Chapter 4.2 Perception, Problem Solving and

Decision MakingHuman Performance Engineering

Robert W. Bailey, Ph.D.

Third Edition

Motivation

Memory

Perceptual IntellectualMovementControl

Figure 7-1 Major components in human information processing

Perception Involves 2 Sources:

1. Information available through our senses

2. Accumulated knowledge of the perceiver

stored in memory

“Matching new with old”

Perceptual Processes:

• Quite flexible

Ex. mirror image

• Responds to a wide range of differing patterns

Ex. Size of type on a page, an object at various distances, spoken words

• Overall arrangement is crucial

Ex. A line segment is identified more accurately when it is part of a picture that looks like a 3-dimensional object (Item A)

Line Segments

Contexts

A B C D E F

Figure 7-2 Visual detection of line segments

Perception and Perceptual Skills

• Find the error in the next slide.

Jack and Jill went

went up the

hill to fetch a

a pail of milk

• We may fail to detect errors because the context leads us to expect a certain pattern.

• Tell me what you see.

l3

Schema

The portion of the perceptual cyclethat is internal to the perceiver, modifiable by experience, and somehow specific to what is being perceived.

• Expectations appear to direct perception.

• People can identify a picture or a word far more easily when it is anticipated or plausible.

World

Schema Perceptual Exploration

Directs

Modifies Samples

Figure 7.4The perceptual cycle (adapted from CognitionAnd Reality: Principles andImplications of Cognitive Psychology. By Ulric Neisser, W.H. Freeman and Company.Copyright 1976).

Perception, Problem Solving and Decision Making

Stand

I

Wear

Long

Cycle

Cycle

Cycle

O

BA

PHD

MD

Chair iii iii

Mind

MatterECNALG

He’s/Himself

G.I.

CCC

CC

CGround

Feet

Feet

Feet

Feet

Feet

Feet

LLLLLWeight

Sand ManBoard

Death/Life

RRoads a d s

TOWn

Le vel

J UYOU S ME T

Profile

TOUCH

DiceDice

KneeLights

R E A D I N G

Developing Perceptual Skills

Training – Guiding a potential user

through the important conditions of an activity in some controlled manner, building schema as the user has each new experience.

Select users who already have a particular set of desirable schema.

Statement of minimum qualifications

• Tell me how many Fs are in the next slide.

FINISHED FILES ARE THE RE-SULT OF YEARS OF SCIENTIF- IC STUDY COMBINED WITH THE EXPERIENCE OF MANY YEARS.

Illusions- result when we make

assumptions about “How things usually are” (rely on inappropriate schema), which causes us to distort or misunderstand the information we actually receive.

Designer’s Objective

1. Ensure the perceptions are accurate

2. Provide means for quickly building perceptual skills

When are accurate perceptions most likely?

• Accurate perceptions are most likely

when a person encounters data,

information, or conditions that are

familiar and consistent with past experiences.

Intellectual Processing -

Second stage in the Human Information

Processing Model:

*Decision Making, *Problem Solving,

*Reasoning

Problem Solving – The combining of existing ideas to form a new combination

of ideas.

Problem – A situation for which the human does not have a ready response.

Steps for Problem Solving

1. Preparation- clarifying and defining the problem, along with gathering a lot of pertinent information.

2. Incubation – A period of unconscious mental activity

3. Inspiration- The “AHA” experience

4. Verification – Checking the solution

Problem Solving in the Real WorldGenerally follows this sequence:1. Problem sensing- A problem is detected

2. Problem formulating- A particular problem is defined

3. Searching- Questioning, gathering, backtracking

4. Problem resolving- Problem is solved

Three Mile Island- March 28, 1979

Table 7-1 Water Jar Problems

Problem Jars Regarded as Given RequiredNo. A B C Amount (quarts)

1 32 4 202 100 20 3 743 14 163 23 994 18 43 10 55 9 42 6 216 20 59 4 317 23 49 3 208 15 39 3 189 28 76 3 2510 18 48 4 2211 14 36 8 6

Barriers to problem solving:1. Habit2. Pressure to conform

Rigidity, fixation, mental set, predisposition, resistance to change

Ex. Water Jar Problem

Three Problem-Solving Dimensions

1. Is the problem really a problem?

2. Does the activity require some

type of systematic, organized approach to problem solving or would trial and error be best?

Ex. Rearrange all of the letters to form one word:

Love to Ruin

What is unique about this statement?

Name no one man

3. Does the activity require one correct solution or many?

Three Problem-Solving Dimensions

How would you solve a problem?

What techniques would you use?

Problem Solving Techniques

Brainstorming-

Criticism is ruled outOriginality is desiredThe greater the number of ideas, the better

Attribute Listing-

Ex. Pencil-size, color, shape, eraser, lead

Checklist-

Examining a list that suggests solutions for a given problem

Ex. Printed or computer – Generated checklist

Design for effective problem solving:

Necessary instruction, performance aids, training materials, computer outputs

Decision Making

The weighing of known alternative responses in terms of their desirability and then selecting one of the alternatives.

Uncertainty adds complexity to decision making.

Four Decision-Making Characteristics that a Designer Should Recognize:

1. Users usually wait longer to decide than needed.

2. Users tend not to use all available information

3. Users tend to be hesitant in revising original opinions

4. Users usually consider too few alternatives

How quickly can you find out what is so unusual about this paragraph? It looks so ordinary that you would think that nothing was wrong with it at all, in fact, nothing is; but, it is unusual. Why? If you study it and think about it you may find out, but I am not going to assist you in any way. You must do it without coaching. No doubt, if you work at it for long, it will dawn on you. Who knows? Go to work and try your skill. Par is about half an hour.

Figure 7-10 “Not so easy” problem.