ise 231 exam 1 improved

Accommodation

The changing shape of the lens to accommodate focus on objects viewed at different distancing

Acuity

The amount of fine detail that can be resolved is far greater when the image falls on closely spaced cones than on the more sparsely spaced rods; often expressed as the inverse of the smallest visual angle (in minutes of arc) that can be detected

Adaptation

When simulated by light, the rods rapidly lose their sensitivity, and it will take longer for them to regain it. However, the cones may become hypersensitive when they have received little simulation

Anthropometry

The study and measurement of human body dimensions

Axure

A wireframing, rapid prototyping, documentation and specification software tool aimed at web and desktop applications

Between-Subjects Design

Different groups of subjects are used for each level or experimental condition

Biomechanics

Analyzes the human musculoskeletal system as a mechanical system that obeys laws of physics. Thus, the most basic concepts of occupational biomechanics are those concerning the structure and properties of the musculoskeletal system and the laws and concepts of physics

Bottom-Up Processing

Lower level of stimulus (touch, smell, sight)

Cognitive Engineering

In essence, it focuses on the complex, cognitive thinking and knowledge related aspects of system performance, independent of whether these operations are carried out by human or by machine agents, the latter dealing closely with elements of artificial intelligence and cognitive science

Color Blindness

Unable to discriminate certain hues from each other. Most prevalent here is so-called red-green "color blindness" (protanopia), in which the wavelengths of these two hues create identical sensations if they are of the same luminance intensity

Color Sensation

Color blindness, color deficiency;
Two additional characteristics of the sensory processing of color that have some effect on its use. Simultaneous contrast refers the tendency of some hues to appear different when viewed adjacent to other hues. The negative afterimage is a similar phenomenon to simultaneous contrast but describes the greater intensity of certain colors when viewed after prolonged viewing of other colors.

Cones

■ Centrally located in field of view
■ Help you see details (acuity)
■ Ability diminishes in the dark
■ Can detect color

Confounding Variables

If another extraneous variable covaries with the independent variable, it becomes a confound and makes interpretation of the data impossible. This is because the researcher does not know which variable caused the differences in the dependent variable.

Conspicuity

In order to ease visual search, make the target conspicuous so it can be easily detected in peripheral vision

Data Compendiums (Databases)

Sources of information to support human factors aspects of system design. One form consists of condensed and categorized databases, with information such as tables and formulas of human capabilities

Dependent Variables

The variable being affected by another's change in an experiment

Descriptive Methods

Only theory; cannot actually be tested. Relies on measurement of variables such as performance, opinion, etc.

Descriptive Statistics

Summarize the dependent variable for the different treatment conditions (usually using mean)

Destination

A target for eye movements

Efficiency

Ideally, high productivity level should be possible for any product made

Engineering Psychology

A discipline within psychology that tends toward greater emphasis on discovering generalizable psychological principles and theory, while human factors tends toward greater emphasis on developing usable design principles.

Environment

The place in which a task or design is being performed/implemented

Environmental Analysis

All tasks should be evaluated in environment in which the tasks will be performed

Equipment

Equipment design- the nature of the physical equipment in which humans must work

Ergonomics

Focused more directly on the aspect of human factors related to physical work lifting, reaching, stress, and fatigue. This discipline is often closely related to aspects of human physiology, hence its closeness to the study of biological psychology and bioengineering. Ergonomics has also been the preferred label in Europe to describe all aspects of human factors

Type I error

Accidentally concluding that independent or causal variables had an effect when it was really just chance is referred to as making

Type II Error

Concluding that the experimental manipulation did not have an effect when in fact it did

Expectancies

Top-down implications of searcher expectancies of where the target might be likely to lie

Experimental Methods

Deliberately producing a change in one or more causal or independent variables and measuring the effect of that change on one or more effect or dependent variable

Steps Include: Defining a hypothesis, specifying an experimental plan, conducting the study, analyzing the data, and drawing conclusionsDeliberately producing a change in one or more causal or independent variables and measuring the effect of that change on one or more effect or dependent variable

Eye

The receptor system:
-Light rays first pass through the cornea, which is a protective surface that will absorb some of the light energy
-Light rays then pass through the pupil, which dilates (in darkness) or constricts (in brightness) to try to admit adaptively more light when illumination is low and less when illumination is high
-The lens of the eye is responsible for adjusting its shape, or accommodating, to bring the image into precise focus on the back of the eyeball, a surface called the retina

Pursuit eye movements

Constant velocity eye movements that are designed to follow moving targets

Saccadic eye movements

Abrupt, discrete eye movements from one location to the next

Factor

Independent Variables

Factorial Design

Evaluates two or more independent variables by combing the different levels of each independent variable

Fovea

In the retina, inhabited exclusively by the cones

Color Sensitivity

The rods cannot discriminate different wavelengths of light; the extent to which the rods can resolve hues declines in both peripheral vision and at night

Front-End Analysis

involves applying human factors methods to identify the users, their needs, and their tasks

Function analysis

Performs an analysis of the basic functions performed by the system; only lists general categories

Task analysis

Specifies the jobs, duties, tasks, and actions that the person will be doing; usually done through interviews, then focus groups, then observations

Gestalt Principle

Things are affected by where they are and by what surrounds them...so that things are better described as "more than the sum of their parts."Gestalists believed that context was very important in perception

Heuristic Evaluation

Analytically considering the characteristics of a product or system design to determine whether they meet human factors criteria

High-Fidelity Prototype

Include fully interactive screens, having the look and feel of the final software.

Human Factors Design Standards

Precise recommendations that relate to very specific areas or topics (e.g. safety, labeling, video/audio displays)

Human Factors Principles and Guidelines

Abstract principles and guidelines for information about design standards(there are thousands of sources)

Illuminance

The amount of the energy that actually strikes the surface of the object to be seen; measured in units of lux

Incident and Accident Analysis

Evaluate the occurrence of incidences (noticeable problems without accident), accidents, or both in order to determine the overall function of the system, esp. with respect to safety.

Independent Variable

The variable being changed by the experimenter in order to see the effect on the dependent variable

Industrial Design

Front-end analysis, Conceptual design, iterative design and testing, interface design, final design and testing

Inferential Statistics

Calculate the likelihood that any differences between our experimental groups are real and not just random fluctuations due to chance

Initiation Latency

Feature of saccadic eye movements

Iterative Design

Using prototypes

Unstructured Interviews

Where the specialist asks the user to describe their activities and tasks but does not have any particular method for structuring the interview

Structured interviews

Particular questions and methods, which makes the process more efficient and complete

Learnability

How easy is it to learn how to use a product?

Lens

The lens of the eye is responsible for adjusting its shape, or accommodating, to bring the image into precise focus on the back of the eyeball, a surface called the retina

Light sensitivity

Although the cones have an advantage over the rods in acuity, the rods have an advantage in terms of sensitivity, characterizing the minimum amount of light that can just be detected or the threshold. Sensitivity and threshold are reciprocally related. Since there are no rods in the fovea, it is not surprising that our fovea is very poor at picking up dim illumination (i.e., it has a high threshold).

Location

The middle region of the retina, called the fovea, is inhabited exclusively by the cones. Outside of the fovea, the periphery is inhabited by rods and cones

Luminance

The amount of light reflected off of objects to be detected, discriminated, and recognized by the observer; measured in units of foot lamberts (FL)

Memorability

Easy to remember how to use a product

Mixed Design

In factorial designs, you can use both within and between subject designs

Movement Time

A feature of saccadic eye movements

Multiple-Group Design

One independent variable with many levels of the variable

Myopia

Known as nearsightedness, results when the lens cannot flatten and hence distant objects cannot be brought into focus

Observation

Spend time watching users perform different tasks under different scenarios

Paper Prototype

Most usability specialists use a variety of "prototypes" which may range in fidelity, with low-fidelity methods including index cards, stickies, paper and pen drawings, and storyboards.

Parallel Search

Items that are extremely conspicuous and search time does not increase with the total number of items

Performance

Monitoring the functioning of an entire system that includes the human as one component; hard to measure as one thing, often measured in clusters

Practical Significance

Is the difference between control and experimental worth the cost of implementation

Presbyopia

Known as farsightedness, results when the lens cannot accommodate to very near stimuli

Primary Colors

Red, blue, and green make up all other colors

Prototyping

Creating models of an actual product in order to test usability, user preference, etc.

Pursuit Movement

Constant velocity eye movements that are designed to follow moving targets

Product Design Lifecycle

Product lifecycle models also add product implementation, utilization and maintenance, and dismantling or disposal. Table 3.3 shows a generic lifecycle model and lists some of the major activities performed by human factors specialists in each stage

Reflectance %

luminance (FL) / Illumance (FC)

Basic research

The development of theory, principles, and findings that generalize over a wide range of people, tasks, and settings

Applied Research

The development of theory, principles, and findings that are relatively specific with respect to particular populations, tasks, products, systems, and/or environments

Descriptive Research

Researchers measure a number of variables and possibly evaluate how they are related to one another

Retina

Back surface of the eyeball, home of the fovea and the periphery

Rods

■ Located on periphery of vision
■ More sensitive to light
■ They are responsible for night vision
■ Cannot detect color

Saccades

A visual search using saccadic eye movements

Saccadic Movements

Abrupt, discrete movements from one location to the next

Safety

A concern for human factors specialist is the ensure a customer's safety

Satisfaction

A HF specialist tries to ensure the satisfaction of their user, meaning that the product is pleasant to use

Selection

Performance can be optimized by selecting operators who possess the best profile of characteristics for the job

Semi-Structured Interview

They have an outline but it's not a strict structure

Serial Search

Each item in a field is inspected in turn to determine whether it is or is not a target.

Average time it will take to find a target

T = [total number of items in the search field (N) * Inspection time for each item (I)] / 2

type I error

accidentally concluding that there is a relationship between variables when there isn't

Type II error

concluding that the experimental manipulation did not have an effect when it did

Structured Interviews

The researcher asks questions and records answers

Surveys and Questionnaires

Both basic and applied research frequently rely on surveys or questionnaires to measure variables. A questionnaire is a set of written questions or scales used for both experimental and descriptive research. Survey research is "the systematic gathering of information about people's beliefs, attitudes, values, and behavior"

Task

What a person must accomplish

Task Performance with Questioning

User is asked specific questions while performing the task (risk of disruption!) or while watching videotape of their task performance

Think-Aloud Verbal Protocol

Having the user think out loud as they perform various tasks; yields insight to underlying goals and strategies
1. Concurrent- obtained during performance
2. Retrospective- obtained after via memo

Top-Down Processing

Toward the higher centers of the brain involved with perception and understanding

Training

Better preparing the worker for conditions that he or she will encounter in the job environment

Two-Group Design

One independent variable is tested with only two conditions (control and experimental)

Unstructured Interview

Where the specialist asks the user to describe their activities and tasks but does not have any particular method for structuring the interview

Usability Testing

1. Learnability- easy to learn
2. Efficiency- high productivity level should be possible
3. Memorability- easy to remember
4. Errors- low error rate
5. Satisfaction- pleasant to use

User Analysis

Potential system users are identified and characterized for each stage of the lifecycle.The most important user population is those people who will be regular users or "operators" of the product or system.