The application of cogntive psychology to User-Interface Design

B.A. Critical and contectual dissertation written in 2011 originally posted at

Do we see our thoughts? A great paradox in plain words, but an inevitable juxtaposition between everyday stimuli and the human thought process. Can a repetitive pattern in our habitualism be the study of much greater things in order to make our lives easier making information more accessible, faster and more accurately. Humans try to analyse and understand how everyday things work often without even noticing the thought process that goes into it, since it has become an extension of their lives. Does this criteria mean that we do respond in similar ways when faced with everyday conundrums? Will our mannerism, reactions, thought process be mostly identical? Can these results be appreciated and applied within modern interactive design by revealing the reasoning behind it. The aim of this study focuses on this exact human brain process while the subject is being stimulated with interaction activities, more specifically through the notion of interface which has become a necessity in modern society.

The discipline that carries out this above course of events is interface design which is a subdivision of interactive design and its main purpose is the demystification of complicated computer systems for human use. It is used vastly in our everyday lives and has to perfect in the fields of accessibility and time consumption. Thus it is very important to see how this is achievable. What is it taken under consideration in the event of designing for the modern user. Are there other science fields that need to be introduced and taken into account? The subdiscipline of psychology which examines people’s analysis and comprehension of our world is cognitive psychology that comes in effect with the field of interface design. In order to investigate deeper into the connection of cognitive psychology and interface design i am going to present a number of scientific papers that have been written on the application of cognitive psychology on interface design. More specifically the reader is going to presented with an extensive selection of references from the human perception study and their outcomes that have turned into rules. These rules have an immediate connection to cognitive psychology and how the human brain acts subconsciously. For instance is it easier to remember the word “circle” or its shape? Micro details that have a large impact on the evolution of human-computer interaction.

The prominent research subject matter of the above reference is going to be Apple’s iPhone, a ground breaking technological achievement, not only based on its immense commercial success, but on the fact that it has turned the field of smartphone development to a new direction. Furthermore it was the first device which brought touch interface into successful massive consumption. Behind this undoubtedly booming smartphone’s success was its software, because the appliance itself is basically just a 3.5” screen. A few of its revolutionary characteristics were the introduction to a multitouch input, the fact that it is finger based and does not need the support of a stylus or any other external device, but the most crucial feature is its interface. An interface that is comprehensive, humane and fills the user with an immense confidence and familiarity towards its usage by the first touch. In other words the user does not need a significant “know how” in order to operate it. Progressing further into this thesis it would be very interesting to see how the research that is mentioned above (about the application of cognitive psychology on interface design) will help us to understand the distinguished interface design of the iPhone. Using these paradigms certain questions will rise, most of them concerning the ability of using cognitive psychology in the evolution of interface design.

Evidently, technology has progressed by interacting with other disciplines so as to focus on the desires and needs of the modern consumer. Technological marketing research is dependable on scientific facts thinking ahead and researching further into the way mankind is thinking and reacting on a psychological, neurological and even anatomical way. It does not see people as a cohesive mass, although it would be safe to say that we do respond in similar ways and that is based and justified by medical points, they way our bodies and brain are constructed and how they tend to react to external factors. By presenting the papers and extracts from a selected bibliography on the connection between interface design and cognitive psychology, we will be able to extend the idea of how can they work together for the most prosperous results, as well as the better revelation of how the most unnoticeable features in interface design are actually great stepping stones in the understanding of the human brain. By drawing parallel lines with the most profitable product of this decade we are going to see weather there is a logical sequence to the above statements and connotations.


It is essential for the flow of the thesis to refer to the essence of cognitive psychology and its fundamental laws and discoveries.

Cognitive psychology is a subdiscipline of psychology exploring internal mental processes. It is the study of how people perceive, remember, think, speak, and solve problems.[1] It is quite complicated to pin down the attributes that compile the mere substance of this discipline. It might be fuzzy for someone to grasp the notion of how can our reactions be studied in order to approach the human brain. Cognitive psychology has researched the way people take in everyday information, process it and form their reactions depended on the external stimuli. Thus it has a very predictive formula by exploring and scrutinising the effect the outside world has on people. It does not just audit the human sentimental subconscious but also the basic human anatomical structure since our main receptors are organs and they vitally trigger specific points to the human brain. It would be quite indefinite to refer to it as just psychology, since it does not just study the human soul (by Greek definition) but more importantly the brain, always based on scientific medical facts.

Cognitive psychology is mapped by four different paths. The first one is experimental cognitive psychology which caucuses on the investigation of how people perceive the outside world. How do they develop their mental abilities not just on an intellectual level but in a more everyday habitual sense contemplating memory, reactions and behaviour.

The second path is computer modeling which involves the development of computer softwares with the prospect to approach the way the human brain works in a mimetic manner. Third one is cognitive neuroscience, its foundations stem from the depicting of the brain through MRI scans while a human is subjected to various stimuli. Therefore, understanding how the brain works through a neurological point of view. Finally there is cognitive neuropsychology which uses the method of examining affected human brains from injuries so as to discover which parts of the brain are not working and induce those abnormal effects, such as speech impairment, memory loss etc.

There have been impressive theories in the progress of cognitive psychology such as “top-down” and “bottom-up” brain processing, as well as the difference between automatic and controlled processing. They are an aspiring model in this discipline, although still the subconscious remains a mystery for most scientists and cannot be pinned down to medical formulas just yet.


In the following section, selected pieces of various researches based on the application of cognitive psychology on interface design will be presented and discussed further. These researches have been chosen over a selection of books, scientific papers and journals mainly based in my opinion on their content and how closely it approached their usage in interface design. The core of the presentation is broken to 3 main theme parts: learning, attention and perception.



This is a phrase that has been used by Donald A. Norman in the Book Design of Everyday Things. His assumption was based on the experiment carried out by Nickerson & Adams with the “One Cent Coin”. In the experiment, students were presented with 15 different drawings of the one cent coin. Only less than half of the group would eventually recognize the correct one. Therefore this helps us understand that people tend not to memorise the exact facts of things but only some generic elements that will later remind them of the subject. The use of a flexible mapping (mapping is a technical term meaning the relationship between two things [2] is quite crucial in order to remind the GUI (Graphical User Interface) the functionality of each controller.

Research shows that time was shorter with symbolic coding than with alphanumerical coding when less than 49 objects are involved.[3.1] People can learn more easily shapes or images thus the use of logotypes or icons in GUI is memorised more easily than words or numbers. This theory works only if the number of objects is no more than 49.


The idea of the abstract theory has stated that human reason using a set of abstract, logic rules that can be applied to any domain of knowledge.[4] An example they were using was the idea of sequencing which implies that an event leads to the occurrence of a second event. The basic idea behind this, is that a GUI which its architecture has certain rules of how things work help the user to predict what to expect through his/hers navigation of the software.


Transference refers to the expectation of a user in an interface behavior based on his/her previous experiences with other interfaces.[4] The previous knowledge that a user has based on the experience he had from software interaction is going to be used in the new software, so the user is going to expect that the new software will interact in the same way. Therefore there is a chain of events which leads up to the familiarity of the user with a sequence of events and allows him to augment this experience every time he is faced with a new reference.


Humans feel difficulty in getting one motor system to do two things at once. For humans it is difficult to do more than one task.[4] Consequently the user cannot be put in a position of carrying out more than one tasks at the same time, because the brain cannot process a multi tasking proposition. Although humans are aware of multiple things taking place around him simultaneously, the brain cannot order the body to cope with so much information.


Short term memory has a limited capacity to hold and process information. Based on different experiments this capacity is general found to be 7+- 2 items or chunks of information.[4]

The process of learning is a very complex procedure and the user cannot be bombarded with tons of new data because of the low capacity in his/hers short term memory capacity, In order to have a successful and extendable learning experience the intake should be limited to 7 +- 2 items at a time for the perpetual intake.


One of the most common laws in grabbing the attention of the user and evaluating the data given is that important information is usually bigger and brighter and less important information is smaller and dimmer. That way the user can archive that information depending on its significance.


People tend to approach information from left to right and from top to the bottom[3].This theory is merely applied in the Western world and is connected to the the early stages of someone’s life where they learn how to read and comprehend the majority of their text-based content. As Gabriels Aberg, Jessica Chang point out that this cultural phenomenon is taken into consideration by the publishing and advertising industry when arranging lay-outs thus to create eye catching media.


This theory asserts that because the cones in our retina which identifies the colour blue are on the outer edges of the eye, blue is a good colour to use to our attention.[3.2]Other colours that have a significance in communication in modern cultures, are red — a colour which transmits a major warning — and green which promotes a more safe notion. The operation procedure is not affected by this juxtaposition but it is summarised in a more personal preference.

When we are trying to grab the user’s attention on some particular part of the GUI the sole color which can be the most effective is blue. On the other hand if we want to send a message of warning e.g. a delete file operation red would be a more applicable color to be used. This is something that has nothing to do with how our brain perceives the colour red but it has to do with how the colour of red has evolved in modern society and how we use it.


According to simon effect people respond faster and more accurate to stimuli that occur in the same relative location as the response, even if the location of information is irrelevant to the actual task. This is because there is an innate tendency in humans to respond towards the source of stimulus.[4] When the GUI user is requested to perform a task pointed at one direction, and its solution is also pointed towards this direction the user has a much better appreciation of where to find the answer since it is exactly where he would expect it.


Schneider and Shiffrin (1977) made a distinction between controlled cognitive processes, which are carried out consciously and intentionally, and automatic cognitive processes, which are not under conscious control.[5] One of the most significant examples that was used to describe this process could be seen in image[1] which shows us that it is impossible for the human not to read the message although this is what the message instructs. In the GUI the usage of this specific theory can provide us with the way with we can force the user to read a selected message and grab his attention towards it.



Rule of proximity indicates that items close together are perceived as being related or associated[4].. Owing to the fact that human perception works instantly and processes information on an eye-brain performance as a whole. The part of decomposing the elements is introduced later in the equation. Looking at the “big picture” influences humans to compose connections.


Rule of similarity indicates that items with a similarity are perceived as being related or associated[4]. Based on that simple theory we can easily create groups of things in our GUI which will be identified as a unified group by the user. As a result, the data will be archived simultaneously and decoded faster.


The best way to describe it is based on the contextual effect which is the aspect of cognitive psychology that describes the influence of environmental factors on one’s perception of a stimulus. The concept is supported by the theoretical approach to perception known as constructive perception.[6] People form their perceptions accordingly to the data given and learn how to formate conclusions indicating that the full context is more immediate because of the adaptation and recognition of its single parts.

Consequently the user applies any past knowledge that has been concocted in the view of perceiving the any images, shape or color synthesis presented by the GUI. The user of course is able to decompose and recompose, but this is done in a more consuming time frame, rather that the immediate process of recognizing the whole.

Taking into consideration the above data, the most appropriate way to examine their use, would be to have a specimen in order to conclude whether these theories are put into practice in interface design.


There has already been a reference to the iPhone in the introduction, being the object of investigation in the adaptation of interface design. Therefore there is going to be a full comparison of the theories mentioned and accordingly utilised by the construction of this smartphone.

By the quote “the knowledge in the world and the knowledge in the head” the comparison between theory and practice is going to start formulating. The greatest revolutionary achievement of the iPhone, as mentioned in its first presentation at the Macworld keynote in 2007 by Steve Jobs was the abolishing of the keyboard and the application of a pointing device, our fingers, with the use of multitouch technology. This gave the opportunity to actually create an appropriate mapping system, thus using different buttons in unique places for each one of the applications. By retrieving the cognitive psychology references it is obvious that having different buttons for each application the user is reminded perpetually how to use the software. As a result, he does not learn “by heart” the utility of the application but holds the apprenticeship with the mobile phone, it being a constant reminder of its usage. Evidently the user learns how to operate it more easily and efficiently in a long term time frame. Since every button can be in any specific area we have the ability to create a natural mappings as mention by Donald A. Norman in his book “Design of Everyday Things”. By all means, this is not the first time this efficiency has taken place, it has occurred before in the desktop graphic interface in personal computers. The advantages of such a design is not only influencing the commodity in usability, but also the creation of various software applications e.t.c.. Finally its smoothness in operation can be explained scientifically by the experiment mentioned above regarding the “one cent coin”.

Further onwards there is going to be an in-depth reference to the rules of proximity and isolation in regards to the iPhone. The core of the UI in the iOS software is the index page in which the applications are set. In addition the iOs is embraced by other aspects such as the qwerty virtual keyboard, the search agent or the basic applications for the iOS, but its fundamental structure is the main applications page, as mentioned above. By the first sight there is a comprehensive adaptation of the rules of proximity and similarity, in the separation of the two groups of applications. This may seem like an easy construction at first glance, but in everyday use this optical segregation influences the user to open the favorite applications much faster and created a plasmatic categorisation in his memory system.

The iOS UI has obviously been influenced by the research that has stated the 49 object remembrance system. Thus this is self explanatory, through the evolution of the iOS UI through the years. Firstly one can gather that through the thorough usage of icons which have self evolved as the application logos. This might be the clear solution to the above conundrum but it is understandable that the UI designers had this research in their minds since they introduced the “folders” when the number of application started to surpass the 49 items limit (the folders in the iOS are spaces where the user can place homogeneous applications according to his likeness). The research is evident in the presentation of these folders. In all other UIs the folder has the icon of a plain box which contains similar data. In the iOS these folders are seen as icons since they reveal to the user their contents, so as to become more memorable. As a result the user can identify easily the usage and the placement of each application.

The “Simon Effect” is in accordance to the iOS in the following paradigms. Firstly before pressing the selected application the icon goes darker in order to outline the brain stimulus. This brain stimulus refers to the fact that the user is accustomed to find the information that he has requested on the same spot where the acquirement took place.

This has been also used on the iOS in some level with the animation of the opening applications. It has not fulfilled the exact theory since the animation always occurs in the middle of the screen, whereas the exact following would be to begin in the exact position of the application button. Other aspects of the theory include the fullscreen aspect of all applications which is obvious in a 3,5” screen. The theory is predominant though in the iPad which continues to have the same full screen effect in a larger screen.

The fullscreen capability does not just use the theory of the “Simon Effect”. The main influence comes from the Limitation of Motor System theory, which underlines the fact that a user when operating a motor system cannot carry out two or more tasks simultaneously. That comes in practice with the fullscreen aspect that forces the user to function one application at a time. Even when the multitasking process was introduced to the iOS (multitasking in technological terms means that a device can operate 2 ore more applications at the same time) still the user was seeing a single application in fullscreen mode. When switching was needed the UI provided a screen with the operating application in order to change. All these decisions were taken considering the fact that humans cannot operate more than one applications at a time. Following this path the navigation was facilitated to an extended level.

At this point it would be efficient to describe the relativity between the cognitive psychology theories and a part of the core applications of the iPhone. Firstly the theory of Transference is applied in most core applications. This theory implies that any previous experience the user has obtained from software interaction will be a guide to any new software because of the habitual learning process. This theory was used literally in the UI of the iOS and this can be noticed in the application design. More specifically the applications that pre-existed in the personal computer, were transferred — on their usability level — in the iOS in the same way minus the adjustments that needed to take place, taking into consideration the smaller sized screen and the fact that the pointing device which substituted the mouse was now the user’s finger. For instance this is applied in the mail, the browser and widget applications. In contradiction, the applications that did not pre-exist in the personal computers, such as the notes and the iBook applications were designed according to a virtual resemblance to what they signified, i.e. the iBook application used a shelved bookcase and the notes application used a notepad page with a handwriting font.

The abstract theory was used in the resemblance of all the core iOS applications. Each core application of the iPhone has a similar navigational system. More specifically the bar on top with a centered title a constant reminder of what the user is operating, the breadcrumb button which is even used on applications such as notes or iBooks.

The applications have various other similarities, more than the ones mentioned above, one thing is for sure, once operated one can understand that there is a fixed architecture in their usability. When the core application needs to provide a significance and attract the user’s attention, it uses the colour blue i.e. in the upper bar mentioned in the previous paragraph. Herby this is down to the Blue Peripheral Vision theory. One could misinterpret that as an aesthetic decision but it can be proven that there has been an assembly of thoughts based on that theory when we view the photos application. As the theory states, when there is a large image the colour blue stops attracting the attention. That is why the colour blue was not used in this application but black tones in order to differentiate it and not to subtract any attention from the image. So one can conclude that this theory was used in the iOS design. Parallell to this theory the shading and toning of blue was carefully selected for a comprehensive categorisation of the data exposed. By noticing the colour palettes that were used even further in the iOS UI, red — a colour traditionally and culturally assigned to danger and prohibition — was used to signify the in-acceptance of a phone call whereas green — a color that provides clearance and permission — was used to accept calls or to signify success in sending an sms.

The left to right theory was used in the top bar of the index page in order to assemble information according to its importance. For instance on the left hand side one can see the signal strength which is one of the most important things on the phone. Looking deeper, analyzing one the core applications such as mail, the top left side is used for the back button and finishes on the right-hand side with the new message function. It is totally logical since once you have finished reading the mail, one would start a new message, or go back to the mail inbox page.

Finally, the utilization of the Notification System in the iOS seems to either obey or ignore the automatic process theory. Surely the way it operates it attracts the attention of the user and makes him read the proposed message. And as it is mentioned above, humans can only single task according to the Limitation of Motor System theory, so the user has his complete attention span on the message. The critiques for the Notification System of the iOS have been mainly on the negative side, but only one thing is for sure, the user will eventually be forced to read the message.


The theories of cognitive psychology mentioned above, have not just been applied to the iPhone’s interface design, but have also been used as an identity for the iOS interface. The fact that its application was pre-researched and not used in vain, can be seen in the adaptation of those theories. Consequently, this adaptation was successful can be justified not only by its commercial triumph but also because it has revolutionized the lucidness of the UI usability universally, even by people who are not considered technological literate enough. Although there are a plethora of cognitive psychology theories that have not been mentioned in the thesis, either because of its vastness or because of it is still being developed internally in the company quarters, one thing is for sure can constitute that cognitive psychology has been extensively used in the iOS interface. Of course, the use of cognitive psychology within the interface did not just turn the iPhone into a successful product but was one of the main reasons for its usability. Based on the above example one can understand that the use of cognitive psychology in interface design can provide the necessary affiliation to create more useful and usable devices.

It is obvious to constitute that the use of cognitive psychology in interface design is more than necessary, but we have to consider that both cognitive psychology and interface design are in their primary level. Although the brain has been identified and researched extensively in a biological way, our knowledge on the connection between these functions and the human behavior is still sparse. Parallel to the above, it is clear that interface design is still under development since technological innovations are still very much evolving, resulting to the fact that even with limited data, there are successful results from this collaboration.

Since the above fields are still under-developed, it would be very interesting to envision their possibilities. The more we understand how the human brain works the less complicated user interaction becomes. The more this relationship evolves the less the user is thinking about how to do things but more about what to do with them. Thus this connection broadens his creative process and reforms it into something more productive. Finally, interface design is the clarification of complex systems for human use. The more we learn about the human brain process the more coherent the interface becomes for a human operation of elaborate computer systems. At the end of the day, computer systems are the sources and tools of the present and future generations and mankind have always been defined by the problem-solving resources it uses in order to progress.

On the other hand the more information there is on how humans perceive, remember, operate and think, the more malleable they become to subversive manipulation. Nowadays, based on the Gestalt theory on the advertising company use, knowledge is used to promote and catch our attention based on the information they want. Theories like automatic processing can be used in by making someone remember and learn information that under other circumstances wouldn’t. How exactly that knowledge can be used in the future for the manipulation of the masses or even for individuals is unknown. The only reasonable conclusion is that if cognitive psychology can be used to make the user operate complicated computer systems, it can certainly be used in other ways — less humanitarian and chivalrous. Concluding the privacy of each user is aquatinted through internet navigation, is still a debatable matter. Rüdiger Heimgärtner’s research on the subject entitled, the “Identification of the User by Analyzing Human-Computer Interaction” [8] states clearly that the user can be identified with a precision of up to 99.1% through the analysis of his behavioral interaction.

Humans are actually very much alike through their individuality, we perceive content the same way, our attention is vulnerable the same way, every human cannot ignore the blue color and that is the fact. But we do not still know how we operate ourselves mainly because beyond our brain and its biological function there could be a mind or even a soul. How far we can go is something unknown and thinking that we could understand how we function in absolution can be derived as “Hubris”. It is certain that knowledge can lead us in creating a better or worst model of the western world — how far, is still unknown. At the end of the day the universe might be a complicated equation which creates a polymorphic pattern waiting for us to discover it.


1. Psychology: Making Connections by Gregory Feist and Erika Rosenberg (Jan. 5, 2009)
2. Book Design of Everyday Things by Donald A. Norman (1999)
3. Applying Cognitive Science Research in Graphical User Interface 
 Paper by: Gabriels Aberg, Jessica Chang (2005)
 3.1 Lampson, B.W. and Sproull, R.F. “An Open Operating System for a Single-User Machine”. Proceedings of the seventh ACM symposium on Operating systems principles ’79, 98–105.
 3.2 The Rods and Cones of the Human Eye. vision/rodcone.html
4. Proceedings of the First International Conference on Intelligent Human Computer Interaction Paper by: Sabben Durrani And Qaiser S. Dirrani (2009)
5. An Introduction to Cognitive Psychology by David Groome (2009) 
6. Pomerantz, J.R. (2003). Perception: Overview. Encyclopedia of cognitive science.
7. Macword Keynote January (2007) presentation of the AppleTv and iPhone by Apple
8. Human-Computer Interaction. Ambient, Ubiquitous and Intelligent Interaction
 Paper by: Rüdiger Heimgärtner (2009)

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