PSY2041 Chap.6 Intelligence Testing
Intelligence Testing
Intelligence Testing links theories of cognitive ability with norm-referenced score patterns. Hierarchical theories organise a general factor, broad abilities and narrower skills, while test batteries operationalise only parts of those structures. Global scores, index scores and subtests answer different questions.
Interpretation begins with the referral, checks score precision and pattern coherence, integrates observations and history, and avoids converting one relative weakness into a diagnosis.
What this chapter covers
- 01
Definitions and competing theories of intelligence
- 02
General, broad and narrow levels in hierarchical models
- 03
Stanford-Binet and Wechsler approaches to intelligence assessment
- 04
Norm-referenced standard scores and percentile ranks
- 05
Global scores, index profiles and subtest evidence
- 06
Genetic and environmental evidence for intelligence variation
- 07
Culture, language, norms and proportional interpretation
Worked example · free
Interpret an uneven illustrative profile
- 1Describe the relative pattern: verbal reasoning is strongest in the profile and processing speed is lowest.
- 1Connect slower processing speed cautiously with the referral about timed work.
- 1Check confidence intervals, discrepancy frequency and whether the broad score remains coherent.
- 1Consider motor, visual, fatigue, anxiety, language and history as alternative explanations.
- 1Recommend support and further evidence without treating the relative weakness as a diagnosis.
Key terms
- General intelligence
- A broad factor proposed to account for shared performance across many cognitive tasks.
- Broad ability
- A major cognitive domain positioned below general ability in a hierarchical model.
- Index score
- A standardised summary of performance across subtests intended to sample a broad cognitive domain.
- Percentile rank
- The percentage of the reference group scoring at or below a given score.
- Norm group
- The defined comparison population used to interpret an individual's test performance.
- Heritability
- A population-specific estimate of variation associated with genetic differences under particular conditions.
Intelligence Testing FAQ
Is an intelligence score a fixed measure of potential?
No. It estimates performance on particular tasks relative to norms under specific conditions. Measurement error, health, opportunity, language, motivation and context affect interpretation. A score can be useful without representing an unchangeable limit on development.
What does the tenth percentile mean?
It means the score is at or above roughly ten percent of the relevant norm group and below roughly ninety percent. It does not mean ten percent intelligence and should be reported with the norm group and score precision.
Does high heritability mean education cannot help?
No. Heritability describes population variation in a particular environment, not one person's genetic percentage or fixed potential. Environmental change can affect individuals, group means and the amount of variation from which the estimate is calculated.
Exam move
Build a three-level intelligence hierarchy and place general, broad and narrow abilities correctly. Compare theories by what structure they predict rather than by memorising names. For profile questions, follow referral, precision, broad pattern, discrepancy meaning, alternative explanations and integrated recommendation. Practise translating percentiles and standard scores without equating them.
Keep relative weakness separate from normative weakness. For nature-nurture questions, repeat the phrase population variation under specified conditions, then explain why this does not determine an individual's development. End score interpretations with a boundary and a source of corroborating evidence.
Reconstruct the hierarchy from a blank page and attach an example of a broad ability and a narrower task demand to each branch. Then compare a global composite, index scores and subtests by the question each can answer and the extra uncertainty introduced as interpretation becomes more specific.
Use invented profiles to distinguish three cases: broadly even performance, a relative weakness that remains average compared with norms, and a score that is both relatively and normatively low. For every discrepancy, list alternative explanations involving measurement error, task demands, language, education, attention, motivation or speed before linking it to the referral.
Practise converting standard scores into plain relational language without claiming fixed capacity. A percentile describes position in a comparison group; it is not the percentage of questions answered correctly. For heritability prompts, draw a boundary around population, environment and time.
Explain that a population estimate partitions observed variation under specified conditions and does not assign a percentage cause to one person's score. Finish with a short integrated paragraph that begins from the referral, comments on precision and pattern, incorporates behaviour and history, and offers a cautious next step.
This structure prevents either a total score or an eye-catching subtest difference from carrying more meaning than the evidence supports. Test your profile interpretation by removing the score labels and asking what additional information would be needed to reach the same recommendation. If history, observation and task demands disappear from the answer, the numerical pattern is carrying too much weight.
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