Human Computer Interaction (HCI) Lecture (3) fourth stage

Human Information Processing

Information Processing

An information system that accepts inputs from the external world and
produces responses directed out to the external world as shown in the following
figure.

Inputs
Outputs

Human Information Processing (HIP)

What exactly is human information processing? Information Processing is
the change in a state of information. It allows us to split information down into
steps which can be easily read and understood by the human brain. It allows
people to store, retrieve and use information with ease. There are four steps to
how information is collected and used:
1. Absorb the information )‫(استيعبة الوعلىهبت‬
2. Analyse the information)‫(تحليل الوعلىهبت‬
3. Use the information )‫(استخذم الوعلىهبت‬
4. Do something with the information )‫(افعل شيئًب ببلوعلىهبت‬
The Model Human Information Processor
An important concept from cognitive psychology is the model human processor
(MHIP). This describes the cognitive process that people go through between
perception and action. It is important to the study of HCI because cognitive
processing can have a significant effect on performance, including task

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Human Computer Interaction (HCI) Lecture (3) fourth stage

completion time, number of errors, and ease of use. This model was based on
the human information processing model.
The model human processor consists of three interacting systems. Each has its
own memory and processor.

Human Information Processing

1.Perceptual processor (Lecture#2)
_ Outputs into audio storage
_ Outputs into visual storage
2.Cognitive processor
_ Outputs into working memory.
_ Has access to:
o Working memory
o Long term memory
3.Motor processor
_ Carries out actions

2.Cognition
Cognition is the processing of information from the world around us. It ncludes
perception, attention, pattern matching, memory, language processing,
decision making, and problem solving. Cognitive load is the amount of mental
resources needed to perform a given task.

All user interfaces make cognitive demands on users. Users must master
special rules of system use, learn new concepts, and retain information in short-
term memory. They must create and refine a mental model of how the system
works and how they should use it. Systems that use purely auditory interfaces
further challenge human memory and attention because they present information
serially and non-persistently.
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Human Computer Interaction (HCI) Lecture (3) fourth stage

Successful user interface designs must respect the limitations of human

cognitive processing. If a design requires the user to hold too many items in
short-term memory or to learn a complex set of commands too quickly, it will
fail.

Cognitive Frameworks
Cognition is the process by which we gain knowledge. The processes, which
contribute to cognition, include:
o Understanding )‫(الفهن‬
o Remembering )‫(التذكز‬
o Reasoning )‫(الونطق او االستنتبج‬
o Attending )‫(الحضىر‬
o Being aware)‫(اى تكىى على على علن او ادراك الوعلىهه‬
o Acquiring skills )‫(اكتسبة الوهبرات‬
o Creating new ideas )‫(خلق أفكبر جذيذة‬
A key aim of HCI is to understand how humans interact with computers,
and to represent how knowledge is passed between the two.

The basis for this aspect of HCI is the science of cognitive psychology. The
results of work of cognitive psychologists provide many lessons, which can be
applied in the design of computer interfaces. These results are expressed in the
form of cognitive frameworks.

HCI is fundamentally an information-processing task. The human

information processing approach is based on the idea that human performance,
from displayed information to a response, is a function of several processing
stages. The nature of these stages, how they are arranged, and the factors that
influence how quickly and accurately a particular stage operates, can be
discovered through appropriate research methods.

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Human Computer Interaction (HCI) Lecture (3) fourth stage

HUMAN MEMORY

It is generally agreed that there are three types of memory or memory function:
sensory buffers, short-term memory or working memory, and long-term memory.
There is some disagreement as to whether these are three separate systems or
different functions of the same system.

A. Sensory memory
The sensory memories act as buffers for stimuli received through each of the
senses: iconic memory for vision, echoic memory for sounds and haptic
memory for touch. These memories are constantly overwritten by new
information coming in on these channels. Information is passed from the sensory
memory into short-term memory by attention, filtering the stimuli to those that
are at that moment of interest (arousal, or shift of attention).

B. Short-term memory
STM is used to store information which is only required fleetingly. STM can
be accessed rapidly, however, also decays rapidly. It has a limited capacity.
Miller stated the 7+/-2 rule, which means that humans can store 5-9 chunks of
information. Chunks can be single items or groups of items, like 2 digits of a
telephone number grouped together. Patterns can be useful as aids to memory.

C. Long-term memory
LTM differs from STM in various ways. It has an unlimited capacity, a slow
access time and forgetting occurs more slowly or not at all. Information is
stored here from the STM through rehearsal. There are 2 types of LTM:
episodic memory and semantic memory. Episodic memory represents our
memory of event and experiences in a serial form. Semantic memory is a
structured record of facts, concepts and skills that we have acquired, derived
from the episodic memory.
There are 3 main activities related to LTM: storage of information, forgetting
and information retrieval.
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Thinking: reasoning and problem solving

Thinking can require different amounts of knowledge. Some thinking
activities are very directed and the knowledge required is constrained.
Others require vast amounts of knowledge from different domains.
Thinking can be divided in reasoning and problem solving.

Reasoning
Reasoning is the process by which we use the knowledge we have to
draw conclusions or infer something new about the domain of interest.

Problem solving
Problem solving is the process of finding a solution to an unfamiliar
taste, using (adapting) the knowledge we have.

3. Motor processor (Movement)

Before leaving this section on the human’s input–output channels, we
need toconsider motor control and how the way we move affects our interaction
with computers. A simple action such as hitting a button in response to a
question involves a number of processing stages. The stimulus (of the question)
is received through the sensory receptors and transmitted to the brain. The
question is processed and a valid response generated. The brain then tells the
appropriate muscles to respond. Each of these stages takes time, which can be
roughly divided into reaction time and movement time.

• Time taken to respond to stimulus:

Reaction time + movement time

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