| Publications of year 2021 |
| Theses |
| Abstract: | This thesis focuses on the application, to French students, of advances in the understanding of how children learn to read, what methods best train literacy and how we can better assess reading deficits-- so that these advances can fuel a virtuous circle between cognitive science and educational interventions. In the case of literacy, there is a global consensus that early explicit phonics instruction is the best means to learning how to read. In this thesis, we propose a tablet-based game to support phonics learning. We also address several unanswered questions of teaching methodology. For example, during what period of time should the teaching of the phonetic method be introduced? Can children learn to read using phonics software before formal literacy? We present the results from our randomized control study with French first graders (N=975). Data collected from pre- and post- tests shows that children only benefited from the phonics game when it was used early in the school year. In a second intervention, we improved the design of the application and research methodology, and then tested the game with French kindergarteners (N=1092). This time students improved in factors that support literacy, irrelevant of the period that the games were used. However, in a follow-up test, benefits disappeared once formal reading education began. In the process of seeking to develop a tablet-based approach to literacy, we also describe a program used by the game engine that automatically creates a phonics progression based on the most frequent and consistent grapheme-phoneme correspondences for any alphabetic language. Historically, some of the greatest insights into the processes involved in reading have come from the examination of the deficits caused by brain lesions. Based on the hypothesis that reading is a complex cognitive activity, and that a deficit in any part of the process could lead to dyslexia, we developed a screener that looks at the types of errors made by readers to assess for selective deficits. After normalizing the screener with French 6th and 7th graders, we examine the different types of errors made by students previously diagnosed with dyslexia by their school. We present the first French cases of two different types of selective deficits: letter position dyslexia and attention dyslexia. The body of this work was developed with the goal of practical application. To this end, the tablet-based game and phonics builder code were developed using open-source software and licenses. Our screener for dyslexia is also open for use in collaboration with our lab. In the general discussion, we discuss ideas for immediate improvements and future studies that could be done using these tools, to the benefit of improved literacy programs for all students. |
| Articles in journals |
| Abstract: | Despite the widespread use of graphs, little is known about how fast and how accurately we can extract information from them. Through a series of four behavioral experiments, we characterized human performance in "mental regression", i.e. the perception of statistical trends from scatterplots. When presented with a noisy scatterplot, even as briefly as 100 ms, human adults could accurately judge if it was increasing or decreasing, fit a regression line, and extrapolate outside the original data range, for both linear and non-linear functions. Performance was highly consistent across those three tasks of trend judgment, line fitting and extrapolation. Participants' linear trend judgments took into account the slope, the noise, and the number of data points, and were tightly correlated with the t-test classically used to evaluate the significance of a linear regression. However, they overestimated the absolute value of the regression slope. This bias was inconsistent with ordinary least squares (OLS) regression, which minimizes the sum of square deviations, but consistent with the use of Deming regression, which treats the x and y axes symmetrically and minimizes the Euclidean distance to the fitting line. We speculate that this fast but biased perception of scatterplots may be based on a "neuronal recycling" of the human visual capacity to identify the medial axis of a shape. |
| Abstract: | The classic cocktail party effect suggests that some, but probably not all levels of language processing can proceed without attention. We used whole-brain functional MRI to investigate how modality-specific and modality-independent language areas are modulated by the withdrawal of attention to another sensory modality (e.g., attending to vision during the presentation of auditory sentences, or vice-versa). We tested the hypotheses that inattention may abolish sentence-level integration and eliminate top-down effects. In both written and spoken modalities, language processing was strongly modulated by the distraction of attention, but this inattention effect varied considerably depending on the area and hierarchical level of language processing. Under inattention, a bottom-up activation remained in early modality-specific areas, particularly in superior temporal spokenlanguage areas, but the difference between sentences and words lists vanished. Under both attended and unattended conditions, ventral temporal cortices were activated in a topdown manner by spoken language more than by control stimuli, reaching posteriorily the Visual Word Form Area. We conclude that inattention prevents sentence-level syntactic and semantic integration, but preserves some top-down crossmodal processing, plus a large degree of bottom-up modality-specific processing, including a ventral occipitotemporal specialization for letter strings in a known alphabet. |
| Abstract: | Functional magnetic resonance imaging (fMRI) has opened the possibility to investigate how brain activity is modulated by behavior. Most studies so far are bound to one single task, in which functional responses to a handful of contrasts are analyzed and reported as a group average brain map. Contrariwise, recent data-collection efforts have started to target a systematic spatial representation of multiple mental functions. In this paper, we leverage the Individual Brain Charting (IBC) dataset--a high-resolution task-fMRI dataset acquired in a fixed environment--in order to study the feasibility of individual mapping. First, we verify that the IBC brain maps reproduce those obtained from previous, large-scale datasets using the same tasks. Second, we confirm that the elementary spatial components, inferred across all tasks, are consistently mapped within and, to a lesser extent, across participants. Third, we demonstrate the relevance of the topographic information of the individual contrast maps, showing that contrasts from one task can be predicted by contrasts from other tasks. At last, we showcase the benefit of contrast accumulation for the fine functional characterization of brain regions within a prespecified network. To this end, we analyze the cognitive profile of functional territories pertaining to the language network and prove that these profiles generalize across participants. |
| Abstract: | The ability to detect the abstract pattern underlying a temporal sequence of events is crucial to many human activities, including language and mathematics, but its cortical correlates remain poorly understood. It is also unclear whether repeated exposure to the same sequence of sensory stimuli is sufficient to induce the encoding of an abstract amodal representation of the pattern. Using functional MRI, we probed the existence of such abstract codes for sequential patterns, their localization in the human brain, and their relation to existing language and math-responsive networks. We used a passive sequence violation paradigm, in which a given sequence is repeatedly presented before rare deviant sequences are introduced. We presented two binary patterns, AABB and ABAB, in four presentation formats, either visual or auditory, and either cued by the identity of the stimuli or by their spatial location. Regardless of the presentation format, a habituation to the repeated pattern and a response to pattern violations were seen in a set of inferior frontal, intraparietal and temporal areas. Within language areas, such pattern-violation responses were only found in the inferior frontal gyrus (IFG), whereas all math-responsive regions responded to pattern changes. Most of these regions also responded whenever the modality or the cue changed, suggesting a general sensitivity to violation detection. Thus, the representation of sequence patterns appears to be distributed, yet to include a core set of abstract amodal regions, particularly the IFG. |