Human Computer Interaction
CSIT-400
By:
Shahid Mahmood
Warning!
 Lecture slides are high-level
description of lectures
 Relying upon only the slides do
not guarantee good grades in
exams
 For achieving good grades in
exams always attend lectures,
Study books, and explore web
resources.
Agenda
• Human aspects of HCI
• Cognitive psychology
• Cognitive Framework
• Cognitive Models
• External Cognition
• Distributed Congnition
 Scenario: Car drive
Cognition
 How the human think
 It is the process by which we became
acquainted with things or in other
words gain knowledge
 Whatever human do some sort of
cognition might have been happening
at the back end
Modes of Cognition
• Experiential Cognition
• Reflective Cognition
Experiential Cognition
In ‘experiential Cognition’ we perceive
act and react events around us
effortlessly. E.g, Car drive
 Less mental effort
 Initially require some learning
Reflective Cognition
In reflective Cognition some mental
exertion is required. E.g., writing an
article or poem OR drawing a picture.
Human Information Processing
 Recognizing something means
processing the information gained
about that thing in your mind. This
depicts the notion that human mind
works like a processor
Human Information Processing
Model (simple format)
Encoding
Response Selection
Comparison
Response Execution
Human Information Processing
Model
 Encoding: Information from
environment is encoded in some kind
of internal representation
 Comparison: Internal representation
is compared with memorized
representations
 Response Selection: Concerned with
deciding on a response to the
encoded stimulus
 Response Execution: Organizing
response and necessary action
Human Information Processing
Model (Extended)
Encoding
Comparison
Attention
Memory
Response Selection
Response Execution
Human Processor Model
 It helps us to conceptualize the human
behavior and to model human processor
 It is composed of three different systems,
each of which having two components i.e. a
processor component and a memory
component:
- Perceptual System
- Motor System
- Cognitive System
 This measures the qualitative aspects of
human performance
GOMS Model
• Goals
• Operators
• Methods
• Selection Rules
 This measures the quantitative aspects
of human performance
Basic purpose of Cognitive
framework
 The basic purpose of Cognitive
framework is to understand and
predict human behavior so that we can
predict the user behavior on use of
computer/ computer-based system
Computational Approach
• Adopts computer metaphor as a
theoretical framework
• What is involved when information is
processed rather than how and when
• Conceptualization of the goals
planning and action in terms of task
performance is done
Connectionist Approach
 Also known as Neural network or Parallel
distributed processing approach where
cognition is presented at the level of neural
network consisting of interconnected nodes
• Cognition process is viewed as activation of
nodes in the neural networks and the
connection between them
• Rejects computer metaphor
• Adopts brain metaphor
Shortcomings of behavior and
cognitive approaches
 They do not represent the real world
(considering the context) which neglect
isolation
 They represent a controlled environment
instead of actual
 They are very simple in nature and ignore
complexity
 Any prediction done on their bases could be
tragically wrong
External Cognition framework
It has got three different elements:
 Externalizing to reduce memory load
(telephone diary)
 Computational Offloading (Calculator)
 Annotating and Cognitive tracing (Modify
representation to reflect changes that are
taking place by Annotating (cross| underline)
and cognitive tracing (re-arrange for better
comprehension)).
 For example In computer we develop graphical
user interfaces for various web pages
Distributed Cognition framework
 The goal is to provide explanation to
conceptualize cognitive activities (attention,
thinking, learning) with in the work context
 Cognitive activities are distributed among
external technology and other people with in
the context
 Information changes its states (verbal, mental,
manifested in a device)
Questions?