentences whose prosodic boundaries would either cooperate or conflict with the syntactic structure. Previous work had shown that this paradigm is difficult for elderly native speakers, however, German L2 learners of English showed very similar ERP components for on-line prosodic phrasing as well as for prosody-syntax mismatches (garden path effects) as the control group of native speakers. These data suggest that L2 immersion is not always necessary to master complex L2 speech processing in a native-like way.

Does it really matter? Separating the effects of musical training on syntax acquisition.

The possible transfer of musical expertise to the acquisition of syntactical structures in first and second language has emerged recently as an intriguing topic in the research of cognitive processes. However, it is unlikely that the benefits of musical training extend equally to the acquisition of all syntactical structures. As cognitive transfer presumably requires overlapping processing components and brain regions involved in these processing components, one can surmise that transfer between musical ability and syntax acquisition would be limited to structural elements that are shared between the two. We propose that musical expertise transfers only to the processing of recursive long-distance dependencies inherent in hierarchical syntactic structures. In this study, we taught fifty-six participants with widely varying degrees of musical expertise the artificial language BROCANTO, which allows the direct comparison of long-distance and local dependencies. We found that the quantity of musical training (measured in accumulated hours of practice and instruction) explained unique variance in performance in the long-distance dependency condition only. These data suggest that musical training facilitates the acquisition specifically of hierarchical syntactic structures.

The impact of auditory working memory training on the fronto-parietal working memory network.

Working memory training has been widely used to investigate working memory processes. We have shown previously that visual working memory benefits only from intra-modal visual but not from across-modal auditory working memory training. In the present functional magnetic resonance imaging study we examined whether auditory working memory processes can also be trained specifically and which training-induced activation changes accompany theses effects. It was investigated whether working memory training with strongly distinct auditory materials transfers exclusively to an auditory (intra-modal) working memory task or whether it generalizes to a (across-modal) visual working memory task. We used adaptive n-back training with tonal sequences and a passive control condition. The memory training led to a reliable training gain. Transfer effects were found for the (intra-modal) auditory but not for the (across-modal) visual transfer task. Training-induced activation decreases in the auditory transfer task were found in two regions in the right inferior frontal gyrus. These effects confirm our previous findings in the visual modality and extents intra-modal effects in the prefrontal cortex to the auditory modality. As the right inferior frontal gyrus is frequently found in maintaining modality-specific auditory information, these results might reflect increased neural efficiency in auditory working memory processes. Furthermore, task-unspecific (amodal) activation decreases in the visual and auditory transfer task were found in the right inferior parietal lobule and the superior portion of the right middle frontal gyrus reflecting less demand on general attentional control processes. These data are in good agreement with amodal activation decreases within the same brain regions on a visual transfer task reported previously.

Emotionality in a second language: it's a matter of time.

The present study investigated the well acknowledged phenomenon of a different sense of emotionality in a person's first (L1) and second language (L2). Event-related potentials were recorded during the reading of pleasant, unpleasant and neutral words in L1 and L2. Enhanced processing of both emotional compared to neutral words was reflected in an amplified early posterior negativity (EPN) about 280-430 ms after word onset. While the EPN did not differ in amplitude between L1 and L2, it was delayed for L2. Interestingly, a better task performance in L2 but not L1 predicted longer delays of the EPN. These results might indicate that the affective valence of L2 words is processed in a less immediate way due to delayed lexical access. This is interpreted in terms of interference in a highly integrated L1/L2 mental lexicon.