HCI-CHAPTER-1-HUMAN

Introduction to HCI

• Human-computer interaction (HCI) studies the interaction between users and computers.

• Challenges in creating effective interfaces include:

  • Lack of care for user experience

  • Absence of common sense in design

  • Time constraints in development

  • Uncertainty on what constitutes good design

Definition and Goals of HCI

• Definition: HCI is the discipline concerned with designing, evaluating, and implementing interactive computing systems for human use.

• Goals:

  1. Improve user-computer interaction for better usability.

  2. Minimize the gap between user's cognitive model and computer's task understanding.

Importance of HCI

• Increasing role of user-centered design.

• Enhances competitiveness in technology.

• Costly inefficiencies from poorly designed systems.

• Users may abandon poorly designed interfaces.

Information Processing in Humans

• Input/Output Channels:

  • Visual, auditory, haptic, and movement interactions.

• Memory:

  • Sensory memory, short-term (working) memory, long-term memory, and storage functions.

• Cognitive Processing:

  • Reasoning and problem-solving abilities influenced by emotions; individual differences in capabilities.

Vision

• Two stages in vision:

  • Physical reception of stimulus.

  • Processing and interpretation of stimulus.

• The eye's mechanism transforms light into electrical signals.

• Retinal structure: rods (low light) and cones (color).

Interpreting Visual Signals

• Size & Depth: Visual angle, visual acuity.

• Brightness: Subjective interpretation of light levels; related to luminance.

• Color: Hue, intensity, saturation; color perception variations.

Optical Illusions

• Examples:

  • The Ponzo illusion and the Muller-Lyer illusion.

• Duck versus rabbit image illustrates perception variability.

Hearing

• Key sensing abilities about environment context.

• Auditory System: Transmits and processes sound waves.

• Human hearing range: 20Hz to 15kHz; auditory filtering in noisy environments.

Touch

• Important for feedback; crucial for users with visual impairments.

• Receptors in skin interpret temperature, pain, and pressure.

Movement

• Reaction time and movement time considerations:

  • Visual (~200ms), auditory (~150ms), pain (~700ms).

• Fitts' Law describes target acquisition time regarding distance and size.

Memory Types

• Different types of memory functions:

  • Sensory Memory: Short-lived buffer for sensory information.

  • Short-term Memory: Limited capacity, rapid access, and decay.

  • Long-term Memory: Repository of knowledge, includes episodic and semantic memories.

Emotion in HCI

• Emotional theories: James-Lange, Cannon, Schachter-Singer models.

• Emotions affect cognition and problem-solving abilities.

• Design implications:

  • Managing user stress and promoting positive affect enhances usability.

Problem Solving and Reasoning

• Types of reasoning: deduction, induction, and abduction.

• Problem-solving frameworks involve Gestalt, analogy, and skill acquisition theories.

Errors Due to Mental Models

• Slips: Errors due to poor execution despite right intentions.

• Mistakes: Errors based on misunderstanding due to incorrect mental models.

Psychology in Design

• Understanding user psychology is crucial for effective design.

• Importance of guidelines and cognitive models for interface design.

Conclusion

• HCI integrates psychological principles to improve interactive systems. The objective is to create interfaces that are user-friendly, reducing confusion and inefficiency.