Human Factors Test 2

Fitt's Law
MT = a + b x log (A/W +1)
what does a mean?
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Terms in this set (64)
Fitt's Law
MT = a + b x log (A/W +1)
what does a mean?
startup time of movement
Fitt's Law
MT = a + b x log (A/W +1)
what does b mean?
slope, efficiency of movement
Fitt's Law
MT = a + b x log (A/W +1)
what are a + b?
constants (device specific)
Fitt's Law
MT = a + b x log (A/W +1)
what does MT mean?
movement time
Fitt's Law
MT = a + b x log (A/W +1)
what does log x (A/W + 1) mean?
index of difficulty
log x (A/W + 1)
what does A mean?
amplitude
log x (A/W + 1)
what does W mean?
width
As a designer, you want to _________ index of difficulty.
minimize
two ways to minimize index of difficulty:
-decrease amplitude
-increase width
-both
Fitt's Cheats
-pop up menus at cursor
-use edges/corners
-radial menus
A(n) ______ display is useful if the operator needs to react quickly, but make sure the system is reliable at choosing the best response.command displayWhat is true about abbreviations with respect to facilitating comprehension?abbreviate by truncation, not contraction. This preserves familiar letter sequence. EX: Abbrev vs. Abbrevt (use second, not first)Positive phrasings vs. negative phrasing-positive phrasings are understood faster than negative phrasings -positive phrasing are understood faster and remembered more accurately than negative phrasingsTo enhance text comprehension, you should:-use positive statements -avoid logical reversals -be clear and direct; avoid unnecessary wordsLogical reversals:keep sequence of instructions congruent with the order they are performed (steps 1, 2, then 3)To enhance icon recognition, cerate icons featuring unique _____, which are simple 3D shapes that can be combined to represent all objectsgeonsGeonssimple 3D shapes that can be combined to represent all objects -objects can be built from geonsTo facilitate comprehension, it is generally recommended (with the exception of one word messages) that text be presented in:mixed case... this preserves word shape and aids in recognition.two concerns in using icons:legibility and interpretationlegibility and icons-icons viewed under poor conditions may not be recognizable -use qualitative, global shape differences (unique geons) to make icons discriminableSingle words are recognized well:in all caps ex: CAUTION!According to Sanders and McCormick an effective warning is made of the following components:signal word, hazard, consequences, instructionWhat influences increase warning effectiveness?-perceived product danger -present warning first -salience -education/trainingWhat influences decrease warning effectiveness?stress and time pressureage trends and hearing-more pronounced in men -2nd only to arthritis as problem for 75+ -relative preservation 500-1000 Hz range -large decline in higher frequenciesOlder adults have a particular problem distinguishing between the colors?blue greenperceived usefulness (U)degree to which an individual that using a system will help him or her achieve a goalperceived ease of use (E)degree to which an individual believes that the system will be easy to usePopular models of technology acceptance such as the Technology Acceptance Model proposes that the two most important factors influencing technology acceptance and adoption are...perceived usefulness and perceived ease of useWhat characterizes old adults' attitudes toward privacy with respect to technologies such as telehealth technology?they are generally more accepting of decreased privacy as their functioning decreases_______ memory is like a mental workbench and is composed of three components: central executive, visuospatial sketchpad, and articulatory loop.Working memory________ memory is relatively permanent and may not have a limit to its capacitylong term memoryChunkingcommon strategy that can allow users to be pass the strict capacity limits (7 plus or mins 2) of short term memorygeneral characteristics of STM-capacity = 7 plus or minus (millers magic number) -based on absolute judgment and memory span data -items held can be complex chunks of info: words, sentences strings of digits or letters -duration = 15-18 secs with rehearsalBrown-Peterson Paradigmremember a nonsense string while performing a distracting taskcentral executiveresponsible for control activities, including working memory subsystemsvisuospatial sketchpadholds mental images and spatial infoarticulatory loopholds mental speech and verbal info, soundslong term memory-holds a large amount of info for a ling time (hours to years) -are not aware of info in long term, it must move into working memory before you are conscious of it -divided nto specialized parts: sensory memories, motor memories, etc -may not have a limit to its capacityLearning progresses through 3 stages. The last stage is called the _________ stage. At this point performance is confident, consistent, and almost error free.autonomous stageLearning progresses through 3 stages. The first stage is called the _________ stage. At this point performance is very error prone and attentionally demanding.cognitive stagecognitive stage1st stage of learning progress -development of basic movement pattern -high degree of cognitive activity -attentional demands high, limited to movement production -movement lack synchronization and appear choppy and deliberate -numerous errors, typically gross in nature -lacks capability to determine cause of errors or correct themassociative stage2nd stage of learning progress -refinement of movement pattern -more consistent -attentional demands for movement production decrease -fewer, less gross errors -better at detecting cause of errors -begin to develop appropriate error correction strategiesautonomous stage3rd and final stage of learning progress -performance os movement virtually automatic -highest level of proficiency -not all learners will reach this stage -attentional reallocated to strategic decision-making -consistent -confident -make few errors and can generally detect and correct those that do occurpros of part-task trainingtask down into manageable chunks, attentional overload avoidedcons of part-task training-little practice with how these chunks are managed together to perform the whole task -does not train time-sharing skillspros of whole-task trainingover the course of practice, learners develop a task representation that includes how elements fit togethercons of whole-task traininglearners may initially be overwhelmed dividing attention across elements of complex taskFor training a complex task, the benefit of ____________ training is that attentional overload can be avoided, but the disadvantage is the learners don't have the opportunity to learn how different parts of the task interact; it does not train time-sharing skills.part-task trainingFor training a complex task, the benefit of ___________ training is that learners develop a task representation that included how task elements fit together, but they may be initially overwhelmed dealing with all of the aspects of the complex task.whole-task trainingCompromise between whole and part task training:variable priority trainingvariable priority training(aka emphasis change training) subtask emphasized, one at a time, but in the context of the whole task.variable priority training leads to:-better overall learning -greater transfer of training -greater retentionachieving expertise requires:deliberate practice -performed with specific goal of improving performance -targeted at developing specific skills -demands effort and heavy concentrationthe 10 year ruleelite level performance requires ~ 10 years/10,000 hours of deliberate practicehigh level (6-10) automationfunction mostly autonomous from an operatorlow level (1-5) automationrequire input from an operator to functionAs systems move from lower 1-5 to higher 6-10 levels of automation, what is the difference?system becomes more autonomous from operatorovertrust-also called complacency -not a problem until automation fails -ironically more reliable system introduce greater riskcomplacency is a cognitive state-reliable automation mean automation failures rare, difficult to detect -less monitoring of the situation as reliability increases: loss of situational awareness- hard to jump back in since the operator hasn't been making choices they are less aware of the pervious actions of the systemskill degradationif operator greatly relies on automation, their skill at performing the task may degrade over timeout of the loop unfamiliaritydegraded detection + awareness + skillbenefits of automation need to be...balanced against wish of out of the loop unfamiliarity syndrome. -intermediate levels of automation may best balance risks and benefitsdisuse of automation-prematurely stopping the use of automation even though it would improve efficiency or reduce negative outcomes -often the result of operators having insufficient trust in automation