AbstractHuman-Computer interaction (HCI) is the discipline regarding the design of computer related technology and the interaction between humans and computers. It is a new field of study, starting only in the 1970’s as the need of personal computers emerged. Nowadays it is of great significance to learn about HCI especially for computer engineering students, which is reason why I wrote this report.As a basis of the study of HCI, we must first introduce the basics of how humans and computers function individually. Both computers and humans have similarly functioning components, such as input channels, output channels, memory and processing unit. The main difference is the relativity and emotional side, which computers do not have. Design is the main approach experts use in order to achieve optimal interaction between humans and computers, as there are some general rules and guidelines to be followed; such as flexibility and consistency for the purpose of increasing usability for users. Also mentioned is the relation to other fields of study such as human factors and cognitive science.I. Introduction Human-Computer Interaction is the area of study concerning the communication between humans and computers. The main focus is design of products or programs for the comfort and ease-of-use for all people.The field of human-computer interaction (HCI) only started in the late 70s to early 80s, as it was the start for ordinary people other than professionals and scientists to use computers. For this reason, the use of personal computers had to be simplified for the pleasure of users of all backgrounds, as it was quite complicated. HCI is a derivation of the topic human-machine interaction which has a richer history. The initiation of the general idea was the Second World War, as there was a need for the study of the ergonomics of machines and weapons. User performance had to be optimized to make best use of current technology. Human factor had to be taken into consideration, whether these where physical or cognitive.This research is aimed at students in the engineering and design departments especially ones interested in computer, design and human factor. It is an introduction to this field, promoting the importance of ergonomics and user interface. Because HCI is a multi-disciplinary territory, my research therefore presents information in many other fields not only in the engineering field but also in cognitive science and psychology.Writing and discussing human-computer interaction rises the overall concern about design in relation with computer engineering and science. It is extremely important for ordinary students to expand their knowledge in addition to their knowhow beyond what they learn as mandatory subjects and classes in the field they are studying at schools and universities as interdisciplinary subjects are the future. II. Fundamentals With the aim of explaining the interaction between humans and computers, one must learn about how each operate separately in different aspects as well as how the interaction started and how it developed throughout the years.A. Human vs. Computer Computers and humans are quite similar in the way they operate. Computer experts and designers try to imitate basic procedures that happen in the human body in creating computers. This requires the need of using sensors and other input methods in place of human senses. Also important to mention are that there are differences and additional properties that exist between them.1. Input and Output The interaction of human beings with the world around them occurs through incoming and outgoing information. The terms output and input are relative in the interaction of humans with computers but usually, one corresponds to the other. For instance, hands or fingers could be an input to a touch screen, while they are output for the person wanting to interact with the screen. Similarly is the voice; it is used for humans to communicate as an output method while the computer receives the voice command as an input. Looking closely at the interaction that occurs from the computer, design or what the user sees on screen in general is an input method to the human eye and eventually the brain -both extremely complex organs- which affects the perception of information. This is why design a key factor in the implementation of Human Computer Interaction (HCI), which will be discussed later on in the report.2. Memory The memory process in humans is mainly divided into two parts; the short term memory and the long term memory. The first is used in temporarily needed information. Such information could be accessed rapidly however it would also be lost fairly quickly which is why it is only efficient in a short period of time. The second has the purpose of storing data for longer periods of time. Basic characteristics of this type include the enormous capacity, slower access rate and slower forgetting time. Both memory types can be enhanced and diminished by practice of lack of it. As per mimicry in the technological field, computers also have similar types of memory. The RAM has a fast access rate while having a rather small capacity, while discs and drives have a variably large capacity with slower access rate. The greatest difference between memory and storage types in both humans and computers is the psychological aspect to it. To explain further, the state of mind and emotion of human beings usually plays a role in what we keep and what we forget.3. Psychology Although it is hard to imagine what it would be like if computers experience emotions just as humans do, it is quite likely that we would be hearing about that in the near future. By the development of affective computing, scientists are trying to create an emotional computer. This does not change the fact that humans are emotionally driven beings, while machines generally only follow commands and orders from users. Psychology greatly influences humans’ lives on a daily basis, it could even affect the way a person may receive and process information. For instance, if a group of people experience a certain incident, each of them would perceive it differently and also interpret it differently based on their feelings, opinions and previous knowledge and other relative factors. This is why the neutrality of computers is a significant advantage and is the reason computers are preferred in many scientific or mathematical calculations. In other words, no matter what is going through a computer if a user gives it certain input and processing formula, it will solve it fully objectively and without any outside factors leading to coherent results.A. The History of Human Computer Interaction In spite of the fact that the field of Human computer interaction is relatively new, it has been developing rapidly in the past 30 years. At first it was founded as a branch out of a more general field but it reached a point where it consists of many other research fields. Creating this direction of research was the step required for the further development not only in informatics and computer related fields but also in cognitive sciences.1. Start of the Interaction HCI is basically derived from previously developed fields such as cognitive science and human factors engineering, which both will be discussed later on in the report. The importance of making personal computers available to the public, especially those with barely any background in the field, forced the study of HCI as a necessity. Just like how engineers discovered the significance of designing weapons in the world war II suitable to their body, comfort, preferences, and needs, computer scientists also made notice of such factors when developing computers to be sold commercially rather than for educational purposes only. In the beginning, scientists’ main concern were the physical features of machines and their influence on users’ performances. This mainly included the mechanical side of the design rather than the informatics behind it. Research in that field affected the development of Information Technology greatly, as it later became a huge influencing factor in creating a successful software.2. Development Up Until Today HCI has become a very broad field of research with so many subtopics deriving from it making it a multi-disciplinary topic. It generally optimizes the use of computers in different fields. Using knowledge of the amplitude of human beings’ mental, interpretational and problem-solving skills, experts can now manipulate their perception of graphical user interface for maximum efficiency and ease of use. This requires a wide range of experts ranging from psychologists and sociologist to computer scientists and engineers (Carroll, 2013).Norman’s model of interaction is one of the most significant models to date concerning the interaction of humans and machines, since it is nearest to the human-being’s common understanding. It mainly consists of a cycle of collaborations between the user and the computer, in which the user gives certain orders or tasks then awaits the processing period of the computer then sees the result the computer presents in order to assess further tasks. This cycle may also be called the execution-evaluation cycle due to the obvious partition of phases. A bad mapping example according to Norman is the activity of switching the lights of larger halls. One is usually baffled by the number of switches in the same panel however a person with no prior experience has to learn through trial and error which switch belongs to which light. This could be fixed by a number of ways such as dividing panels according to room or type of light, icons and color coding may be useful as well. II. Design Design is the leading method in the process of how scientists could control the interaction between humans and computers. It is used by experts to optimize usage as well as decrease the gap in the understanding between computers and human.A. The Golden Rule of Design In order to create good designs, one should understand both computers and humans, for computer one must comprehend limitations, capacities and technological advances while for humans one should learn about the psychological side and studying human error.B. The Process of Design The design process is divided into stages, as shown in the figure below. The first one is determining what is already present and what is additionally required to begin the design, from that it is the analysis stage, in which evaluation of different tasks. The third stage is the actual design procedure, according to guidelines and rules, scientist would model different design in connection with given limitations. The following stage is prototyping, which includes trying designs out in order to find out what to modify and alter. The last two stages may be repeated multiple times according to need until the both the client and designer are both satisfied with, just then progress to implementation of the design is scheduled.A. Guidelines and Rules There are certain rules that must be followed in order to reach maximum precision with least amounts of alterations. Rules like mentioned should have few characteristics to enable usability, for instance the ease of usage as soon as a new user gets to interact with the designed software and how quickly he would be able to master all functions. Another property is the flexibility of the structure and how broad in ways it could be. The last quality is the degree of help the user would be able to get in order to finish particular tasks. It is very important to keep the design consistent throughout the whole project, this helps the user familiarize and group functions to thoroughgoing efficiency. The ability to customize according to users’ preference and needs is major in designing flexible software that serve general users with different needs. An additional principle vital to design is prohibiting users from entering incorrect data into any process which prevents problems afterwards as well as allowing users from withdrawing actions that might have been done by mistake, which saves a lot of time and effort.II. Relation to other FieldsAs previously mentioned, human computer interaction is derived from other fairly wide fields, such as human factors engineering and cognitive science. Both disciplines are not entirely related to computer design created this field. A. Human Factors According to techtarget.com “human factors (also known as ergonomics) is the study of how humans behave physically and psychologically in relation to particular environments, products or services” (Rouse, 2005). This study contributes to HCI by setting constraints on the design of computer interfaces, while also demonstrating certain standards. Such standards apply mostly on the hardware of computers rather than the graphical interface. Hardware design includes arrangements of buttons and other controls based on physical features, position and state of users. There are three different ways controls and displays are usually grouped together; functional, where they are grouped together based on function, sequential, where they are organized based on the sequence one uses them in, and lastly frequency, where they are arranged based on the recurrence of usage. Such organization and design methods require studying the targeted users for any equipment designed according to their jobs, education and also position. Aviation equipment, for example, have a lot of buttons and complicated display that require special education and practice. What also has be taken into regard is the health aspect, which includes the guidelines concerning time spent using screens, physical positioning and comfort as well as noise levels. All above mentioned rules serve as basis for the study of Human-Computer interaction.B. Cognitive Science There has been a debate dealing with the definition of cognitive science as it includes many subtopics, but generally speaking, it is science of the mind, which could either be defined as the brain, a “representational system responsible for behavior, language and thoughts”, as Ronald L. Boring mentioned in his paper, “or the central processing system”(Boring, 2002). Cognitive science could explain many mental phenomena, which the study of human computer interaction needs. Both fields have common origin being human factors, which began in World War II, when scientists were forced to study how the mind of the enemy works as well as designing war equipment according to soldiers’ body and comfort. The reason why human computer interaction needs cognitive science mainly to understand the user, which is the most important factor in HCI. In addition to computer scientists, cognitivist take up a huge sum of experts in HCI. They use processing paradigms from cognitive science such as the model human processor and GOMS (Goals, Operations, Methods, and Selection rules) model, which provide a flowchart of processes in HCI. All in all, cognitive science represents the mental side behind the study of human computer interaction, basically it always answers the question “why” for every process or design change. For instance, changing colors of certain software proving the effect of perception of certain colors on the display, is a use of cognitive science in HCI (Boring, 2002).II. Conclusion The study of human computer interaction starts with learning how humans and computers operate individually. Both computers and humans have input and output channels; for computers these are sensors, keyboard and display screen while for humans these are represented in the human senses and gestures. The storage and memory are also similar as humans have their brains as storage space with long term memory and short term memory, which computers also have as RAM and hard drives. Concerning the third topic in comparing how humans and computer perform, psychology, in humans, this plays a big role in processing information based on previous experience and emotion. On the contrary are computers, which usually follow commands blindly without contributing in any way.Human-computer interaction has only been a research field since the late 1970’s, which is regarded as a relatively new study. It started when experts started producing personal computers to the public rather than to professionals and skilled individuals. It wasn’t about getting the job done anymore but getting it done efficiently with maximum comfort of users. This includes the size and design, at first scientists were concerned with only hardware, but later on the study included software and programs. Not only did human-computer interaction drastically develop itself, but it has even reached a point where other subfields have merged. Now HCI is used as the manipulation of a user’s perception of colors and design.Design in HCI is not limited by creating software or hardware, but also includes the interaction between users and the software. Its main goal is improving different features of performance in many fields. In order for anyone to create good design, one must understand the human and his restraints (based on cognitive sciences) and the capability of technology of computers to achieve this design. Good design does not depend solely on learning from the study of human computer interaction and implementing its strict rules and guidelines but also depends on good skill of graphical design.Human computer interaction is a daughter topic of human factors engineering, which relates to design of machines based on physical and psychological traits of targeted users. HCI is also a subtopic of the study of cognitive sciences, which is concerned with the human brain and perception of different stimuli.All in all, human computer interaction is of great importance nowadays in the computer engineering and science fields due to growing demands of computer development. It plays a huge role behind the scenes and is one of the main reasons behind the success of computers and their software.