This thesis concerns selective attention in the context of the Stroop task (identify the colour) and Reverse Stroop task (identify the word). When a person is asked to select and identify one dimension of a bidimensional stimulus (e. g. , the word RED printed in green) the typical finding is that the word influences colour identification (i. e. , the Stroop effect) but the colour does not influence word identification (i. e. , no Reverse Stroop effect). A major account of performance in these tasks posits that one dimension interferes with the other only when a translation occurs (e. g. , Roelofs, <i>Psychological Review, 2003</i>; Sugg & McDonald, <i>Journal of Experimental Psychology: Human Perception & Performance, 1994</i>; Virzi & Egeth, <i>Memory & Cognition, 1985</i>). This translation assumption is implicit in virtually all work in the field. The first part of this thesis completely undermines the translation assumption. In a series of four experiments (two unique paradigms), I demonstrate that interference from the colour in a Reverse Stroop task occurs in the absence of a translation. The second part of this thesis contains two additional experiments designed to discriminate between translation effects and response conflict effects. The results of these experiments confirm that a translation was not required because no stimulus conflict effect, the most likely locus of a translation effect, was observed. However, response conflict effects were observed. The third part of this thesis implements a computational model based on the principle that the strength of association (Cohen, Dunbar, & McClelland, <i>Psychological Review, 1990</i>) between a specific stimulus and its response (Logan, </i>Psychological Review, 1988</i>) is important in determining the influence of the irrelevant dimension. This model has no translation mechanism. A final experiment was conducted to test this model; the model accounted for over 98% of the variance in RTs and 92% of the variance in interference and facilitation scores in both the Stroop and Reverse Stroop tasks independent of whether a translation was required.

This thesis concerns selective attention in the context of the Stroop task (identify the colour) and Reverse Stroop task (identify the word). When a person is asked to select and identify one dimension of a bidimensional stimulus (e. g. , the word RED printed in green) the typical finding is that the word influences colour identification (i. e. , the Stroop effect) but the colour does not influence word identification (i. e. , no Reverse Stroop effect). A major account of performance in these tasks posits that one dimension interferes with the other only when a translation occurs (e. g. , Roelofs, <i>Psychological Review, 2003</i>; Sugg & McDonald, <i>Journal of Experimental Psychology: Human Perception & Performance, 1994</i>; Virzi & Egeth, <i>Memory & Cognition, 1985</i>). This translation assumption is implicit in virtually all work in the field. The first part of this thesis completely undermines the translation assumption. In a series of four experiments (two unique paradigms), I demonstrate that interference from the colour in a Reverse Stroop task occurs in the absence of a translation. The second part of this thesis contains two additional experiments designed to discriminate between translation effects and response conflict effects. The results of these experiments confirm that a translation was not required because no stimulus conflict effect, the most likely locus of a translation effect, was observed. However, response conflict effects were observed. The third part of this thesis implements a computational model based on the principle that the strength of association (Cohen, Dunbar, & McClelland, <i>Psychological Review, 1990</i>) between a specific stimulus and its response (Logan, </i>Psychological Review, 1988</i>) is important in determining the influence of the irrelevant dimension. This model has no translation mechanism. A final experiment was conducted to test this model; the model accounted for over 98% of the variance in RTs and 92% of the variance in interference and facilitation scores in both the Stroop and Reverse Stroop tasks independent of whether a translation was required.

Neurons are connected to form functional networks in the brain. When neurons are combined in sequence, nontrivial effects arise. One example is disinhibition; that is, inhibition to another inhibitory factor. Disinhibition may be serving an important purpose because a large number of local circuits in the brain contain disinhibitory connections. However, their exact functional role is not well understood. The objective of this dissertation is to analyze the computational role of disinhibition in brain function, especially in visual perception and attentional control. My approach is to propose computational models of disinhibition and then map the model to the local circuits in the brain to explain psychological phenomena. Several computational models are proposed in this dissertation to account for disinhibition. (1) A static inverse difference of Gaussian filter (IDoG) is derived to account explicitly for the spatial effects of disinhibition. IDoG can explain a number of complex brightness-contrast illusions, such as the periphery problem in the Hermann grid and the White's effect. The IDoG model can also be used to explain orientation perception of multiple lines as in the modified version of Poggendorff illusion. (2) A spatio-temporal model (IDoGS) in early vision is derived and it successfully explains the scintillating grid illusion, which is a stationary display giving rise to a striking, dynamic, scintillating effect. (3) An interconnected Cohen-Grossberg neural network model (iCGNN) is proposed to address the dynamics of disinhibitory neural networks with a layered structure. I derive a set of sufficient conditions for such an interconnected system to reach asymptotic stability. (4) A computational model combining recurrent and feed-forward disinhibition is designed to account for input-modulation in temporal selective attention. The main contribution of this research is that it developed a unified framework of disinhibition to model several different kinds of neural circuits to account for various perceptual and attentional phenomena. Investigating the role of disinhibition in the brain can provide us with a deeper understanding of how the brain can give rise to intelligent and complex functions.

Master’s thesis deals with the measurement of biological signals for the effect of psychological burden. To monitor this effect was elected Stroop test, which is in the psychology used to detect disorders of attention and concentration. EEG and ECG signals during Stroop test were obtained using the EEG recording systém, in the context of research evoked potentials. As a part of the work it has been designed custom application for analyzing and interpreting data and statistical analysis by t-test.

Participants demonstrate the Stroop effect when, in naming the color in which a word appears, reaction times are longer when the color and word are incongruent (e.g., "yellow" printed in blue) compared to when they are congruent (e.g., "yellow" printed in yellow). The literature commonly refers to the difference in reaction times as a measure of the interference of word stimuli upon color stimuli, and is taken as support for the theory of automaticity. This study asks whether the Stroop effect can be analyzed as interactions within and across stimulus classes. Adult participants learned three 3-member classes (color, word, and pattern) in a serialized order of training. In the testing phase, participants were presented with compound stimuli formed from combinations of members within and across classes (e.g., word and color), and reaction times were recorded in similar fashion to the Stroop task. Results show that averaged participants' reaction times are faster to compound stimuli comprised of members within the same class, compared to compound stimuli formed with members from different classes. These group-level data are consistent with the Stroop literature in that congruent compounds produce faster reaction times relative to incongruent compounds. However, individual participant data do not consistently reflect the Stroop effect. Further considerations for future research in this area are discussed.

In open skill sports and other tasks, decision-making can be as important as physical performance. Whereas many studies have investigated visual perception there is little research on auditory perception as one aspect of decision making. Auditory localisation studies have almost exclusively focussed on underlying processes, such as interaural time difference and interaural level difference. It is not known, however, whether semantic spatial information contained in the sound is actually used, and whether it assists pure auditory localisation. The aim of this study was to investigate the effect on auditory localisation of spatial semantic information. In Experiment One, this was explored by measuring whole body orientation to the words &quotLeft", &quotRight", &quotBack", &quotFront" and &quotYes", as well as a tone, each presented from left right, front and back locations. Experiment Two explored the effect of the four spatial semantic words presented either from their matching locations, or from a position rotated 20 degrees anticlockwise. In both experiments there were two conditions, with subjects required to face the position indicated by the sound location, or the meaning of the word. Movements of the head were recorded in three dimensions with a Polhemus Fastrak system, and were analysed with a custom program. Ten young adult volunteers participated in each experiment. Reaction time, movement time, initial rotation direction, rotation direction at peak velocity, and the accuracy of the final position were the dependent measures. The results confirmed previous reports of confusions between front and back locations, that is, errors about the interaural axis. Unlike previous studies, many more back-to-front than front-toback errors was made. The experiments provided some evidence for a spatial Stroop interference effect, that is, an effect on performance of conflicting information provided by the irrelevant dimension of the stimulus, but only for reaction time and initial movement direction, and only in the Word condition. The results are interpreted using a model of the processes needed to respond to the stimulus and produce an orienting movement. They suggest that there is an asymmetric interference effect in which auditory localisation can interfere with localisation based on semantic content of words, but not the reverse. In addition, final accuracy was unaffected by any interference, suggesting that these effects are restricted to the initial stages of response selection.

Ce travail de thèse a pour but d’examiner l’émergence et l’évolution du caractère obligatoire des automatismes cognitifs. Pour satisfaire cet objectif, nous avons conçu une nouvelle situation expérimentale que nous avons appelée Stroop musical. Il s’agit d’une portée en clé de sol comprenant une note, présentée dans différentes positions, dans laquelle un nom de note, congruent ou incongruent avec la position, est écrit. Nous avons montré, à l’aide de ce paradigme, que les musiciens traitent plus lentement les noms de notes dans la condition incongruente que dans la condition congruente (Etude 1). Cet effet, nommé effet Stroop musical (MSE), est généré par l’automaticité de la dénomination de notes. Le Stroop musical offre la possibilité d’étudier l’évolution du caractère obligatoire de la dénomination de notes en évitant les biais liés à l’âge des sujets. Ainsi, nous avons testé plusieurs groupes d’enfants musiciens d’âge similaire dont le niveau de solfège variait de 1 à 5 ans. Nos résultats indiquent une relation linéaire positive entre le MSE et le niveau de pratique musicale (Etude 3), ce qui tend à montrer que le caractère obligatoire du traitement automatique augmente de façon monotone avec la pratique. En soumettant des musiciens adultes (Etude 2) et enfants (Etude 4) aux deux tâches conflictuelles du paradigme de Stroop musical, la lecture de mots et la dénomination de notes, nous avons également révélé que le pattern d’interférence dépend de la force relative des deux traitements en compétition. Enfin, nous avons constaté que l’automaticité de la dénomination de notes persiste malgré un arrêt total et prolongé de la pratique (Etude 5). / The aim of this thesis is to examine the emergence and the evolution of the obligatory characteristic of cognitive automatisms. To achieve this, we devised a new experimental situation called musical Stroop. The basic arrangement comprises a treble staff with a note in various positions. A name of a note is printed inside the note. For the congruent condition, the note name is congruent with the note position on the staff, whereas in the incongruent condition, note name and position are incongruent. We showed that musicians process the incongruent condition slower than the congruent condition (Study 1). This effect, named Musical Stroop Effect (MSE), is generated by the automaticity of note naming. The musical Stroop offers the possibility to investigate the evolution of the irrepressibility of note naming, while avoiding bias related to subject age. Thus, we tested several groups of musician children of similar age whose the level of musical education varied from 1 to 5 years. Our results indicate a positive linear relation between the MSE and the level of musical training (Study 3). Consequently, the irrepressibility of the automatic processing seems to increase monotonically with practice (that is to say in parallel with the other characteristics of automatisms). We also showed, by submitting adults (Study 2) and children (Study 4) musicians to the two conflicting tasks of the musical Stroop paradigm, word reading and note naming, that the pattern of interference depends on the relative strength of the two competing processing. Finally, we noted that the automaticity of note naming persists despite a total and protracted cessation of practice (Study 5).

Made available in DSpace on 2015-05-14T12:43:04Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2438500 bytes, checksum: d5b82b593d0da6e288762e3d5e5d24de (MD5) Previous issue date: 2014-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This research is an investigation of how complex words formed with bound words, in Brazilian Portuguese (BP), are processed (represented and accessed in the mental lexicon). We are concerned to know whether they are accessed in its complete form (whole-form) or are accessible by their morphemes, with separation of affixes (affix stripping) when processing. Two experiments were made to know about this performance among adult native speakers of Brazilian Portuguese. The first experiment was based on the paradigm of the Stroop Effect and the second experiment was based on masked priming paradigm. The results of the first experiment revealed that complex words formed with bound bases were processed longer than complex words formed with free bases and which caused this delay was the Stroop effect that acted as a extra linguistic, thus resulting in the need to conduct the second experiment, the masked priming that in addition revealed that the words formed with bound bases are actually processed faster than the free bases, also revealed that words formed with bound bases in condition of morphologically related prime and target are processed faster than words formed with bound bases in prime condition and targets phonetically related or unrelated. In general, the results showed that complex words formed with bound bases are stored in the mental lexicon in full and do not undergo any process prior decomposition when they are accessed. / Esta pesquisa é uma investigação sobre como palavras complexas formadas com bases presas, no português brasileiro (PB), são processadas (representadas e acessadas no léxico mental). Interessa-nos saber se elas são acessadas em sua forma completa (whole-form) ou se são acessadas por seus morfemas, havendo separação dos afixos (affix stripping) quando de seu processamento. Dois experimentos foram feitos para averiguação dessas possibilidades, entre falantes nativos adultos do português brasileiro. O primeiro experimento foi baseado no paradigma do Efeito Stroop e o segundo experimento baseou-se no paradigma de priming encoberto. Os resultados do primeiro experimento revelaram que as palavras complexas formadas com bases presas foram processadas em maior tempo do que as palavras complexas formadas com bases livres e o que provocou esse atraso foi o efeito stroop, que atuou como efeito extralinguístico, induzindo uma prévia decomposição. Surgiu, assim, a necessidade da realização do segundo experimento, o de priming encoberto, que, além de revelar que as palavras formadas com bases presas são de fato, processadas mais rapidamente do que as bases livres, revelaram também que palavras formadas com bases presas na condição de prime e alvo relacionados morfologicamente são processadas mais rapidamente do que palavras formadas com bases presas na condição de prime e alvos relacionados foneticamente ou sem nenhuma relação. Em geral, os resultados mostraram que palavras complexas formadas com bases presas estão estocadas no léxico mental por inteiro e não passam por nenhum processo de prévia decomposição quando são acessadas.

The Stroop effect is the delay in reaction times due to interference. Since the original experiments of 1935, it has been used primarily in linguistic context. Language is a complex skill unique to humans, which involves a large part of the cerebral cortex and many subcortical regions. It is perceived primarily in auditory form (spoken) and secondarily in visual form (written), but it is also always perceived in representational form (natural sounds, images, smells, etc). Auditory signals are processed much faster than visual signals, and the language processing centres are closer to the primary auditory cortex than the primary visual cortex, but due to the integration of stimuli and the role of the executive functions, we are able to perceive both simultaneously and coherently. However, auditory signals are still processed faster, and this study focused on establishing how auditory and visual, linguistic and representational stimuli interact with each other and affect reaction times in four Stroop tasks with four archetypal mammals (dog, cat, mouse and pig): a written word against an image, a spoken word against an image, a written word against a natural sound and a spoken word against a natural sound. Four hypotheses were tested: in all tasks reaction times would be faster when the stimuli were congruent (Stroop Hypothesis); reaction times would be faster when both stimuli are auditory than when they are visual (Audiovisual Hypothesis); reaction times would be similar in the tasks where one stimulus is auditory and the other visual (Similarity Hypothesis); finally, reaction times would be slower when stimuli come from two sources than when they come from one source (Attention Hypothesis). Twelve native speakers of Swedish between the ages of 22 and 40 participated. The experiment took place in the EEG lab of the Linguistics Department of Stockholm University. The same researcher (the author) and equipment was used for all participants. The results confirmed the Stroop Hypothesis, did not confirm the Audiovisual and Similarity Hypothesis, and the results of the Attention Hypothesis were mixed. The somewhat controversial results were mostly attributed to a false initial assumption, namely that having two different auditory stimuli (one on each ear) was considered one source of stimuli, and possibly the poor quality of some natural sounds. With this additional consideration, the results seemed to be in accord with previous research. Future research could focus on more efficient ways to test the reaction times of Stroop tasks involving auditory and visual stimuli, as well as different populations, especially neurodiverse and bilingual populations.

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