R-3 Repository :: Browsing by Author "Fischer-Baum, Simon"

Browsing by Author "Fischer-Baum, Simon"

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A position paper on researching braille in the cognitive sciences: decentering the sighted norm
(Cambridge University Press, 2023) Englebretson, Robert; Holbrook, M. Cay; Fischer-Baum, Simon
This article positions braille as a writing system worthy of study in its own right and on its own terms. We begin with a discussion of the role of braille in the lives of those who read and write it and a call for more attention to braille in the reading sciences. We then give an overview of the history and development of braille, focusing on its formal characteristics as a writing system, in order to acquaint sighted print readers with the basics of braille and to spark further interest among reading researchers. We then explore how print-centric assumptions and sight-centric motivations have potentially negative consequences, not only for braille users but also for the types of questions researchers think to pursue. We conclude with recommendations for conducting responsible and informed research about braille. We affirm that blindness is most equitably understood as but one of the many diverse ways humans experience the world. Researching braille literacy from an equity and diversity perspective provides positive, fruitful insights into perception and cognition, contributes to the typologically oriented work on the world’s writing systems, and contributes to equity by centering the perspectives and literacy of the people who read and write braille.
All cumulative semantic interference is not equal: A test of the Dark Side Model of lexical access
(2013-09-16) Walker Hughes, Julie; Schnur, Tatiana T.; Martin, Randi C.; Fischer-Baum, Simon
Language production depends upon the context in which words are named. Renaming previous items results in facilitation while naming pictures semantically related to previous items causes interference. A computational model (Oppenheim, Dell, & Schwartz, 2010) proposes that both facilitation and interference are the result of using naming events as “learning experiences” to ensure future accuracy. The model successfully simulates naming data from different semantic interference paradigms by implementing a learning mechanism that creates interference and a boosting mechanism that resolves interference. This study tested this model’s assumptions that semantic interference effects in naming are created by learning and resolved by boosting. Findings revealed no relationship between individual performance across semantic interference tasks, and measured learning and boosting abilities did not predict performance. These results suggest that learning and boosting mechanisms do not fully characterize the processes underlying semantic interference when naming.
Brain Modularity Mediates the Relation between Task Complexity and Performance
(The MIT Press, 2017) Yue, Qiuhai; Martin, Randi; Fischer-Baum, Simon; Ramos-Nuñez, Aurora I.; Ye, Fengdan; Deem, Michael W.; Center for Theoretical Biological Physics
Recent work in cognitive neuroscience has focused on analyzing the brain as a network, rather than as a collection of independent regions. Prior studies taking this approach have found that individual differences in the degree of modularity of the brain network relate to performance on cognitive tasks. However, inconsistent results concerning the direction of this relationship have been obtained, with some tasks showing better performance as modularity increases and other tasks showing worse performance. A recent theoretical model [Chen, M., & Deem, M. W. 2015. Development of modularity in the neural activity of children's brains. Physical Biology, 12, 016009] suggests that these inconsistencies may be explained on the grounds that high-modularity networks favor performance on simple tasks whereas low-modularity networks favor performance on more complex tasks. The current study tests these predictions by relating modularity from resting-state fMRI to performance on a set of simple and complex behavioral tasks. Complex and simple tasks were defined on the basis of whether they did or did not draw on executive attention. Consistent with predictions, we found a negative correlation between individuals' modularity and their performance on a composite measure combining scores from the complex tasks but a positive correlation with performance on a composite measure combining scores from the simple tasks. These results and theory presented here provide a framework for linking measures of whole-brain organization from network neuroscience to cognitive processing.
Cognitive Correlate of the N1 Response to Speech Sounds
(2023-04-21) Noe, Colin; Fischer-Baum, Simon
The ability to perceive speech requires first encoding the acoustics of the speech inputs and then transforming them into an internal linguistic space where they map onto familiar words and concepts. A critical stage of processing mediating this transformation is sublexical processing, in which acoustic patterns are mapped onto language-specific speech segments. Understanding how and when sublexical processing occurs is important – but the tools to study this transformation are underdeveloped. Because sublexical processing is an intermediate stage of processing, subjects cannot respond based only on activation at this level. Further, because speech perception is a cascading process, information flows rapidly across all levels. Thus, to study the sublexical level of speech encoding, it is necessary to record these processes directly, and then to understand how patterns in neural activations reveal the cognitive processes that are their corollary. The goal of this dissertation is to understand how one such neural activation measure, the N1 electrophysiological response, relates to acoustic and sublexical processing. The N1 response measured with EEG is the first non-invasive (and therefore widely deployable) neural measure that relates to sublexical level aspects of the speech input. Toscano, McMurray, Dennhardt, and Luck (2010) demonstrated that the N1 response patterns linearly with the voice onset time (VOT), of the eliciting speech sound. VOT is important because it is a linguistic cue used in many languages (Lisker, 1986), that separates voiced sound categories (e.g., /d/) from unvoiced sound categories (e.g., /t/). It is also the most frequently studied speech contrast. The pattern of the N1 response to VOT has been interpreted as evidence for how the speech perception system represents VOT. Based on the linear pattern of the N1 response to VOT, Toscano et al. (2010) claim support for a pre-categorical neural encoding of phonetic features. However, this claim may be slightly premature. It is not yet known how the N1 relates to acoustic or to sublexical levels of sound processing. That is, we do not yet know how the neural measure the N1 relates to cognitive theoretic levels of processing. Despite the ambiguity about its cognitive correlate, the N1 has since been used to examine important theoretical questions about early speech sound processing. These have included including whether VOT encoding (as measured by the N1) is sensitive to lexical bias (Noe & Fischer-Baum, 2020) and is sensitive to predictive context (Getz & Toscano, 2019). However, we do not yet fully understand the N1 as a tool. Understanding what type of neural information processing drives the N1-voice-onset-time relationship relates to is foundational to its deployment to study speech processing. A better characterization of the relationship of the N1 to cognitive levels of processing would clarify how these N1-lexical bias and N1- predictive context effects should be interpreted. The focus of this dissertation will be to improve our understanding of how the N1 relates to cognitive processes. Specifically, we will evaluate whether the N1 is indexing neural representations that are primarily responsive to acoustic level variations in the sound or are responsive to phonetic level variations. I propose several lines of experimentation to examine this question. In the first, I propose a set of neuropsychological experiments where we test the intactness of the N1-VOT response in a pure-word-deaf patient to investigate how the N1 response is disrupted or preserved in a patient with deficits in sublexical levels of encoding. If the N1 is intact in a patient in whom phonetic levels of speech processing are damaged, this is evidence that the N1 is pre-phonetic, and thus indexes acoustic processing. In the second line of work, we investigate how the N1 response changes in aging and in cochlear implant populations. By looking at how the N1 response to VOT varies across populations that systematically vary in how acoustic cues are mapped to language, we can test which acoustic cues drive the N1-VOT relationship. Older adult listeners have intact access to spectral cues but disruption of fine- grained temporal information. Cochlear implant populations have greatly decreased spectral resolution but relatively intact amplitude encoding. Young adult listeners, in whom the N1-VOT is normally studied have access to both these acoustic cues, so by comparing across these atypical populations we can gain some traction on which acoustic cues are necessary for the N1-VOT relationship.
The Cognitive Neuroplasticity of Reading Recovery following Chronic Stroke: A Representational Similarity Analysis Approach
(Hindawi, 2017) Fischer-Baum, Simon; Jang, Ava; Kajander, David
Damage to certain left hemisphere regions leads to reading impairments, at least acutely, though some individuals eventually recover reading. Previous neuroimaging studies have shown a relationship between reading recovery and increases in contralesional and perilesional activation during word reading tasks, relative to controls. Questions remain about how to interpret these changes in activation. Do these changes reflect functional take-over, a reorganization of functions in the damaged brain? Or do they reveal compensatory masquerade or the use of alternative neural pathways to reading that are available in both patients and controls? We address these questions by studying a single individual, CH, who has made a partial recovery of reading familiar words following stroke. We use an fMRI analysis technique, representational similarity analysis (RSA), which allows us to decode cognitive function from distributed patterns of neural activity. Relative to controls, we find that CH shows a shift from visual to orthographic processing in contralesional regions, with a marginally significant result in perilesional regions as well. This pattern supports a contralesional reorganization of orthographic processing following stroke. More generally, these analyses demonstrate how powerful RSA can be for mapping the neural plasticity of language function.
Exploring the dynamics underlying taxonomic and thematic representations
(2022-08-11) Zhai, Mingjun; Fischer-Baum, Simon
Semantic knowledge about concepts has been argued to be organized in two different ways: based on shared features (taxonomic) or based on co-occurrence in common scenes, events, or scenarios (thematic). Contemporary theories of semantic cognition, such as the dual-hub hypothesis (Mirman et al., 2017) and the controlled semantic cognition (CSC) framework (Ralph et al., 2017)assume that task-context influences which semantic systems are engaged, though competing theories differ in details about how this flexibility operates, for example, whether both taxonomic and thematic systems are equally engaged or disengaged (dual-hub) or whether the taxonomic organization is the core structure of semantic knowledge, with thematic organization flexibly engaged only in appropriate task settings (CSC). The first goal of the current study is to examine how flexibly the two semantic systems can be engaged under different task demands. To achieve this goal, my analyses largely rely on a multivariate analysis method called representational similarity analysis (RSA), a methodology that allows me to relate the pairwise similarity structure generated by neuroimaging data including EEG and fMRI to multiple computational models of taxonomic/thematic relations between concepts under different task contexts and make comparisons between models. The current project investigates datasets of a series of picture naming tasks with different semantic contexts. Across all task contexts, the similarity structure of neural activity correlated better with taxonomic than thematic measures in the time window of semantic processing. Most strikingly, patterns of neural activity between taxonomically related items were more similar to each than the patterns of neural activity for thematically related or unrelated items, even in tasks that focused attention on thematic relationships. At least in picture naming tasks, concepts are organized according to taxonomic knowledge in semantic space. These findings are not in line with the assumption task contexts influence the engagement of semantic systems indicated by the dual-hub theory or CSC account. The second part of my dissertation tests whether the taxonomic and thematic relations can be learned from texts using the same algorithm, focusing on different statistical regularities. Specifically, different types of word embeddings are learned through the same skip-gram model with negative sampling and their performances in measuring the strength of taxonomic and thematic relations were assessed based on human subjective ratings. The assessment results indicated that word2vec-based measures are essentially taxonomic measures. Although there is some flexibility in torquing the computational measure towards the thematic end by increasing the sliding window size within the same architecture of a skip-gram model, the effect is not large enough to make it an efficient thematic measure.
Frequency and regularity effects in reading are task dependent: evidence from ERPs
(Taylor & Francis, 2014) Fischer-Baum, Simon; Dickson, Danielle S.; Federmeier, Kara D.
Many theories of visual word processing assume obligatory semantic access and phonological recoding whenever a written word is encountered. However, the relative importance of different reading processes depends on task. The current study uses event related potentials (ERPs) to investigate whether -- and, if so, when and how-- effects of task modulate how visually-presented words are processed. Participants were presented written words in the context of two tasks, delayed reading aloud and proper name detection. Stimuli varied factorially on lexical frequency and on spellingto-sound regularity, while controlling for other lexical variables. Effects of both lexical frequency and regularity were modulated by task. Lexical frequency modulated N400 amplitude, but only in the reading aloud task, whereas spellingto-sound regularity interacted with frequency to modulate the LPC, again only in the reading aloud task. Taken together, these results demonstrate that task demands affect how meaning and sound are generated from written words.
Individual Differences in the Neural and Cognitive Mechanisms of Single Word Reading
(Frontiers Media SA, 2018) Fischer-Baum, Simon; Kook, Jeong Hwan; Lee, Yoseph; Ramos-Nuñez, Aurora; Vannucci, Marina
Written language is a human invention that our brains did not evolve for. Yet, most research has focused on finding a single theory of reading, identifying the common set of cognitive and neural processes shared across individuals, neglecting individual differences. In contrast, we investigated variation in single word reading. Using a novel statistical method for analyzing heterogeneity in multi-subject task-based functional magnetic resonance imaging (fMRI), we clustered readers based on their brain’s response to written stimuli. Separate behavioral testing and neuroimaging analysis shows that these clusters differed in the role of the sublexical pathway in processing written language, but not in reading skill. Taken together, these results suggest that individuals vary in the cognitive and neural mechanisms involved in word reading. In general, neurocognitive theories need to account not only for what tends to be true of the population, but also the types of variation that exist, even within a neurotypical population.
Modality and Morphology: What We Write May Not Be What We Say
(Sage, 2015) Rapp, Brenda; Fischer-Baum, Simon; Miozzo, Michele
Written language is an evolutionarily recent human invention; consequently, its neural substrates cannot be determined by the genetic code. How, then, does the brain incorporate skills of this type? One possibility is that written language is dependent on evolutionarily older skills, such as spoken language; another is that dedicated substrates develop with expertise. If written language does depend on spoken language, then acquired deficits of spoken and written language should necessarily co-occur. Alternatively, if at least some substrates are dedicated to written language, such deficits may doubly dissociate. We report on 5 individuals with aphasia, documenting a double dissociation in which the production of affixes (e.g., the -ing in jumping) is disrupted in writing but not speaking or vice versa. The findings reveal that written- and spoken-language systems are considerably independent from the standpoint of morpho-orthographic operations. Understanding this independence of the orthographic system in adults has implications for the education and rehabilitation of people with written-language deficits.
Neuroplasticity and the logic of cognitive neuropsychology
(Taylor & Francis, 2017) Fischer-Baum, Simon; Campana, Giulia Elise
More than thirty years ago, Alfonso Caramazza laid out assumptions for drawing inferences about the undamaged cognitive system from individuals with brain damage. Since then, these assumptions have been challenged including the transparency or subtractivity assumption, that the cognitive system does not reorganize following brain damage. It has been repeatedly demonstrated that brains are highly plastic. However, there is no clear connection between brain plasticity and cognitive reorganization. Brain plasticity research does not require a rethinking of the core logic of cognitive neuropsychology. Differences in task-based activation between damaged and undamaged brains provide little insight into the cognitive architectures of brain-damaged patients. Theory and methods are needed to understand cognitive neuroplasticity, or how neural reorganization that follows brain damage relates to reorganization of functions. We discuss alternative types of cognitive neuroplasticity that may occur in damaged brains and consider how they impact the basic logic of cognitive neuropsychology.
Pathways: for Chamber Orchestra
(2014-11-21) Krause, Benjamin Alan; Jalbert, Pierre; Gottschalk, Arthur; Bailey, Walter; Fischer-Baum, Simon
Pathways is scored for two flutes (second doubling piccolo), two oboes, two clarinets in Bflat, two bassoons, two horns in F, two trumpets in C, percussion (two players), harp, piano/celesta, and strings. It presents a progression of primary musical ideas and then explores various "pathways" by which they may be connected. The initial idea is characterized by a rapid ascending arpeggio followed by a gradual, syncopated registral descent punctated throughout the orchestra. This then culminates with a climactic outburst of rapid repeated notes, in turn giving way to a declamatory series of chorale-like harmonies. The following music, characterized by both the ebulliance of a scherzo and the propulsion of a toccata, develops the opening material without ever fully reiterating it. When a sense of recapitulation finally does arrive, the main ideas appear in reverse order, their functions altered. A peaceful coda supplies the harmonic progression "missing" from the recapitulated material and provides a sense of respite and reflection to balance the energy of the preceding music. An experience of the piece may be compared to a walk along a winding, looping path in which one perceives the journey as linear but sees the same objects from different perspectives and in varying sequences. The music moves very quickly but tends to "circle back" on itself. The title "Pathways" also relates to my working process, in which I first constructed and then connected the structural pillars, as well as to a specific voice-leading technique in which melodic lines trace varying paths through two alternating harmonies.
Relationship between Verbal Working Memory and Prediction Performance in Sentence Processing
(2024-06-17) Lu, Yu; Martin, Randi; Fischer-Baum, Simon
Extensive research has shown converging evidence for prediction in the context of sentence comprehension tasks. While there is little debate that predictive processing is happening during language comprehension, precisely how we are able to generate these predictions is relatively unknown. The current project explores the cognitive factors supporting accurate prediction performance, focusing on the role of verbal working memory. The project takes a case study approach, examining the ability to predict upcoming words in individuals with different types of verbal working deficits following brain damage. Evidence from brain damaged individuals has shown that verbal WM can be divided into separable semantic and phonological WM systems which can be separably damaged. Four aphasic individuals were recruited as participants, one with phonological WM deficit (TP), two with semantic WM deficit (WC, DW), and one with both a phonological and semantic deficit (KA). We hypothesized that semantic WM, but not phonological WM, is related to the ability to make predictions during a language processing task. Experiment 1 compared the aphasic participants’ the prediction performance measured through a sentence completion task to a group of control older adults. All 4 participants showed worse prediction performance than controls, suggesting both phonological and semantic WM are important for accurate prediction, contra our prediction. However, it is possible that deficits in the speed with which language can be processed also contributes to the ability to predict particular for those individuals with phonological WM deficits. Experiment 2 explored this possibility by slowing down the audio presentation rate in the sentence completion task with the same four brain-damaged participants. However, no clear effect of presentation rate on prediction performance was observed. What these results mean for the role of different kinds of verbal working memory in prediction will be discussed.
Role of Features and Categories in Representing Object Knowledge
(2015-04-21) Geng, Jingyi; Schnur, Tatiana T.; Martin, Randi C; Fischer-Baum, Simon; Cox, Steven; Hernandez, Arturo
Understanding how our knowledge about the world is organized can help us understand how we are able to access that knowledge to easily identify objects and communicate with others. One general view of object knowledge organization assumes that object knowledge is represented by how we perceive and interact with objects (for example features like the color or shape we see and touch) (i.e., feature view; e.g., Allport, 1985; Barsalou, 1999, 2008; Gallese & Lakoff, 2005; Tyler & Moss, 2001). In contrast, an alternative view hypothesizes that in addition to features from different modalities (e.g., visual, motor, and tactile), taxonomic (e.g., dog and rabbit are animal) and thematic category information (e.g., eating theme: a dog is chewing a bone) is also critical for representing object knowledge (i.e., feature-plus-category view; e.g., Crutch & Warrington, 2005, 2010; Patterson et al., 2007; Schwartz et al., 2011; Mirman & Graziano, 2012). In order to examine these two general views of object knowledge organization, I investigated whether feature and category information is activated when people access the meaning of words using both behavioral (i.e., response times and errors; Experiments 1 and 2) and functional magnetic resonance neuroimaging measures (Experiment 3). Consistent with the feature-plus-category view, Experiments 1 and 2 showed that when people access the meaning of words, this access was affected (slower/faster) by manipulating visual features (e.g., shape), taxonomic and thematic category information associated with objects. In support of the feature-plus-category view, Experiment 3 revealed that action features (e.g., cutting) associated with objects (e.g., saw) activated the motor brain region (i.e., primary motor cortex) and the taxonomic and thematic categories recruited the bilateral anterior temporal lobes and left temporo-parietal junction respectively. Taken together, my dissertation provides converging evidence from both behavioral and neuroimaging perspectives showing that both feature and category information play a key role in representing object concepts.
Semantic interference in language production and comprehension: Same or separable loci?
(2014-04-22) Harvey, Denise Y.; Schnur, Tatiana T.; Martin, Randi C.; Fischer-Baum, Simon; O'Callaghan, Casey
The ability to speak and understand language is consciously a fast and easy process. However, the language system can err, either in normal processes or as a result of neural damage following stroke. Often, in both production and comprehension, errors are semantically related to the intended word, such as saying or understanding “cat” when the intended meaning is “dog”. This semantic interference (SI) effect suggests that the processing stages involved in language production and comprehension overlap to some extent. However, because language production and comprehension are usually investigated separately, this has led to different conclusions about how SI arises in each language modality. By most accounts, SI in production occurs at the lexical-semantic level, whereas SI in comprehension arises within the semantic system itself. In this dissertation, I distinguish between SI in production and comprehension by examining how (cognitive mechanisms) and where (neural loci) SI arises during picture naming and word-picture matching tasks that elicit SI by manipulating the semantic context with which target items appear. Aim I of my dissertation directly compared the behavioral characteristics of SI in healthy participants’ production and comprehension performance in order to elucidate the level and cognitive mechanism by which SI arises in each language modality. Aim II explored patients’ susceptibility to SI as it related to cortical gray matter and subcortical white matter damage. The results provided converging evidence that not only do the SI characteristics differ in production and comprehension, but also the neural locus of SI differs across language modality. However, the time course of SI is similar in both language modalities. Accordingly, I conclude SI arises when mapping meanings with words in production vs. mapping words with meanings in comprehension, but that the same cognitive mechanism operates over lexical-semantic processes across modalities. In the end, I argue that because of inherent differences between the order with which lexical and semantic representations are accessed in production vs. comprehension, the mechanism produces different behavioral manifestations of SI in each language modality and places differential demands on cognitive control mechanisms required to resolve interference.
Single-case cognitive neuropsychology in the age of big data
(Taylor & Francis, 2017) Medina, Jared; Fischer-Baum, Simon
Historically, single-case studies of brain-damaged individuals have contributed substantially to our understanding of cognitive processes. However, the role of single-case cognitive neuropsychology has diminished with the proliferation of techniques that measure neural activity in humans. Instead, large-scale informatics approaches in which data are gathered from hundreds of neuroimaging studies have become popular. It has been claimed that utilizing these informatics approaches can address problems found in single imaging studies. We first discuss reasons for why cognitive neuropsychology is thought to be in decline. Next, we note how these informatics approaches, while having benefits, are not particularly suited for understanding functional architectures. We propose that the single-case cognitive neuropsychological approach, which is focused on developing models of cognitive processing, addresses several of the weaknesses inherent in informatics approaches. Furthermore, we discuss how using neural data from brain-damaged individuals provides data that can inform both cognitive and neural models of cognitive processing.
Static and Dynamic Measures of Human Brain Connectivity Predict Complementary Aspects of Human Cognitive Performance
(Frontiers Media S.A., 2017) Ramos-Nuñez, Aurora I.; Fischer-Baum, Simon; Martin, Randi C.; Yue, Qiuhai; Ye, Fengdan; Deem, Michael W.
In cognitive network neuroscience, the connectivity and community structure of the brain network is related to measures of cognitive performance, like attention and memory. Research in this emerging discipline has largely focused on two measures of connectivity—modularity and flexibility—which, for the most part, have been examined in isolation. The current project investigates the relationship between these two measures of connectivity and how they make separable contribution to predicting individual differences in performance on cognitive tasks. Using resting state fMRI data from 52 young adults, we show that flexibility and modularity are highly negatively correlated. We use a Brodmann parcellation of the fMRI data and a sliding window approach for calculation of the flexibility. We also demonstrate that flexibility and modularity make unique contributions to explain task performance, with a clear result showing that modularity, not flexibility, predicts performance for simple tasks and that flexibility plays a greater role in predicting performance on complex tasks that require cognitive control and executive functioning. The theory and results presented here allow for stronger links between measures of brain network connectivity and cognitive processes.
The analysis of perseverations in acquired dysgraphia reveals the internal structure of orthographic representations
(Taylor & Francis, 2014) Fischer-Baum, Simon; Rapp, Brenda
At a minimum, our long-term memory representations of word spellings consist of ordered strings of single letter identities. While letter identity and position must certainly be represented, it is by no means obvious that this is the only information that is included in orthographic representations, nor that representations necessarily have a one-dimensional “flat” structure. Evidence favours the alternative hypothesis that orthographic representations, much like phonological ones, are internally rich, complex multidimensional structures, though many questions remain regarding the precise nature of the internal complexity of orthographic representations. In this investigation, we test competing accounts of the internal structure of orthographic representations by analysing the perseveration errors produced by an individual with acquired dysgraphia, L.S.S. The analysis of perseveration errors provides a novel and powerful method for investigating the question of the independence of different representational components. The results provide clear support for the hypothesis that letter quantity and syllabic role information are associated with, but separable from, letter identity information. Furthermore, the results indicate that digraphs—letter pairs associated with a single phoneme (e.g., the SH in FISH)—are units of orthographic representation. These results contribute substantially to the further development of the multidimensional hypothesis, providing both new and converging evidence regarding the nature of the internal complexity of orthographic representations.
The Domain-Specificity of Serial Order Short-Term Memory
(2018-04-11) Tian, Yingxue; Fischer-Baum, Simon
The capacity to remember a sequence of items is critical to various cognitive functions, including short-term memory (STM). The information in a sequence is at least twofold, including item-identity and the serial order of items. In both the verbal and nonverbal domains, it is well established that the STM capacity supporting serial order information dissociates from item-identity information. The research in this thesis addresses whether the serial order STM capacity is shared for sequences in different content domains. One hypothesis is that there are domain-specific serial order STM capacities exclusive to distinct domains, whereas an alternative hypothesis is that one general serial order STM capacity is being recruited for sequences in different domains. Although various studies have explored the domain-generality of serial order STM capacity, a conclusive result has not been reached. In the thesis, I examine these two hypotheses from an individual difference perspective. The two hypotheses were operationalized by manifest variables from four sequence matching tasks with verbal stimuli (letters and words) and nonverbal stimuli (locations and arrows). Participants had to decide whether two six-item sequences were identical. Non-identical trials differed either by a single item identity or by a transposition of two adjacent items, and they presumably were supported by item and serial order STM capacity, respectively. Accuracy was used to manifest individual differences at detecting item and order changes in STM at the behavioral level. With nested model comparison, the domain-specific model represented by distinct item and serial order STM capacities in both domains best fits the data from 153 participants. On this basis, the current study supports the hypothesis that serial order STM capacity is domain-specific.
The primacy of morphology in English braille spelling: an analysis of bridging contractions
(Springer Nature, 2024) Englebretson, Robert; Holbrook, M. Cay; Treiman, Rebecca; Fischer-Baum, Simon
This study examines the use of braille contractions in a corpus of spelling tests from braille-reading children in grades 1-4, with particular attention to braille contractions that create mismatches with morphological structure. Braille is a tactile writing system that enables people who are blind or visually impaired to read and write. In English and many other languages, reading and writing braille is not simply a matter of transliterating between print letters and their braille equivalents; Unified English Braille (the official braille system used in the United States, Canada, the United Kingdom, and several other English-speaking countries) contains 180 contractions—one or more braille cells that represent whole words or strings of letters. In some words, the prescriptive rules for correct braille usage cause contractions to bridge morphological boundaries and to obscure the spellings of stems and affixes. We demonstrate that, when the prescriptive rules for correct braille usage flout morphological structure, young braille spellers generally follow the morphology rather than the orthographic rules. This work establishes that morphology matters for young braille learners. We discuss the potential impact of our findings on braille research, development, and pedagogy, and we suggest ways in which our findings contribute to understanding the nature of orthographic morphemes and the place of braille in the reading sciences.
The role of working memory in interference resolution during Chinese sentence comprehension: Evidence from event-related potentials (ERPs)
(2015-09-24) Tan, Yingying; Martin, Randi C.; Lane, David; Fischer-Baum, Simon; Shibatani, Matt
Interference during sentence comprehension occurs when readers use semantic and syntactic cues to retrieve earlier sentence information to integrate with later information and intervening material partially matches these cues, resulting in more parsing difficulty. This thesis collected event-related brain potentials (ERPs) while participants processed Chinese sentences with semantic and syntactic interference to address two main questions: 1) When do semantic and syntactic interference effects occur and do they interact with each other? 2) What is the role of working memory (WM) mechanisms in interference resolution? Semantic and syntactic interference were examined during processing of the critical main clause verb (e.g., “complain”) that required the retrieval of a human subject noun. The degree of semantic interference was manipulated through varying the semantic plausibility of a distracting noun (e.g., human vs. non-human), and syntactic interference was manipulated through varying the distracting noun’s grammatical role in the relative clause (i.e., subject vs. object). Individual differences measures were collected on aspects of working memory, executive function, and verbal knowledge. Regarding the timing of interference effects, the ERP results at the critical verb showed negative anterior effects between 300 – 500 ms for both syntactic and semantic interference. Syntactic interference also induced a P600 effect and semantic interference also induced a late left anterior negativity. I interpret the early anterior negativities as reflecting a first stage process of detecting the semantic or syntactic interference, and the late ERPs as reflecting a second stage of reanalysis/revision during sentence processing. Importantly, the current results demonstrated that semantic processing plays an immediate and important role in Chinese, because the semantic interference effect was observed as early as the syntactic interference effect even when the distracting noun’s syntactic features strongly eliminated it from the distractor set. In contrast, semantic interference has been shown to be delayed and even blocked in previous English studies using similar materials. Regarding the role of WM in interference resolution, the present study supports a role of attentional control underlying sentence comprehension. Subjects with better resistance to proactive interference, as measured by a recent negatives task, had less difficulty in syntactic interference resolution, as indexed by a reduced mean amplitude of the P600 effect elicited by the high syntactic interference condition, even after controlling for their verbal knowledge and general processing speed. This result is consistent with the argument that attentional control helps subjects to recover from interference during later controlled aspects of sentence processing.

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