uses of intelligence tests

• PSYC5016 Personality, Individual Differences and Psychometrics Uses and abuses of intelligence tests Week 4, 2024 Prof Anna Barnett
• Recap of last week: Historical aspects of intelligence testing, Standard scores, Norms and the 'Flynn effect', Evaluating aspects of reliability and validity
• Preparation for Week 4: Read Weiss, L.G. & Saklofske, D.H. (2020). Mediators of IQ test score differences across racial and ethnic groups: The case for environmental and social justice. Personality and Individual Differences, 161, 109962. (See the Week 4 Key Text link on Moodle) General reading: book chapters in recommended books
• Intended learning outcomes


  • Describe the Cattell-Horn-Carroll (CHC) theory of intelligence
  • Explain ways in which intelligence tests have been misused
  • Discuss the mediators of IQ test score differences across racial and ethnic groups
  • Locate information on current professional standards in testing
  • Outline key ethical considerations in the administration and interpretation of intelligence tests
• WAIS-IV (2008) Four Factor Model

  • Verbal Comprehension
  • Perceptual Reasoning
  • Working Memory
  • Processing Speed
• Cattell-Horn-Carroll theory


  • CHC theory of cognitive and academic abilities
  • Formed from amalgamation of Gf-Gc theory (Cattell, 1941; Horn, 1965) and 3-stratum theory (Carroll, 1993)
  • Promotes view that rather than perceive cognitive abilities & academic attainments as qualitatively different and distinct, better to perceive as part of a continuum ranging from broad to fine abilities
  • Stratum I – narrow abilities – over 70
  • Stratum II – broad abilities -10
  • Stratum III – general abilities (g)
• CHC – 10 broad abilities

  • Fluid
  • Quantitative reasoning
  • Crystallised
  • Short term memory
  • Visual processing
  • Auditory processing
  • Long term storage & retrieval
  • Processing speed
  • Reaction time
  • Basic reading & writing
• Very low scores on tests

  Learning difficulties/intellectual disability
• Issues with terminology and definitions for both very low and very high scores on tests
• Psychometric tests as part of a broader assessment for both very low and very high scores on tests
• Theiling & Petermann (2016) investigated pattern of profiles and overall scores on the WAIS-IV relative to controls, 116 adults (16-71 years) with ADHD, plus controls. Results: ADHD group had decrements in WM & PS
• Dr Nigel King: 'Consultant Clinical Neuropsychologist, Neuropsychology Lead & Clinical Tutor, The Oxford Institute of Clinical Psychology Training & Research, Oxford Health NHS Foundation Trust, University of Oxford, Isis Education Centre, Warneford Hospital, Oxford. Nigel talks about use of the Wechsler scales in his work – in particular use of the individual sub-tests'
• Robert Jeffrey Sternberg (1949– )


  • Intelligence is the ability of the individual to use adaptive behaviours and to perform in culturally valued ways and to produce culturally valued products
  • It involves the individual interacting with the environment
  • Criticized IQ tests
• Sternberg: IQ tests test IQ – not intelligence. They are "convenient partial operationalizations of the construct of intelligence, and nothing more. They do not provide the kind of measurement of intelligence that tape measures provide of height" (Sternberg, 1999)
• Sternberg: No relation between scores on tests of practical intelligence given to business executives and scores on conventional tests of intelligence
• Sternberg's Triarchic Theory (1985)

  • Intelligence involves 3 sets of skills: Analytical, Creative, Practical
  • Later added 'Wisdom' to ensure ideas help achieve a common good over the long term
• By adulthood, approx. 2/3 of intelligence differences are caused by how people vary in their genetic inheritance
• Genome-wide association studies (GWAS) show intelligence is a polygenic trait
• The dark ages - the USA

  • 1907 Indiana compulsory sterilisation
  • By 1930 - 28 states had laws permitting involuntary sterilisation
  • Main targets "feebleminded" and mentally ill
  • Also applied to range of people – incl. those with epilepsy, bipolar disorder, schizophrenia, dementia etc.
  • Native Americans sterilized against their will in many states
• The dark ages - Germany


  • 1933 compulsory sterilisation law
  • By 1939 over 350,000 citizens sterilised
  • 1935 abortion laws including for "social feebleminded"
  • Government funded facilities to raise "racially pure" children
  • Minority groups, especially Jews, murdered in concentration camps during The Holocaust
• People who endorsed eugenics

  • Alexander Graham Bell
  • Winston Churchill
  • Calvin Coolidge
  • Charles Darwin
  • F. Scott Fitzgerald
  • Sigmund Freud
  • John Harvey Kellogg
  • Karl Pearson
  • Theodore Roosevelt
  • George Bernard Shaw
  • Charles Spearman
  • H.G. Wells
• Eugenics policies persisted after WWII. Forced sterilisations in USA continued into the 1970s. Japan repealed compulsory sterilisation law in 1996 (Denmark 1967, Finland 1970, Sweden 1975, Norway 1977). Eugenics Society (in Britain) did not change name till 1989. Today – genetic counselling to learn probabilities of having a child with disease and choose whether to have children. Sperm banks/egg donation clinics advertise psychological traits of donors. Growing technology for gene modification of human embryos
• Herrnstein & Murray (1994) highly controversial book, particularly on connections between race and intelligence - and policy implications. Not subjected to peer review prior to publication. Included reviews of literature and new data analyses of National Longitudinal Survey of Youth (1979). Considered association between intelligence test scores and social outcomes. Discussed ethnic differences in cognitive ability – means for Asian Americans > white Americans > black Americans
• Response by APA Task Force (Neisser et al, 1996): "The reasons for intelligence test score differences between various groups are not known." "The cause of that differential is not known; it is apparently not due to any simple form of bias in the content or administration of the tests themselves….. Several culturally based explanations of the Black/White IQ differential have been proposed; some are plausible, but so far none has been conclusively supported. There is even less empirical support for a genetic interpretation. In short, no adequate explanation of the differential between the IQ means of Blacks and Whites is presently available."
• BBC iPlayer. Subnormal: A British Scandal
• Potential misuse of intelligence tests

  • Inappropriate application of tests
  • Inappropriate interpretation of test scores
  • Adverse impact/consequences of testing
• Weiss & Saklofske (2020): Mean IQ score differences across racial/ethnic groups in the standardisation samples, BUT educational level of parents/participants differ across these groups. Variances in IQ score differences can be accounted for by SES and selected home environment factors
• Weiss & Saklofske (2020): 15% variance, 9.2% variance, 11.2 points unexplained
• Professional and ethical standards in testing

  • Test bias
  • Bias and fairness in testing
  • National guidelines & codes of practice
  • Quality of tests and materials
  • Test user competence
  • Privacy and confidentiality
• Preparation for Week 5: Read Cropley, A.J. (2000). Defining and measuring creativity: Are creativity tests worth using? Roeper Review, 23(2), 72-79. (See the Week 5 Key Text link on Moodle) General reading: book chapters in recommended books