Human-Computer Interaction Lecture 2

The Human (Lec 2)

• Humans are the primary focus of computer system design. Their needs and capabilities are paramount.
• Understanding cognitive psychology is essential to design effective interactive computer systems.
• This field helps understand how humans perceive, process, remember information, and interact with objects.
• Designers can create simpler, more intuitive, and user-friendly systems by considering human capabilities and limitations.

Introduction Cont.

• The Model Human Processor (1983) is a simplified view of human processing.
• It comprises three subsystems: perceptual, motor, and cognitive.
• Each subsystem has its own processing units and operations, varying in complexity depending on the task.

Input-Output Channels

• Humans interact with the environment (and computers) through input and output channels.
• Input primarily occurs through sight, hearing, touch, taste, and smell. Vision, hearing, and touch are crucial in HCI.
• Output involves motor control of effectors like limbs, fingers, eyes, and vocal tract.

Input-Output Channels Cont.

• Interaction with a personal computer predominantly uses visual input from the screen and auditory feedback.
• Touch input (e.g., mouse, keyboard) is also vital for feedback.

Vision

• Human vision is a complex process with physical and perceptual limitations.
• It involves physical reception of stimuli by the eye and processing by the visual system.

Visual Perception

• Vision begins with light; the eye converts light into electrical energy, creating an upside-down image on the retina.
• The retina contains rods for low-light vision and cones for colour vision.
• Visual information must be processed to interpret scenes, relative distances, colors, and perceive size, depth, brightness, and colour.

Capabilities and Limitations of Visual Processing

• Not only the physical but also the cognitive processes of the eye influence visual perception.
• Expectations and prior experiences affect how we perceive images.

Hearing

• Hearing provides information on the environment (distance, direction, objects).
• Sound waves stimulate the ear (outer, middle, inner ear), converting the vibrations into neural impulses in the auditory nerve.
• The human ear's frequency range is 20 Hz to 15 kHz.

Sound

• Sound conveys a wealth of information.
• The auditory system filters sounds to prioritize crucial information while disregarding background noise.
• Besides warnings and notifications, multimedia uses sound extensively.

Characteristics of Sound

• Frequency (measured in Hz) corresponds to the pitch.
• Amplitude corresponds to loudness, reflecting energy.
• Wavelength is inversely related to frequency.

Touch

• Touch provides vital environmental information and is a vital form of feedback for computer systems.
• Haptic perception also includes kinesthesis (awareness of body position).
• Receptors like thermoreceptors, nociceptors, and mechanoreceptors are found in the skin.

Touch Cont.

• Receptors in joints provide information about limb positions and movement.

Movement

• Reaction time plus movement time dictates how long it takes to respond to stimuli.
• Speed and accuracy in movement are vital aspects in interactive system design.

Human Memory

• Human memory is crucial for interaction with computer systems.
• Understanding its structure and limitations is essential for designing user-friendly interfaces.
• Memory is divided into three types, Sensory, Short-term, and Long-term.

Sensory Memory

• Sensory memories function as buffers, temporarily storing sensory input.
• Iconic memory, echoic memory, and haptic memory are specific to visual, auditory and tactile input, respectively.
• They are limited and brief, lasting less than a second.

Short-Term (Working) Memory

• Working memory holds a limited amount of information (7 ± 2 chunks).
• It's crucial for immediate processing and manipulation, acting as a short-term storage system for information.
• Chunking (grouping items) and rehearsal (repeating) can improve its capacity and duration.

Long-term Memory

• This system stores information over long periods, potentially indefinitely.
• It's vastly larger capacity than Short-term memory.
• It's divided, into different memory types, like Episodic and Semantic.

Long-term Memory Cont.

• Semantic networks, Frames, Scripts, and Production Rules represent and organize stored knowledge.

Semantic Networks

• Networks depict relationships between units of information, enabling inference, and storing attributes that inherit properties from their parent classes.
• Limitation: Representing complex or multi-component objects or events is challenging with this structure.

Frames

• Frame structures organize information into slots that can hold default, fixed or variable values.
• These structures represent the relative importance of information and links to other frame structures.
• Frames use slots that hold specific values, helping to organize and understand information.

Scripts

• Scripts represent stereotypical knowledge about event sequences (e.g., visiting a doctor), organizing events in a typical format.
• Different parts of a script include: entry conditions, result conditions, props, roles, scenes and tracks.

Production Rules

• These rules match conditions to actions, stored in long-term memory.
• A condition in a rule triggers a related action in memory, as needed.

Long-term Memory Processes

• Storage, forgetting, and retrieval are the core long-term memory processes.
• Information from Short-Term memory is stored in Long-Term through repetition or rehearsal.
• Forgetting can be due to decay (fading) or interference (new information hindering the retrieval of old).

Long-term Memory Processes Cont

• Theories about the processes and causes of forgetting (decay and interference) are discussed.
• True forgetting (loss of information) is compared with retrieval issues.

Retrieval Information

• Recall and recognition are the two forms of retrieving information stored in long-term memory.
• In recall, information is reproduced from memory.
• Recognition requires knowing that information has already been seen or experienced in some form.
• Retrieval cues like categories and imagery help enhance memory retrieval.

Thinking: Reasoning and Problem-Solving

• Thinking can span from simple calculations to vast amounts of knowledge-intensive tasks requiring complex reasoning and problem-solving.
• Humans engage in a variety of reasoning processes to draw conclusions or solve problems.
• Deductive reasoning derives logical conclusions from premises.
• Inductive reasoning generalizes from specific cases to broader conclusions.

Deductive Reasoning

• Deductive reasoning involves deriving the logically necessary consequence from given premises, but it doesn't necessarily imply a true real-world consequence.

Inductive Reasoning

• Inductive reasoning generalizes from observed cases to broader conclusions, relying on patterns with an inherent risk of error.

Abductive Reasoning

• Abduction reasons from a fact, proposing actions or states that could lead to that observation being true.
• However, abduction can produce erroneous conclusions since multiple explanations are often possible for any given fact.

Problem Solving

• Problem-solving uses existing knowledge to address unfamiliar tasks through various approaches.

Problem Solving Cont.

• Common errors in problem-solving (slips & mistakes) and their causes are discussed.

Emotion

• Our emotional responses influence our performance and decision making in problem solving.
• Positive emotions foster creativity and problem-solving; negative emotions can hinder these processes.

Emotion Cont.

• Theories discussing the physiological and psychological responses related to emotion are highlighted.
• Affect is the biological response to stimuli.

Individual Differences

• Human cognitive and perceptual processes vary significantly, impacting design requirements.
• Various individual factors (sex, physical abilities, intellectual capacity, age, and current state) influence an individual's performance.
• Design should consider these differences for accessible and usable systems.

Psychology and the Design of Interactive Systems

• Psychological knowledge is crucial in designing usable interfaces.
• Direct application of psychology concepts and principles can lead to better, more user-friendly systems.
• Knowledge in areas like cognitive models, guidelines or evaluation methodology needs to be applied correctly.

This quiz focuses on the principles of Human-Computer Interaction, emphasizing the understanding of human needs and cognitive psychology in designing effective systems. It explores the Model Human Processor and how humans interact with computers through various input-output channels.