CH. 4 Cognitive Mental Models

Human Computer Interaction: Cognition and Mental Models

• Human-computer interaction (HCI) encompasses the human aspects of designing computer applications and hardware, focusing on effective interaction between humans and computers.
• HCI considers human capabilities and limitations to create intuitive and accessible designs.
• Understanding how people process information (cognition) plays a vital role in designing effective interfaces.
• Everyday frustrations with software highlight the importance of understanding user needs.
• Studying how people think and behave helps designers craft more user-friendly systems.
• Human factors study examines human behavior in the context of technology; it differs from experimental psychology, which studies human behavior in general, by focusing on how humans interact with technology.
• Human factors (ergonomics) combines insights from engineering, psychology, and physiology & medicine.
• HCI incorporates user considerations in tools, which means considering user perception, cognitive limitations, and ways of interacting with various technological systems (e.g. computer applications & hardware).
• Color, organization, and spacing are critical for user attention and perception in interface design.
• Perceptible aspects of an interface (e.g. legible text, icons) are crucial to good design.
• Memory, both short-term and long-term, significantly impacts how efficiently people use a technology.
• Encoding, or interpreting information, is the first stage of memory processing. The more attention paid to something, and the more it's processed intellectually, means the more likely it is to be remembered.
• Immediate memory capacity is limited (Miller's Magic Number 7 ± 2).
• Design should facilitate recognition instead of having to recall details.
• Mental models of a system are developed through learning and use—these include knowledge of how to use a system, process information, and handle unfamiliar situations.
• Users apply mental models to every day situations, such as operating a thermostat to heat a house or using an ATM to withdraw money.
• Users can sometimes hold erroneous mental models that impact their experience with a product (e.g. thinking a thermostat is like a valve).
• Norman's (1986) seven-stage model of action describes a structured way of implementing an activity.
• Cognitive user modeling attempts to predict how a user will interact with an interface based on their cognitive characteristics and knowledge.
• Modeling aspects of a user's cognition, knowledge, intentions, and processing is crucial for predicting user interaction.
• Models can range in specificity, from high-level plans and problems to basic user actions like keystrokes.
• Different modeling approaches exist, including models based on human info processing.
• Externalizing potentially complex functions or memory requirements to the environment can reduce a user's memory load (e.g. external calendars, notes, etc).