HCI Quiz 2

Direct Manipulation

Users interact with task objects as directly as possible, minimizing the gap between intentions and actions.

Invisible Interface

Users focus on the task rather than the interface; the goal is to achieve this through intuitive design from first use, not practice

Gulf of Execution

Gap between the user’s goal and the actions available to achieve it

Gulf of Evaluation

Gap between the system’s state and the user’s ability to perceive and understand it

Distance

Cognitive effort required to translate goals into actions and evaluate results

Semantic Distance

Difficulty mapping goals to the system’s available concepts and actions

Articulatory Distance

Difficulty expressing and executing an intended action through the system

Direct Engagement

Feeling of controlling task objects rather than the computer or its controls

Direct Manipulation requires both

low distance and direct engagement

Feedback cycle

Translate goals into intentions, intentions into actions, execute actions, interpret system output, and evaluate it against goals

Gesture-based interaction

support direct manipulation when they correspond naturally to actions on the task object; arbitrary mappings require learning

Feedback in direct manipulation

immediate, mapped feedback helps users understand action outcomes. visual and auditory feedback are easier to provide than physical resistance in VR

Invisible Interface Principles

Leverage prior expectations, provide rapid feedback, and align users’ mental models with the system

Novice vs Expert Design

first need natural discoverable interactions, second needs efficiency. Menus and keyboard shortcuts can support both

Usability Evaluation

Observe whether users focus on the task or discuss how to operate the interface. Attention to interface mechanics can indicate poor ____

Direct manipulation Design Principle

preserve directness of manual tasks when digitizing them; minimize unnecessary interaction steps and learning effort

Human Information Processing

Input (perception) → processing (cognition) → output (action)

Process Model

Models humans as systems that process information and act on it.

Central vs Peripheral Vision

First supports color and fine detail, second detects motion but has limited detail

Visual Acuity

Ability to perceive fine detail, generally declines with age

Auditory perception

sound characterized by pitch and loudness, hearing supports sound localization but is difficult to selectively ignore

tactile perception

detects contact based stimuli such as pressure, vibration, and temperature

Haptic feedback

touch based interface feedback; useful for discreet notifications and physical interaction

Multimodal interaction

combines visual, auditory, and haptic channels. feedback should complement other modalities and suit the user’s context

Context Aware Interfaces

Use sensor data to infer context and adapt behavior; senosor readingsare indirect evidence not certainty

perceptual store

brief sensory memory lasting less than a second

Working memory

temporary processing system comprizing: visuospatial sketchpad, phonological loop, episodic buffer, central executive

visuospatial sketchpad

working memory component for visual and spatial information

phonological loop

working memory component for verbal and auditory information

episodic buffer

working memory component for integrating information across systems and organizes it into episodes

central executive

working memory component for coordinating the other components

domain expertise

prior knowledge supports efficient recognition and processing of familiar patterns; the advantage may disappear with unfamiliar or random configurations

rehearsal

repeated mental processing helps retain information

short term memory capacity

approx 4-5 chunks

chunking

group information into meaninful units to reduce memory demands

recognition vs recall

the first identifies presented information; the second retrieves information without direct cues. The first is easier

Long term memory

large capacity storage requiring repeated exposure or rehearsal for effective encoding

Procedural Knowledge

knowing how to perform an action, can be automatic and difficult to explain

Declarative Knowledge

knowing facts that can be stated

Cognitive Load

mental resources required for a task. Stress, anxiety, and distractions compete for limited resources

Cognitive Offloading

use external tools or interfaces to reduce mental demands, such as displaying previously entered information or automatically checking code

distributed cognition

cognitive work is shared across people, tools, and external representations

cognitive load design principles

use complementary modalities, let users control pacing, emphasize essential content while reducing clutter, automate tasks, and externalize information users whould otherwise need to remember

motor system constraints

physical abilities, including movement speed and targeting precisison affect interaction

Motor Errors

Occurs when users understand the intented action but cannot accurately execute it under the circumstances or undo mechanisms

Error Tolerant Design

Reduce accidental activation through adequate target spacing, confirmation, or undo mechanisms

Domain dependent human factors

releveant abilities vary by application, for example motor control for wearables cogntion for educational technology, and perception for VR

Human Centered Design

Account for users’ perceptual, cognitive, and motor abilities within the context of user

Design Alternatives

Second design life cycle stage to generate many possible solutions then synthesize and narrow to a handful for prototyping

problem space

the problem and user needs to address

design space

the range of possible solutions, devices, and interact methods to address problem anduser needs

Premature Design Commitment

choosing a solution or technology before understanding the problem, limits exporlation and can produce inferior designs

divergent thinking

generate many diverse ideas before evaluating or selecting them. Discarded ideas can inform better solutions

Brainstorming principles

prioritize quantity, defer judgement, build on others’ ideas, stay focused, state ideas briefly, and encourage participation. Aim for at least 20 ideas

brainstorming techniques

individual brainstorming before group discussion; constrained brainstorming to encourage diversity; incubation (take breaks); divide and conquer (brainstorm subproblems seperately)

Social loafing in brainstorming

reduced individual effort, the tendency of individuals to put forth less effort and generate fewer ideas when working in a group compared to when they work alone

Conformity in Brainstorming

happens when group members change their ideas, censor themselves, or agree with others just to fit in or avoid standing out

Production Blocking in Brainstorming

When participants knowingly or unintentionally block the ideas of others usually due to difficulyt of those participants to speakp

Performance Matching in brainstorming

tendency for individuals to match their effort and performance to others in the group, tendency for excited and motivated participants to match less enthusiastic participants

Power Dynamics in Brainstorming

occur when formal authority (such as titles and rank) or informal influence (such as experience, status, or personality) shapes who speaks, whose ideas are valued, and how the group makes decisions

Effective Group Brainstorming

Make rules explicit, discuss each person’s ideas, keep groups small, limit speaking time, and defer final decisions

Personas

Fictional representations of real user types, including goals, motivations, behaviors, context, and emotions; use multiple personas to represent distinct users and stakeholders.

Formulaic user profiles

 Systematically define user characteristics and their possible values to delineate the target audience and explore combinations of user types

User-model dimensions

Expertise, engagement, motivation, technological literacy, and usage frequency. Frequent users need efficiency; infrequent users need discoverability. Design can support both through visible controls and shortcuts.

Timelines

 Map what a user does, thinks, and feels across the stages of a task, including triggers, preparation, task activities, and aftermath. Reveal needs and opportunities over time.

Scenarios

 Describe a specific user interacting with a design in a particular context or situation. Useful for evaluating alternatives and identifying edge cases that routine-focused methods may miss.

Storyboards

 Sequences of drawings illustrating how a scenario and interaction unfold. Video prototypes: Video mockups of interactions in real-world contexts

User Modeling

 Compare how users accomplish goals across design alternatives, including task steps, cognitive demands, time, and efficiency.

GOMS

Model user interaction through Goals, Operators, Methods, and Selection rules to analyze task execution.

Personas support

empathetic understanding

user profiles define

target users systematically

 timelines examine

experiences over time

 scenarios test

specific situations and edge cases

user modeling supports

structured efficiency comparisons

Stakeholder diversity

 Represent relevant stakeholder groups with personas and evaluate alternatives through scenarios affecting each group

Prototyping

Creating representations of design ideas for user evaluation; prototypes are for feedback, not necessarily deployment.

Design alternatives vs. prototype

Alternatives explore possible solutions; prototypes make solutions tangible and testable.

Fidelity

Prototype completeness and detail.

Low fidelity

is quick to build and revise

high fidelity

supports detailed evaluation but costs more resources.

Rapid, iterative prototyping

 Repeatedly build, evaluate with users, and revise prototypes; each iteration may revisit needfinding, alternatives, or prototyping.

Progressive fidelity

Start with low-fidelity prototypes; increase fidelity when evaluation supports the design. Test early to reduce the cost of failed designs

Horizontal prototype

Broad coverage of many features with little detail; evaluates overall design.

Vertical prototype

 Detailed implementation of a narrow feature; evaluates specific interactions.

Mixed-fidelity prototyping

Different system components can have different fidelity levels simultaneously

Bottom-up design

Design individual screens/components before integrating the overall experience.

Top-down design

Design the overall experience and navigation before individual screens/components.

Verbal prototype

 Describes a proposed design; easy to create but may be difficult for users to evaluate accurately.

Paper prototype

Hand-drawn interface or control layout; supports rapid revision and early layout feedback.

Card-based prototyping

 Represents screens on separate cards to simulate navigation and multistep interactions.

Wizard of Oz prototyping

A human simulates unimplemented system functionality, enabling realistic interaction testing before implementation; useful for voice and gesture interfaces.

Wireframe

A more formal visual representation of interface layout and appearance; useful for evaluating screen space, visual details, and remote feedback.

Physical prototype

Tangible representation of a physical design; evaluates size, shape, ergonomics, and interaction within users’ activities.

Look-and-feel prototyping

 Evaluates user-impacting visual or sensory details, such as colors, fonts, and appearance.

Interaction simulation

Tests how a system responds to user actions and how users navigate between screens or interact physically.

Revisability

Ease of changing a prototype during evaluation in response to feedback, verbal,, paper, card, wizard

Design fixation

Excessive focus on building or refining a design rather than learning from users.

Prototype design principles

 Keep prototypes easy to revise, visibly incomplete when appropriate, and focused on specific uncertainties; evaluate major risks early.

Verbal-prototype biases

Social desirability bias may discourage criticism; the novice-expert blind spot causes designers to overestimate users’ understanding. Analogies can clarify unfamiliar concepts.

Domain-specific prototyping

Adapt prototype formats to unfamiliar interaction modalities and real-world contexts, including mobility.