Human processor model or MHP (Model Human Processor[1]) is a cognitive modeling method developed by Stuart K. Card, Thomas P. Moran, & Allen Newell (1983) used to calculate how long it takes to perform a certain task. Other cognitive modeling methods include parallel design, GOMS, and keystroke-level model (KLM).
Cognitive modeling is one way to evaluate the usability of a product. This method uses experimental times to calculate cognitive and motor processing time. The value of the human processor model is that it allows a system designer to predict the performance with respect to time it takes a person to complete a task without performing experiments. Other modeling methods include inspection methods, inquiry methods, prototyping methods, and testing methods.
The standard definition for MHP is: The MHP draws an analogy between the processing and storage areas of a computer, with the perceptual, motor, cognitive and memory areas of the computer user.
The human processor model uses the cognitive, perceptual, and motor processors along with the visual image, working memory, and long term memory storages. A diagram is shown below. Each processor has a cycle time and each memory has a decay time. These values are also included below. By following the connections diagrammed below, along with the associated cycle or decay times, the time it takes a user to perform a certain task can be calculated. Studies into this field were initially done by Stuart K. Card, Thomas P. Moran, & Allen Newell in 1983.[1] Current studies in the field include work to distinguish process times in older adults by Tiffany Jastrembski and Neil Charness (2007).
The calculations depend on the ability to break down every step of a task into the basic process level. The more detailed the analysis, the more accurate the model will be to predict human performance. The method for determining processes can be broken down into the following steps.
Write out main steps based on: a working prototype, simulation, step by step walk-through of all steps
Clearly identify the specific task and method to accomplish that task
For each final step identify sub-levels down to a basic process (in the diagram or chart below)
Convert into pseudo code (writing out methods for each step)
List all assumptions (will be helpful as multiple iterations are completed)
Determine time of each operation (based on the table below)
Determine if operation times should be adjusted (slower for elderly, disability, unfamiliarity, etc.)
Sum up execution times
Iterate as needed and check with prototyping if possible
Parameter
Mean
Range
Eye movement time
230 ms
70–700 ms
Decay half-life of visual image storage
200 ms
90–1000 ms
Visual Capacity
17 letters
7–17 letters
Decay half-life of auditory storage
1500 ms
900–3500 ms
Auditory Capacity
5 letters
4.4–6.2 letters
Perceptual processor cycle time
100 ms
50–200 ms
Cognitive processor cycle time
70 ms
25–170 ms
Motor processor cycle time
70 ms
30–100 ms
Effective working memory capacity
7 chunks
5–9 chunks
Pure working memory capacity
3 chunks
2.5–4.2 chunks
Decay half-life of working memory
7 sec
5–226 sec
Decay half-life of 1 chunk working memory
73 sec
73–226 sec
Decay half-life of 3 chunks working memory
7 sec
5–34 sec
Potential usesedit
Once complete, the calculations can then be used to determine the probability of a user remembering an item that may have been encountered in the process. The following formula can be used to find the probability: P = e-K*t where K is the decay constant for the respective memory in question (working or long term) and t is the amount of time elapsed (with units corresponding to that of K). The probability could then be used to determine whether or not a user would be likely to recall an important piece of information they were presented with while doing an activity.
It is important to deduce beforehand whether the user would be able to repeat the vital information throughout time t, as this has a negative impact on the working memory if they cannot. For example, if a user is reading lines of text and is presented with an important phone number in that text, they may not be able to repeat the number if they have to continue to read. This would cause the user’s working memory’s decay time to be smaller, thus reducing their probability of recall.
Card, S.K; Moran, T. P; and Newell, A. The Model Human Processor: An Engineering Model of Human Performance. In K. R. Boff, L. Kaufman, & J. P. Thomas (Eds.), Handbook of Perception and Human Performance. Vol. 2: Cognitive Processes and Performance, 1986, pages 1–35.
Liu, Yili; Feyen, Robert; and Tsimhoni, Omer. Queueing Network-Model Human Processor(QN-MHP): A Computational Architecture for Multitask Performance in Human-Machine Systems.ACM Transactions on Computer-Human Interaction. Volume 13, Number 1, March 2006, pages 37-70.
Jastrzembski, Tiffany; and Charness, Neil. The Model Human Processor and the Older Adult: Parameter Estimation and Validation within a Mobile Phone Task.Journal of Experimental Psychology: Applied. Volume 13, Number 4, 2007, pages 224-248.
Specific
^ abK., Card, Stuart (1983). The psychology of human-computer interaction. Moran, Thomas P., Newell, Allen. Hillsdale, N.J.: L. Erlbaum Associates. ISBN9780898592436. OCLC 9042220.{{cite book}}: CS1 maint: multiple names: authors list (link)
December 18, 2023
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This article includes a list of references related reading or external links but its sources remain unclear because it lacks inline citations Please help to improve this article by introducing more precise citations June 2015 Learn how and when to remove this template message Human processor model or MHP Model Human Processor 1 is a cognitive modeling method developed by Stuart K Card Thomas P Moran amp Allen Newell 1983 used to calculate how long it takes to perform a certain task Other cognitive modeling methods include parallel design GOMS and keystroke level model KLM Cognitive modeling is one way to evaluate the usability of a product This method uses experimental times to calculate cognitive and motor processing time The value of the human processor model is that it allows a system designer to predict the performance with respect to time it takes a person to complete a task without performing experiments Other modeling methods include inspection methods inquiry methods prototyping methods and testing methods The standard definition for MHP is The MHP draws an analogy between the processing and storage areas of a computer with the perceptual motor cognitive and memory areas of the computer user The human processor model uses the cognitive perceptual and motor processors along with the visual image working memory and long term memory storages A diagram is shown below Each processor has a cycle time and each memory has a decay time These values are also included below By following the connections diagrammed below along with the associated cycle or decay times the time it takes a user to perform a certain task can be calculated Studies into this field were initially done by Stuart K Card Thomas P Moran amp Allen Newell in 1983 1 Current studies in the field include work to distinguish process times in older adults by Tiffany Jastrembski and Neil Charness 2007 Contents 1 How to calculate 2 Potential uses 3 See also 4 ReferencesHow to calculate editThe calculations depend on the ability to break down every step of a task into the basic process level The more detailed the analysis the more accurate the model will be to predict human performance The method for determining processes can be broken down into the following steps Write out main steps based on a working prototype simulation step by step walk through of all steps Clearly identify the specific task and method to accomplish that task For each final step identify sub levels down to a basic process in the diagram or chart below Convert into pseudo code writing out methods for each step List all assumptions will be helpful as multiple iterations are completed Determine time of each operation based on the table below Determine if operation times should be adjusted slower for elderly disability unfamiliarity etc Sum up execution times Iterate as needed and check with prototyping if possible nbsp Parameter Mean RangeEye movement time 230 ms 70 700 msDecay half life of visual image storage 200 ms 90 1000 msVisual Capacity 17 letters 7 17 lettersDecay half life of auditory storage 1500 ms 900 3500 msAuditory Capacity 5 letters 4 4 6 2 lettersPerceptual processor cycle time 100 ms 50 200 msCognitive processor cycle time 70 ms 25 170 msMotor processor cycle time 70 ms 30 100 msEffective working memory capacity 7 chunks 5 9 chunksPure working memory capacity 3 chunks 2 5 4 2 chunksDecay half life of working memory 7 sec 5 226 secDecay half life of 1 chunk working memory 73 sec 73 226 secDecay half life of 3 chunks working memory 7 sec 5 34 secPotential uses editOnce complete the calculations can then be used to determine the probability of a user remembering an item that may have been encountered in the process The following formula can be used to find the probability P e K t where K is the decay constant for the respective memory in question working or long term and t is the amount of time elapsed with units corresponding to that of K The probability could then be used to determine whether or not a user would be likely to recall an important piece of information they were presented with while doing an activity It is important to deduce beforehand whether the user would be able to repeat the vital information throughout time t as this has a negative impact on the working memory if they cannot For example if a user is reading lines of text and is presented with an important phone number in that text they may not be able to repeat the number if they have to continue to read This would cause the user s working memory s decay time to be smaller thus reducing their probability of recall See also editWorking memory GOMS KLM human computer interaction Human reliabilityReferences editCard S K Moran T P and Newell A The Model Human Processor An Engineering Model of Human Performance In K R Boff L Kaufman amp J P Thomas Eds Handbook of Perception and Human Performance Vol 2 Cognitive Processes and Performance 1986 pages 1 35 Liu Yili Feyen Robert and Tsimhoni Omer Queueing Network Model Human Processor QN MHP A Computational Architecture for Multitask Performance in Human Machine Systems ACM Transactions on Computer Human Interaction Volume 13 Number 1 March 2006 pages 37 70 Jastrzembski Tiffany and Charness Neil The Model Human Processor and the Older Adult Parameter Estimation and Validation within a Mobile Phone Task Journal of Experimental Psychology Applied Volume 13 Number 4 2007 pages 224 248 Specific a b K Card Stuart 1983 The psychology of human computer interaction Moran Thomas P Newell Allen Hillsdale N J L Erlbaum Associates ISBN 9780898592436 OCLC 9042220 a href Template Cite book html title Template Cite book cite book a CS1 maint multiple names authors list link Retrieved from https en wikipedia org w index php title Human processor model amp oldid 1152990927, wikipedia, wiki, book, books, library,
