Individual differences among human play a greater role to fit the individual for the job,

1. INDIVIDUAL DIFFERENCES AND BIG 5 PERSONALITY TRAIT THEORY
Why do people behave as they do? What makes them tick? Some people never seem to have a
problem.Othersseemtobe accidentswaitingtohappen.Some get alongwitheveryone.Othersare
impossible to deal with. Some days we feel good and enjoy family, work and life. Some days we do
not feel good and become irritable to everyone. Human behaviour is very complex. It is not fully
predictable. Often, behaviour contribute to accidents. Many factors affect behaviour. Examples are
physiological condition,biochemistry, health, relationships withothers, personal desires and career
goals. These behavioural factors constitute the Individual Differences among human-beings.
INDIVIDUAL DIFFERENCES:
People are notalike.Theydifferinsize,shape,strength,reactiontime,physical condition,healthand
physiological performance. They differ in ability to perform actions and in knowledge, skills and
abilitiesTheydifferinthe abilityto form judgmentsandmake decisions.Theydifferinattitudesand
beliefs, in emotions and in other ways.Individualsdiffer within themselves.They do not behave the
same in every similar situation. Factors can change their behaviour over time. Some differences are
variable. Some differences take care of themselves. The heart and respiratory rates elevate when
people exercise.After resting, their physiological responses return to normal. In other cases, people
change through variousmeans.Training,increasedknowledge andexpandedexperience canchange
someone performance. Medication may cause changesphysically or behaviourally. Individuals differ
from other people. They are not all alike. Individuals differ with themselves and change over time.
They do not behave the same always.
ATTITUDES, OPINIONS AND BELIEFS:
Attitudes, opinions and beliefs are much the same. They are sentiments that someone forms about
somethingorsomeone.Someone mayalsoholdattitudesaboutgroupsof people,social institutions,
topicsor issues.Attitudesmaybe positive ornegative.Theyare usuallyenduringand slow tochange.
In some cases, it is possible to infer a person’s attitudesfrom their actions in certain situationsand
fromverbal statements.Formal assessmentof attitudesinvolvesthe useof carefullydevelopedsurvey
instruments. An attitude survey has many statements about situations or actions with which
respondents agree or disagree. Survey results provide a picture of attitudes held by individualsor
groupsaboutsituationscoveredinthe survey.Attitudesmaylinktobehaviour.Forexample,one may
have attitudes about another person, such as a supervisor. Attitudes may not predict behaviour. In
some cases a person may know that an action will have bad effects, but continue to do it. Some call
thiscognitive dissonance.Anexample isapersonwho knowsthatsmokingcanleadtoheartandlung
disease,butcontinuestosmoke.Individualsmayhave attitudes,opinionsandbeliefsaboutsafetyor
certainaspects of safety.A safetyspecialistwill needtounderstandthemanddevelopstrategiesfor
changing them to improve safe behaviours.
MOTIVATION:
Motivationisthat part of psychologythatdealswithgettingsomeone toperformdesiredbehaviours
or actions. Motivation involves content and process theories. Content looks at the characteristics of
an individual or the environment that stimulate performance or action. Content identifies the
variables that influence desired actions. Process looks at the linkages between content and specific
actions and addresses the question of how to tap needs and outcomes to achieve desired actions.
Althoughresearchstudiesdonotfullysupportspecifictheoriesof motivation,some theoriesprovide
a framework for working with people toward desired actions and performance. This section
summarizes a few theories from among many others. Maslow. Maslow developed a hierarchy of

2. needs. The concept has been popular. His theory is a content theory that looks within an individual
for variablesthateffectdesiredperformance.Hishierarchyconsistedof five classesof needsranked
in importance from low to high. He thought that needs at the base of the hierarchy required
satisfactionfirst.Higheronesbecamemore importantasloweronesbecame satisfied.Hisfiveclasses
of needs in ascending order are: 1. Physiological needs, such as hunger and thirst. 2. Safety needs
(primary body needs). 3. Social needs, such as friendshipand affiliation. 4. Esteem, including self-
esteem and the esteem of others. 5. Self-actualization, such, as reaching one's potential. Research
suggeststhat basic needsdo not diminishastheybecome satisfied.Herzberg.Herzberg'stheoryisa
contenttheorythat looksat work outcomesratherthan needs.He proposedtwotypesof outcomes
that affectbehaviour.Theyare intrinsicfactorsandextrinsicfactors. Intrinsicfactorsinvolvethe work
itself andrecognitionof one'swork.Extrinsicfactors include rewardsassociatedwiththe work,such
as pay,relationswithco-workersandsuperiorsand workingconditions.Herzbergbelievedthatonly
attainment of intrinsic factors can sustain motivation toward organization goals. Research suggests
that both are important and there are significant differences among people in their preference for
types of outcomes.
Moslow’s Theory of Motivation: Maslow developed a hierarchy of needs. The concept has been
popular.Histheoryisa contenttheorythatlookswithinanindividual forvariablesthateffectdesired
performance.Hishierarchyconsistedof five classesof needsrankedinimportance fromlow to high.
He thought that needs at the base of the hierarchy required satisfaction first. Higher ones became
more important as lower ones became satisfied. His five classes of needs in ascending order are:
 1. Physiological needs, such as hunger and thirst.
 2. Safety needs (primary body needs).
 3. Social needs, such as friendship and affiliation.
 4. Esteem, including self-esteem and the esteem of others.
 5. Self-actualization, such, as reaching one's potential.
Herzberg’sTheory of Motivation: Herzberg'stheoryisa contenttheorythatlooksat work outcomes
ratherthanneeds.He proposedtwotypesof outcomesthataffectbehaviour.Theyare intrinsicfactors
and extrinsic factors. Intrinsic factors involve the work itself and recognition of one's work. Extrinsic
factorsinclude rewardsassociatedwiththe work,suchaspay,relationswithco-workersandsuperiors
and working conditions. Herzberg believed that only attainment of intrinsic factors can sustain
motivation toward organization goals. Research suggests that both are important and there are
significant differences among people in their preference for types of outcomes.
DESIGNING FOR HUMAN BEHAVIOUR:
There are many ways to remove or reduce hazards through design. Sometimes engineers forget to
consider user capabilities and limitations, user behaviour and the use environment. Understanding
people andtheirbehaviourisanimportantconsiderationindesign.Forexample,runningapipe along
a floor surface creates a tripping hazard. It does not make any difference whether the activity near
the pipe isa productionactivityor a maintenance andrepair activity.The probabilityforan accident
during maintenance and repair may be lower because access is less frequent than a production
activity. However, the tripping hazard remains. Any person walking or working near the pipe must
avoidfallingoverit.Thatrequiresrecognitionof the hazardandthenaspecificbehaviourtostepover
it. Good design would not place the pipe on the floor and create a tripping hazard. Design problems
may be even more subtle. A change in surface friction properties may create a slipping hazard. A
personmayinitiallywalkonone surface.The persongainsafeelforthe resistance underfoot.Suppose
the personencountersa suddenchange in a floorsurface that ismore slippery.The personmay not

3. notice the change andthe needtoadjustthe gait.The stride maybe toolongandleadtofeetslipping
outfromunderthe person.The resultisafall.Similarly,asuddenchange to ahighfrictionsurface can
require adjustments.The secondsurface maypreventmovementbetweenthe shoe andthe surface.
Failure to adjust may lead to a fall forward. Designing for human behaviour must anticipate
foreseeable activities.
Defining for foreseeable behaviour requires knowledge of what people do in variouscircumstances.
For example, it is not enough to safeguard machines for normal operations or production use. A
designer must also protect workers involvedin cleaning, setup and maintenance. In many cases a
designercanreduce hazards by incorporatingfeaturesthatare lessdependentonpeople protecting
themselves.A designer may include featuresthat eliminate the need for behaviours that could lead
to accidents. That idea is consistent with the Hierarchy of Controls.
Understanding the term “PERCENTILE”:
Percentileisdefinedasthe value belowwhichagivenpercentage fallsunder.Forexample,inagroup
of 20 children, Ben is the 4th tallest and 80% of the children are shorter than you. Hence, it means
that Ben is at the 80th percentile. Thus, the Percentile is different from the ‘percentage’.

4. BIG 5 PERSONALITY TRAITS THEORY:
 The Big Five personality traits are openness to experience, conscientiousness,
extraversion, agreeableness, and neuroticism.
 Each traitrepresentsacontinuum.Individualscanfall anywhere onthecontinuumforeach
trait.
 Evidence suggests that personality is highly stable during adulthood, although small
changes may be possible.
Individual personalitiesare thoughtto feature each of these five broadtraits to some degree.When
the traits are measured, some people rate higher and others rate lower: Someone can be
more conscientious and less agreeable than most people, for instance, while scoring about average
on the other traits. These traits remain fairly stable during adulthood.
People can also differ on the more specific facets that make up each of the Big Five traits. A
relatively extroverted person might be highly sociable but not especially assertive.