Chapter 4:
I. The Measurement of Individual Differences
Clyde Kluckhohn and Henry Murray
o Certain psychological properties and processes are universal (like all other men)
o Other properties of people differ but in ways that allow individuals to be grouped (like
some other men)
o Each individual is unique and cannot be meaningfully compared with anyone else (like
no other man)
The trait approach is based on the ideas that all men are “like some other men” and that it is
meaningful and useful to assess broad categories of individual difference, it assumes that in some
real sense people are their traits
Dimensions of individual differences are the building blocks from which personality is
constructed
o Raises a fundamental problem
II. People Are Inconsistent
Causal observation is sufficient to confirm that personality traits are not the only factors that
control an individual’s behavior
o Situations also matter
Situations vary according to the people who are present and the implicit rules
apply
Perhaps individuals’ behaviour is so inconsistent and apt to change according to the given
situation that there is no use characterizing them in terms of broad personality traits
Research shows that the stability of the differences between people increases with age
o 30 yr olds more stable across time than children and adolescents
o 50-70 yr olds most stable
People differ from each other in the degree to which they have developed a consistent personality
for themselves
o Related to psychological adjustment as well as age
o Several studies suggest that the consistency of personality is associated with maturity and
general mental health
III. The Person-Situation Debate
The debate was triggered by the publication in 1968 of a book by Walter Mischel entitled
Personality and Assessment
o He argued that behaviour is too inconsistent from one situation to the next to allow
individual differences to be characterized accurately in terms of broad personality traits
o Other psychologists disagreed
3 issues:
o Does the personality of an individual transcend the immediate situation and provide a
consistent guide to her actions, or is what a person does utterly dependent on the situation
she is in at the time?
o Are common, ordinary intuitions about people fundamentally flawed, or basically
correct?
o Why do psychologists continue to argue about the consistency of personality, year after
year, decade after decade, when the basic empirical questions were settled long ago?
The situationist argument has 3 parts
o There is an upper limit to how well one can predict what a person will do based on any
measurement of that person’s personality, and this upper limit is a low upper limit
o Situations are more important than personality traits in determining behaviour
(situationism) o The trait words used to describe people are not legitimately descriptive, since people
generally tend to see others as being more consistent across situations than they really are
a. Predictability
There is no trait that you can use to predict someone’s behaviour with enough accuracy to be
useful
Mischel’s book surveys some of the research concerning the relationships between:
o Self-descriptions of personality and direct measurements of behaviour (S data and B data)
Addresses the ability of personality trait judgments to predict behaviour
o Others’ descriptions of personality and direct measurements of behaviour (I data and B
data)
Addresses the ability of personality trait judgments to predict behaviour
o One measurement of behaviour and another (B data and other B data)
Addresses the consistency of behaviour across situations
The critical question is how well a person’s behaviour in one situation can be predicted either
from his behaviour in another situation or from his personality-trait scores
In research literature, predictability and consistency are indexed by a correlation coefficient
o Mischel’s argued that correlations between personality and behaviour or behaviour in one
situation and behaviour in another, rarely exceed 0.30
o Richard Nisbett (1980) revised the estimate upward to 0.40
Correlations are small, personality traits are therefore unimportant
Some psychologists concluded that personality doesn’t exist
o 0.40 is the upper limit for the predictability of a given behaviour from personality
variables or behaviour in other situations
o Upper limit is low
The Response
Unfair literature review
o Mischel’s review is quite short and concentrates on a few studies that obtained
disappointing results rather than on the studies that obtained more impressive findings
Didn’t go out of his way to find the best studies in the literature
o The Mischel-Nisbett figure: assume that a correlation about 0.40 is the upper limit for
how well personality traits can predict behaviour, as well as for how consistent behaviour
is from one situation to another
We can do better
o The weak findings summarized by Mischel do not imply that personality is unimportant,
merely that psychologists can and must do better research
o One way to improve research to move out of the laboratory more often
Personality is much more likely to become relevant in situations that are real,
vivid and important
nd Real life behaviour is not easy to asses
o 2 way to improve research that some people might be more consistent than others
Individual differences in consistency may be subtle and difficult to measure
o 3 way to improve research to focus on general behavioural trends instead of single
actions at particular moments
The prediction of behavioural trends requires that the researcher observe many
behaviours, not just few
o The issue is more than just a matter of statistics, it concerns the whole meaning and
purpose of personality-trait judgments
o The 3 suggestions measure behaviour in real life, check for variations in consistency, and
seek to predict behavioural trends rather than single acts
However, they represent potential more than reality A correlation of 0.40 is not small
o To evaluate this correlation against an absolute standard calculate how many correct
and incorrect predictions of behaviour a trait measurement with this degree of validity
would yield in a hypothetical context
According to BESD, a correlation of 0.40 means that a prediction of behaviour
based on a personality-trait score is likely to be accurate 70% of the time
(assuming a chance accuracy rate of 50%)
o To evaluate this correlation against a relative standard compare this degree of
predictability for personality traits with the accuracy of other methods used to predict
behaviour
To evaluate the ability of personality trai
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