Objetivo Desenvolver um teste psicofísico apoiado em tecnologia móvel em que o desempenho do participante possa revelar à influência da ingestão de álcool pelas alterações cognitivas e motoras produzidas por essa droga. Método Foram 3 protocolos experimentais preliminares. Protocolo experimental 1: Um total de 11 participantes (6 homens e 5 mulheres, de 30 a 53 anos) executaram um teste de tempo de reação go-no-go a três estímulos (semáforo verde:go, semáforo vermelho: no-go, semáforo amarelo: no-go e um estímulo preparatório: semáforo apagado). Protocolo experimental 2: Um total de 13 participantes (mulheres, de 18 a 37 anos) executaram 3 testes: a) Teste de tempo de reação escolha a três estímulos (semáforo verde, semáforo vermelho, semáforo amarelo) e um estímulo preparatório (semáforo apagado). b) Teste de memória em que a tarefa era a de pressionar um botão informando se a imagem que aparecia na tela era nova e outro botão caso a imagem fosse repetida. c) Teste de associação em que a tarefa era a de associar figuras a um número seguindo uma tabela de comparação. Protocolo experimental 3: Um total de 8 participantes (5 homens e 2 mulheres, de 22 a 42 anos) executaram os mesmos testes aplicados no protocolo experimental 2 com apenas uma diferença em uma das tarefas do teste de tempo de reação escolha. A análise de dados privilegiou a análise dos tempos de reação e o índice de acertos. Resultados Protocolo experimental 1 Os testes pareados, tanto para os tempos de reação (t(5)=0,199, p=0,850), quanto para a quantidade de erros (t(5)=0,675, p=0,529), não apontaram nenhuma diferença significativa entre as condições sem e com álcool. Resultados Protocolo experimental 2 As ANOVAs-MR dos tempos de reação e do número de erros do teste de reação escolha não revelaram diferenças significativas para a condição (F(2,36)=1,175, p=0.315, hp 2 =0.32 e F(2,36)=1.944, p=0.165, respectivamente), para cor de semáforo (F(2,36)=0.289, p>0.5, hp 2 =0.16) e tampouco para interação condição x cor de semáforo (F(2,36)=0,355, p=0.840, hp 2 =0.19). No teste de memória, as ANOVAs-MR não revelaram nenhuma 6 diferença significativa para a condição dos tempos de reação (F(2,36)=0,693, p>0,05, n2 =0,05). No teste de associação uma ANOVA-MR revelou uma diferença significativa nos tempos de reação F(2,36)=4,924, p=0,016, n2=0,291), porém nenhuma diferença foi encontrada para erros absolutos (F(2,36)=0,255, p>0,5, n2=0,090) e erros absolutos (F(2,36)=0,255, p>0.5, n=0,02) para a condição sem álcool e com álcool acima de 0.06 %BAC. Resultados Protocolo experimental 3 No teste de tempo de reação escolha não houve indícios de diferenças significantes para as condições com e sem álcool. Os níveis descritivos encontrados no teste Kruskall-Walis foram 0,309, 0,222 e 0,323 para percentual de acerto, tempo médio de reação verde e vermelho, respectivamente. No teste de memória nenhuma das variáveis de tempo de reação (média, maior e menor) apresentou indícios estatisticamente significantes (p-valores 0,633 0,975 e 0,431, respectivamente), tampouco o padrão e indices descritivos (p=0,238) para a média de acertos e o número de acertos. No teste de associação a variável tempo de resposta apresentou evidências estatisticamente significantes de que os grupos não apresentaram valores médios e medianos iguais entre si (p<0,001), houve evidências de que o grupo de 0 a 0,1 %BAC e maior de 0,1 %BAC eram diferentes entre si (p=0,003). Discussão Parece promissor a realização do teste de associação com um aumento da carga cognitiva afim de poder verificar diferenças mesmo quando o indivíduo consumir pequenas doses de álcool. Considerações Finais Os resultados expostos acima dão margem a otimismo e abrem um amplo horizonte de perspectivas em situações ecológicas da vida real, e não mais nas situações tradicionais e artificiais de laboratório, estendendo o ambiente de experimentação e viabilizando a coleta de grandes conjuntos de dados / Objective To Develop a psychophysical test supported by mobile technology in which the performance of the participant could reveal the influence of alcohol intake by cognitive and motor changes produced by this drug. Method There were 3 preliminary experiments. Experiment 1: A total of 11 participants (6 males and 5 females, 30-53 years) performed a go-no-go reaction time test to three stimuli (green traffic light: go, red trafic light: no-go, yellow trafic light: no-go and a preparatory stimulus: black trafic light). Experiment 2: A total of 13 participants (women, 18-37 years) performed three tests: a) A choice reaction time test to three stimuli (green trafic light, red trafic light, yellow trafic light) and a preparatory stimulus (black trafic light). b) A memory test where the task was to press a button stating that the image that was displayed on the screen was new and another button stating that the image was repeated. c) An association test where the task was to associate figures to a number, following a comparison chart. Experiment 3: A total of 8 participants (5 men and 2 women, 22 to 42 years) performed the same tests applied in experiment number 2 with only one difference in a task of the choice reaction time test. Data analysis focused on standart deviations and coefficients of variation. Results Experiment 1 A paired test for both, reaction times (t (5) = 0.199, p = 0.850) and for the number of errors (t (5) = 0.675, p = 0.529) did not show any significant difference between the conditions with and without alcohol. Results Experiment 2 In the choice reaction time test the ANOVAs 2-MR reaction times and the number of reaction errors revealed no significant differences in both conditions (F (2,36) = 1.175, p = 0.315, HP2 and F = 12:32 (2, 36) = 1.944, p = 0.165, respectively) for color signal (F (2,36) = 0.289, p> 0.5, HP2 = 0:16) and also for condition x color signal (F (2,36) = 0.355, p = 0.840, hp2 = 12:19). In the memory test, the ANOVAs-MR showed no significant differences of the reaction time in all conditions (F (2,36) = 0.693, p> 0.05, n2 = 0.05). In the association test ANOVA-MR revealed a significant difference in 8 reaction times F (2,36) = 4.924, p = 0.016, n 2 = 0.291), but no difference was found for absolute errors (F (2,36) = 0.255, p> 0.5, n2 = 0.090) and absolute errors (F (2,36) = 0.255, p> 0.5, n = 0.02) for the alcohol and alcohol above condition 0.06% BAC. Results Experiment 3 In the choice reaction time test there were no significant evidence of a difference between their position values for the condition with and without alcohol. Descriptive levels found in the Kruskal-Wallis test were 0.309, 0.222 and 0.323 for percentage of correct answers, average reaction time of green and red, respectively. In the memory test, none of the reaction time variables (average, highest and lowest) showed statistically significant evidence (p-value 0.633 0.975 and 0.431, respectively), p-value standard (p = 0.238) for the mean score and the number of hits. In the association test the time variable response presented significant statistically evidence that the groups didnt have mean values equal to each other (p <0.001) there were evidence that the group 0 to 0.1% BAC, and the group larger than 0,1% BAC were different from each other (p = 0.003.) Discussion It sounds promising do to more research with the association test with an increase of the cognitive challange in order to verify differences even when the individual takes use of small doses of alcohol. Conlusion The results presented above give rise to optimism and open up a wide horizon of perspectives on ecological situations of real life, and not just in the traditional and artificial situations of the laboratory, extending the experimentation environment and enabling the collection of large data sets

Verkehrsschilder gelten als das gängigste Mittel zur Regulation des Straßenverkehrs und der Kommunikation zu den Straßennutzer*innen. Die Fähigkeit eines Fahrers bzw. einer Fahrerin, ein Verkehrsschild zu verstehen, ist deshalb essentiell für die Verkehrssicherheit. Zahlreiche Studien zeigen allerdings, dass mit einem durchschnittlichen Verständnis zwischen 50 und 70% der Verkehrsschilder z.T. große Verständnisschwierigkeiten bei den Fahrer*innen vorliegen. Die Verwendung von Piktogrammen stellt eine Möglichkeit dar, um vereinfachte, auf das Wesentliche reduzierte standardisierte Informationen zu übermitteln. In Folge der Zunahme des Verkehrsvolumens über die letzten Dekaden haben viele Länder solche symbolischen Schilder eingeführt, um internationale Reisen dort zu erleichtern, wo Sprachdifferenzen Barrieren darstellen könnten. Die vorliegende Arbeit beschäftigt sich deshalb mit der Verbesserung von Beschilderungen im Straßenverkehr für in- und ausländische Fahrer*innen in Bezug auf Verständlichkeit, Korrektheit von Entscheidungen und Reaktionszeiten. Derzeit gibt es eine Fülle an Forschung zu Symbolen auf Warn- und Gebotsschildern, allerdings nicht auf Wegweisern. Ziel dieser Studie war es, einen Forschungsbeitrag zur Nutzung von Piktogrammen im Straßenverkehr und zur Verkehrssicherheit zu leisten. Dazu wurde in einem Reaktionszeitexperiment zum einen die gerichtete Hypothese untersucht, dass Piktogramme schneller und sicherer erkannt werden als verbale Zielangaben. Diese Hypothese konnte nicht bestätigt werden, stattdessen wurde ein gegenteiliger Effekt gefunden. Zum anderen wurde die gerichtete Hypothese untersucht, dass deutsche Muttersprachler*innen sowohl bei symbolischen als auch bei verbalen Zielangaben insgesamt schnellere Reaktionszeiten und mehr korrekte Antworten zeigen; dies konnte bestätigt werden. Unter Einbezug der Kovariaten Alter, Geschlecht und Fahrerfahrung zeigten sich besonders ein signifikanter Effekt des Alters und des Schildes, das die Versuchspersonen präsentiert bekamen; der zuvor noch gefundene Haupteffekt der Art der Zielangabe (symbolisch/ verbal) war dann nicht mehr signifikant. Mögliche Gründe werden abschließend diskutiert. / Road signs can be regarded as the most common means of traffic regulation and communication to road users. The driver’s ability to understand a road sign therefore is essential for traffic safety. However, a large body of research shows that – with a mean comprehension value that varies between 50 and 70% - drivers have difficulties in understanding the meaning of traffic signs. The use of pictorials represents one way of conveying simplified, standardized pieces of information. With the increase in traffic volumes over the last decades, a lot of countries have introduced such symbolic signs to facilitate international travelling where language differences constitute linguistic barriers. Currently, a variety of studies on symbolic warning and mandatory signs, but not on directory signs exists. The present study subsequently deals with the improvement of directory signs in road traffic for national and international drivers regarding comprehensibility, correctness of decisions and reaction times. The aim of this study is to contribute to existing research on the topic of use of pictorials in road traffic and on traffic safety. A reaction time experiment was developed and carried out with 101 participants aged 18 to 87. 63 of the test persons had acquired German as mother language; for 38 of the participants, German was not the native tongue. Each participant was presented with 32 German directory signs that had specially been developed for the experiment. Participants had to indicate the direction they would use to reach a certain predetermined target location that could either be represented verbally or as a symbol. Two hypotheses were tested: the first hypothesis stated that pictorials should be detected faster and more accurately than verbal targets. This could not be confirmed; instead, we found the opposite pattern. The second hypothesis assumed that German native speakers would show faster reaction times and a greater number of correct answers for symbolic as well as for verbal targets compared to non-native German speakers; this hypothesis could be confirmed. Including the covariates age, sex and driving experience, a very significant effect of age as well as of the specific sign that the subjects were presented with could be shown; the previously found main effect of target type (verbal/pictorial) was not significant, anymore. Finally, the present study discusses possible reasons and influencing factors for the observed effects like arrangement and number of targets on a sign as well as the word length of the used targets.

La perception d’un mouvement biologique correspond à l’aptitude à recueillir des informations (comme par exemple, le type d’activité) issues d’un objet animé en mouvement à partir d’indices visuels restreints. Cette méthode a été élaborée et instaurée par Johansson en 1973, à l’aide de simples points lumineux placés sur des individus, à des endroits stratégiques de leurs articulations. Il a été démontré que la perception, ou reconnaissance, du mouvement biologique joue un rôle déterminant dans des activités cruciales pour la survie et la vie sociale des humains et des primates. Par conséquent, l’étude de l’analyse visuelle de l’action chez l’Homme a retenu l’attention des scientifiques pendant plusieurs décennies. Ces études sont essentiellement axées sur informations cinématiques en provenance de différents mouvements (comme le type d’activité ou les états émotionnels), le rôle moteur dans la perception des actions ainsi que les mécanismes sous-jacents et les substrats neurobiologiques associés. Ces derniers constituent le principal centre d’intérêt de la présente étude, dans laquelle nous proposons un nouveau modèle descriptif de simulation bayésienne avec minimisation du risque. Ce modèle est capable de distinguer la direction d’un ballon à partir d’un mouvement biologique complexe correspondant à un tir de soccer. Ce modèle de simulation est inspiré de précédents modèles, neurophysiologiquement possibles, de la perception du mouvement biologique ainsi que de récentes études. De ce fait, le modèle présenté ici ne s’intéresse qu’à la voie dorsale qui traite les informations visuelles relatives au mouvement, conformément à la théorie des deux voies visuelles. Les stimuli visuels utilisés, quant à eux, proviennent d’une précédente étude psychophysique menée dans notre laboratoire chez des athlètes. En utilisant les données psychophysiques de cette étude antérieure 3 et en ajustant une série de paramètres, le modèle proposé a été capable de simuler la fonction psychométrique ainsi que le temps de réaction moyen mesurés expérimentalement chez les athlètes. Bien qu’il ait été établi que le système visuel intègre de manière optimale l’ensemble des indices visuels pendant le processus de prise de décision, les résultats obtenus sont en lien avec l’hypothèse selon laquelle les indices de mouvement sont plus importants que la forme dynamique dans le traitement des informations relatives au mouvement. Les simulations étant concluantes, le présent modèle permet non seulement de mieux comprendre le sujet en question, mais s’avère également prometteur pour le secteur de l’industrie. Il permettrait, par exemple, de prédire l’impact des distorsions optiques, induites par la conception de verres progressifs, sur la prise de décision chez l’Homme. Mots-clés : Mouvement biologique, Bayésien, Voie dorsale, Modèle de simulation hiérarchique, Fonction psychométrique, Temps de réaction / The ability to recover information (e.g., identity or type of activity) about a moving living object from a sparse input is known as Biological Motion perception. This sparse input has been created and introduced by Johansson in 1973, using only light points placed on an individual's strategic joints. Biological motion perception/recognition proves to play a significant role in activities that are critical to the survival and social life of humans and primates. In this regard, the study of visual analysis of human action had the attention of scientists for decades. These studies are mainly focused on: kinematics information of the different movements (such as type of activity, emotional states), motor role in the perception of actions and underlying mechanisms, and associated neurobiological substrates. The latter being the main focus of the present study, a new descriptive risk-averse Bayesian simulation model, capable of discerning the ball’s direction from a set of complex biological motion soccer-kick stimuli is proposed. Inspired by the previous, neurophysiologically plausible, biological motion perception models and recent studies, the simulation model only represents the dorsal pathway as a motion information processing section of the visual system according to the two-stream theory, while the stimuli used have been obtained from a previous psychophysical study on athletes. Moreover, using the psychophysical data from the same study and tuning a set of parameters, the model could successfully simulate the psychometric function and average reaction time of the athlete participants of the aforementioned study. 5 Although it is established that the visual system optimally integrates all available visual cues in the decision-making process, the results conform to the speculations favouring motion cue importance over dynamic form by only depending on motion information processing. As a functioning simulator, the present simulation model not only introduces some insight into the subject at hand but also shows promise for industry use. For example, predicting the impact of the lens-induced distortions, caused by various lens designs, on human decision-making. Keywords: Biological motion, Bayesian, Dorsal pathway, Hierarchical simulation model, Psychometric function, Reaction time

Overtaking maneuver is very complex event influenced by many parameters. The most important parameters are vehicle performance, longitudinal slope, the speed at the beginning of the maneuver, the reaction time of the driver. Overtaking distance at CSN 73 6101 is determined on the basis of a simplified physical model. It considers constant speed of vehicles (overtaking and overtaken) and it does not consider a longitudinal gradient of road. This calculation is used for several decades and it is required to verify this procedure. That was the purpose of this work. Detailed physical model was performed for several types of passenger vehicles, performance curves and gear changes were included too. Distances between vehicles at the beginning and in the end of the maneuver were chosen with regard to reaction times of drivers. Distances were compared with conclusions of observation studies. Input values of some parameters were determined by own measurement and compared with data reported in the literature. The analysis was performed using the video camera positioned at the front and rear of the vehicle. For selected vehicle were conducted simulations testing the influence of particular parameters. The parameters with the biggest influence were longitudal slope of the road and rolling friction. To achieve results useful for a possible regulations update for the design of roads another simulation models for 43 variants of passenger cars with different engines and transmissions were done. The vehicles were divided into categories based on engine capacity and engine power (up to 1400 ccm, over 1400 ccm; 66 kW to over 66 kW). Results were compiled in tabular form that could be used to discuss modifications to CSN 73 6101 Design of roads.

Verkehrsschilder gelten als das gängigste Mittel zur Regulation des Straßenverkehrs und der Kommunikation zu den Straßennutzer*innen. Die Fähigkeit eines Fahrers bzw. einer Fahrerin, ein Verkehrsschild zu verstehen, ist deshalb essentiell für die Verkehrssicherheit. Zahlreiche Studien zeigen allerdings, dass mit einem durchschnittlichen Verständnis zwischen 50 und 70% der Verkehrsschilder z.T. große Verständnisschwierigkeiten bei den Fahrer*innen vorliegen. Die Verwendung von Piktogrammen stellt eine Möglichkeit dar, um vereinfachte, auf das Wesentliche reduzierte standardisierte Informationen zu übermitteln. In Folge der Zunahme des Verkehrsvolumens über die letzten Dekaden haben viele Länder solche symbolischen Schilder eingeführt, um internationale Reisen dort zu erleichtern, wo Sprachdifferenzen Barrieren darstellen könnten. Die vorliegende Arbeit beschäftigt sich deshalb mit der Verbesserung von Beschilderungen im Straßenverkehr für in- und ausländische Fahrer*innen in Bezug auf Verständlichkeit, Korrektheit von Entscheidungen und Reaktionszeiten. Derzeit gibt es eine Fülle an Forschung zu Symbolen auf Warn- und Gebotsschildern, allerdings nicht auf Wegweisern. Ziel dieser Studie war es, einen Forschungsbeitrag zur Nutzung von Piktogrammen im Straßenverkehr und zur Verkehrssicherheit zu leisten. Dazu wurde in einem Reaktionszeitexperiment zum einen die gerichtete Hypothese untersucht, dass Piktogramme schneller und sicherer erkannt werden als verbale Zielangaben. Diese Hypothese konnte nicht bestätigt werden, stattdessen wurde ein gegenteiliger Effekt gefunden. Zum anderen wurde die gerichtete Hypothese untersucht, dass deutsche Muttersprachler*innen sowohl bei symbolischen als auch bei verbalen Zielangaben insgesamt schnellere Reaktionszeiten und mehr korrekte Antworten zeigen; dies konnte bestätigt werden. Unter Einbezug der Kovariaten Alter, Geschlecht und Fahrerfahrung zeigten sich besonders ein signifikanter Effekt des Alters und des Schildes, das die Versuchspersonen präsentiert bekamen; der zuvor noch gefundene Haupteffekt der Art der Zielangabe (symbolisch/ verbal) war dann nicht mehr signifikant. Mögliche Gründe werden abschließend diskutiert.:Danksagung Zusammenfassung 1. Hinführung und Ziele 2. Theorie 2.1 Überblick über bisherige Literatur 2.2 Überlegungen zum Studiendesign 3. Hypothesen 3.1 Reaktionszeitunterschiede zwischen symbolischen und verbalen Zielangaben 3.2 Reaktionszeitunterschiede zwischen deutschen Muttersprachler*innen und Nicht-Muttersprachler*innen 4. Methoden 4.1 Stichprobe 4.2 Ablauf und Materialien 4.3 Design 4.4 Statistische Analyse 5. Ergebnisse 5.1 Deskriptive Analyse der abhängigen Variablen 5.2 Überprüfung auf Normalverteilung 5.3 Deskriptive Analyse der Daten der Nachbefragung 5.4 Überprüfung der Hypothesen 6. Diskussion 6.1 Vergleich verbaler und symbolisches Zielangaben 6.2 Vergleich deutscher und nicht-deutscher Muttersprachler*innen 6.3 Weitere Ergebnisse und Überlegungen 7. Literaturverzeichnis Anhang Abbildungsverzeichnis Tabellenverzeichnis / Road signs can be regarded as the most common means of traffic regulation and communication to road users. The driver’s ability to understand a road sign therefore is essential for traffic safety. However, a large body of research shows that – with a mean comprehension value that varies between 50 and 70% - drivers have difficulties in understanding the meaning of traffic signs. The use of pictorials represents one way of conveying simplified, standardized pieces of information. With the increase in traffic volumes over the last decades, a lot of countries have introduced such symbolic signs to facilitate international travelling where language differences constitute linguistic barriers. Currently, a variety of studies on symbolic warning and mandatory signs, but not on directory signs exists. The present study subsequently deals with the improvement of directory signs in road traffic for national and international drivers regarding comprehensibility, correctness of decisions and reaction times. The aim of this study is to contribute to existing research on the topic of use of pictorials in road traffic and on traffic safety. A reaction time experiment was developed and carried out with 101 participants aged 18 to 87. 63 of the test persons had acquired German as mother language; for 38 of the participants, German was not the native tongue. Each participant was presented with 32 German directory signs that had specially been developed for the experiment. Participants had to indicate the direction they would use to reach a certain predetermined target location that could either be represented verbally or as a symbol. Two hypotheses were tested: the first hypothesis stated that pictorials should be detected faster and more accurately than verbal targets. This could not be confirmed; instead, we found the opposite pattern. The second hypothesis assumed that German native speakers would show faster reaction times and a greater number of correct answers for symbolic as well as for verbal targets compared to non-native German speakers; this hypothesis could be confirmed. Including the covariates age, sex and driving experience, a very significant effect of age as well as of the specific sign that the subjects were presented with could be shown; the previously found main effect of target type (verbal/pictorial) was not significant, anymore. Finally, the present study discusses possible reasons and influencing factors for the observed effects like arrangement and number of targets on a sign as well as the word length of the used targets.:Danksagung Zusammenfassung 1. Hinführung und Ziele 2. Theorie 2.1 Überblick über bisherige Literatur 2.2 Überlegungen zum Studiendesign 3. Hypothesen 3.1 Reaktionszeitunterschiede zwischen symbolischen und verbalen Zielangaben 3.2 Reaktionszeitunterschiede zwischen deutschen Muttersprachler*innen und Nicht-Muttersprachler*innen 4. Methoden 4.1 Stichprobe 4.2 Ablauf und Materialien 4.3 Design 4.4 Statistische Analyse 5. Ergebnisse 5.1 Deskriptive Analyse der abhängigen Variablen 5.2 Überprüfung auf Normalverteilung 5.3 Deskriptive Analyse der Daten der Nachbefragung 5.4 Überprüfung der Hypothesen 6. Diskussion 6.1 Vergleich verbaler und symbolisches Zielangaben 6.2 Vergleich deutscher und nicht-deutscher Muttersprachler*innen 6.3 Weitere Ergebnisse und Überlegungen 7. Literaturverzeichnis Anhang Abbildungsverzeichnis Tabellenverzeichnis

In this thesis, a new approach for generating reaction time predictions for Bayesian cognitive models of sequential decision-making is proposed. The method is based on a Markov chain Monte Carlo algorithm that, by utilizing prior distributions and likelihood functions of possible action sequences, generates predictions about the time needed to choose one of these sequences. The plausibility of the reaction time predictions produced by this algorithm was investigated for simple exemplary distributions as well as for prior distributions and likelihood functions of a Bayesian model of habit learning. Simulations showed that the reaction time distributions generated by the Markov chain Monte Carlo sampler exhibit key characteristics of reaction time distributions typically observed in decision-making tasks. The introduced method can be easily applied to various Bayesian models for decision-making tasks with any number of choice alternatives. It thus provides the means to derive reaction time predictions for models where this has not been possible before. / In dieser Arbeit wird ein neuer Ansatz zum Generieren von Reaktionszeitvorhersagen für bayesianische Modelle sequenzieller Entscheidungsprozesse vorgestellt. Der Ansatz basiert auf einem Markov-Chain-Monte-Carlo-Algorithmus, der anhand von gegebenen A-priori-Verteilungen und Likelihood-Funktionen von möglichen Handlungssequenzen Vorhersagen über die Dauer einer Entscheidung für eine dieser Handlungssequenzen erstellt. Die Plausibilität der mit diesem Algorithmus generierten Reaktionszeitvorhersagen wurde für einfache Beispielverteilungen sowie für A-priori-Verteilungen und Likelihood-Funktionen eines bayesianischen Modells zur Beschreibung von Gewohnheitslernen untersucht. Simulationen zeigten, dass die vom Markov-Chain-Monte-Carlo-Sampler erzeugten Reaktionszeitverteilungen charakteristische Eigenschaften von typischen Reaktionszeitverteilungen im Kontext sequenzieller Entscheidungsprozesse aufweisen. Das Verfahren lässt sich problemlos auf verschiedene bayesianische Modelle für Entscheidungsparadigmen mit beliebig vielen Handlungsalternativen anwenden und eröffnet damit die Möglichkeit, Reaktionszeitvorhersagen für Modelle abzuleiten, für die dies bislang nicht möglich war.

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Phosphatidylserine (PS) is an endogenously occurring phospholipid that has been shown to have cognition and mood enhancing properties in humans, possibly through its role as an enzyme co-factor in cellular signal transduction. Specifically, PS has been identified as activator of classical isoforms of protein kinase C, an enzyme known to be involved in the growth and differentiation of neural cells, and is therefore thought to play a role in the protection of neurons. The purpose of this study was to examine the effects of supplementation with PS and caffeine on measures of cognition, reaction time and mood prior to and following an exercise stress. Twenty, healthy, resistance trained males (17) and females (3) (mean ± SD; age: 22.75 ± 3.27 yrs; height: 177.03 ± 8.44cm; weight: 78.98 ± 11.24kg; body fat%: 14.28 ± 6.6), volunteered to participate in this randomized, double-blind, placebo-controlled study. Participants were assigned to a PS group (400mg/day PS; 100mg/day caffeine, N=9) or PL (16g/day Carbs, N=11) delivered in the form of 4 candy chews identical in size, shape and color. Subjects performed an acute bout of full body resistance exercise, prior to (T1) and following 14 days of supplementation (T2). Measures of reaction time (Dynavision® D2 Visuomotor Training Device), cognition (Serial Subtraction Test, SST), and mood (Profile of Mood States, POMS) were assessed immediately before and following resistance exercise in both T1 and T2. Data was analyzed using two-way ANCOVA and repeated measures ANOVA. Supplementation with 400mg PS and 100mg caffeine did not have a significant impact upon measures of reaction time or cognition between groups at baseline or following acute resistance exercise. However, there was a non-significant trend to the attenuation of fatigue iv between groups, following acute resistance exercise (p = 0.071). Interestingly, our data suggests that acute resistance exercise alone may improve cognitive function. Although more research is necessary regarding optimal dosage and supplementation duration, the current findings suggest that supplementation 400mg/day PS with 100mg/day caffeine may attenuate fatigue following acute resistance exercise. It is possible that the lack of significance may be the result of both an inhibition of the PS activated pathway and a withdrawal effect from caffeine.