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1	Neuroimaging in Human Category Learning: A Comparison Between Functional Near-Infrared Spectroscopy (fNIR) and Functional Magnetic Resonance Imaging (fMRI) Viegas, Carina 01 January 2014 (has links) The objective of this thesis is to examine the validity of functional near-infrared spectroscopy (fNIR) to examine brain regions involved in rule based (RB) and information integration (II) category learning. We predicted similar patterns of activation found by past studies that used fMRI scans. Our goal was to test if fNIR would be able to detect changes in blood oxygenation levels of participants who learned to categorize (learners) vs. those that did not (non learners). The stimulus set comprised of lines that differed in length and orientation. Participants had to learn to categorize by trial and error based on the feedback provided. Behavioral and neuroimaging data was recorded for both RB and II conditions. Results showed an upward trend in response accuracy over trials for participants identified as learners. Furthermore, blood oxygenation levels reported by fNIR indicated a systematic increase in oxygen consumption for learners as compared to non learners. These areas of increased prefrontal cortex activity recorded by fNIR correspond to the same areas found to be involved in categorization by fMRI. This paper reviews the background of category learning, explores various neuroimaging techniques in categorization research, and investigates the efficacy of fNIR as a relatively new neuroimaging modality by comparing it to fMRI. Category learning; Fnir; Neuroimaging Psychology
2	Exploring The Effects Of Working Memory Capacity, Attention, And Expertise On Situation Awareness In A Flight Simulation Environment Ozcan, Orcun Orkan 01 October 2012 (has links) (PDF) Experienced and novice simulator pilots are subject to some of the constraints of a real flight (or a full flight simulator) situation in a PC based flight simulation. In this thesis, the effects of expertise, working memory capacity, inhibition and divided attention on situation awareness (SA) in simulated flight task environments are investigated. The cognitive aspects underlying the process of situation awareness are explored by analyzing the compound effects of above listed factors. Online and Offline SA measurements obtained from a simulated flight task are used with flight hours standing for expertise and scores of Automated Operation Span Task, Stroop and Coskun&ouml / z visual attention tasks as measurements for working memory capacity, inhibition and divided attention respectively. Regression analyses reveal that expected relationships of simulator pilots&rsquo / SA with expertise and inhibition capacity are supported. On the other hand, expected relationships of SA with working memory and divided attention capacities are not revealed. This situation probably results from unsystematic differences in simulator pilots&rsquo / practices. In addition to the main experiment, simulator pilots&rsquo / levels of neural activity at their dorsolateral prefrontal cortex are also measured during their behavioral performance. The relationships among neural correlates of mental workload induced by the simulated flight are investigated by the functional near-infrared (fNIR) spectroscopy optical brain imaging technology. Theorized mental workload distinction in the scenario of the simulated flight task is successfully observed in both perceived workload declarations and oxygenation measurements by fNIR.
3	Effects Of Way Finding Affordances On Usability Of Virtual World Environments In Terms Of Users Cansiz, Yaver 01 March 2012 (has links) (PDF) This study aims to test the effects of different way finding affordances on the usability of METU virtual campus built in Second Life virtual world in terms of users&rsquo / satisfaction, performance and mental workload. This study was conducted with 36 participants who are students at the Middle East Technical University. Participants were randomly put on of the five groups namely map, signboard, voice and agent groups and a control group. The participants were given navigational tasks in METU virtual campus within Second Life. In the experiment, the eye movements of the participants were examined with eye tracking tool in order to determine the areas which participants paid attention most. Also mental work load in their prefrontal cortex was examined with fNIR device. There was no significant difference among groups in terms of satisfaction, however / there were significant difference among groups in terms of task completion accuracy, time, length, navigation cue gaze duration and mental workload. Agent group has the highest accuracy score, map group has the highest time, length and navigation cue gaze duration score. Moreover, agent group has the highest mental workload but control group has the lowest mental workload. The results of the tests were used to provide guidance for the design of way finding affordances in METU virtual campus.
4	Investigating The Universality And Comprehensive Ability Of Measures To Assess The State Of Workload Abich, Julian 01 January 2013 (has links) Measures of workload have been developed on the basis of the various definitions, some are designed to capture the multi-dimensional aspects of a unitary resource pool (Kahneman, 1973) while others are developed on the basis of multiple resource theory (Wickens, 2002). Although many theory based workload measures exist, others have often been constructed to serve the purpose of specific experimental tasks. As a result, it is likely that not every workload measure is reliable and valid for all tasks, much less each domain. To date, no single measure, systematically tested across experimental tasks, domains, and other measures is considered a universal measure of workload. Most researchers would argue that multiple measures from various categories should be applied to a given task to comprehensively assess workload. The goal for Study 1 to establish task load manipulations for two theoretically different tasks that induce distinct levels of workload assessed by both subjective and performance measures was successful. The results of the subjective responses support standardization and validation of the tasks and demands of that task for investigating workload. After investigating the use of subjective and objective measures of workload to identify a universal and comprehensive measure or set of measures, based on Study 2, it can only be concluded that not one or a set of measures exists. Arguably, it is not to say that one will never be conceived and developed, but at this time, one does not reside in the psychometric catalog. Instead, it appears that a more suitable approach is to customize a set of workload measures based on the task. The novel approach of assessing the sensitivity and comprehensive ability of conjointly utilizing subjective, performance, and physiological workload measures for theoretically different tasks within the same domain contributes to the theory by laying the foundation for improving methodology for researching workload. The applicable contribution of this project is a stepping-stone towards developing complex profiles of workload for use in closed-loop systems, such as human-robot team iv interaction. Identifying the best combination of workload measures enables human factors practitioners, trainers, and task designers to improve methodology and evaluation of system designs, training requirements, and personnel selection Workload cognitive unitary resource theory multiple resource theory assessments measures instantaneous self assessment isa task load index tlx multiple resource questionnaire mrq electroencephalogram eeg transcranial doppler tcd functional near infrared imaging fnir electrocardiogram ecg eye tracking universal comprehensive workload profile signal detection change detection change blindness intelligence surveillance response isr Engineering

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