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Glossary » Psychology

mental map

(website navigation) a representation in a person’s mind of the structure of a website, which is likely to be incomplete and simplified. A mental map helps people simplify the job of remembering what they’ve seen to the problem of remembering…

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mental model

Humans establish mental models of how things work, or how they would behave in a particular situation. For example, having been a student at a university for a while, a student can establish a “mental model” of attending a university.…

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Meyer’s Law

T = A + B * SQRT(D/W)

T = time to move to a target
D = distance to target
W = width of target
A ~ -13 msec
B ~ 108 msec

Meyer’s Law is…

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Model Human Processor. A simple cognitive architecture used as the basis of the GOMS family of user modeling techniques. This representation of human cognition consists of separate components for cognitive, motor, and perceptual processors (and associated buffers), as well as…

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an error of reasoning or inappropriate subgoals, such as making a bad choice or failing to think through the full implications of an action.

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mode error

a type of slip where a user performs an action appropriate to one situation in another situation, common in software with multiple modes. Examples include drawing software, where a user tries to use one drawing tool as if it were…

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mundane realism

the extent to which a study, such as user testing, matches the real-world situation to which its results will be applied. This is an example of an external validity concern. This means matching the types of users being tested and…

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Natural GOMS Language. NGOMSL was developed as a formally defined version of CMN-GOMS based on cognitive complexity theory (CCT). It has a more structured hierarchy than CMN-GOMS and a well-defined analysis methodology for developing models. In addition to the execution…

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nominal-ordinal-interval-ratio. A mnemonic for remembering common data scales used in empirical measurement.

Nominal – a set of items that can be distinguished by name or category. Ordinal – items that can be ordered, such as military rank, or units of

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opportunistic goals

user goals that are formulated on the spot in reaction to prominent system events or displays that suggest those goals.

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pilot test

or formative test; an initial run of a study (e.g. an experiment, survey, or interview) for the purpose of verifying that the test itself is well-formulated. For instance, a colleague or friend can be asked to participate in a user…

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power law of practice

an expression of time to perform a task based on practice trials, saying that people improve in speed at a decaying exponential rate.

Tn = T1 n-a, a ~ 0.4

Tn = the time to perform a task after n…

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prototype-instance model

(programming) a version of object-oriented programming that does not have classes. Instead, objects inherit behavior directly from other objects. This dramatically simplifies the language by removing unnecessary concepts such as metaclasses. This approach was popularized by the “Self” language.


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psychology of programming

PoP; the study of how programmers create software, including such topics as learning a programming language, planning a program, how language features affect coding time and accuracy, and how programmers isolate and repair bugs.

In addition to understanding basic principles…

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a discipline of psychology that measures the response characteristics of human perception in a method parallel to measuring the response characteristics of physical materials. The prototypical examples are human perception of the intensity of light and sound. People report the…

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question-asking protocol

in contrast to the think aloud protocol, in which users are asked to speak freely about their thoughts without prompting from the tester, in the question-asking protocol, the tester explicitly asks the user questions during the user testing session, to…

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a means of expressing that participants in a conversation come with different skills and interests and should have a user-interface that reflects their personal needs.

Roles such as chairperson, scribe, and facilitator reflect a set of access capabilities to shared…

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a theory of human reasoning that says that people minimize cognitive load by minimizing reasoning and using quick heuristics to make decisions. Thus, people avoid complex memory, planning, and decision-making in favor of acting upon information immediately available perceptually, well-known…

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schedule chart

a diagram used in project management, planning, and scheduling. The schedule chart shows the different resources and activities involved in a project and time dependencies between them. With this diagram, a critical path can be found that indicates the shortest…

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selection bias

in choosing test users for a usability study, selection bias is any imperfection in the selection process that gets either the wrong types of users (people who aren’t in your target audience) or a sample of users that is not…

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any method of gathering usability data through having the user report what happened. This may be by having users record themselves on tape or writing down in diaries. They may range from open-ended reflections to very specific questionnaires that users…

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semantic differential

a type of survey question where respondents are asked to rate their opinion on a linear scale between 2 endpoints, typically with 7 levels. For example:

Please rate this software on the following dimensions:

easy to use 1 2 3

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sensory modality

A communication channel associated with one of the human senses of sound, vision, touch, smell or taste. As used in discussing usability this may imply input to and output from the computer as well as the human user. E.g., the…

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single-case experimental design

a method for determining the effect of an experimental manipulation with only one test subject (one user, one organization, etc.), basically by applying and removing the intervention over time:

    measure the dependent variable initially apply the intervention, and measure

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situated action

the notion that people’s behavior is contextualized, i.e. the situation is a very important factor in determining what people will do. In the extreme view, this is the idea that you can’t generalize and predict people’s behavior from one situation…

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