Measuring cognitive load and cognition: metrics for technology-enhanced learning

This critical and reflective literature review examines international research published over the last decade to summarise the different kinds of measures that have been used to explore cognitive load and critiques the strengths and limitations of those focussed on the development of direct empirical approaches. Over the last 40 years, cognitive load theory has become established as one of the most successful and influential theoretical explanations of cognitive processing during learning. Despite this success, attempts to obtain direct objective measures of the theory's central theoretical construct – cognitive load – have proved elusive. This obstacle represents the most significant outstanding challenge for successfully embedding the theoretical and experimental work on cognitive load in empirical data from authentic learning situations. Progress to date on the theoretical and practical approaches to cognitive load are discussed along with the influences of individual differences on cognitive load in order to assess the prospects for the development and application of direct empirical measures of cognitive load especially in technology-rich contexts

Metastability, Criticality and Phase Transitions in brain and its Models

This essay extends the previously deposited paper "Oscillations, Metastability and Phase Transitions" to incorporate the theory of Self-organizing Criticality. The twin concepts of Scaling and Universality of the theory of nonequilibrium phase transitions is applied to the role of reentrant activity in neural circuits of cerebral cortex and subcortical neural structures

Oscillations, metastability and phase transitions in brain and models of cognition

Neuroscience is being practiced in many different forms and at many different organizational levels of the Nervous System. Which of these levels and associated conceptual frameworks is most informative for elucidating the association of neural processes with processes of Cognition is an empirical question and subject to pragmatic validation. In this essay, I select the framework of Dynamic System Theory. Several investigators have applied in recent years tools and concepts of this theory to interpretation of observational data, and for designing neuronal models of cognitive functions. I will first trace the essentials of conceptual development and hypotheses separately for discerning observational tests and criteria for functional realism and conceptual plausibility of the alternatives they offer. I will then show that the statistical mechanics of phase transitions in brain activity, and some of its models, provides a new and possibly revealing perspective on brain events in cognition

Empirical and theoretical psychophysiological considerations regarding information processing during skilled reading

Current psychophysiological research regarding eye movements, cortical alpha rhythm, and memory mechanisms is reviewed in light of the role these phenomena may play in the process of skilled reading. A model of perceptual constriction leading to a decrease in reading performance is advanced. The psychological and physical manifestations of perceptual constriction are developed, and are discussed relative to the psychophysiological phenomena mentioned above. An attempt is made to provide a synthetic model of skilled reading and reading difficulties consistent with current theoretical and empirical knowledge. Such a model is useful to optometrists and other professionals interested in learning and reading difficulties

Temperament and arousal systems: A new synthesis of differential psychology and functional neurochemistry.

This paper critically reviews the unidimensional construct of General Arousal as utilised by models of temperament in differential psychology for example, to underlie 'Extraversion'. Evidence suggests that specialization within monoamine neurotransmitter systems contrasts with the attribution of a "general arousal" of the Ascending Reticular Activating System. Experimental findings show specialized roles of noradrenaline, dopamine, and serotonin systems in hypothetically mediating three complementary forms of arousal that are similar to three functional blocks described in classical models of behaviour within kinesiology, clinical neuropsychology, psychophysiology and temperament research. In spite of functional diversity of monoamine receptors, we suggest that their functionality can be classified using three universal aspects of actions related to expansion, to selection-integration and to maintenance of chosen behavioural alternatives. Monoamine systems also differentially regulate analytic vs. routine aspects of activities at cortical and striatal neural levels. A convergence between main temperament models in terms of traits related to described functional aspects of behavioural arousal also supports the idea of differentiation between these aspects analysed here in a functional perspective

A hybrid feature selection approach for the early diagnosis of Alzheimer's disease

Objective. Recently, significant advances have been made in the early diagnosis of Alzheimer’s disease from EEG. However, choosing suitable measures is a challenging task. Among other measures, frequency Relative Power and loss of complexity have been used with promising results. In the present study we investigate the early diagnosis of AD using synchrony measures and frequency Relative Power on EEG signals, examining the changes found in different frequency ranges. Approach. We first explore the use of a single feature for computing the classification rate, looking for the best frequency range. Then, we present a multiple feature classification system that outperforms all previous results using a feature selection strategy. These two approaches are tested in two different databases, one containing MCI and healthy subjects (patients age: 71.9 ± 10.2, healthy subjects age: 71.7 ± 8.3), and the other containing Mild AD and healthy subjects (patients age: 77.6 ± 10.0; healthy subjects age: 69.4± 11.5). Main Results. Using a single feature to compute classification rates we achieve a performance of 78.33% for the MCI data set and of 97.56 % for Mild AD. Results are clearly improved using the multiple feature classification, where a classification rate of 95% is found for the MCI data set using 11 features, and 100% for the Mild AD data set using 4 features. Significance. The new features selection method described in this work may be a reliable tool that could help to design a realistic system that does not require prior knowledge of a patient's status. With that aim, we explore the standardization of features for MCI and Mild AD data sets with promising results

Functional network antagonism and consciousness

Spontaneous brain activity changes across states of consciousness. A particular consciousness-mediated configuration is the anticorrelations between the default mode network and other brain regions. What this antagonistic organization implies about consciousness to date remains inconclusive. In this Perspective Article, we propose that anticorrelations are the physiological expression of the concept of segregation, namely the brain’s capacity to show selectivity in the way areas will be functionally connected. We postulate that this effect is mediated by the process of neural inhibition, by regulating global and local inhibitory activity. While recognizing that this effect can also result from other mechanisms, neural inhibition helps the understanding of how network metastability is affected after disrupting local and global neural balance. In combination with relevant theories of consciousness, we suggest that anticorrelations are a physiological prior that can work as a marker of preserved consciousness. We predict that if the brain is not in a state to host anticorrelations, then most likely the individual does not entertain subjective experience. We believe that this link between anticorrelations and the underlying physiology will help not only to comprehend how consciousness happens, but also conceptualize effective interventions for treating consciousness disorders in which anticorrelations seem particularly affected

Processamento da confiabilidade em caras: o papel das diferenças individuais nos estilos de vinculação

Research suggests that the presence of a human face elicits automatic appraisals of its trustworthiness. To completely understand trust-based interactions, research must consider not only the characteristics of the person that make him or her trustworthy but also the observer effects that contribute to individual variation in such judgments. Based on the assumption that different attachment styles can influence attention mechanisms and information processing, the main goal of the current dissertation was to investigate the impact of attachment representations on the processing of facial cues that resemble (un)trustworthiness. Using a multi-method approach, this thesis investigated the novel issue of whether and how attachment styles are related to interpretational (Study 1) and/or attentional biases of facial (un)trustworthiness (Study 2 and 3). In Study 1, using a sample of 179 participants, we asked the simple but fundamental question of whether individuals with different attachment styles differ in their conscious appraisal of facial trustworthiness. Given that recent studies have shown that individuals high in trait anxiety are also biased to interpret ambiguous stimuli in a threatening way, we also explored whether individuals level of (trait and state) anxiety would also impact judgments of trustworthiness. We found that both anxiosuly-attached and highly trait-anxious individuals were more sensitive to changes in untrustworthy than trustworthy faces, judging unfamiliar untrustworthy and neutral-looking faces as more untrustworthy than less anxious individuals. In study 2, using one of the most widely used tasks in attention bias research, we aimed to investigate the extent to which an individual’s attachment style is associated with selective attention to un(trustworthy) faces. Specifically, our second study introduced an adapted dot-probe design to more clearly investigate what specific selective attention processes (orienting or disengaging) is responsible for a potential attentional bias in insecure individuals. With a sample of 167 participants, our findings suggested that both individuals who scored high on anxious-attachment and trait-anxiety have a difficulty disengaging their attention from untrustworthy faces. Finally, in our third study, we employed another widely used electroencephalography paradigm (the oddball task) to examine the neural correlates of facial untrustworthiness processing and shed light on the temporal characteristics of a possible processing bias toward untrustworthy faces. With a sample of 56 participants, our results revealed greater P3 (350-600 ms) amplitude in response to untrustworthy than neutral faces, suggesting that untrustworthy faces are more salient to all individuals. To our knowledge, the present investigation is the first one to assess whether and how attachment styles are associated with the processing of facial cues that resemble (un)trustworthiness.Investigações sugerem que a presença de uma cara humana provoca uma avaliação automática do seu nível de confiabilidade. Para compreender completamente as interações baseadas na confiança, a investigação deve considerar, para além das características do parceiro que o/a tornam confiável, os efeitos do observador que contribuem para a variação individual nesses julgamentos. Tendo como base a ideia de que diferentes tipos de vinculação podem influenciar os mecanismos atencionais e o processamento de informação, a presente tese teve como principal objetivo investigar o impacto do estilo de vinculação no processamento da confiabilidade em caras. Com o recurso a diferentes métodos de investigação, o presente trabalho investigou o tópico inovador de uma potencial correlação entre o tipo de vinculação e a presença de um viés interpretativo (Estudo 1) e/ou atencional (Estudos 2 e 3) em relação a caras que variam na sua confiabilidade. O Estudo 1, com uma amostra de 179 participantes, teve como base a simples, mas pertinente, questão de saber se indivíduos com estilos de vinculação diferentes diferem na sua avaliação consciente da confiabilidade com base na aparência facial. Dado que estudos recentes demonstraram que indivíduos com graus elevados de ansiedade-traço interpretam estímulos ambíguos como ameaçadores, o primeiro estudo também explorou se o grau de ansiedade (traço e estado) impacta avaliações de confiabilidade. Os resultados sugeriram que tanto indivíduos com uma vinculação ansiosa como indivíduos com graus elevados de ansiedade traço são mais sensíveis a mudanças em faces de baixa, comparativamente a alta, confiabilidade, julgando caras que parecem pouco confiáveis e neutras como menos confiáveis, do que indivíduos menos ansiosos. O Estudo 2, recorrendo a uma das tarefas mais usadas na investigação sobre enviesamentos atencionais, teve como objetivo investigar o grau de associação entre o estilo de vinculação e a atenção seletiva para caras que variam em confiabilidade. Especificamente, o segundo estudo introduziu uma adaptação no design da tarefa de dot-probe, com o intuito de investigar de forma mais precisa quais os processos responsáveis por um potencial viés atencional em indivíduos com uma vinculação insegura. Utilizando uma amostra de 167 participantes, os resultados sugeriram que ambos os indivíduos que pontuaram alto no estilo de vinculação insegura e na ansiedade-traço demonstram dificuldade em desviar a sua atenção de caras com baixa confiabilidade percebida. Por fim, no terceiro estudo, aplicamos uma tarefa amplamente usada em estudos eletroencefalográficos (a tarefa de oddball), com o intuito de avaliar os correlatos neuronais do processamento de confiabilidade em caras e identificar as características temporais de um possível enviesamento em relação a faces pouco confiáveis. Recorrendo a uma amostra de 56 participantes, os resultados revelaram uma maior amplitude na P3 em resposta a caras de baixa confiabilidade comparativamente a caras neutras, sugerindo que estas faces parecem ter um elevado grau de saliência para todos os indivíduos. Tanto quanto sabemos, a presente investigação é a primeira a avaliar se e como é que os estilos de vinculação se associam ao processamento de pistas faciais que aparentam baixa ou alta confiabilidade.Programa Doutoral em Psicologi