An independent component analysis of fMRI data of grapheme-colour synaesthesia

The independent component analysis (ICA) method was applied to fMRI data from two synaesthetes and their matched controls while they performed the coloured-word Stroop task and the single-letter (synaesthetic) Stroop task. ICA identified an 'attention' network, a 'perceptual' network as well as a 'conflict monitoring' network. Increased activity was observed in right V4 during the single-letter Stroop task for synaesthetes only. The finding confirms that the same neural substrate that is known to support the experience of physical colours also supports the experience of synaesthetic colours.     

Measuring perceptual centers using the phase correction response

The perceptual center (P-center) is fundamental to the timing of heterogeneous event sequences, including music and speech. Unfortunately, there is currently no comprehensive and reliable model of P-centers in acoustic events, so P-centers must instead be measured empirically. This study reviews existing measurement methods and evaluates two methods in detail-the rhythm adjustment method and a new method based on the phase correction response (PCR) in a synchronous tapping task. The two methods yielded consistent P-center estimates and showed no evidence of P-center context dependence. The PCR method appears promising because it is accurate and efficient and does not require explicit perceptual judgments. As a secondary result, the magnitude of the PCR is shown to vary systematically with the onset complexity of speech sounds, which presumably reflects the perceived clarity of a sound's P-center.     

Multiple-look effects on temporal discrimination within sound sequences

The multiple-look notion holds that the difference limen (DL) decreases with multiple observations. We investigated this notion for temporal discrimination in isochronous sound sequences. In Experiment 1, we established a multiple-look effect when sequences comprised nine standard time intervals (S) followed by an increasing number of comparison time intervals (C), but no multiple-look effect when one trailing C interval was preceded by an increasing number of S intervals. In Experiment 2, we extended the design. There were four sequential conditions: (a) 9 leading S intervals followed by 1, 2, …, or 9 C-intervals; (b) 9 leading C intervals followed by 1, 2, …, or 9 S intervals; (c) 9 trailing C-intervals preceded by 1, 2, …, or 9 S-intervals; and (d) 9 trailing S-intervals preceded by 1, 2, …, or 9 C-intervals. Both the interval accretions before and after the tempo change caused multiple-look effects, irrespective of the time order of S and C. Complete deconfounding of the number of intervals before and after the tempo change was accomplished in Experiment 3. The multiple-look effect of interval accretion before the tempo change was twice as big as that after the tempo change. The diminishing returns relation between the DL and interval accretion could be described well by a reciprocal function.     

Facilitation by Variation: Right-to-Left Learning of English Yes/No Questions

This study advances the hypothesis that optional structural variation in language facilitates syntactic learning (facilitation‐by‐variation). Support for this is provided by a right‐to‐left‐elaboration acquisition model for English yes/no questions (YNQs). Previous studies have focused on the acquisition of ‘‘inverted’’ YNQs, a cornerstone of nativist theories of language development. Data from five American children (1;3 to 5;1) and their parents show that children hear a range of adult questions (Coming?You coming?Are you coming?), not all inverted. These variants are ordered from structurally least complex noncanonical forms to complex canonical inverted forms. I use state‐of‐the‐art econometric techniques to estimate breakpoints in YNQ time series and show that noncanonical questions emerge early in children’s speech and facilitate acquisition of canonical ones. This incremental structure‐building process relies on an adjunction strategy that augments noncanonical questions with initial auxiliaries and subjects. Development proceeds incrementally from right to left to derive auxiliary‐initial structures.     

Electrophysiological correlates of the composite face illusion: Disentangling perceptual and decisional components of holistic face processing in the human brain

When the bottom halves of two faces differ, people’s behavioral judgment of the identical top halves of those faces is impaired: they report that the top halves are different, and/or take more time than usual to provide a response. This behavioral measure is known as the composite face effect (CFE) and has traditionally been taken as evidence that faces are perceived holistically. Recently, however, it has been claimed that this effect is driven almost entirely by decisional, rather than perceptual, factors ( Richler, Gauthier, Wenger, & Palmeri, 2008). To disentangle the contribution of perceptual and decisional brain processes, we aimed to obtain an event-related potential (ERP) measure of the CFE at a stage of face encoding ( Jacques & Rossion, 2009) in the absence of a behavioral CFE effect. Sixteen participants performed a go/no-go task in an oddball paradigm, lifting a finger of their right or left hand when the top half of a face changed identity. This change of identity of the top of the face was associated with an increased ERP signal on occipito-temporal electrode sites at the N170 face-sensitive component (∼160 ms), the later decisional P3b component, and the lateralized readiness potential (LRP) starting at ∼350 ms. The N170 effect was observed equally early when only the unattended bottom part of the face changed, indicating that an identity change was perceived across the whole face in this condition. Importantly, there was no behavioral response bias for the bottom change trials, and no evidence of decisional biases from electrophysiological data (no P3b and LRP deflection in no-go trials). These data show that an early CFE can be measured in ERPs in the absence of any decisional response bias, indicating that the CFE reflects primarily the visual perception of the whole face.     

Education and interactivism: Levels of interaction influencing learning processes

The aim of this paper is to explore some consequences of interactivism within learning situations. Since the original interactivist point of view focused on the Subject/Object relationship, much research has stressed the importance of the non-individualistic aspects of learning, and we have found it revealing to point out the mediation processes occurring inside and outside the S/O relationship (e.g. mediation involving cultural context or artifacts). We have combined different learning theory frameworks, chosen for their complementary conceptions of learning, with a view toward describing the system of interactions involved in teaching/learning processes.The cultural-historical approach to learning insists on the fundamental role of socially constructed tools in human development and education (Vygotsky). Clot and Engeström consider educational institutions as working communities that constrain Subject/Object interaction by rules and habits. Chevallard describes the implications of various categories of actors in the definition of curricula. Within the classroom, besides the obvious mutual influences of individual participants, problems to be solved, as organized by the teacher, influence the attitude of the learner towards the knowledge to be acquired (Brousseau). Furthermore, these situations contain multiple artifacts aimed at facilitating the acquisition of the skills necessary in order to use artifacts outside of the educational context (Rabardel & Bourmaud). Finally, Vergnaud suggests that it is more fruitful to consider the relationship between scheme and situation rather than that between subject and object.We will consider how these various levels of mediation shape the Subject/Object relationship and the learning process.     

Effects of study list composition on the word frequency effect and metacognitive attributions in recognition memory

In two experiments, study-list composition was manipulated and its impact was observed on metacognitive judgements associated with recognition hits (Hs) and false alarms (FAs). Both studies involved recognition of high-frequency (HF) and low-frequency (LF) words, and focused on the FA portion of the word frequency effect. Our hypothesis was that participants can actively reject items that are distinctive from the study list, and that this effect may be strong enough to overcome the FA word frequency effect. Experiment 1 manipulated list composition with a conjunctive rule and Experiment 2 varied it by having participants study either HF or LF items prior to a test consisting of words of both frequencies. In each study H rate, FA rate, and metacognitive attributions underlying recognition decisions were investigated. In both studies, participants reported rejecting test items predominantly through a process of active rejection, which was more often reported for LF items. This effect was strong enough to reverse the FA portion of the word frequency effect in Experiment 2, but not Experiment 1. The results are discussed in terms of metacognitive rejection mechanisms in recognition memory.     

Action blindness in response to gradual changes

The goal of this study is to characterize observers’ abilities to detect gradual changes and to explore putative dissociations between conscious experience of change and behavioral adaptation to a changing stimulus. We developed a new experimental paradigm in which, on each trial, participants were shown a dot pattern on the screen. Next, the pattern disappeared and participants had to reproduce it. In some conditions, the target pattern was incrementally rotated over successive trials and participants were either informed or not of this change. We analyzed both awareness of the changes and the dynamics of behavioral adaptation, in a way that makes it possible to assess both variability and accuracy as they change over time. Results indicate a dissociation between change awareness and behavioral adaptation to the changes, and support the notion that unconscious representations of visual stimuli are more precise and detailed than previously suggested. We discuss the implications of these results for theories of change detection.     

Depression, Anxiety and Anger in Subtypes of Irritable Bowel Syndrome Patients

The present study aimed to elucidate the differences in depression, anxiety, anger, and quality of life in a sample of non-psychiatric IBS patients, starting from the hypothesis that IBS subtypes may have different symptomatic expressions of negative emotions with different outcomes on quality of life measures. Forty-two constipation-predominant IBS (C-IBS) subjects and 44 diarrhea-predominant IBS (D-IBS) subjects, after an examination by a gastroenterologist and a total colonoscopy, underwent a clinical interview and psychometric examination for the assessment of depression, anxiety, anger and quality of life. IBS subtypes showed different symptomatic profiles in depression, anxiety and anger, with C-IBS patients more psychologically distressed than D-IBS subjects. Affective and emotional symptoms should be considered as specific and integral to the syndrome, and recognizing the differences between IBS subtypes may have relevant implications for treatment options and clinical outcome.