Human-Computer Interaction Overview

Human-Computer Interaction (HCI)

• HCI is the study of interaction between humans and computers, specifically the design of technology.
• It's a multidisciplinary field focusing on how people interact with computers.
• It focuses on designing interactive computer interfaces to satisfy user needs.
• HCI considers individual users or groups of users interacting with technology.
• Users interact with computers using their senses and effectors.
• The goal of HCI is to develop usable, safe, and efficient systems for end-users.
• End-users need sound understanding of computing systems.
• Design methods, tools, and techniques should allow users access based on their needs.
• System design needs to ensure effective communication and interaction with systems.
• End users' needs always take priority. 
• HCI lays the foundation for successful human-computer interaction.
• Usability is important for easy use of computing systems by all types of users.
• HCI user experience (UX): a subjective trait focusing on how users feel about the system.
• User feelings are studied individually to evoke positive feelings while using the system. 

HCI Standards 

• HCI standards refer to guidelines, principles, and specifications ensuring consistent and effective human-computer interaction.
• Standards aim to improve user experience, usability, accessibility. 
• Standards help ensure good practice.
• Standards provide guidance for organizations unfamiliar with user-centered design.
• Standards help support consistency in software and hardware interaction.
• Standards are about usability and quality. 
• Standards are related to how usable a product is, including user interface and interaction, plus the development process.
• Organizations such as ISO, IEEE, W3C, ANSI/HFES contribute to HCI standards.

The Human Part 

• Humans are central to interactive systems.
• Humans are influenced by external factors like social and organizational environments. 
• Systems are designed to assist users.

Input and Output Channels 

• Input: primarily through the senses (Sight, Hearing, Touch, Taste, Smell).
• Output: via motor control of effectors (Limbs, Fingers, Eyes, Head, Vocal system).
• Input and output channels are used for communication in interaction with the system.

Visual Processing

• Visual processing involves transforming and interpreting images onto the retina. 
• Expectations affect the way we perceive images.
• Optical illusions affect how we perceive size, distance, and symmetry.
• Visual perception of size, distance and familiarity. 
• Rods and Cones in the eye help with vision. 

Hearing Processing 

• Sound is changes or vibrations in air pressure.
• Sound waves travel through the ear (outer, middle, inner) to the auditory nerves.
• Hearing begins with vibrations, and sounds are transmitted and processed. 
• Hearing is related to frequency and pitch (high freq./ high pitch).

Touch Processing

• Touch or Haptic Perception gives vital feedback.
• Skin is sensory receptors (thermoreceptors, nociceptors, mechanoreceptors).
• Pressure sensation relates to immediate or continuous input. 
• Kinesthesis awareness of position (body and limbs) has impact on comfort, performance. 
• Two-point threshold test measures body sensitivity.

Movement Processing

• Movement involves stimulus reception, processing, response generation.
• Reaction time involves input, processing, and response.
• Accuracy and speed of movement important in systems design.
• Variables such as skill, practice, and fatigue influence speed, accuracy.
• Fitt's Law is involved in interaction, target-size and distance influence movement time.