Human Computer Interaction: Chapters 4 to 8

A comprehensive set of vocabulary flashcards covering interaction techniques, text entry input devices, pointing metrics (Fitts' Law), human memory and learning, and visual perception design principles from CIS1104.

Interaction Techniques

The methods through which users input commands and systems provide feedback and output, serving as the communication bridge between humans and computers.

Direct Manipulation

An interaction style where users interact with visible interface objects and receive immediate feedback, such as dragging and dropping or using touch gestures.

Command-Line Interaction

An interaction style reliant on memorized text commands, offering high efficiency for expert users but demanding a steep learning curve.

Haptic Feedback

An output modality that provides tactile sensations, such as vibrations in mobile phones or game controllers, to enhance realism and awareness of system state.

QWERTY Keyboard

A dominant keyboard layout originally designed to reduce mechanical jams in typewriters; despite speed inefficiencies, users type fastest on it due to familiarity.

Dvorak Keyboard

An alternative keyboard layout designed to maximize typing efficiency and reduce finger travel, which has seen limited adoption due to user transition costs.

Words Per Minute (WPM)

A standard empirical text entry metric defined by the formula where $1\,\text{word} = 5\,\text{characters}$, including spaces.

Keystrokes Per Character (KSPC)

An empirical text entry metric that assesses typing efficiency by measuring the average number of physical key actions needed to output a single text character.

Target Acquisition

The task process of reaching and selecting an on-screen target, whose performance depends on target size, target distance, and the pointing device used.

Fitts' Law

A predictive model of human motor movement determining movement time to a target using the equation $MT = a + b \log_{2}(D / W + 1)$, where $D$ is distance and $W$ is target width.

Index of Difficulty (ID)

A Fitts' Law formulation calculated as $ID = \log_{2}(D / W + 1)$, quantifying the difficulty of a target acquisition task in units of bits.

Throughput

A performance measure of a pointing device combining speed and accuracy into a single metric expressed in bits per second ($\text{bps}$).

Sensory Memory

A human memory buffer with a very brief duration that preserves raw, unprocessed sensory input, such as visual afterimages or auditory echoes.

Short-Term (Working) Memory

A temporary human memory system with a limited capacity of approximately $7 \pm 2$ items and a duration measured in seconds, critical for decision making and active task execution.

Long-Term Memory

A memory repository with large capacity and long retention that stores declarative knowledge (facts) and procedural knowledge (skills).

Power Law of Practice

A learning principle stating that task performance time declines predictably as practice increases, yielding rapid initial improvement followed by smaller gains that never reach zero.

Transfer of Learning

The influence of past experience on acquiring new system skills, manifesting positively through familiar design patterns or negatively when identical elements perform different functions.

Visual Acuity

The capacity of the human visual system to discern fine detail, necessitating adequate font sizes, legible icon scaling, and ample interface spacing.

Visual Search

The perceptual task of identifying a target element among visual distractors, which progresses faster when elements have high visual distinction and structured grouping.

Gestalt Principles

A set of perceptual psychology laws detailing how humans perceive visual elements as unified groups, including proximity, similarity, continuity, closure, and common region.

Visual Hierarchy

The arrangement of interface elements using size, contrast, position, and color to guide human visual attention deliberately toward the most critical components.

Progressive Disclosure

An interface design method that conserves display real estate by presenting essential content first and revealing complex details or secondary controls on demand.