Table of Contents
List of Figures
List of Tables
List of Abbreviations of Technical
Symbols and Terms
Chapter 1. Introduction
1.3 Back Ground of this Thesis
1.5 Thesis Layout
Chapter 2. Literature Review
2.1 Literature Review
Chapter 3. Cognitive Load
3.2 Types of Cognitive load
3.2.1. Intrinsic load
3.2.2. Extraneous load
3.2.3. Germane Load
Chapter 4. Galvanic Skin Response
4.2 The Background of GSR signals
4.3 GSR signals explained
Chapter 5. Data Collection
5.1. Task Description
5..3. QS222 GSR Sensor
5.4. Labquest Mini
5.5 Logger Pro Software
Chapter 6. Process of GSR Analysis
6.2. Simulation Example 01
6.3. Simulation Example 02
6.4. Time domain feature
6.5 Frequency domain features
Chapter 7. Analysis of Varince Test
7.2 Types of Tests
7.2.1 One Way ANOVA
7.2.2 Two Way ANOVA
7.3 ANOVA vs. T Test
7.4 Alpha Level
7.6 Difference between an alpha level and a p-value
Chapter 8. Experimental Results & Discussion
8.2 For time domain
8.3 For frequency Domain
Chapter 9. Conclusions and Future Research
List of Publications
1.Delowar Hossain, Shah Md. Salimullah, Abrar Nayeem Chowdhury, Erfan Kabir, Syed Md. Nishad Hasan, Rahi Mahmudi and Md Mahbubul Islam. “Measurement of Cognative load for writing tasks using galvanic skin response”. paper number 6th International Conference on Networking, System and Security 2019, BUET, Dhaka, Bangladesh.
2. Delowar Hossain, Shah Md. Salimullah, Abrar Nayeem Chowdhury, Erfan Kabir, Syed Md. Nishad Hasan, Rahi Mahmudi and Md Mahbubul Islam, “Cognitive Load Measurement Using Galvanic Skin Response for Listening Tasks” , paper no. 59, 4th International Conference on Electrical Information and Communication Technology (EICT), 2019, KUET, Khulna, Bangladesh.
The galvanic skin response alludes to changes in perspiration organ movement that are intelligent of the power of our passionate state, also called enthusiastic excitement. it has normally been explored through single or few measures and in one exploratory situation. Galvanic Skin Response (GSR) has as of late stood out for researchers as a planned physiological marker of intellectual feelings. In this exploration, intending to play out a far reaching study, we have evaluated GSR information capture for fifteen writing task and three difficulty levels and determined time and frequency domain feature. We determined that cognitive load is proportional to the task difficulty level. If cognitive load increases, task difficulty level will increase. If cognitive load decreases, task difficulty level will decrease.
First and foremost, I would like to thank Almighty Allah for giving me the strength to finish this work. The satisfaction that accompanies the successful completion of this thesis would be incomplete without the mention of people whose ceaseless cooperation made it possible, whose constant guidance and encouragement crown all efforts with success. I am grateful to my honorable thesis Supervisor Shah Md. Salimullah, Assistant Professor, Department of Electrical & Electronic Engineering, Bangladesh Army International University of Science & Technology (BAIUST), for the guidance, inspiration and constructive suggestions which were helpful in the preparation of this project. I also convey special thanks and gratitude to Dr. Umma Hany, honorable head of the Electrical & Electronic Engineering for their kind advice. I would also like to extend my gratitude to all of my teachers for their valuable guidance in every step of mine during the four years of learning stage. Finally I would like to thank my friends, senior, juniors and the staffs of the department for their valuable suggestion and assistance that has helped in successful completion of the project.
List of Figures
Figure 5.1: QS222 GSR Sensor
Figure 5.2: Labquest Mini
Figure no 6.1: GSR signal of subject 1 at the time of performing different tasks
Figure 6.2: GSR Signal of subject 2 at the time of performing different tasks
Figure 6.3: Noisy signal and it’s filtered signal of Subject 1
Figure 6.4: Noisy signal and it’s filtered signal of Subject 2
Fig 8.1: Accumulated GSR Values for different task difficulty level for all subjects without normalization
Fig 8.2: Accumulated GSR Values for different task difficulty level for all subjects with normalization
List of Tables
Table no 8.1: Anova Test Result of Time Domain Feature
Table no 8.2: Anova Test Results of Frequency Power Spectrum
List of Abbreviations of Technical
Abbildung in dieser Leseprobe nicht enthalten
Symbols and Terms
Abbildung in dieser Leseprobe nicht enthalten
Emotions play an important and powerful role in people's daily lives. At present, human feeling is something imperative and has turned into a worry in different fields of research, including electrical engineering  . There exist completely different studies that attempt to find people’s emotional states, together with tries to seek out whether or not somebody is tormented by stress or isn't. Studies  and  use EEG to classify the different information non-inheritable by brain activity. They extract completely different frequency options of the signals for their posterior classification with sensible results. Heart Rate Variability is another parameter accustomed live stress levels . To induce stress the authors in  propose victimization respiration and speak preparation. Then, they gift a technique based mostly on formal logic to research the various information from unit of time and electrodermal response. Associate ambulant device is developed in  so as to judge stress in blind individuals. This device additionally includes the mensuration of skin temperature that is another parameter accustomed analyze stress  . As regards Galvanic Skin Response (GSR), there are many studies that propose completely different methods of police work stress levels by measure skin electrical phenomenon   . For the identification of emotions, speech analytics and facial expressions were used. This phenomenon is genuine, taking into account that feeling as a human demeanor infers exercises done by people and their fervor can be recognized dependent on the information estimated from them: voice, face99 body, and physiology , . Furthermore, using only speech or facial expression signals has disadvantages: it is not accurate to use them every day to identify emotions, especially when people want to hide their feelings. Galvanic Skin Response (GSR) as a prospective physiological marker of cognitive load and emotions has recently attracted the attention of researchers. GSR is a result of thrilling physiological reactions. It measures signals sent by the human skin which is considered as a reflection of physiological changes , . Skin responds when exposed to emotionally charged pictures, videos, events or other stimuli, regardless of whether they are positive or negative. Emotional adjustments cause a sweat reaction that is especially prominent on the skin of the arms and hands and the bottom of the feet. As people get so excited, the body sweats, the amount of salt in the skin increases, and the electrical resistance of the skin also tends to increase. Changing feelings activate and trigger the sweat glands in our body. They secrete moisture to the skin surface as sweat glands become more active. This shifts the balance of positive and negative ions and influences the movement properties of the electrical currents on the skin and is most evident on the hands and feet. It shifts the combination of positive and negative ions and affects the movement properties of electrical currents on the skin and on the hands and feet is quite apparent  . The GSR (galvanic skin response) is known to become the most reliable recording in polygraph examinations, and the best discriminator between people who provided fraudulent answers to test questions and anti-deceptive subjects. GSR improvements are the most widely used predictor in various simplified lying detection procedures. One of them makes use of a replacement device introduced by the Americans in Asian nation and Al-Iraq for the initial screening of suspects. it's the so called Preliminary Credibility Assessment Screening System: (PCASS). The PCASS may be a hand-held laptop or personal digital assistant that makes an attempt to live stress to decide whether or not a subject matter is telling the truth. To notice deception, the PCASS uses external physiological data (GSR and cardiovascular) collected throughout an interview with a photoplethysmograph. In 1849, Emil du Bois-Reymond in Deutschland discovered that the human skin is electrically active. within the later years of the nineteenth century, Romain Vigouroux, a collaborator of the French specialist Jean brain doctor (1825–1893), measured tonic skin resistance levels in numerous showing emotion distressed patient teams once trying to find clinical diagnostic signs throughout studies of hysteria and psychological state in Charcot’s laboratory. He detected that the resistivity of the skin will increase on the insensible half of the body of his hysteric patients . In the same laboratory, Charles Féré (1852–1907) found that by passing a coffee electrical current between 2 electrodes placed on the surface on the skin, one could use a meter to live fleeting decreases in skin resistance in response to a variety of stimuli of varied sorts, as well as visual and sensory system ones . In this method Féré discovered that the skin becomes a more robust conductor of electricity in the presence of external stimuli. In 1890, a Russian biologist of Georgian origin, Ivan Tarchanoff (Tarchanov,Tarkhanishvili,1846–1908) discovered that one may live changes within the electrical potential between 2 electrodes placed on the surface of the skin, however not like in Féré’s experiment, while not applying associate external supply of current. numerous stimuli result in a amendment within the electrical potential and build the pointer of the meter move . As Jaff res tested, the Fere phenomenon and Tarchanoff phenomenon have same physiological mechanism and are 2 ways in which of perceptive and measurement an equivalent phenomenon . The North American country Féré and Tarchanoff are the joint discoverers of the galvanic skin response. It is due to these 2 scientists that we will resort to galvanic skin responses in contemporary instrumental lie detection.
To become familiar with procedures for recording the galvanic skin response. To identify and record changes associated with cognitive behavior and emotional skin resistance. In the percentage of stress levels we can evaluate the stress level when we write. The GSR electrode has to place on the fingers of the on hand for right prediction of stress level percentage.
1.3 Back Ground of This Thesis
In 1897, a German, Georg Sticker, was the first to counsel the utilization of a meter (psychogalvanometer) for lie-detection , and in 1909 Otto Veraguth used Tarchanoff phenomenon for his experiments with word association. More than 85 years agone, John Larson complemented what had antecedently been a binaural polygraph with the psychogalvanometer. Since then a psychogalvanometer has been a significant and customary part of all medical instrument devices , while the Galvanic Skin Response (GSR) is among the prime and most evident and accurate physiological changes utilized in instrumental detection of deception. It is typically assumed that the us is home to the medical instrument. Even at the most recent, fiftieth Seminar of the yank medical instrument Association in Chicago, held from thirty August to four Sept 2015, Frank Horvath and Stanley Slowik, in a paper delivered below the title of “The Birthplace of contemporary Polygraphy”, tried to convince the audience that the particular birthplace is Chicago. It’s true that the United is that the country wherever the modern medical instrument was made, and which also boasts the longest apply within the use of the machine that began in the Nineteen Twenties. However, it goes while not expression that medical instrument examination has European roots. Without these, moreover as while not European psychological science and without the European discoveries in physiology and psychological science of the late nineteenth and early twentieth centuries, while not European scientists WHO in some cases (notably Hugo Münsterberg) were additionally active within the us, the origin and development of polygraph examinations wouldn't are possible. in a very shell, while not European students of the order of Angelo Mosso, Vittorio Benussi, Cesare Lombroso, Charles Féré, and Ivan Tarchanoff , the works of John Larson and Dutch Leonard Keeler, whom Americans justifiably bear in mind to be the ‘fathers of the medical instrument examination, would not are potential. Also, numerous specialists revealed the utilization of GSR for physiological phenomena , . GSR signal shows electrical changes estimated at the outside of the human skin that fluctuates with the adjustments in skin dampness level (perspiring) and mirrors the distinctions in their thoughtful sensory system . The GSR sign are shaped by the changing body obstruction because of the changing body conductivity brought about by the creation of sweat. This apparatus has been very most loved as it is sufficiently sensitive and modest. In its advancement, the utilization of GSR to recognize feeling can be done because of the unconstrained response which can't be constrained by the client. Moreover, it is considered as perhaps the most grounded sign that can be utilized for feeling discovery , . The aim of our experiment is to detect cognitive load levels for listening task.
The aim of our research is to focuses on the detection of cognitive load fluctuations with respect to the multiple cognitive load levels for listening task. With respect to different task difficulty level we have determine time and frequency domain features. So far in our knowledge, no proper study regarding cognitive load change with writing task has been done. That’s why I have motivated to do this.
1.5 Thesis Layout
Chapter 1 is on Introduction of this thesis.
Chapter 2 is based on Literature Review
Chapter 3 is a brief description over Cognitive Load
Chapter 4 Galvanic Skin Response analysis
Chapter 5 shows the method of collecting data
Chapter 6 is on process of GSR Analysis
Chapter 7 overview on Analysis of Variance Test
Chapter 8 based on experiment result and discussion
Chapter 9 is about future work and conclusion
2.1 Literature Review
In thousands of articles, more than one hundred and twenty years since this seminal discovery of this relation of emotional response to the GSR signal was discussed. Galvanic skin response is often used as a psychophysiological methodology, as a result of it's simple to use and for the most part non-intrusive for the participant. EDA and galvanic skin response mostly assess activity of the “fight-or-flight response,” that is controlled by the sympathetic nervous system  . The level to which this response is triggered can be calculated by sweat secretion; during a strong emotional reaction, more sweat is released compared to a weak one. The hands have a high density of sweating that are sensitive both to changes in external stimuli (for example, temperature) and internal stimuli (for example, changes in emotions). GSR is related to tension, anticipation, commitment, frustration and anger and is linked to self-reporting arousal measures  . Attention-requiring tasks increase the frequency and magnitude of GSR. GSR is widely used in decision making and studies on emotions.
During interactions with an online poker game, a recent study evaluated GSR where numerous and fast decisions are required. Poker hand strength was correlated with GSR response and GSR was therefore useful to show the expected usefulness of poker game decisions. Skin Conductance Measure Emotion.
GSR consists of tonic activity and phasic activity. Arousal tonic changes occur slowly and are measured over a long period of time  . Arousal tonic changes occur gradually and are calculated over a long time period. For example, the tonic level of emotional excitement can be determined at the start and offset of an advertisement and is basically a level of excitement "baseline". However, phase activity consists of rapid sweat secretions in response to a discrete stimulus. While changes in tonic levels of excitement are measured over time, in response to stimuli that are startling, surprising, funny or disgusting, phasic activity occurs rapidly. Researchers are interested in measuring their participants ' tonic and phasic behavior, but accurate measurement may be troublesome.
Although GSR information is useful, tonic and phasic behavior dynamic analysis is complex, requiring trained experts. In consumer neuroscience, a general problem is that clearly specified threshold values are often left out of reporting  . Researchers often ignore fact that activity overlaps, but this is inevitable because a skin conductance response (SCR) rise time is shorter than the recovery time, and this information may be important in analysis of results. If researchers are interested in how emotional intensity changes over time, they often use approaches that only evaluate skin conductance (SC) tonic levels. Such techniques are problematic because the phasic behavior is overlooked and only half the story is told. In other cases, if researchers want to measure phasical behavior, they can use a testthat measures the mean score of change before and during stimulation. This method is unfortunately considered arbitrary and not completely correct. The most common method in consumer neuroscience is to use the sum of the SCR amplitudes, but it is still not entirely accurate  . In order to be completely correct in analyzing SCR data, it must include information on the amplitude and duration of an SCR. The integrated SCR (ISCR) is calculated by one such correct method. Calculating the ISCR will identify an SCR in your users more precisely and will help you make user group comparisons. Many UX researchers are going to sacrifice best practices and proper analytical techniques for easier but incorrect analyzes. This is, and should be avoided, bad practice. GSR indicates the strength of the anticipation, but not the valence, as with other physiological response tests. It is therefore important to combine SCR measurements with other specific indicators so that we can know if users have a positive or negative experience. GSR has a strong potential to quantify user experience, similar to facial expression recognition, but more work is certainly needed.Galvanic Skin Response has already getting used in activity trust and cognitive Load within the text-chat setting .. To Evaluate the Impact of environmental complexness on driver workload psychological feature load mensuration is employed.
Cognitive load is total amount of effort being used in working memory. Working memory is like a memory buffer we use it to manipulate the information for the task at hand. The idea of cognitive load came from the work of John Sweller, Richard Mayer, Paul Ayres, Slava Kalyuga and others. Working memory is limited and as we learn it can become overloaded which reduces the amount of information, we can move to our long term memory. The way we present information as teacher can reduce cognitive load and increase learning. We do that considering how we taking information when learning new materials we primarily use our eyes and ears which is called visual and audio channels. Everything we learned creates some cognitive load and some subjects are might be more difficult than others. Mayer call this built-in difficulty, intrinsic load. While we can match the intrinsic load to the experience of the learner there’s not a lot we can do to reduce the inherent load. We can control the way we present our information called extraneous load. By reducing extraneous load, more room and working memory thereby increasing retention. Richard Mayer developed several load reducing techniques for presenting information that are simple to understand and easily implemented. Most of these techniques are developed for multimedia presentation like power point.
3.2 Types of Cognitive load
Richard Mayer differentiate the cognitive load in three types-
1. Intrinsic Load
2. Extraneous Load
3. Germane Load
3.2.1. Intrinsic Load
Intrinsic cognitive load illustrate the inherent difficulty involved in certain tasks. Some activities harder to bring under control over than other. If activities get more difficult, subject can cause an intrinsic cognitive load. As example, complex math calculation are more difficult than basic mathematical calculation like 5+7/6.Intrinsic cognitive load is associated with the nature and subject matter of the task.
As example, if a person have to memories a complex histogram with too many parameters, which is more complicated than memories a simple bar graph is easier to understand, causes higher intrinsic cognitive load level. The inherent complexity level of the content cannot be changed, but it can be managed according to the learner’s capacity for learning. According to John Sweller, the intrinsic cognitive load can “only be altered by changing the nature of what is learned or by the act of learning itself.”
3.2.2. Extraneous Load
Extraneous cognitive loads are created by the way a person knows information of a phenomenon. This type of cognitive load is the result of unnecessary or unimportant information of a phenomenon and the person get confused and complicated.
3.2.3 Germane Load
Germane cognitive load is the result of approximate method of learning handling information, in such a way to learning. Germane load alludes to the work that is put into approximate a long-lasting store of knowledge
Galvanic Skin Response
The galvanic skin response (GSR, which falls under the umbrella term of electrodermal activity, or EDA) refers to changes in sweat gland activity that are reflective of the intensity of our emotional state, otherwise known as emotional arousal. GSR also known as Skin Conductance (SC), refers to changes in sweat gland activity, which reflect the intensity of participants’ emotional state or ‘emotional arousal’. GSR provides an additional source of insight into the level of emotional arousal, to validate self-reports, surveys, or interviews of participants within a study. Our level of emotional arousal changes in response to the environment we’re in if something is scary, threatening, joyful, or otherwise emotionally relevant, then the subsequent change in emotional response that we experience also increases eccrine sweat gland activity. Research has shown how this is linked to emotional arousal.
4.2 The Background of GSR Signals
Vigouroux was the first researcher to uncover a link between mental state and GSR activity, finding an association with the level of sedation in patients and skin resistance [1, 5]. This connection of emotional response to GSR signal has been explored in thousands of articles in the 120+ years since this seminal finding .While sweat secretion plays a major role for thermoregulation and sensory discrimination, changes in skin conductance are also triggered robustly by emotional stimulation the higher the arousal, the higher the skin conductance. The amount of sweat glands varies across the human body, but is the highest in hand and foot regions (200–600 sweat glands per cm2, where the GSR signal is typically collected from . It can be used as an additional source of insight to validate self-reports, surveys, or interviews of participants within a study.
4.3 GSR Signals Explained
The time course of the signal is considered to be the result of two additive processes: a tonic base level driver, which fluctuates very slowly, and a faster-varying phasic component. Changes in phasic activity can be identified in the continuous data stream as these bursts have a steep incline to a distinctive peak and a slow decline relative to the baseline level. Researchers focus on the latency and amplitudes of the phasic bursts with respect to stimulus onset when investigating GSR signal changes in response to sensory stimuli (images, videos, sounds).
The GSR signal is very easy to record. In general just two electrodes put at the second and third finger of one hand are necessary. The variation of a low-voltage applied current between the two electrodes is used as measure of the EDA. Recently, new commercial healthcare devices more and more wearable and fancy (bracelets, watchs) have been developed, thus such measure is usable in each research activity in the neuroscience domain also in no-laboratory settings.
When there are significant changes in GSR activity in response to a stimulus, it is referred to as an Event-Related Skin Conductance Response (ER-SCR). These responses, otherwise known as GSR peaks, can provide information about emotional arousal to stimuli.Other peaks in GSR activity that are not related to the presentation of a stimulus are referred to as Non-Stimulus-locked Skin Conductance Responses (NS-SCR). By using the skin conductance values, or the number of GSR peaks, it’s possible to add quantitative data to studies of emotional arousal. With more data at hand, it’s easier to uncover new findings, and make new discoveries about human behavior.
The Galvanic Skin Response (GSR), is the measure of the continuous variations in the electrical characteristics of the skin, i.e. for instance the conductance, caused by the variation of the human body sweating. The traditional theory of the GSR analysis is based on the assumption that skin resistance varies with the state of sweat glands in the skin. Human body sweating is regulated by the Autonomic Nervous System (ANS). In particular, if the sympathetic branch (SNS) of the autonomic nervous system is highly aroused, then sweat gland activity also increases, which in turn increases skin conductance, and viceversa. In this way, skin conductance can be a measure of the human Sympathetic Nervous System responses. Such system is directly involved in the emotional behavioural regualation in the humans. Additional studies highlighted the relationship between GSR signal and some mental states, such as stress, drowsiness and engagement. The GSR signal is very easy to record: in general just two electrodes put at the second and third finger of one hand are necessary. The variation of a low-voltage applied current between the two electrodes is used as measure of the EDA. Recently, new commercial healthcare devices more and more wearable and fancy (bracelets, watchs) have been developed, thus such measure is usable in each research activity in the neuroscience domain also in no-laboratory settings.