The Human - Lecture 2

The Human (Lec 2)

• The human, as the user, is the primary focus of computer system design.
• Understanding human capabilities and limitations, particularly cognitive psychology, is essential for creating effective interactive systems.
• Cognitive psychology provides insights into how humans perceive, process, store information, problem-solve, and physically interact with objects.
• Effective design considers human capabilities to create intuitive systems.

Introduction Cont

• The Model Human Processor (1983) is a simplified model of human processing, consisting of perceptual, motor, and cognitive systems.
• Each subsystem involves information processing and interaction.
• Understanding input-output channels, memory function, complex problem solving, learning and human errors are key aspects in computer system designs.

Input-Output Channels

• Humans interact with the outside world through receiving (input) and sending (output) information.
• Input primarily involves sensory perception (sight, hearing, touch, taste and smell). Visual, auditory, and tactile perception are vital to Human-Computer Interaction (HCI). Taste and smell are less important.
• Output involves the motor control of effectors, such as limbs, fingers, eyes, head and vocal system. Physical interaction plays a crucial role through typing or mouse use, and other interactions.

Input-Output Channels Cont

• Input using computer devices involves visual perception from screens and screens and auditory feedback (like beeps or voices).
• Touch, through feel and sounds from pressing keys or moving a mouse, is an important aspect of feedback.
• Information is transmitted using input devices to the computer.

Vision

• Human vision is a complex process with physical and perceptual limitations.
• It involves physical reception of stimuli and the processing/interpretation of this stimulus. Understanding both of these stages is important for computer system design.
• Visual processing occurs from the physical receptor (eye) and the processing stages from there.

Visual Perception

• Vision starts with light that is converted to electrical energy by the eye’s receptors, forming an upside down image on the back of the eye.
• Images are focused upside down on the retina, where rods and cones process light vision and color vision.
• Visual perception is a complex process that involves filtering and processing information to recognize scenes, determine relative distances and differentiate colors, impacting how we perceive elements like size, depth, brightness and color.

The Capabilities and Limitations of Visual Processing

• Visual processing relies on transformation, interpretation; expectations also influence how we perceive an image.
• Examples demonstrate ambiguity in perception.

Hearing

• Human hearing provides information about the environment, such as distance, direction, and objects.
• Sound involves vibrations in the air or sound waves.
• The ear is divided into three sections: outer, middle, and inner. Sound waves/vibrations are transmitted to the auditory nerves. Chemical transmissions follow the vibration process to cause impulses in the auditory nerve.

Sound

• The human ear can hear frequencies ranging from 20 Hz to 15 kHz.
• The auditory system filters sounds, allowing us to focus on important information.
• Sound is infrequently used in a positive way in HCI systems but it can convey a lot of varied information, for example through notifications and multimedia.

Characteristics of Sound

• Frequency is the number of sound wave cycles per second (measured in Hertz). Perception of sound relates to its pitch (higher frequency=higher pitch).
• Amplitude refers to the energy of a sound wave/sound. Louder sounds have a higher amplitude.
• Wavelength refers to the length between wave crests. Frequency has an inverse relationship with wavelength. Higher frequency sounds have shorter wavelengths.

Touch

• Touch provides crucial information about the environment.
• Touch is important especially for feedback, vital to computer systems that rely on physical interactions.
• Touch perception is not localized unlike sight or hearing.
• Our skin contains three receptors; thermoreceptors, nociceptors and mechanoreceptors. Thermoreceptors detect temperature change, nociceptors respond to pressure, heat and pain. Mechanoreceptors respond to physical pressure.

Touch Cont.

• Kinesthesis, another aspect of haptic perception, relates to awareness of the body's position and limbs through receptors in joints.
• Three types of receptors exist in this aspect of haptic perception: rapidly adapting(responds to movement), slowly adapting(responds to movement and static positions) and positional receptors(respond only to static positions).

Movement

• Movement time is a critical aspect of HCI.
• Reaction time and movement time are crucial in determining time-taken calculations and involve skill and practice in order to reduce reaction time.
• Speed and accuracy of movement are essential when designing interactive systems (for instance, targets on a screen).

Human Memory

• Human memory plays a critical role in how users interact with computer systems.
• Understanding memory functions and limitations is key to designing user-friendly interfaces. - Three types of memory include sensory memory, short-term memory, and long-term memory.

Sensory Memory

• Sensory memory acts as a buffer for incoming sensory information, briefly storing information from the five senses (visual, echoic, and haptic).
• Information is transferred from sensory memory to short-term memory through attention and the information filtering/competing with other sensory stimuli.
• It has limited capacity and duration (0.5 seconds).

Short-Term (Working) Memory

• Holds a small amount of information (approximately 7±2 items) for short periods (approximately 20-30 seconds).
• This memory allows for the immediate processing and manipulation of information.
• Chunking (grouping into larger units), and rehearsal (repeating) are used to enhance capacity and duration.
• In HCI, design needs to consider the limitations of short-term memory.

Long-Term Memory

• Stores information over extended periods (potentially indefinitely).
• It differs from sensory and short-term memory in capacity and access time.
• Episodic memory stores events and experiences, and semantic memory stores facts, concepts, and skills.
• Memory structures include semantic networks, frames and scripts, and production rules.

Long-Term Memory cont.

• Different memory structures like semantic networks, frames, scripts, and production rules, help access information and represent relationships.
• Semantic networks link related information.
• Frames organize information into data structures (attribute-value pairs).
• Scripts are stereotypical patterns of events.
• Production rules are condition-action rules.

Semantic Network

• This network structure highlights relationships between pieces of information.
• Elements are linked in classes, inheriting attributes from parent classes, not well designed to represent more complex activities.

Frames

• They are organized info, with slots storing attribute values.
• Fixed and default slots maintain consistent values. Variable slots allow specific instances to vary.
• Frames extend links from the semantic network.

Scripts

• These are stereotypical sequences of events (like a coffee shop visit).
• Elements can have entry conditions, result conditions, roles, actions, and scenes. It gives a detailed plan of events taking place.

Script

• Scripts detail stereotypical scenarios and situations for different activities. Elements include entry conditions, result states, participants, props, sequences of actions, and variations (tracks).

Production Rule

• Production rules represent procedural knowledge or how to do things in a condition-action format.
• Conditions matched in short-term memory activate associated actions. For example, if a dog wags its tail, you pat it.

Long-Term Memory Processes

• Long-term memory processes involve three key activities: storage (remembering), forgetting, and retrieval.
• Rehearsal helps move information from short-term to long-term.
• Understanding how memory processes work can improve retention and retrieval
• Semantic structuring aids better retention

Long-Term Memory processes cont…

• Decay, interference theory are memory processes that account for forgetting
• Retroactive interference describes forgetting of old information due to newly acquired information. Proactive interference occurs when older information interefers with newer information.
• Tip-of-the-tongue phenomenon relates to information present but difficult to retrieve immediately.

Long-Term Memory processes cont…

• True forgetting is difficult, often due to retrieval problems.
• Recognition and recall, with prompts or cues, assist in better long-term memory retrieval.
• Emotional factors can impact information retrieval and storage.

Retrieval Information

• Information retrieval is a critical process for accessing stored memories.
• Recognition (knowing something has been seen before) is less complex than recall (reproducing it from memory).
• Retrieval cues (like categories and imagery) help access information more easily.

Thinking: Reasoning and Problem-Solving

• Thinking can vary in knowledge requirements; a simple task needs less knowledge than more complex ones that may involve extensive amounts.
• Two types of thinking include reasoning and problem-solving, involving deductive, inductive and abductive reasoning.

Deductive Reasoning

• Deductive reasoning starts from general rules to derive specific conclusions (ex: if it is Friday, then she will go to work).
• The conclusions are logically valid, but they may not always correspond with reality.

Inductive Reasoning

• Inductive reasoning is about generalizing from specific examples (ex: every elephant seen has a trunk, therefore all elephants have trunks).
• This is generally reliable but can sometimes result in false conclusions.

Abductive Reasoning

• Abductive reasoning derives explanations from observed facts. (ex: Sam's fast driving suggests he is drunk).
• The explanations determined may not be accurate explanations. There may be other reasons why something has happened.

Problem Solving

• Problem-solving involves using existing knowledge to tackle new tasks.
• Approaches include the Gestalt viewpoint, Problem Space theory & Analogical reasoning. These approaches are important to HCI design.

Problem Solving cont…

• Errors can occur in problem-solving (slips, mistakes); slips are unintended failures(for example, poor physical skill), and mistakes result from wrong intentions or misunderstandings (ex: wrong mental model of the system).

Emotion

• Emotional responses affect performance; positive emotions foster creativity and problem-solving, while negative emotions narrow thinking.
• Various theories explain how emotion works, including James-Lange, Cannon, and Schacter-Singer approaches.
• Affect (biological response) influences how we respond to situations (ex: positive = creative problem solving and negative=narrow thinking).

Individual Differences

• Human cognitive and perceptual processes vary between individuals, and these differences need to be considered in the design process.
• Differences exist in the long-term (sex, physical abilities, intelligence) and short term (stress/fatigue).
• Temporal changes affect responses to situations, for instance, in aging; and understanding these differences is vital to create accessible and usable products.

Psychology and Interactive Systems Design

• Psychology informs the design of interactive systems, making them more user-friendly.
• Psychological principles like recognition being faster than recall should be put into practice in design (for example, using menus, and easy selection of commands, instead of inputting it manually).
• Context of usage and experiments, cognitive models and evaluation techniques for appropriate application.

This quiz focuses on the importance of understanding human capabilities and limitations in the design of computer systems. It covers concepts from cognitive psychology, the Model Human Processor, and how input-output channels influence interactive system design. Dive deep into how human cognition impacts effective system usability.