Human Information Processing

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Pages 24-76.

Reading Responses

Erik Gui - 2/9/2012 22:32:14

"The Model Human Processor" essentially tries to compare the human mind with that of a computer processor. There are a lot of formulas and technical details that went into describing the human mind in parallel to a CPU. The perceptual system involves detecting physical stimulus from the real world that is detected by the human body. The author painstaking described how to use certain formulas to model the perceptual system. The cognitive system refers to connect inputs from the perceptual system to the right outputs of the motor system. Long-term memory is a part of the human cognitive system which stores the bulk of an individual's memory. In the next section, the author outlined how to measure human performance similar to how to benchmark processors. From reading this article, instead of feeling enlightened about the human mind, I feel more confused about these formulas and equations. However, perhaps the lecture would help clarify the reading.

Lichen Han - 2/10/2012 21:00:43

This reading provided insightful information regarding the human physical and cognitive mind as a processor. I thought it had some great examples of how our mind filters information and processes interfaces, great both because they were well demonstrated and because of their scientific backing. Given the way our human processor works, it stands to reason that a good interface design should avoid excessive visual stimulation and auditory interference.

The reading also went in good depths about the types of human memory: perceptual, working, and long-term and their respective decay. The reading made a point that new knowledge overwrites similarly associated old knowledge, which I thought was intriguing because it ties into our discussion about keeping consistency in interface design. Every time users have to learn a new way to use an interface, they lose some knowledge of their accustomed preferences which can result in the user becoming frustrated by both familiar and unfamiliar interfaces.

Peter Beardshear - 2/11/2012 12:25:35

While modeling the human mind as an information processor may provide some insight to the greater cognitive architecture, benchmarking aspects of cognition and perception (particularly as pertains to memory) are shallow and often fail to provide useful information. It is possible to measure the time that it takes for a user to perform some action, but without knowledge of the underlying architecture (component-level, as the author calls it), attributing these results to some fundamental makeup of the brain is difficult if not impossible. Additionally, I do not see how such benchmarked results in any way improve human-computer interaction, unless your interface relies on flashing letters and numbers at 100 ms and seeing how many can be remembered.

Brennan Polley - 2/11/2012 18:45:55

Newell starts off the chapter discussing perceptual memories. He models humans' brains in terms of memories and processors and explains that two such memories are the Visual and Auditory Image Stores. Experiments were done in which it was determined that Auditory Image Store decays slower than the Visual Image Store. Another memory system discussed is the cognitive system, which includes working memory and long term memory. He then moves on the perception and how similar visual stimuli taking place in the same Perceptual Processor cycle can fuse together, becoming a single perception. He gives an example of this with video frame and then explains that a way for this "fusing" to happen is when one event appears to cause the other event. I found Fitts's Law interesting in that when we move our hand it is not a continuous movement to the target but a series of microcorrections. I also found the keyboard layouts and their associated typing speeds interesting because I did not realize the QWERTY style allows for faster typing.

Brandon Young - 2/11/2012 19:48:43

The reading introduces a model of human perception and action as simple processors, and examines quantitatively the effects of different environments and stimuli on the human ability to perform tasks and perceive stimuli. In particular, it claims that uncertainty reduces the speed of tasks and that multiple speeds of perception and action have to be considered. The importance of chunking, or the grouping of pieces of information, is also mentioned. The authors also claim the difficulty in a task comes primarily from the complexity of the task itself and not the users. The reading also acknowledges the difficulties in forming and studying memories. While reading about the fact that semantically-linked information was easier to recall, while phonetically-similar information was more difficult, I thought of the difficulty of choosing options for the user that are spatially grouped by meaning without being easy to mix up. For example, "Save" and "Save As" are easily mixed up by users. This also becomes an issue with graphic icons as well. One solution is to change the names of similar-sounding options, but that conflicts with several decades of precedent. Perhaps "Copy Document" would be a suitable replacement, and better describe the option, than "Save As."

Jonathan Sulistio - 2/11/2012 22:35:22

An interesting point raised regarding long term memory is that people don’t usually forget things, but rather, they fail to retrieve it from memory. The key is to provide the person with cues of related material that will spark the recollection process. In terms of user applications, a good interface should, first of all, minimize and simplify the data that relies on the user’s memory so as to reduce the user’s necessity to struggle with his or her long term memory. Then, equally as important, the interface should provide cues for the user to recall critical information, or even better, make sure that the data is readily available and easily found if required. The act of finding the location of stored data should be among the simplest of tasks; otherwise, it defeats the whole purpose of having that location and the user will instead be preoccupied with trying to remember how to get to the page with the stored data, for example, which may in turn cause them to forget what they were searching for in the first place.

Lida Wang - 2/12/2012 0:48:29

Some things that I picked out from the reading that seemed relevant to UI design are: it's easier to remember things in chunks, in order for two events to be perceived as to be related ie one causes the other, the delay between the two events cannot exceed 100msec, the speed of moving one's hand depends on the precision required, working memory encodes with acoustics/visual cues versus long term memory encodes with meanings. These all relate to designing an interface, the first in regards to learning the interface, the second and third are a very direct relation, and the last about memory is important as well for learning the interface.

Sherman Ng - 2/12/2012 5:10:29

To describe the human mind and its capacity, whose full complexity is still unknown to psychology in the familiar terms of computing presents an opportunity to extract generalities about what the average human is capable of. While this simplification of human mental ability does underestimate or neglect some facets of the human mind that is superior to a computer, these generalities allow for some guidelines to be formed about a human's ability to interface with another computational processor. Therefore, with the data provided by this text, an interface can be designed that provides the right flow of data from the hardware of a computer to the wetware that is the human information processor.

Alvin Chang - 2/12/2012 12:03:39

This week's article on Human Information Processing was an in-depth look at how design functions could be engineered specifically for the Human Processor. The Human Processor was separated into three distinct subcategories, the Perceptual, Cognitive, and Motor processors. I especially took notice of their examples and relations between human-computer interaction such as Fitt's Law, and the Power Law of Practice. With this information, the design-prototype-evaluate cycle can be further improved with less iterations, allowing for efficient and effective interface designs.

Sahana Rajasekar - 2/12/2012 12:18:01

The Model Human Processor is described by a set of memories and processors together with the principles of operation, which arise in context. The three subsystems in the Model Human Processor are 1) the perceptual syster, 2) the motor system, and 3) the cognitive system. The perceptual system turns the physical sensations in the world into internal representations of the mind.I n doing so, an acoustically-coded or visually-coded representation of the stimuli occurs in the Working Memory. In the motor system, certain muscles are activated to turn thoughts into actions. The cognitive system connects the perceptual system and the motor system in a recognize-act cycle. It was interesting to read about the 2 kinds of memory, working memory and long-term memory. The study of human performance was very relevant to out group design project. Topics like Learning and Retrieval will help us understand how a user retains and understands new information and will help us create a more user friendly interface.

Shu-Chen Chen - 2/12/2012 13:02:03

The reading from Card Moran Newell chapter 2 attempts to explain the human machine in terms of memory and processor. The authors illustrate the human mind as a combination of sensor recognition, memory allocation and recall, and action processes, which they can then characterize time cycles. These time cycles can then be used to predict, quite accurately, user behavior across different inputs and scenarios. With this information, designers can compare different usability scenarios by modeling the human response to various inputs. One interesting example in the reading was the comparison of the Sholes, alphabetic, and Dvorak keyboards as a function of typing speed. By characterizing the human response time and motor control functions, the designer can estimate what is the efficiency of typing on the different layouts and determine which one to implement on their keyboard. In the reading, alphabetic was 8% slower than the Sholes keyboard, which was 2.5% slower than Dvorak.

Darren Sue - 2/12/2012 13:25:43

The author uses computer lingo when describing human behavior and uses the comparison to justify his numerical analysis. At some point, the overextended metaphor feels silly.

The human mind likes to deal with digestible chunks, and these chunks may be adjacent from one another. Our memory access facilities are limited so we can possibly lose memory by focusing on another subject. This working memory described here is functionally equivalent to the previous author’s description of the locus of attention.

One new topic is the idea of long term memory. We can "lose" long term memory by losing the pointers to it, but otherwise it never vanishes.

Another topic is that accuracy and speed are a tradeoff for physical interactions.

This article would help us numerically rationalize our design decisions for computer interface. However, I doubt that we'll get to the point where this type of analysis is useful. Moreover, if you're designing the system to require this type of numerical precision, you might have your priorities mixed up. It’s more important for interfaces to be non-threatening and easy to use than efficient. And given the age of the target audience for our project, the conclusions drawn here may not even be valid.

Arturo Wu-Zhou - 2/12/2012 13:42:12

The human mind is information processing system. Dumbed down, it contains memories and processors and principles (an instruction set?). It can be subdivided into 3 smaller modules: sensory input system, motor (action) system, and cognitive (encoder, decoder) system. The sensory input system feeds the mind information to do whatever it wants with it. This information is encoded physically (huh?) into an internal memory databank waiting to be processed by the cognitive system. However, the life of the input is short. The motor system translates the cognitive signals, instructions into physical, real world actions. The cognitive system is the middle man between the input and motor systems. It has 2 memory modules: working memory to hold current information under consideration and long term memory, which stores info for later use. In one cycle time: (get input, process, do something) the cognitive processor seems to fuse certain inputs into one percept: e.g. aggregating many still pictures to simulate dynamicity. When this system processes info from the working memory, certain information gets erased. The interactions between these systems happen on the order of milliseconds.

Erik Gui - 2/12/2012 14:23:34

"The Model Human Processor" essentially tries to compare the human mind with that of a computer processor. There are a lot of formulas and technical details that went into describing the human mind in parallel to a CPU. The perceptual system involves detecting physical stimulus from the real world that is detected by the human body. The author painstaking described how to use certain formulas to model the perceptual system. The cognitive system refers to connect inputs from the perceptual system to the right outputs of the motor system. Long-term memory is a part of the human cognitive system which stores the bulk of an individual's memory. In the next section, the author outlined how to measure human performance similar to how to benchmark processors. From reading this article, instead of feeling enlightened about the human mind, I feel more confused about these formulas and equations. However, perhaps the lecture would help clarify the reading.

Sally Lee - 2/12/2012 15:03:17

The article talks about the model human processor as composed into three parts perceptual system, motor system, and the cognitive system. The human processor is described as a set of memories and processors with set of principles known as the principles of operation. The perceptual system takes physical sensations and interprets them to an internal representation in the mind. The motors system is in charge of turning thought into action. And there's the cognitive system, which connects that right input from the perceptual system to the right output of the motor system. Due to the fact that human's tasks are generally more complex, the the memories and processor of a cognitive system is more complicated than the other two systems. Then he talks about working memory and long term memory. Then there is talk about simple reaction time, carried out by perceptual and motor systems. Overall I found the reading very dry. There were a lot of graphs and mathematical symbols that made the reading hard to follow.

Shuqun Zhang - 2/12/2012 15:10:32

The human mind is much too complex to be emulated by a machine, but how it behaves can be approximated by a processor model. The model human processor is made up of memories and principles of operation. The parameters that are assigned to the human memory and processor (processor cycle time, memory capacity, decay rate, etc.) help us estimate human performance and use these estimates to improve computer interfaces for human use. The many formulas presented throughout the reading gives a reasonable expectation of how fast humans can perform certain tasks such as recognition and decision. Some examples where such data helped improve an interface include the keyboard and Morse code.

Jeffrey Yu - 2/12/2012 15:16:26

The reading starts off describing the model human processor, and its three subsystems, the motor system, the perceptual system, and the cognitive system. The cognitive system is the most complex of the three, since the human cognitive mind is very intricate. Cognitive system is the one that connects the perceptual to the motor. Perceptual system takes the thoughts and formulates them, and the motor system carries out the actions of the perceptual's thoughts. There are two types of memories, a working memory and a long term memory. I found it interesting that when people are asked to recall something right after hearing it, they use both working memory and long term memory to retrieve it. And that long term memory is actually accessed from the working memory, and takes longer to retrieve than working memory. The article describes a lot of theories, such a simple reaction time and working term memory capacity in terms of math symbols and formulas, and that was hard to follow. I thought the reading could've been less technical and more friendly to read, as it's bombarded by graphs and math formulas/symbols that rendered the reading unnecessarily difficult.

Tobit Narciso - 2/12/2012 15:47:07

This week's reading is about a model on human information processing. We can treat the human as a set of memories and processors together, that can be divided into three systems: perceptual (inputs), cognitive (decides the course of action), and motor (the actual response), each with its own set of processors and memory. The rest of the article discusses how each process works, and the resulting time estimates for each process. It then proceeds giving examples of human information processing using this model. It also models other human behavior such as the effect of practice on the process speed.

This model is useful since it provides us with reasonable estimates for timing our human-computer interactions, and enables us to design our interfaces suitably for effective and efficient human use.

Hywel Lo - 2/12/2012 15:52:19

Today's reading was about the Model Human Processor and how humans use our mind and perception to interpret and analyze everything around us. Based on the article, there are three interacting subsystems: the perceptual system, the motor system and the cognitive system. Each of which has its own functioning and process that allows the flow of the human mind to work. Honestly, I don't get the point of this reading, it seemed pointless and unrelated to what we're learning, I suppose the question I pose is how is this going to translate to Monday's lecture. I don't think anyone actually reads the comments I post as well for these reading. I find this article very mathematical and unimportant but mostly, it's common sense. Hopefully Monday's lecture will have some answers.

Matthew Leung - 2/12/2012 18:42:54

"The Model Human Processor" discusses how the actions of human beings can be described as a computer processor. The human being is split into three interacting subsystems, the perceptual, the motor, and the cognitive systems. Each of these rely on the other in order to perform tasks, such as remembering which words were seen before. This task would take input from the perceptual system, attempt to recall the memory cues from Working Memory, retrieve the right words from Long Term Memory, and at last, it will select the correct words and select the correct outputs with the motor system. All of these processes take microseconds, and when put together, describe how long it takes a person to perform tasks.

Joseph Schadlick - 2/12/2012 18:44:55

The human brain can be modeled as a computer. In this analogy, the mind has three systems: the perceptual system, the motor system, and the cognitive system. The perceptual system acts as the input and low level analysis of information. The motor system is the physical output of the system. The cognitive system relays between the perceptual system and the motor system, does complex analysis, and stores information into both short term working memory and long term memory. The brain remembers large amounts of data through successive chunking of data into structured bits. By taking these into account, systems can be engineered with the human brain in mind. To Create the illusion of continuity out of discrete events, such as frames of video, studies must be done to find the rate at which humans take in visual data. Taking the motor system into account leads to better engineering of input systems, such as the Dvorak keyboard.

Ken Yu - 2/12/2012 19:29:18

The human mind processes information just like a computer processor. This can be modeled as the Model Human Processor, which can be divided into three categories: the perceptual system, the motor system, and the cognitive system. The perceptual system is basically the sensory readings, such as those from what we see to those from what we hear. The motor system is where thought is translated into action; essentially it is the part of the human mind that carries out the response. Lastly, the cognitive system is what connects the perceptual system with the motor system; it serves as the middleman - connecting the sensory inputs to the motor outputs.

Bernard Julve - 2/12/2012 19:42:51

The reading describes a model for the human mind, that of a human processor. It consists of a set of "memories and processors", as well as a set of "principles of operation" that governs how they interact. It describes how it is helpful to think of the human mind as an information processing system with three main subsystems: the perceptual system, consisting of sensors such as eyes and touch that take in stimuli as input to the brain; the motor system, which carries out responses to the stimuli, which in the context of computers mostly consists of the arm-hand-finger dynamic as well as hand-eye coordination; and lastly the cognitive system, which mostly interprets input from the perceptual system and decides on proper actions to be expressed through the motor system. The cognitive system makes use of two types of memory, working memory (to store info on the task at hand) and long-term memory (to store knowledge for future use). All of these function together in the recognize-act cycle (analogous to the fetch-execute cycle of computers) which represents the basic unit of cognitive processing. It then goes on to advocate for an engineering approach to psychology, suggesting approximation of uncertainty and formulation of more general psychological theories to tie together already known facts. Lastly, it describes various phenomena that pertain to human computer interaction, as well as various principles such as the rationality principle and problem space principle, all in terms of the human processor model to demonstrate its usefulness in the study of human cognition.

David Squeri - 2/12/2012 20:19:13

People often compare the human mind to computers by relating memories to files and folders, but the authors go further and break down the human experience into very digital components. While I understand the general concepts, I’m not the biggest fan of “simplifying” the human condition into bits of binary hardware, but I digress. The “Model Human Processor” is divided into the perceptual, motor, and cognitive sub systems which are each responsible for the reception of physical sensation, activation of muscle patterns, and the connection of the prior two systems respectively. What I actually found most interesting about the article were all of the reaction and movement times recorded for different human processors. Being able to see how fast an individual can receive sensory information, move a muscle, or read a piece of text was really interesting. I’m a little confused though on one page, where some pseudo-math proves that typing on the QWERTY keyboard is actually faster than an alphabetic one. I was always told that the reason the QWERTY keyboard was adapted was because people were typing too quickly on typewriters and jamming the mechanisms.

Whitney Lai - 2/12/2012 20:51:10

I thought the parallels drawn between the human mind and a computer were interesting. However, I don't agree that our sensory operations and processes can be quantified so easily, as the reading suggests. I think people differ in these areas too broadly to just create one general model with which to define how the average human mind works. General rules could be stated, but definitely not attempts at putting them into mathematical equations or models.

Bei He - 2/12/2012 21:12:32

The human mind behaves as a processor at a high level with different subdivisions. The actual thinking takes place in the cognitive division that links perception and action. Memories of this system also behave like the computer metaphor with working memory as RAM and long-term memory as hard drives. By understanding this system, we can understand the limitations of the human mind and the methods it uses to process information. Thus, when creating interfaces, we can base it off of said limitations and make their usage easily integrated into how the human mind functions.

Tamzid Islam - 2/12/2012 21:33:40

The reading assignment on Human Information Processing describes the Model Human Processor: a cognitive modeling method used to calculate how long it takes to perform a certain task. The Model Human Processor, according to the book, consists of a set of "interconnected memories and processors, and a set of principles of operation." The memories and processors are grouped into three subsystems: a perceptual system, a cognitive system, and a motor system. The prominent attributes of the Human Processor can be modeled by using a few parameters.

While such a simple model cannot completely model the intricate details and subtlety of a real human being, it can help us understand and predict and even calculate human performance related to Human Computer Interaction.

Yuki O'Brien - 2/12/2012 21:42:32

It was interesting to see the way the author separated a person's information processing into specific areas, and further describing detailed observations of how these systems work. It made me think of last week's reading's 10 heuristics of human usablity, and how these separate modes of information processing all contribute to the way human interact with interfaces. Before taking this class I had never really thought about the amount of time and research that went into design in general.

WenJie Zhou - 2/12/2012 21:48:54

reading response for "The Model Human Processor"

    The chapter is very thorough in describing several different areas of human perception and reaction, and our typical behavior and response time. This is very important when it comes to interface design because we are, of course, designing interfaces for people. For example, understanding how much information a user can handle at once and how much can be remembered is important. If the user is at the end of a 10 step process and then must recall what happened at the beginning but has trouble doing so, the designers should probably re-consider the interface and possibly dividing up the steps across pages or providing more visual feedback. At the same time, we donnot want to dumb down our interfaces too much where there are an unnecessary number of steps to perform a task. It also crucial to get a strong understanding of users, especially since characteristics vary from person to person.One important aspect of creating a successful user interface is the ease of habitual learning and pushing tasks to long term memory. The chapter provides useful information that could help engineers make design decisions that would optimize the development of habits and long term memory retrieval.
    When we are making design choice, we also need to keep in mind that the functions of these items that are associated with long term memory also work in a similar way. If they look similar but are completely 

different in terms of how they are used, it can often lead to confusion. This is the concept of interference in long term memory where associated items act differently and can corrupt a users memory of how things work. For example, pasting in emacs is Cntrl+y whereas normally it is Cntrl+v even though they typically serve the same function. This can create problems where you try to Cntrl+v in emacs and Cntrl+y in other programs. Having a similar setup to previous iterations is a very important aspect of designing user interfaces for people already used to a certain way programs work.

Rohan Cribbs - 2/12/2012 22:04:28

This article talked about the "model human processor" which can be broken down into three parts, thee perceptual system, the motor system, and the cognitive system. These are then incorporated into mathmatical formulas to describe efficiency and bounds on human interaction with the world. This is particularly relative to HCI in that you can use this knowledge to understand what can and can't be perceived by your users as well as how significant an optimization will be once put into use.

Huan Do - 2/12/2012 22:17:50

The reading brings much insight on the unseen sophistication of some products. It is nice how much we can analysis and build around the human's mental capabilities and limits. I like this reading because it gave insightful information on the design of the keyboard in which I did not know had so much analysis in.

Chenkai Gao - 2/12/2012 22:38:15

The model human processor can be described by a set of memories and processors together with a set of principles, hereafter called the "principles of operation". The model human processor can be divided into three interacting subsystem: the perceptual system, the motor system, and the cognitive system. The perceptual system carries sensations of the physical world detected by the body's sensory systems into internal representations of the mind by means of integrated sensory systems. The perceptual memory hold information coded physically, that is , as an unidentified, non-symbolic analogue to the external stimulus. Motor system is the action by activating patterns of voluntary muscles which thought is translated into. In simplest task, the cognitive system merely serves to connect from the perceptual system to the right outputs of the motor system. Two important memories in the cognitive system: a Working Memory to hold the information under current consideration and a long-term memory to store knowledge for future use. Working memory holds the intermediate products of thinking and the representations produced by the perceptual system. Long-term memory holds the user's mass of available knowledge.

Kurtis Freedland - 2/12/2012 22:41:22

I thought that the concept of a human processor is pretty important in order to understand how a user will perceive an interface. The analysis of perception forms of media is pretty awesome. Since images last in the memory so long we can use that to our advantage and present our users with images and other forms of information and displays that will help them better interact with the interface.

Samuel Zhu - 2/12/2012 22:45:08

I believe that using a computer system as an analogy for a human has some merits, but may end up being overall too restrictive. The analogy provides some good shorthands for things that humans do, and perhaps some good reasoning behind them. However, in my experience, humans are far too unpredictable to be put into such a strict analogy.

Sylvain Royer - 2/12/2012 23:05:05

Beep boop beep, I am a computer.

The readings explore the idea that humans can be modeled as a computer, with each specific system acting as a processor. The three main processes that the readings talk about are the perceptual, cognitive, and motor process. The names are pretty self explanatory. The perceptual process is the process which takes in information from our surroundings. The cognitive process is the process which takes said information and does the calculations. The motor process is the process which executes the instructions given by the cognitive process. By breaking the human mind into these three processes, we can figure out how fast humans can be at specific tasks, and how to re-write the tasks in such a way as to make humans faster.

For example, the readings speak of the change between two different methods of telegraph operations. The original system had the dashes represented by longer pauses between beeps. This meant though that the minimum amount of time humans needed to wait in order for that longer period to register went up. This is because after a certain point, we can't differentiate between things. Animation works on this principle. However, once it was changed to a system where the dashes became actual dashes, differentiating took much less time, and thus it became much easier for telegraph operators to send messages at faster speed.

Also, the paper talks about an increase in practice increasing the speed at which you can perform a task. This is obvious to those who have practiced a task extensively, but the paper takes it even further and gives us an equation which can be used to approximate the speedup.

Kenny Shiu - 2/12/2012 23:16:50

This week's reading on the Model Human Processor went over the "specs" of the average human being. It was a bit strange hearing a human being described as an information processing system, but it also makes a lot of sense. It kind of ties in with Raskin's idea of cognetics; we should design computer systems to match the capabilities of the human mind. If we are not able to quantify a human's ability to process information, then designing a system based upon the limits of this ability would be very difficult. The reading describes many processes that were used to give a rough estimate of the performance of the human brain on various information processing tasks. For example, morse code listening rate was measured. As another example, the speed at which the human cognitive system can issue commands was measured by tasking a person to draw between two closely spaced lines as fast as they could. Various timing calculations can be approximated using pseudo-laws such as Fitts's Law and the Power Law of Practice.

Kenneth Do - 2/13/2012 0:15:28

Summary: Humans can be divided into a perceptual system of sensors and memories, a motor system that carries out actions, and a cognitive system that utilizes working memory and long-term memory. Each of these systems can operate in parallel. Working memory is a subset of long-term memory. Memory is stored in nested chunks. Long-term memory doesn't lose chunks of data, but it is possible to lose access to chunks due to interference or the ineffectiveness of retrieval cues. By using a range of values for the storage capacity, decay time, and code time for each of these subsystems, once can calculate the performance of a Slowman, Middleman, and Fastman at various tasks.

Response: It's disappointing that to actively store information from working memory by associating to chunks in long-term memory requires using up capacity in working memory to handle what was just brought from long-term memory. Humans should have a better caching system, such as a secondary brain.

Yu Gan - 2/13/2012 0:19:19

The Model Human Processor is a description (not without its own faults) of how the human mind works in terms of human-computer interactions. It is described by a set of memories and processors and a set of principles of operation. The physical systems can be divided into the three subsystems of the perceptive system, the motor system, and the cognitive system. Memories have a storage capacity, decay time, a code type (sensory type), while processors have a cycle time. The perceptive system takes in input which often is translated as an auditory or visual memory. These memories are interpreted by the cognitive system, which can choose which parts of the memory to interpret before the memory fades. The cycle of the perceptive system also gives us a limit to the frequency of inputs that we can recognize – for example, the perceptive cycle for auditory input is about 10 per second, meaning that clicks at a faster frequency may be recognized as a single click. The motor system has a similar cycle, significantly longer, that limits reaction time. Quick motions such as typing are often issued in bursts, and do not reflect individual motor system actions. Working memory is often stored in chunks, which can be associated symbolically or physically. A consequence of this is that sequences that are more easily chunked are more easily remembered, and skills that develop chunking techniques also can help memory. As more chunks are recalled, the speed at which working memory fades increases. Long term memory, on the other hand, does not fade, is quicker to access, but slower to write. The most efficient way of storing to long term memory involves creating new and novel associates with a memory. The cognitive processor also has a cycle of about a tenth of a second. It can perform recognition in parallel, but acts serially.

When evaluating with the Model Human Processor, a middleman and fastman-slowman approach help define proper averages and bounds. The middleman is the average user, the fastman the exceptional user, and the slowman the subpar user. This helps evaluate things such as the proper frame rate for movies to give the illusion of movement, the appropriate time between movements to give the illusion of causality, and even keying rates, among other practical uses. In calculating these things, we must also remember the “power law of practice”, which is that practice decreases the amount of time it takes to complete a task, modeled as a simple rational function. The MHP can also be used to evaluate how long responses to decisions can be made. Some key points are that, since long term memory has a longer access time than working memory, name matches require more time than symbol matches. Also, the time it takes to choose is logarithmic in the number of choices.

Timothy Zhu - 2/13/2012 0:32:41

In the end of this reading, after going through the data which backs their speculations on how a person models a computer (yes, yes, it does, in the sense that both process inputs, at some speed that they have decided is significant) -- what is the purpose of modeling a person by paradigms that apply to a computer? Unfortunately after reaching the end of the reading it is still something I dn not understand. In some oblique way it seems that they are saying to advance human-computer interaction the human and computer must be rearded at the same level, but it's still not clear to me from where that necessity that derives or what further work leads from what they have laid out.

Ahmed Afifi - 2/13/2012 0:33:42

The weeks reading, Human Information Processing, delves into the idea that the human mind and its processing capabilities can be described similarly to a computer's. Just as we take into account a computer's capabilities when we design systems for it, we should do the same for human's. The interactivity of a system should play off the strengths and weaknesses of how we process information. Key factors include the rate at which we process information, and the order, and how we store memories and the sizes of which we store them in. These affect perceptions, which directly concern the human computer interface.

Kaiyuan Deng - 2/13/2012 0:42:15

This article was very exact in its calculation of cognitive reactions. This is very interesting because I can see a correlation between the human mind and computer hardware. The long term memory is analogous to Hard Disk reads and unconscious/reactions are akin to memory reads. And concepts/ides/memories fresh in the head are like L1 L2 caches. But I wonder if following the human model is the correct way to build computers because humans have not used the full capacity fo the brain and so much is unknown.

Minzhi Zhao - 2/13/2012 0:59:44

The Model Human Processor can be described by: a set of memories and processors; a set of principles, hereafter called the "principles of operation." The Model human processor can be divided into three interacting subsystems: 1, the perceptual system. 2, the motor system, and 3 the cognitive system perceptual system integrate the human body sensory systems into internal representations of the mind. That 's thought and thought is finally translated into action by motor system. Cognitive system in this model is far more complicated than those of the other systems. Working memory and Long Term Memory are two important memory in the cognitive system. Working memory is use to store intermediate products while Long Term Memory is used to stored things for future uses. An applied information-processing psychology owns the qualities which are very important for the model human processor.

Jacob Rashoff - 2/13/2012 1:00:04

The reading for this week describes the human mind in terms similar to a computer, such as storage, cycle time, etc but does emphasize that the model is an approximation and simplified. Although the equations seem difficult to apply in practice, they can be useful guidelines for designing a system that people can use. For example, it could be useful in understanding how many digits/characters an average person can keep track of, for passwords and shortcuts. Or using the limits/strengths of human motor skills to place buttons strategically. However useful these equations may actually be in design, I feel that they are no replacement for actually testing the design with an actual set of users. Often times the equations were admittedly not exact, so there is plenty of room for iteration and input to find a desired configuration that meets your users needs.

Benjamin Le - 2/13/2012 1:04:57

I thought this article was interesting because it thought us how to quantify good interfaces over bad interfaces. The part where they measured the efficiency of an alphabetized keyboard over a qwerty keyboard really surprised me as well. It shows that even though an interface may not intuitive make sense, you can still find it to be more efficient than the "standard" layout. I also thought the article brought up a good point when they talked about choosing names that the user is familiar with and have learned before. It is definitely more efficient to keep consistent with function names and function mappings throughout programs. It allows the user to easily transition to new software as they can recall alot of the functions easily without having to relearn them.

Raphael Townshend - 2/13/2012 1:06:45

Today's reading is quite interesting in terms of its application of mathematics to the field of human perception/cognition/motorization. Especially in contrast to my previous comment where I heavily implied UI was a 'softer' part of Computer Science.

However, I do fear we are getting dangerously close to using the technology of the day to approximate the human brain. As mentioned in previous readings, humans have a tendency to approximate their own inner workings via applying the inventions that take the most hold in their current life. In this case the computer analogy is taken to an extreme and I fear it may be inaccurate at some level.

Pedro Tanaka - 2/13/2012 1:45:52

In chapter 2, The Model Human Processor, of the book The Psychology of Human-Computer Interaction, the authors draw an analogy between the human mind and a computer. They describe their model human processor as a set of interconnected memories, processors and, principles of operation. The memories and processors are subdivided in three categories: a perceptual system, a cognitive system, and a motor system. The authors them describe various experiments, their results, and how they may be used. They then close the chapter discussing expansions of their model and alternatives to it. This week’s reading was pretty dense and long, but interesting. The examples present on the reading describe some points that I probably would never recognize.

JinWoo Roh - 2/13/2012 2:13:40

I thought the reading was really interesting, for it made intriguing analogies between the human mind and computer components. One part that caught my attention was the recognize-act cycle, which is analogous to the fetch-execute cycle of standard computers. It was important to realize that humans are inefficient at multi-tasking because as the author states, "the cognitive system is fundamentally parallel in its recognizing phase and fundamentally in its action phase." This states that recognizing and action phases cannot happen simultaneously due to the way our mind is wired: thus only one locus of attention can be present at a time. It was interesting to see the retrieval rate of the mind. The mind generally takes longer if it has to access its long term memory, compared to simple reaction actions to stimulus.

Christopher Nguyen - 2/13/2012 2:25:37

In this reading, we look at the at the Model Human Processor which consists of the Cognitive Processor, a Perceptual Processor, and a Motor Processor. The Cognitive processor uses its Working Memory to retrieve information from its Long-Term memory to make decisions. The Perceptual Processor consists of sensors, and the motor processor carries out the response. There are certain principles that guide human processing such as Fitt's Law which gives the time it takes to move a hand to a position a certain distance away and the Uncertainty Principle which says decision making takes longer as uncertainty increases. One of the most interesting discussions in the reading was that of simple decision making in which the perceptual, cognitive, and motor processors work together for simple reaction. It was interesting to see the calculation involved taking into account all three cycles for what seemed like a fairly trivial task (pressing a space bar in response to a symbol).

Andrew Wun - 2/13/2012 2:38:21

The Model Human Processor was an interesting take. Dividing everything into three main subsystems which all follow a set of principles of operations simplifies human performance into a mathematical examination; this shows even the complex human brain can be explained with math. Using the equations that arise by noticing rates within movements, perception and reaction time can be deduced into a logical approximation. All decision tasks are estimated with a probability that have more mental steps with the greater difficulty in uncertainty. Making a simplified account of the human information processing makes the mind easier to analyze, but the methods involved are still confusing.

Bhavik Singh - 2/13/2012 2:39:30

This weeks reading seemed to be a new spin on how users can interact with interfaces. While human biology, and the limits of our abilities often play a part in our day to day actions, I never thought that user interfaces could, or were, designed keeping them in mind. I specifically liked the example of the calculator. Through it, for the first time, an interface problem was dealt with using mathematical and scientific methods, instead of more abstract concepts.

That being said, i found it very difficult to see how this reading would apply to most computer based interfaces. Most of the problems proposed by the reading (such as the refresh rate for eyes), are solved by using modern day hardware that makes these limitations inconsequential. In the case of the Kinect however, perhaps we can apply the same strategy as used in the reading, and break down our UI problem into a mathematical one by collecting and analyzing data.

Connie Guo - 2/13/2012 2:44:20

The human brain can be described as an information processor with three different subsystems: a perceptual processor, a cognitive processor and a motor processor. Some tasks require these systems to be processed serially, whereas others require a parallel integration of the systems. The perceptual system translates aspects of the physical world and encodes them into sensory responses within the body. The motor system is responsible for translating neural responses into motion. Finally, the cognitive system mediates between the perceptual and motor systems.

Benjamin Shapiro - 2/13/2012 2:49:21

This week's readings concern the model of the human mind as an information processing system. I think that this reading really emphasizes how important and useful this model can be to design, but in some ways it overemphasizes it as well.

There was one particular example of this that interested me, the power law of practice. Essentially, this "law" dictates that with practice, a user's time to do a task decreases as a function of the number of times to the power of some constant. This directly implies that it is impossible to stop improving on time. I think this is a good example of the shortcomings of this chapter. While I agree that these mathematical models are helpful to understanding, in reality, it is not necessarily useful to assume that a user will continue to improve as they practice... In fact, there tends to be a cap on how much a user can improve, and sometimes they will get worse over time as well.

In other words, I think that the human mind is far too complex for us to take these models for granted. They are helpful and very useful, but I would venture to say that they may need to be taken with a slightly bigger grain of salt than is conveyed in the reading. That said, this is a really cool way of looking at HCI!

Praneet Wadge - 2/13/2012 3:26:50

This reading was definitely a very interesting one as it combined together psychology and computer architecture. I liked that it was very scientific and displayed many trend graphs, such as the decay of auditory images or working memory etc, since much psychological literature usually describes this analogy more qualitatively. I also found it quite interesting how the author divided the model into the three components of perceptual, motor, and cognitive, because there is still so much overlap from a neurological perspective of the three system. The question that occured to me quite often though throughout this reading was how they had gathered data while formulating concepts such as the Visual Image Store half life etc, and how robust the findings and methods really were.

Eugenia Lee - 2/13/2012 3:40:42

The reading for Feb 13 was on the human brain and how to model the way it functions as a processor, which was broken up into three parts: a perceptual system, a motor system, and a cognitive system. The perceptual system takes in input, the motor system interacts with the world, and the cognitive system is largely involved in connecting the perceptive input with the proper motor response. The reading gave the average latency of various human tasks such as perceiving a sound or pressing a button. It also discussed memory, and the difference between working memory and long-term memory. One thing I found most interesting is that in the example of the calculator button, where placing the button in a more favorable location, despite it being farther away, is still faster for users to press (or more likely, to find and then press). This is something to keep in mind while designing interfaces.

Jessica Ho - 2/13/2012 3:44:29

It's interesting to compare computer processors to humans. Perhaps computers were modeled on the human ideal. Many of the computer processes are similar to human ones, just more efficient.

Lu Cheng - 2/13/2012 3:45:37

I feel like the author brings up a very good point in the end of the first section. "A model so simple does not, of course, do justice to the richness and subtlety of the human mind". Many of the things he mentioned about memory and the motor system are pretty obvious except he explained them in more detail. However, I believe it is paying attention to the "richness and subtlety of the human mind" that really makes a difference towards good design. Looking at human limitations such as the average human's performance in listening, moving, and reaction time, most designs are already taken into account for this since most people do share the same average human performance. Therefore the people who design a product already have human limitations in mind. This article would have been a lot better if it expanded on the subtleties and richness of the human mind. After all, the best designs don't have to push human physical limits and instead should appeal to the intricacies of the human mind.

Kate Greenwood - 2/13/2012 3:56:23

This reading talks about a model we can use to describe how we, as humans, process and interact with information. This, the authors assert, we can do with a model along the lines of any information processing system.**

The model they present divides the "Model Human Processor" into three main principles - those of the (1) perceptual system (2) motor system (3) cognitive system.

This model I think is particularly useful when going about designing an interface since we must make sure to take the workings of these systems into account when designating the affordances of those interface elements. For example, one must make sure that the timing of a required user response to an UI event allows for the user to not just visually perceive said event, but also interpret and understand the meaning of the event, and follow the appropriate motor response.

Jessica Chou - 2/13/2012 4:08:10

The three subsystems of the Model Human Processor are 1) the perceptual system, 2) the motor system, and 3) the cognitive system. The perceptual system stories physical sensations into representations of the mind. The Perceptual Processor Rate Principle states that the cycle time varies inversely with the intensity of the stimulus. The motor system is where thought becomes action. The cognitive system connects perceptual system inputs to motor outputs. The Power Law of Practice says that it will take less time to do a certain task the more you practice. If information is retrieved a few seconds after input, it can be stored in Working Memory or Long-Term Memory or both, but if it is longer than that, it can only be accessed from Long-Term Memory. The Rationality Principle is the fundamental principle of task analysis and states Goals + Task + Operators + Inputs + Knowledge + Process-limits -> Behavior.

Kelvin Jie Lam - 2/13/2012 4:22:04

The reading, The Human Information-Processor, detailed an often used metaphor between a human and a computer processor, but to a much more meticulous and scientific extent. The three major subsystems that the reading goes into, the perceptual system, the motor system, and the cognitive system piqued my interest in how the Kinect could be treated as big part of the perceptual system of a computer, and to an extent the motor system(the auto face tracking/body calibration that the Kinect does is similar to the Head-Eye movement that reading speaks of as part of the motor system). The experiments done to figure out the Fastman-Slowman Ranges, and the Middleman timings for certain human tasks should be very useful when designing any interface for humans. The ranges allow designers to “trick” users into certain perceptions(good example from the reading was how movies are run at 24fps with sound, and 18fps without sound due to those frame rates being around the range humans are no longer able to perceive the unsmooth stuttering between frames). The logarithmic rate at which we improve on skills seems to be very true, and the typing example given was a good example illustrating this point. At the same time though, as I saw the keyboard example, I remembered the more efficient calculator design by moving the f button closer to the user’s default position, and couldn’t’ help but think of the often touted more efficient dvorak keyboard layout compared to the qwerty layout. While the dvorak keyboard may have been more efficient, the gains achieved from using the keyboard perhaps did not exceed the cost of relearning a new layout

Raj Khare - 2/13/2012 4:32:33

I thoroughly enjoyed the readings representations of the human processes. The perceptual system, motor system, and the cognitive system all play parts in the overall system that is the human being. I thought about the human parallel to the processor before but never to such a detailed parallel. Even the representation of remembering memories from events and the operation principles work well in real life examples. The operation principles P2 and P3 describe temporal and spacial locality but also allude to memory tricks people use to help them remember things.

The analyses of moving hands to specific targets and of keystrokes on a keyboard seemed a little over the top as these did not seem like general trends but rather a specific and special case example.

Neel Rao - 2/13/2012 4:38:29

In the big picture, The Model Human Processor treats the human as a computational model. With this abstraction, we can use math to describe human processes like visual processing, auditory processing, memory and reaction times. With these equations, designers can develop responsive interfaces relative to human processing speed. Many of these equations deal with rates. There are discrete amounts of time where human perception breaks down, and at these cutoff points is where a lot of time/rate related programming occurs. Other equations deal with human psychology and cognitive science.

Juan Banda - 2/13/2012 5:22:31

In this chapter, Raskin describes in great detail some of the things the human mind does. He uses analogies for us to better understand the mind in an abstract sense and at many times relates implicitly compares it to/like a process of a computer. He describes the performance/perception/cognition/motor/etc of the brain/body for us to better understand how the mind interacts with the world. He informs us with this type of information, such as memory and its accuracy, motor skills, and reaction time, because he believes that understanding the body at a lower abstract level, we can fine-tune interfaces to be more compatible with the human body. From previous readings and lecture slides, this chapter provides the necessary information for cognetics.

Victor Kmita - 2/13/2012 5:42:45

I never realized how much of our brain's natural response to stimuli is scientifically described and how much it can draw analogies from a processor. The unit impulse response by the perceptual processor is a good example about how much we have studied different aspects of body function. Measurements are done in milliseconds on this scale when computing this unit impulse response, and also the recognize-act cycle. We have even developed a variable cognitive processor rate principle, which states the cognitive processor cycle time is shorter when greater effort is induced by increased task demands or information loads, also diminishing with practice. This diminishing with practice can be attributed to forming habits as discussed in our previous readings..

Danube Phan - 2/13/2012 6:03:14

The Model Human Processor can be best described as an integration of memories and processors operating according to a set of principles, called the principles of operation. The Model Human Processor is composed of three integral subsystems: the perceptual system, the cognitive system, and the motor system. Likewise, each subsystem comes with a corresponding processor in order for the human to be able to react appropriately and make decisions about the world. I find it rather interesting that the author is making a sort of mechanical analogy of the human with processors and technology. How the human mind is integrated together so perfectly and how humans are able to adapt and perform quickly might still be too difficult to grasp in implementing today's technology.

Douglas Treadwell - 2/13/2012 6:23:03

I'm not sure what to say about The Model Human Processor other than that it is interesting. The article provides a lot of detailed quantitative information about human processing capabilities that could be useful as a reference later, but are difficult to remember. I'm not new to this idea, and I'm sure most EECS students have come across it before, so maybe it's less interesting because there isn't any novelty in the idea anymore. There are obviously many applications of the detailed quantitative information though, such as determining how long it should take for a fast or slow user to input information, estimating time savings by automation, and so on.

Robert Marks - 2/13/2012 6:33:48

This week's reading presented a tremendous amount of information about the process and operation of cognition. I was astounded to see how fast the brain processes sensory information, and that it is necessary due to the short storage time for this data. I was very interested by the methods and models they used to measure improvements in time for repeated tasks, and that they got somebody to repeat the same test 50,000 times. It is interesting how it follows a logarithmic scale.

This information about improved performance, makes it seem like I should design interfaces that allow users to quickly gain skills, in order to get them up to the transition point.

This reading made me think about the speed of information that I display to users, and why it is important to make previous information easily accessible for review.

Varad Kishore - 2/13/2012 7:10:38

The reading introspectively creates a high level model for the human mind or 'processor', which t divides into the perceptual system, the motor system and the cognitive system. The perceptual system enables us to perceive with eyes and other sensory organs. These signals then form perceptual memories such as those in the Visual Image Store and the Auditory Image Store, which decay over time. The author goes on to expand on the three systems and their various sub-components. While the material in the reading was intriguing, I found the mathematical portrayals tedious since a higher level description would have sufficed.

Mark Peng - 2/13/2012 7:17:34

It's interesting to see the human mind being broken down into a software-like system-- the three interacting subsystems and even as far as naming variables like memory decay. Perception is like the input reading system of a human, which correlates to perceptual memories. This subsystem itself has a "processing speed", related to the frequency with which we can perceive events. Then there is the motor system, which is responsible for all motor activities, which can also have measured variables. Unsurprisingly, the cognitive system is the most complex, with it's processing split into a "recognize-act" cycle. From breaking down the systems like this, we can find upper limits for certain activities, which can serve as barriers to human capability. We can only recognize a certain number of frames per second, we can hear Morse code at a certain speed, etc, seem more like physical limitations, while reading rate, motor skill, or choice reaction time seem to be more of an estimate of human ability. There is also the complex interaction of learning and retrieving information, whether it happens in current (working) memory, or stored (long-term) memory. These systems are made even more complex, producing more inconsistent behavior, due to memory strength, interference, and decay.

Camilo King - 2/13/2012 7:25:29

This reading describes the human mind as a "processor", and divides it into 3 parts: the perpetual system, the motor system, and the cognitive system. The perpetual system consists of sensors and memory buffers. The motor system is responsible for physical actions and muscle control. And lastly the cognitive system connects the perpetual and motor system. I found it interesting that the cognitive system was responsible for two kinds of memories: the long term and short term. I also found the uncertainty principle very interesting because of the fact that it seems very true and is supported with an equation

Ashley Hsu - 2/13/2012 8:19:24

While doing this reading, I found it interesting to see that people can and have quantified the way humans think and act. It made me feel slightly uncomfortable, actually, thinking that everything I do and think has a variable and standard time associated with it. However even the authors conceded that these numbers are meant for predicting actions for the gross population and not just one individual. It is relevant to design because it gives us a base of concrete numerical analysis to build our design from, and the readings presented good examples of how to approach human actions with a numerical analysis mindset. The readings also illustrated several theories of psychology that can produce obstacles to design such as the time it takes for humans to react to choices.

Can Zhang - 2/13/2012 8:21:21

How useful are these data to HCI anyway? Sure, there might be a lot of hard stats, but HCI is powered as much by inertia as usability. How might these data be meaningfully used given that for example there's just way too much inertia for QWERTY keyboards so that dvorak never really would catch up despite claims of being a superior layout?

Adib Kashem - 2/13/2012 8:34:03

According to the reading, it is useful to construct a model of human cognition and action such as the Human Model Processor and the overall purpose is to somewhat quantize and emulate the way a human mind might work when accessing a certain user interface. By simulating how the UI would work with different users , i.e. different set of motor skills, and different cognition attributes, one can test how well the UI would work. If there are problems apparent with the UI, then they can adequately be fixed. This model, however, has limits including that it is very general and that it does not account for human variations. Furthermore, since the Model Human Processor is quantitative, it does not do a good job of revealing other information, such as how comfortable the user feels with the UI or how aesthetically pleasing it is.

Ritu Kiragi - 2/13/2012 8:45:34

Humans are often compared to computers, especially when one tries to explain the steps in the inner workings of a computer, but this is the first time I've seen the metaphor taken so literally and so in depth. The idea that there is a basic quantum of experience stood out to me. I always thought of it as being more of a flow but now that I think about it, I realized it has to be a quantum experience. We take an input, process it, and then move on to the next one. However, we do this so quickly that it seems fluid to us. This is an analogy often seen in manmade technologies and interfaces.This reading is useful in giving a different perspective to keep in mind while designing user interfaces. We were presented with a lot of quantitative details, which is a nice change from the usual abstract concepts we deal with while talking about user interfaces. I also have to applaud the authors; they gathered so much specific, minute information and then calculated so many movements that I have never even tried quantifying. I also never did so because I didn't think it would even make sense to do so because people are so different in their manner of thinking, reacting, and behavior that I thought even an average wouldn't be of much use. However, I can now see that I can use this data in designing a better user interface. I also appreciate the things I learned about my short term and long term memory that I can apply to my life in general, especially studying. Interference in working memory seems similar to what I've learned in linguistics, and is an important point to remember in design.

Danny Tan - 2/13/2012 8:46:12

The Model Human Processor is a model of the human mind as an information-processing system, used to remember facts and predict user-computer interaction. It is a set of memories and processes along with a set of principles called the principles of operation. The most important parameters of memories are the storage capacity in items, the decay time of the an item, and the main code type (physical, acoustic, visual, semantic). The most important parameter of processes the cycle time. The Model Human Processor can also be divided into three subsystems: the perceptual system, the motor system, and the cognitive system. The perceptual system deals with sensory information and the associated buffer memories for visual and auditory information. The cognitive system makes decisions based on coded information from both Working Memory and Long Term Memory. The motor system carries out the responses based on the decisions. All three can systems can be considered its own processor and work simultaneously in parallel.

Jessica Miller - 2/13/2012 8:46:24

This reading discussed the similarities between human information processing and a computer's information processing. The article broke down human information processing into three components: perceptual processing which takes in information from the physical world, cognitive processing which is responsible for chunking perceptions and information as well as fetch info from memory, and motor processing which is comprised of the physical movement to complete an action ( ie reaching for a pen or cup) I thought the most interesting part of the article is that it discussed how we can use all this information to design for human-computer interaction. The article broke down how long each process takes for a human to process. For example, the keyboard was designed with all these components in mind. It was designed in a way that the most commonly used letters in the alphabet are more easily and quickly typed. Overall, this article showed me the amount of details and research needed in order to develop and design a good human-computer interaction.

Lingbo Zhang - 2/13/2012 8:59:09

The reading introduces the Model Human Processor (drawing an analogy to information-processing system), which is an interconnected set of memories and processors governed by a set of operational principles. Each of three subsystems in the Model Human Processor has its own set of memories and processors, and their characteristics may be summarized by processor cycle time, memory decay rate, memory capacity, memory code type. The reading goes on to describe this model in application, through consideration of factors impacting human performance such as perception, reading rate, Power's Law of Practice, searching Long-Term memory etc. Lastly, the reading considers shortfalls and expansions to the Model Human Processor (in its descriptions of the Long-Term Memory, Perceptual Processing, Cognitive Processor), and defends the model's usefulness in the face of alternative models.

Paige Dunn-Rankin - 2/13/2012 9:01:37

This reading treats humans as computer processors (or rather it uses this analogy to explain phisiological and psychological capabilities). It talks about three systems: perception, motor, and cognition, and discusses the interactions between the three. Sometimes they interact in series, sometimes in parallel; memory is thought by most to be the bottleneck and gets the most treatment here. Most interesting to me was the rate of decay of items in working memory an the fact that breaking things into specific and recognizable chunks helps with memory retrieval. I think it's useful to think about how to help users break down and retrieve the information in a UI as systems aren't necessarily getting more complex in terms of motor or perception, but are getting more complex in terms of the amount of information they display.

Bhavik Singh - 2/13/2012 11:10:28

This weeks reading seemed to be a new spin on how users can interact with interfaces. While human biology, and the limits of our abilities often play a part in our day to day actions, I never thought that user interfaces could, or were, designed keeping them in mind. I specifically liked the example of the calculator. Through it, for the first time, an interface problem was dealt with using mathematical and scientific methods, instead of more abstract concepts.

That being said, i found it very difficult to see how this reading would apply to most computer based interfaces. Most of the problems proposed by the reading (such as the refresh rate for eyes), are solved by using modern day hardware that makes these limitations inconsequential. In the case of the Kinect however, perhaps we can apply the same strategy as used in the reading, and break down our UI problem into a mathematical one by collecting and analyzing data.


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