Cognition or personality?

Raymond Cattell (the first C in CHC…) considered intelligence to be a facet of personality.  Intelligence/reasoning is one of the 16 personality factors in Cattell's model. 

We know that responses to items in tests that measure intelligence and cognitive abilities also reflect facets of personality, and that responses to items in tests that assess personality also reflect cognitive abilities.

The American Psychological Association (APA) defines personality as “individual differences in characteristic patterns of thinking, feeling, and behaving”.  APA’s 1996 Intelligence Task Force likewise provides a definition of intelligence as “individual differences in the ability to understand complex ideas, to adapt effectively to the environment, to learn from experience, to engage in various forms of reasoning, to overcome obstacles by taking thought”.

Intelligence, personality and the assessment method

For a combination of historical, accidental, and practical reasons, two broad approaches to measuring these two constructs have emerged and come to dominate how we think of them. For personality, the dominant methodology has to do with endorsements of descriptions of characteristic behavior, thoughts, beliefs, or attitudes. The endorsements can be done by the self or by others—peers, teachers, or supervisors. The essence of the method is that it involves evaluating the target’s “characteristic patterns of thinking, feeling, and behaving” represented by descriptions.  For intelligence, the dominant method is the standardized test, with a problem and response format (multiple choice, short answer, and essay), scored as right or wrong, or in some cases, partially right.

However, intelligence can just as easily as personality be evaluated with the statement endorsement methodology. That is, rather than giving a test, we can ask examinees their level of agreement to statements such as “I understand complex ideas”, “I adapt effectively to the environment”, “I learn from experience”, or “I engage in various forms of reasoning to overcome obstacles by taking thought".  The correlation between self-estimates of intelligence and intelligence test scores is about r = 0.33.

In order to have meaning, the assessment of personality via questionnaires should be useful.  It should explain, for example, interpersonal differences in the ability to learn new things and solve new problems, or to explain individual differences in school achievement.   The ways in which people assess their intellectual abilities affect their motivation.  It's possible that these perceptions also affect individual differences in knowledge acquisition and in academic achievement.

Likewise, personality can be measured with tests.  James’ conditional reasoning test (CRT) presents five alternative multiple-choice reading comprehension problems with two correct answers. The two correct answers reflect different world views, which are presumed to be revealed by one’s selection.  There are personality tests that measure the tendency to take risks.  The willingness to exert effort and to persevere can also be measured with simple tests (like processing speed tests).

We see that personality and intelligence are intertwined.  Our challenge, argue Kyllonen and Kell, is to distinguish between the construct we wish to measure (personality or intelligence) and its measurement method.   The present state of affairs, in which the construct and the measurement method are indistinguishable, lead to distortions in our perception of the constructs and in our ability to measure them properly.  Boring said that intelligence is "what intelligence tests measure".  This is also true for personality.  The desired state of affairs is to measure each of these constructs in versatile ways:  with tests, questionnaires and other approaches.  In the existing state of affairs, the method of measurement determines whether we measure personality or intelligence…

Cognitive influences on personality and personality influences on cognition

It's possible to discern between general and specific non-cognitive factors that affect performance in cognitive tests:

General factors: personality traits, attitudes, emotional reactions, habits generally operating in situations like the test situation.  Other influencing factors can be health, motivation, mood, and the person's level of attention.  Personality factors that affect performance in cognitive tests can be, for instance, openness to new experiences, flexibility, the ability to tolerate ambiguousness, frustration and difficulties and the ability to monitor performance.  Personality factors related to externalization can underlie a tendency for speed over acuity.  Anxiety can disrupt cognitive functioning.  A person can have a tendency for internal attribution (I'm not smart enough/when I make an effort I usually succeed) or a tendency for external attribution (these questions are dumb/ I was lucky to be asked about things I just learned in class).  A person's performance can be affected by his perception of his intelligence/cognitive abilities as fixed or flexible.

Specific factors:  attitudes, emotional reactions or habits that arise in response to a specific test.  Training in a similar task can affect the quality of response to a specific test.  Relevant background knowledge can affect the quality of response to a specific test.  The health and fatigue of the child at the time of testing can also affect performance.  If the child is troubled at the time of testing – this can impede his ability to concentrate.

On the other hand there are cognitive and attentional factors that affect performance on personality questionnaires.  A child's linguistic ability can affect his reading comprehension (or listening comprehension, in case we read the items for him).  A child's ability to understand complexity in the wording of the items (fluid ability) and his ability for introspection and mentalization (in its cognitive aspects) can also affect performance.

A child's ability to observe himself from a third person viewpoint, the attentional capacities of the child, the test being culturally and linguistically appropriate for the country in which it is being used, the child's experience or familiarity with questionnaires, the child's strategies for dealing with questionnaires and/or his ability to form such strategies – all these factors influence performance.

In principle, test developers want to minimize the impact of non-cognitive factors on performance in cognitive tests and the impact of cognitive factors on personality questionnaires.  On the other hand, the existence of such influences emphasizes the extent to which these dimensions are not separate in reality.

Typical versus maximal performance.

Personality traits are often defined in terms of typicality—stable patterns of behavior over an extended period of time. If person A frequently acts in an assertive, talkative manner across a wide variety of everyday situations, she would be considered more extraverted overall than person B, who is only moderately talkative and assertive on average. However, person B, if properly motivated, may be able to act in ways more extraverted than usual, and the upper limit of person B’s extraversion may even exceed person A’s, because of situational press.

Intelligence is usually conceptualized and measured in terms of maximal performance - as what people are able to do.  Intelligence is defined as the limit of a person’s intellectual repertoire, which can be expressed when that person is exerting maximum effort.  When intelligence tests are administered under high-stakes conditions, all individuals are expected to be maximally motivated and, as a consequence, cognitive ability is assumed to be the primary (and perhaps only) source of test score variance. As we know from our work with children, the assumption of maximal performance does not always apply.  Nevertheless, since taking an IQ test is a limited-time event, the assumption is that a person can perform maximally throughout the test.  Maximal performance is not possible over longer time periods.

We've noted that personality traits are often conceptualized in terms of typical performance.  Personality is usually measured with questionnaires that refer to typical behaviors and thoughts, and in this respect they are typical performance tests.  But questionnaires are not tests…

What distinguishes between tests that measure maximal versus typical performance?

Maximal performance tests	Typical performance tests
Tests that measure mostly maximal performance:  Wechsler, Kaufman, REY – AVLT, BENDER.	Tests that measure mostly typical performance:  TAT, HTP, reading comprehension (as assessed dynamically with a text).
Typical items: what is South Korea's currency?  Scan these drawings as fast as you can, and when you see a ball, cross it out.	Typical items: tell me a story about this picture; draw a person.  Tell me the story you've just read.
Mostly assess an ability.	Mostly assess a tendency.
Predict ability in situations that are similar to the test situation.	Predict the ability to organize and to respond in ambiguous situations.
Expose mainly product and only a little of the process that led up to it.  Expose knowledge but not the use of knowledge.	Expose both process and product.
The problem is explicit and clear.	Very little instructions.  The person has to decipher the situation, to recognize that there is a problem and to create a solution.
The presented problems are relatively simple.	The presented problems are complex and require the synthesis of ideas, the organization of a sequence of actions, monitoring performance etc.
There usually is only one right solution.	Many "right" answers.
There is a clear performance standard according to which the response is judged.	General criteria for judging the response (coherence, logic, relation with the stimulus etc.)
Coping time with each problem is short.  Because of the short time period, it's possible to invest effort for maximal performance.	Require coping for a long time period - it's harder to maintain maximal performance for an extended time period.

Is it possible to measure intelligence with typical performance tests? Is it meaningful to talk about maximal performance in personality tests?

Typical performance tests assess the tendency to think in different life situations.  The tendency to think is affected by the person's sensitivity to identify moments that call for thinking and by his tendency to invest the necessary energy.  There are individual differences in people's tendency to look for new information in their surroundings, and to act upon the information they discover.

It's important to know how a person usually thinks in ordinary life situations, not only whether he is capable of thinking under maximal performance conditions, that call for solutions to clearly defined problems.  This distinction is important both for task with social – emotional content and for tasks with a cognitive/ achievement content.

Chamorro-Premuzic & Furhnam suggest the term "intellectual competence" as a way to broaden the traditional concept of intelligence.  Intellectual competence refers to a person's ability to acquire knowledge throughout life, an ability that depends not only on traditional cognitive abilities but also on his appraisal of his intelligence and personality traits. 

Intellectual competence is a marker for a person's ability to succeed in professional and learning environments, especially in environments that require both cognitive and emotional adaptation.

Chamorro-Premuzic, T., & Furhnam, A. (2006). Intellectual competence and the intelligent personality: A third way in differential psychology. Review of General Psychology, 10(3), 251.

Kyllonen,C &  Kell, H. (2018).  Ability Tests Measure Personality, Personality Tests Measure Ability: Disentangling Construct and Method in Evaluating the Relationship between Personality and Ability. Journal of Intelligence.  6, 32.