Engineering psychology is the science of human behaviour and capability, affecting the design and operation of systems and technology. The field developed during the 20th century as complex technologies such as aviation and radio became common.
Engineering psychology is an interdisciplinary part of ergonomics and studies the relationships of people to machines, with the intent of improving such relationships. This may involve redesigning equipment, changing the way people use machines, or changing the location in which the work takes place. Often, the work of an engineering psychologist is described as making the relationship more “user-friendly.”
Engineering psychology is an applied field of psychology concerned with psychological factors in the design and use of equipment. Human factors is broader than engineering psychology, which is focused specifically on designing systems that accommodate the information-processing capabilities of the brain.
Related, but different topics
- Engineering psychology – This topic is about the science of human behaviour and capability in terms of how it affects design and operation of systems.
- Cognitive ergonomics & cognitive engineering – studies cognition in work settings, in order to optimize human well-being and system performance. It is a subset of the larger field of human factors and ergonomics.
- Applied psychology – The use of psychological principles to overcome problems in other domains. It has been argued that engineering psychology is separate from applied (cognitive) psychology because advances in cognitive psychology have infrequently informed engineering psychology research. Surprisingly, work in engineering psychology often seems to inform developments in cognitive psychology. For example, engineering psychology research has enabled cognitive psychologists to explain why GUIs seem easier to use than character-based computer interfaces (such as DOS).
Engineering Psychology, Ergonomics, & Human Factors
Although the comparability of these terms and many others have been a topic of debate, the differences of these fields can be seen in the applications of the respective fields.
Engineering psychology is concerned with the adaptation of the equipment and environment to people, based upon their psychological capacities and limitations with the objective of improving overall system performance, involving human and machine elements Engineering psychologists strive to match equipment requirements with the capabilities of human operators by changing the design of the equipment. An example of this matching was the redesign of the mailbags used by letter carriers. Engineering psychologists discovered that mailbag with a waist-support strap, and a double bag that requires the use of both shoulders, reduces muscle fatigue. Another example involves the cumulative trauma disorders grocery checkout workers suffered as the result of repetitive wrist movements using electronic scanners. Engineering psychologists found that the optimal checkout station design would allow for workers to easily use either hand to distribute the workload between both wrists.
The field of ergonomics is based on scientific studies of ordinary people in work situations and is applied to the design of processes and machines, to the layout of work places, to methods of work, and to the control of the physical environment, in order to achieve greater efficiency of both men and machines An example of an ergonomics study is the evaluation of the effects of screwdriver handle shape, surface material and workpiece orientation on torque performance, finger force distribution and muscle activity in a maximum screwdriving torque task. Another example of an ergonomics study is the effects of shoe traction and obstacle height on friction. Similarly, many topics in ergonomics deal with the actual science of matching man to equipment and encompasses narrower fields such as Engineering Psychology.
At one point in time, the term human factors was used in place of ergonomics in Europe. Human factors involve interdisciplinary scientific research and studies to seek to realize greater recognition and understanding of the worker’s characteristics, needs, abilities, and limitations when the procedures and products of technology are being designed. This field utilizes knowledge from several fields such as mechanical engineering, psychology, and industrial engineering to design instruments.
Although the work in the respective fields differ, there are some similarties between these. These fields share the same objectives which are to optimize the effectiveness and efficiency with which human activities are conducted as well as to improve the general quality of life through increased safety, reduced fatigue and stress, increased comfort, and satisfaction.
Pioneers
Lillian Gilbreth combined the talents of an engineer, psychologist and mother of twelve. Her appreciation of human factors made her successful in the implementation of time and motion studies and scientific management. She went on to pioneer ergonomics in the kitchen, inventing the pedal bin, for example.
In Britain, the two world wars generated much formal study of human factors which affected the efficiency of munitions output and warfare. In WWI, the Health of Munitions Workers Committee was created in 1915. This made recommendations based upon studies of the effects of overwork on efficiency which resulted in policies of providing breaks and limiting hours of work, including avoidance of work on Sunday. The Industrial Fatigue Research Board was created in 1918 to take this work forward. In WW2, researchers at Cambridge University such as Frederic Bartlett and Kenneth Craik started work on the operation of equipment in 1939 and this resulted in the creation of the Unit for Research in Applied Psychology in 1944.
History
Engineering psychology was created from within experimental psychology. Engineering psychology started during World War II (1940). The reason why this subject was developed during this time was because many of America’s weapons were failing; from bombs not falling in the right place to weapons attacking normal marine life. The fault was traced back to human errors. One of the first designs to be built to restrain human error was the use of psychoacoustics by S.S. Stevens. S.S. Stevens and L.L. Beranek were two of the first American psychologists called upon to help change how people and machinery worked together. One of their first assignments was to try and reduce noise levels in military aircrafts. The work was directed at improving intelligibility of military communication systems and appeared to have been very successful. However it was not until after August 1945 that you saw the level of research increase in engineering psychology. This occurred because the research that started in 1940 now began to show.
Reducing the Human role
There are many ways engineering psychology have influenced our workplace and more so our everyday lives. What most people do not know is that engineering psychology is reducing the need for humans more and more. Mass transit and airplanes such as Boeing 77 are ran by computers. Such technology are incapable of being overrode if needed to. Workers’ skills are now diminishing because they are not using them as they used to or as often as skills should be used. If computers fail and workers are not able to override them, there is a significant exposure to threat.
Cognitive walkthrough
The cognitive walkthrough method is a usability inspection method used to identify usability issues in a piece of software or web site, focusing on how easy it is for new users to accomplish tasks with the system. Whereas cognitive walkthrough is task-specific, heuristic evaluation takes a holistic view to catch problems not caught by this and other usability inspection methods. The method is rooted in the notion that users typically prefer to learn a system by using it to accomplish tasks, rather than, for example, studying a manual. The method is prized for its ability to generate results quickly with low cost, especially when compared to usability testing, as well as the ability to apply the method early in the design phases, before coding has even begun.
Introduction
A cognitive walkthrough starts with a task analysis that specifies the sequence of steps or actions required by a user to accomplish a task, and the system responses to those actions. The designers and developers of the software then walkthrough the steps as a group, asking themselves a set of questions at each step. Data is gathered during the walkthrough, and afterwards a report of potential issues is compiled. Finally the software is redesigned to address the issues identified.
The effectiveness of methods such as cognitive walkthroughs is hard to measure in applied settings, as there is very limited opportunity for controlled experiments while developing software. Typically measurements involve comparing the number of usability problems found by applying different methods. However, Gray and Salzman called into question the validity of those studies in their dramatic 1998 paper “Damaged Merchandise”, demonstrating how very difficult it is to measure the effectiveness of usability inspection methods. However, the consensus in the usability community is that the cognitive walkthrough method works well in a variety of settings and applications.
Walking through the tasks
After the task analysis has been made the participants perform the walkthrough by asking themselves a set of questions for each subtask. Typically four questions are asked:
- Will the user try to achieve the effect that the subtask has? Does the user understand that this subtask is needed to reach the user’s goal?
- Will the user notice that the correct action is available? E.g. is the button visible?
- Will the user understand that the wanted subtask can be achieved by the action? E.g. the right button is visible but the user does not understand the text and will therefore not click on it.
- Does the user get feedback? Will the user know that they have done the right thing after performing the action?
By answering the questions for each subtask usability problems will be noticed.
Common Mistakes
In teaching people to use the walkthrough method, Lewis & Rieman have found that there are two common misunderstandings :
- The evaluator doesn’t know how to perform the task themself, so they stumble through the interface trying to discover the correct sequence of actions — and then they evaluate the stumbling process. (The user should identify and perform the optimal action sequence.)
- The walkthrough does not test real users on the system. The walkthrough will often identify many more problems than you would find with a single, unique user in a single test session.
History
The method was developed in the early nineties by Wharton, et al., and reached a large usability audience when it was published as a chapter in Jakob Nielsen’s seminal book on usability, “Usability Inspection Methods.” The Wharton, et al. method required asking four questions at each step, along with extensive documentation of the analysis. In 2000 there was a resurgence in interest in the method in response to a CHI paper by Spencer who described modifications to the method to make it effective in a real software development setting. Spencer’s streamlined method required asking only two questions at each step, and involved creating less documentation. Spencer’s paper followed the example set by Rowley, et al. who described the modifications to the method that they made based on their experience applying the methods in their 1992 CHI paper “The Cognitive Jogthrough”.