Methodological Artefacts in Consciousness Science

Consciousness is scientifically challenging to study because of its subjective aspect. This leads researchers to rely on report-based experimental paradigms in order to discover neural correlates of consciousness (NCCs). I argue that the reliance on reports has biased the search for NCCs, thus creating what I call 'methodological artefacts'. This paper has three main goals: first, describe the measurement problem in consciousness science and argue that this problem led to the emergence of methodological artefacts. Second, provide a critical assessment of the NCCs put forward by the global neuronal workspace theory. Third, provide the means of dissociating genuine NCCs from methodological artefacts

Learning Strategies Employed by College Aged Students with Disabilities: The Link Between Metacognition, Motivation, and Working Memory

The aim of this study is two-fold. First, we want to understand the levels of metacognitive awareness of learning strategies in undergraduates with learning disabilities. Previous research states that recall is the most effective method of studying, but most students prefer to reread their notes or textbook which is ineffective. Second, we want to explore the link between Working Memory and metacognitive awareness of learning strategies in undergraduates with learning disabilities. The learning strategies that college students with and without disabilities is examined, we found that students in both groups preferred the usage of the same strategies equally. The most preferred strategy was rereading notes/textbook, and least preferred was studying in groups. Interestingly, we found no differences between the groups with regards to their: motivation, metacognition, and working memory. Initially, it was found that the group of students with disabilities greatly differed in visual-spatial working memory, however, once we controlled for those who were visually-impaired or had attention deficit hyperactivity disorder (ADHD), the results became non-significant. Gender differences in learning strategies was examined and we found that males preferred the usage of completing practice problems and the usage of mnemonic devices, whereas females preferred highlighting their notes or textbook

Assessing the Role of the Left Dorsal Frontal Cortex in Working Memory Guidance: Attentional or Mnemonic? A Neurostimulation Study

Available online 17 May 2019Perceptual selection can be guided by the contents of working memory (WM). Neuroimaging and neuropsychological data point to a role of a fronto-parietal and fronto-thalamic networks in WM guidance. Here we assessed the effect of transcranial direct current stimulation of the left dorsal frontal cortex (lDFC) in a combined WM/attention paradigm. We asked the extent to which the lDFC is implicated in mnemonic and selective attention functions during WM guidance of behavior. Observers were asked to keep information in memory while searching for a visual target, while the validity of WM contents for the search task varied. We tested the effects of lDFC-tDCS on the strength of WM guidance of search, whether any tDCS effect is dependent on the amount of WM load, and whether lDFC-tDCS primarily influences how WM contents are retained, the process of selective attention in search task, or both. Consistent with prior behavioral findings, we found that (i) selection of items that matched the contents of WM was facilitated relative to non-matching items and (ii) this WM guidance effect was reduced when the level processing/cognitive load in WM was higher. Notably, across two experiments we found that lDFC-tDCS modulated WM guidance of visual selection in the context of high processing loads in WM. No effects of tDCS were observed in WM accuracy. These findings suggest that the role of the left dorsal frontal cortex in WM guidance is associated with selective attentional control rather than mnemonic processing.J.B-T. was supported by a grant from the Bial Foundation. D. S. acknowledges support from the Spanish Ministry of Economy and Competitiveness (MINECO), through the ‘Severo Ochoa’ Programme for Centres/Units of Excellence in R&D (SEV-2015-490) and project grants PSI2016-76443-P from MINECO and PI-2017-25 from the Basque Governmen

Distinct contributions of attention and working memory to visual statistical learning and ensemble processing

The brain exploits redundancies in the environment to efficiently represent the complexity of the visual world. One example of this is ensemble processing, which provides a statistical summary of elements within a set (e.g., mean size). Another is statistical learning, which involves the encoding of stable spatial or temporal relationships between objects. It has been suggested that ensemble processing over arrays of oriented lines disrupts statistical learning of structure within the arrays (Zhao, Ngo, McKendrick, & Turk-Browne, 2011). Here we asked whether ensemble processing and statistical learning are mutually incompatible, or whether this disruption might occur because ensemble processing encourages participants to process the stimulus arrays in a way that impedes statistical learning. In Experiment 1, we replicated Zhao and colleagues' finding that ensemble processing disrupts statistical learning. In Experiments 2 and 3, we found that statistical learning was unimpaired by ensemble processing when task demands necessitated (a) focal attention to individual items within the stimulus arrays and (b) the retention of individual items in working memory. Together, these results are consistent with an account suggesting that ensemble processing and statistical learning can operate over the same stimuli given appropriate stimulus processing demands during exposure to regularities

Interocular suppression prevents interference in a flanker task

Executive control of attention refers to processes that detect and resolve conflict among competing thoughts and actions. Despite the high-level nature of this faculty, the role of awareness in executive control of attention is not well understood. In this study, we used interocular suppression to mask the flankers in an arrow flanker task, in which the flankers and the target arrow were presented simultaneously in order to elicit executive control of attention. Participants were unable to detect the flanker arrows or to reliably identify their direction when masked. There was a typical conflict effect (prolonged reaction time and increased error rate under flanker-target incongruent condition compared to congruent condition) when the flanker arrows were unmasked, while the conflict effect was absent when the flanker arrows were masked with interocular suppression. These results suggest that blocking awareness of competing stimuli with interocular suppression prevents the involvement of executive control of attention

Decoding the Meaning of Unconsciously Processed Words Using fMRI-based MVPA

Available online 21 February 2019Does the human brain elicit patterns of activity associated with the meaning of words in the absence of conscious awareness? Do such non-conscious semantic representations generalize across languages? This study aimed to address these questions using fMRI-based multivariate pattern analysis (MVPA) in a masked word paradigm. Animal and non-animal words were visually presented in two different languages (i.e. Spanish and Basque). Words were presented very briefly and were masked. On each trial, participants identified the semantic category and provided a visibility rating of the word. A support vector machine (SVM) was used to decode word category from multivoxel patterns of BOLD responses in seven canonical semantic regions of a left-lateralized network that were prespecified based on a previous meta-analysis. We show that the semantic category of non-conscious words (i.e. associated with null visual experience and chance-level discrimination performance) can be significantly decoded from BOLD response patterns. For Spanish, such discriminative patterns of BOLD responses were consistently found in inferior parietal lobe, dorsomedial prefrontal cortex, inferior frontal gyrus and posterior cingulate gyrus. While for Basque, these were found in ventromedial temporal lobe and posterior cingulate gyrus. All of the areas identified have previously been associated with semantic processing in studies involving animals-tools and animals-artifacts contrasts. In conscious trials, such patterns were found to be distributed over all seven regions of the semantic network in both Spanish and Basque. However, we found no evidence of across-language generalization. These results demonstrate that even in the absence of conscious awareness and lack of behavioural sensitivity to the words, putative semantic brain areas carry information related to the meanings of the words. The generalization of semantic representations across languages, however, may require deeper conscious semantic access.D.S. acknowledges support from the Spanish Ministry of Economy and Competitiveness (MINECO), through the ’Severo Ochoa’ Programme for Centres/Units of Excellence in R&D (SEV-2015-490; grant number BES-2016-078130). The authors also thank Cesar Caballero Gaudes for his support with the imaging protocol and BCBL's lab staff for their help in fMRI acquisition

Strongly masked content retained in memory made accessible through repetition.

A growing body of evidence indicates that information can be stored even in the absence of conscious awareness. Despite these findings, unconscious memory is still poorly understood with limited evidence for unconscious iconic memory storage. Here we show that strongly masked visual data can be stored and accumulate to elicit clear perception. We used a repetition method across a wide range of conditions (Experiment 1) and a more focused follow-up experiment with enhanced masking conditions (Experiment 2). Information was stored despite being masked, demonstrating that masking did not erase or overwrite memory traces but limited perception. We examined the temporal properties and found that stored information followed a gradual but rapid decay. Extraction of meaningful information was severely impaired after 300 ms, and most data was lost after 700 ms. Our findings are congruent with theories of consciousness that are based on an integration of subliminal information and support theoretical predictions based on the global workspace theory of consciousness, especially the existence of an implicit iconic memory buffer store

Working memory modules on the threshold to consciousness

Current literature is claiming for an important relationship between conscious experiencing and executive functions (mainly working memory). Since there is still a lack of empirical evidence relating those mental processes, the aim of this research is to continue exploring those relations by finding out how different components of working memory may affect the threshold to consciousness. The experiment contained three groups of people who performed two concurrent computerized tasks. The first one consisted of a replication of a priming and subjective visibility task (de Loof et al., 2013) for all the groups. Both experimental groups differed from the control group in the additional mental load due to the second task and differed between them in the nature of the load (remembering phonological or spatial information). Psychology students participated in the study facing the pc monitor to perform the first task alone if assigned to the control group, or concurrent to a Corsi Block-Tapping Test or a Phonological Maintenance Task if assigned to the experimental groups. The results seem to suggest that the spatial overload group had more trouble when trying to be conscious of the prime number in comparison to the other two. These results show accordance with previous research and could be the first to show a possible working memory module-dependence when it comes to conscious perception. This view could lead to new important reformulations of theories of consciousness and language

Entwicklungsabhängige schlafassoziierte Konsolidierung emotional relevanter impliziter Gedächtnisinhalte

Schlaf hat auf die Konsolidierung der untersuchten impliziten Gedächtnisinhalte weder bei Kindern noch bei Erwachsenen einen anderen Einfluss als der Wachzustand