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Posts Tagged ‘natural sciences versus people’s behavior sciences”

Article 40

 “Experimentation: natural sciences versus people’s behavior sciences”

This article is intended to compare the kind of controlled experiments that are applied by scientists in physical natural phenomena and those developed by scientists dealing with the behavior of people or employing human participants in the experiments.

Although the physical sciences such as all the branches in physics and chemistry used controlled experimentations long time ago to develop the huge body of knowledge on the natural phenomena, it was the social and psychological sciences that tried to develop the appropriate and complex statistical modeling packages in order to study the more complex and more varied human behaviors.  It appears that the restricted and countable number of variables in studying the physical nature and their relative lack of variability with time did not encourage the physical scientists to contemplate sophisticated statistical models for their controlled experiments or even to teaching the design of experiments in the engineering curriculum. 

Before we expand on the variability of human behaviors it might be more appropriate to analyze the most critical difference in the two sciences. Knowing that any concept is synonymous with the corresponding necessary set of operations in order to be able to measure it scientifically in experiments we can understand the big leap forward of the body of knowledge in natural sciences compared to the social and psychological sciences.  Whereas the physical scientists can define the concepts of force, moment, power and the like through the relationships of measurable variables based on length, time, and mass the scientists investigating human behaviors have to surmount that hurdle before seriously contemplating to measure human concepts.  Human behavior and the cognitive concepts of attitudes, mental abilities, and moods, problem solving mechanisms, perception, and the like cannot be measured scientifically until sets of operations are agreed on for each one of these concepts through the study of human activities or the things that people do while performing a valid task or a set of purposeful tasks.  For example, saying that color blindness is a deficiency that confuses colors will not cut it; what is needed are a set of instances that could define this illness such as what exactly are the colors of the spectrum with mixtures of two primary colors can a protanope (color blind individual) match that are different from normal people, he will confuse a blue-green color with white or gray, will confuse red, orange, yellow, yellow-green, and green when suitable brightness and saturations of these colors are used, and has reduced visibility in the red end of the spectrum.

Two decades ago the air force in the USA contracted out groups of psychologists and human factors professionals to specifically establish a set of operations that could be submitted to potential airplane fighters to measure and evaluate their capabilities for the mental and perception workload needed for the job. This set of ten or twelve operations measuring short term memory capacity, reaction times, computational abilities, attention span, and types of errors committed in each operation is the kind of hurdles that the study of human behavior have to surmount.

The operationism of a single human concept may be a life project for a group of scientists that require secure and continuing funding from concerned parties who have vested interests in thorough study of the concept.  It is obvious that limited human concepts will enjoy deeper and more complete investigations than others.

May be because the physical scientists did not face the problems of establishing sets of operations that the method of controlled experimentations was not deemed essential enough to rigorously teach in high school programs and ultimately failed to initiate the students to the experimental methods; until recently when social sciences made significant in roads into the educational programs.  This lack of early initiation of students to experimental methodology might also be the main reason why rational thinking and the experimental mind is not that widespread throughout all societies and are just confined to the privileged who could afford higher educations at select universities.

Whereas physical scientists rely on equipments to objectively observe and measure, the more the equipments are precise the more accurate are the data; scientists of human behavior have to rely on people’s responses and observations.  It has been proven that man is not a good observer of complex events; even when viewers are forewarned that they are to see a movie about a crime and that that are to answer questions about details later the accuracy of the observers are very low. 

Man is unable to be an objective recorder of the events that transpire because he gets involved in the scene actions.  Man has a very narrow range of attention and barely can satisfactorily attend to a couple of stimuli. This observation deficiency is compounded by our sensory differences and illusions; for example, one in sixteen is color blind, many suffer from tone deafness, taste blindness and so on.

Man does not think of himself objectively but rather has convictions, feelings, and explanations based on very restricted experiences, hearsays, memories and he tends to generalize and develop a set of beliefs concerning the operation of the mind.  Man usually expects to see and then see what he wants to see and hardly deviates from his beliefs and sometimes even when faced with facts.  For example, many scientists have overlooked obvious data because they clanged to their hypotheses and theories.  Man has to generate an abundance of reliable information and assimilate them before he could eliminate a few systematic biases that he acquired from previous generations and his personal experiences.  Consequently, experimenting with people is more complex and more difficult than the physical scientists or engineers have to cope with.

First, there are no design drawings for people’s mind and behavior as engineers are familiar with because the structure of human organisms is approximately delineated and the mechanisms are imperfectly understood.

Second, people vastly differ in anthropometric dimensions, cognitive abilities, sensory capabilities, motor abilities, personalities, and attitudes.  Thus, the challenge of variability is different from physics where phenomena behave in stable fashions, are countable, and can be controlled with minimal management. 

Third, people change with time; they change in dimensions, abilities and skills as well as from moment to moment attributable to boredom, fatigue, lapse of attention, interactions among people and with the environment.  People deficiencies in senses, physical abilities and cognitive capabilities changes with time and thus, the techniques of selecting subjects have to account for the differences in age, gender, specific deficiencies, training, educational levels, communication skills, and incentives to participate in an experiment.

Fourth, the world is constantly changing and systems used by people are changing accordingly.  Thus, interfaces for designing jobs, operations and environment have to be revisited frequently to account for new behavior and trends.

Fifth, everyone feels is an expert about human behavior on the basis of common sense acquired from life and specific experiences and we tend to generalize our feelings to all kinds of human behaviors but not so expert in the fundamentals of natural sciences such as physics or chemistry.  We think that we have convictions concerning the effects of sleep, dreams, age, and fatigue; we believe that we are rather good judges of people’s motives, we have explanations for people’s good memories and abilities, and we have strong positions on the relative influence of nature and nurture in shaping people’s behavior.  Consequently, the expertise of psychologists and human factors professionals are not viewed as based on science.

Six, physical scientists may enjoy the possibility of “testing to destruction” of prototypes or the materials under study, a luxury that experiments on people forbid or are impossible to do outside the safety range allowed by moral standards, laws, and regulations.  Research on people has to circumvent this major difficulty by using dummies, animals, or willing subjects thoroughly aware and educated to the dangers of the procedures.

Seventh, research on people is regulated by privacy laws and concepts such as consciousness, mental images, fatigue, and motives are highly personal experiences and not open to public inspection while science must be a public affair and repeatable by other researchers.

“Fundamentals of controlled experimentation methods” (Article 39, April 1st, 2006)

An experiment is designed to study the behavior of the values/responses of a dependent variable (for example data collected) as the values/stimuli of an independent variable/factor are changed, manipulated, or presented randomly or in fixed manner.

Besides the independent variables, there are other factors that need to be controlled because they could have serious effects on the behavior of the selected dependent variable, and if the researcher fails to hold these factors constant or fixed by appropriate techniques, procedures, instructions, experimental setting, and environmental conditions, the study will most likely have confounding results.

Controlled experimentation methods are versions of current simulations methods, but are essentially more structured and physically controlled.  In a nut shell, an experimental method is a series of controlled observations undertaken in an artificial situation with the deliberate manipulation of variables in order to answer specific hypotheses.

In general, a scientist plans, controls and describes all the circumstances surrounding his tests in a way they can be repeated by anyone else, a condition that offer dependability for validation.

The requisite of repeatability encourages artificial settings that can be controlled, especially because:

1. The participants/subjects in the experiment are not usually involved or engrossed in their tasks,

2. and it enables a scientist to try combinations of conditions that have not yet occurred.

Controlled experiments are time-consuming, expensive, and require a staff of skilled researchers and investigators so that they are conducted for basic research, publishing scientific papers, and when sponsored by deep pocket private companies and well-funded public institutions.

            There are different types of experiments, some are designed to extract cause and effects among the variables and, especially their interactions in the performance of a system, and others are not so well structured and are intended to explore a phenomenon at an initial phase in order to comprehend the subject matter…

Experiments varies in their design purposes and levels of control:  there are experiments on inanimate objects, natural phenomena that follow fixed trends and do not change much with time, and experiments using human subjects to select the better performing system or product, and experiments intended to study the cognitive concepts of people such as attitudes, mental abilities, problem solving aptitudes, attention span and the like.

The next article entitled “Controlled experimentation: natural sciences versus people’s behavior sciences” is intended to compare the complexity, differences, and levels of difficulties among the various experiments.

This article is striving to establish the fundamental processes or necessary structured steps to conducting a controlled experiment. In the spectrum of complexity, innovation and difficulty, the experiments in natural sciences are the easiest, and psychology experiments the hardest. Within the human-targeted research, fall experiments in the disciplines of agriculture, econometrics, education, social sciences, and marketing.

Early researchers in the phenomenon of electricity had to experiment with simple methods of one dependent and one independent variable, rudimentary equipments, and to rely on an exploratory knowledge of how electricity works and what are the factors that cause definite change in the behavior of certain criteria.

For example, scientists observed that there are relationships among voltage/power, the intensity of the current and the material the current is flowing through, then a scientist set up an experiment to study how the voltage changes when the intensity of the current varies or when the resistance of a material changes.  By conducting several experiments, first by working with a specific conducting material, thus fixing the resistance, and varying the intensity of the current and repeating this simple experiment many times and, second by fixing the current at a certain level and working with different kinds of conducting materials, then the scientist managed to observe a steady mathematical relationship among these three variables. As the body of knowledge in electricity expanded and more experiments were undertaken, the physical science of electricity discovered many more factors that entered into the mathematical relationship with varying degrees of importance and consequences.

            Obviously, physical scientists can now enjoy more powerful, time-saving, and effective experimental designs that can employ several independent variables and several dependent variables in the same experiment, thanks to the development in statistical/mathematical modeling and the number crunching computers.

These developments in controlled experimentations allow observations of the interactions among the various variables simultaneously, if physical scientists deign to apply them!

Controlled experimentation methods have a set of requisite structured steps that are common to both natural and social studies. Usually, an investigator has to review the research papers on the topic to be investigated, sort out the articles that are scientifically valid and experimentally sound, consider the variables that have been satisfactorily examined and those that were controlled, or not even considered…

Or the researcher may explore the topic by systematic observation of the problem, then he has to propose a hypothesis that could be rejected but never accepted no matter how often it was not rejected, then has to conceive a design for the experiment such as the types, numbers of variables, their levels, and how to manipulate the trials, then he has to decide on the best method for selecting the subjects, the materials, or products to be tested, the setting conditions, the procedures, the operations or tasks to be performed, the instructions, the equipments, the appropriate statistical model, then conducting the experiment, running the data, analyzing the results, interpreting the results, and finally providing guidelines or practical suggestions to be applied in engineering projects.

The motors of statistical packages used to analyze data are mathematical models or sets of algebraic equations with as many equations as unknown variables and relying on the two main statistical concepts of means and variances among data.

The purpose of controlled experimentation methods is to strictly control systematic errors due to biases and then to sort out the errors that are due to differences among the independent variables and those introduced randomly by human variability.  Once the size of random errors is accounted for then it is possible to study the relationships among the independent variables and to claim that a hypothesis could or could not be rejected at a criterion level of statistical significance, set frequently at 5%.  This criterion level of 5% of statistical significance means that there is still a 5% chance that an amount of random error might be the cause in the differences of the results.

Types of errors and mistakes committed in controlled experimentations will be reviewed in article #45.  However, it is important to differentiate between evaluation/testing methods and strictly controlled experimentation.

In human factors discipline, evaluation methods are applied to compare the effectiveness of several products or systems by measuring end-users behaviors, like/dislike, acceptance/rejection, or satisfying rules and regulations with the purpose that management would be able to decide on the choice among the products offered within specifications.

Controlled experimental methods are mainly applied to study the cause and effects of the main factors on objective measurements that represents valid behaviors of representative samples of end-users with the purpose of reaching design guidelines for products or systems planned for productions.

What is Human Factors in design? (Article #39, April 1st, 2006)

Fundamentals of controlled experimentation methods

An experiment is designed to study the behavior of the responses of subjects (dependent variables or what are measured as performance), as the values/stimuli of an independent variables or factors are changed, manipulated, or presented randomly or in fixed manner.

There are other factors that need to be controlled because they could have serious effects on the behavior of the selected dependent variables, and thus are held constant or fixed by appropriate techniques, procedures, instructions, experimental setting, and environmental conditions.

Controlled experimentation methods are versions of current simulations methods, but are essentially more structured and controlled.

In a nut shell, an experimental method is a series of controlled observations undertaken in an artificial situation with the deliberate manipulation of variables in order to answer specific hypotheses.

In general, a scientist plans, controls and describes all the circumstances surrounding his tests, in a way they can be repeated by anyone else, which offer dependability for validation.

The requisite of repeatability encourages artificial settings that can be controlled, especially because the participants/subjects in the experiment are not usually involved or engrossed in their tasks, and because it enables a scientist to try combinations of conditions that have not yet occurred.

Controlled experimentation are time-consuming, expensive, and require a staff of skilled researchers and investigators so that they are conducted for basic research, publishing scientific papers, and when sponsored by deep pockets private companies and well-funded public institutions.

There are different types of experiments, some are designed to extract cause and effects among the variables, and especially their interactions in the performance of a system.

Others experiments are not so well structured and are intended to explore a phenomenon at an initial phase.

Experiments varies in their design purposes and levels of control:  there are experiments on inanimate objects or natural phenomena that follow fixed trends and do not change much with time.

Experiments using human subjects in order to select the better performing system or product, and experiments intended to study the cognitive concepts of people such as attitudes, mental abilities, problem solving aptitudes, attention span and the like are very complex, very intricate,  highly time-consuming and expensive to conduct.

The next article entitled “Controlled experimentation: natural sciences versus people’s behavior sciences” is intended to compare the complexity, differences, and levels of difficulties among the various experiments.

This article is striving to establish the fundamental processes or necessary structured steps to conducting a controlled experiment.

In the spectrum of complexity, innovation, and difficulty the experiments in natural sciences are the easiest, and psychology the hardest; within that spectrum fall experiments in the disciplines of agriculture, econometrics, education, social sciences, and marketing.

Early researchers in the phenomenon of electricity had to experiment with simple methods of one dependent and one independent variable, rudimentary equipments, and to rely on an exploratory knowledge of how electricity works and what are the factors that cause definite change in the behavior of certain criteria.

For example, scientists observed that there are relationships among voltage/power, the intensity of the current and the material the current is flowing through, then a scientist set up an experiment to study how the voltage changes when the intensity of the current varies or when the resistance of a material varies.  By conducting several experiments, first by working with a specific conducting material, thus fixing the resistance, and varying the intensity of the current and repeating this simple experiment many times and, second by fixing the current at a certain level and working with different kinds of conducting materials, then the scientist managed to observe a steady mathematical relationship among these three variables.

As the body of knowledge in electricity expanded and more experiments were undertaken, the physical science of electricity discovered many more factors that entered into the mathematical relationship with varying degrees of importance and consequences.

Obviously, physical scientists can now enjoy more powerful, time-saving, and effective experimental designs that can employ several independent variables and several dependent variables in the same experiment thanks to the development in statistical/mathematical modeling and the number crunching computers; these developments in controlled experimentation allow observations of the interactions among the various variables simultaneously, if physical scientists deign to apply them!

Controlled experimentation methods have a set of requisite structured steps that are common to both natural and social studies. Usually, an investigator has to review the research papers on the topic to be investigated, sort out the articles that are scientifically valid and experimentally sound, consider the variables that have been satisfactorily examined and those that were controlled, or not even considered.   Or the scientist may explore the topic by systematic observation of the problem, then he has to propose a hypothesis that could be rejected, but never accepted no matter how often it was not rejected.  He has to conceive a design for the experiment such as the types, numbers of variables, their levels, and how to manipulate the trials, then he has to decide on the best method for selecting the subjects, the materials, or products to be tested, the setting conditions, the procedures, the operations or tasks to be performed, the instructions, the equipments, the appropriate statistical model.

Then the scientist has to conduct the experiment, running the data, analyzing the results, interpreting the results, and finally providing guidelines or practical suggestions to be applied in engineering projects.

The motors of statistical packages used to analyze data are mathematical models or sets of algebraic equations with as many equations as unknown variables and relying on the two main statistical concepts of means and variances among data.

The purpose of controlled experimentation methods is to strictly control systematic errors due to biases and then to sort out the errors that are due to differences among the independent variables and those introduced randomly by human variability.  Once the size of random errors is accounted for then it is possible to study the relationships among the independent variables and to claim that a hypothesis could or could not be rejected at a criterion level of statistical significance, set frequently at 5%.  This criterion level of 5% of statistical significance, means that there is still a 5% chance that an amount of random error might be the cause in the differences of the results.

Types of errors and mistakes committed in controlled experimentation will be reviewed in article #45.   However, it is important to differentiate between evaluation/testing methods and strictly controlled experimentation. In human factors discipline, evaluation methods are applied to compare the effectiveness of several products or systems by measuring end-users behaviors, like/dislike, acceptance/rejection, or satisfying rules and regulations with the purpose that management would be able to decide on the choice among the products offered within specifications.

Controlled experimental methods are mainly applied to study the cause and effects of the main factors on objective measurements that represents valid behaviors of representative samples of end-users with the purpose of reaching design guidelines for products or systems planned for productions.


adonis49

adonis49

adonis49

October 2020
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