Assessment of intelligence

Question 1

Types of Reliability:

Answer 1

1. Test-Retest Reliability: This assesses the consistency of test scores over time. If the same test is given at two different points, high test-retest reliability means that results will be similar.
   
   • Statistical Measure: Pearson’s r, Intraclass Correlation
     2. Equivalent Forms Reliability: Refers to the consistency of test scores across different versions of a test that aim to measure the same construct, avoiding the “practice effect.”
   • Statistical Measure: Pearson’s r
     3. Split-Half Reliability: Checks internal consistency by splitting a test into two halves and measuring if both halves give similar results.
   • Statistical Measure: Pearson’s r
     4. Internal Consistency Reliability: Looks at how well the items on a test measure the same construct, often measured using Cronbach’s alpha.
   • Statistical Measure: Cronbach’s alpha
     5. Interrater Reliability: Measures the degree of agreement among different raters.
   • Statistical Measure: Kappa statistic

Question 2

Types of Validity:

Answer 2

1. Content Validity: Examines whether the test adequately covers the domain of the variable it seeks to measure.
   
   2. Predictive Validity: Refers to how well the test can predict future performance or behaviors.
   3. Concurrent Validity: Measures whether the test correlates with a criterion measured at the same time (e.g., if a test matches the current state or ability).
   4. Construct Validity: Refers to how well the test relates to other measures and theories of the construct it claims to assess.

Question 3

Definitions

Answer 3

• Intelligence can be seen as the capacity to solve problems, think abstractly, and adapt to one’s environment. It involves reasoning, planning, learning from experience, and understanding complex ideas.
  
  • Various schools of thought define intelligence differently—some emphasize the role of problem-solving, while others focus on adaptability.

Question 4

Factor Analysis’s approaches

Answer 4

• Spearman’s Theory: Intelligence can be split into a general factor (g) and specific factors (s). The general factor refers to the broad mental capacity, while the specific factors refer to skills in particular domains.
  
  • Thurstone’s Theory: He proposed several “primary mental abilities” rather than a single general intelligence factor.
    3. Cattell’s Theory: Intelligence is split into fluid intelligence (the ability to solve novel problems) and crystallized intelligence (knowledge acquired through experience).
    4. Guilford’s Structure of Intellect (SOI) Model: He categorized intellectual abilities into 180 different categories based on operations, contents, and products.
    5. Gardner’s Multiple Intelligences: Gardner identified eight distinct types of intelligence, such as linguistic, logical-mathematical, and interpersonal.

Question 5

IQ and Intelligence

Answer 5

• IQ as an Outcome: IQ (Intelligence Quotient) is the result derived from certain intelligence tests but is not synonymous with intelligence. Intelligence is a broader concept, encompassing various cognitive abilities, while IQ is merely a score reflecting a person’s performance on specific standardized tests.
  
  • Common Confusion: Although people often use “IQ” and “intelligence” interchangeably, they are not the same. Intelligence involves a wider scope of cognitive functioning beyond what IQ tests measure.

Question 6

Ways IQ is Calculated

Answer 6

There are two main ways IQ is determined:

1.	Ratio IQ:
*	Historically used in the Stanford-Binet test, Ratio IQ uses the formula  \text{IQ} = \frac{\text{Mental Age (MA)}}{\text{Chronological Age (CA)}} \times 100 .
*	For example, if a child’s mental age matches their chronological age, their IQ will be 100.
*	Key Limitation: As individuals age, their chronological age increases, but their mental age remains relatively stable. This can give the false impression that IQ declines with age, which is not accurate.
*	Problem: Ratio IQ is less effective with older individuals because it doesn’t accommodate the natural aging process.
2.	Deviation IQ:
*	Introduced by Wechsler, deviation IQ addresses the limitations of the Ratio IQ by comparing an individual’s score to that of their age group.
*	The key assumption is that intelligence is normally distributed throughout the population.
*	IQ is not absolute; it’s a relative score based on the performance of others in the same age bracket.

Question 7

Reliability of IQ

Answer 7

• Youth Instability:
  
  • IQ scores can be unstable in younger children due to environmental influences or cognitive development stages.
  • Test-retest reliability: IQ scores can fluctuate more in children when measured at short intervals, indicating instability in younger age groups.
  • Stability in Older Age:
  • IQ scores tend to stabilize in adulthood and generally remain consistent until the onset of cognitive declines, such as those seen in dementia.
  • Studies such as Gow et al., 2011 found strong correlations between IQ measured at age 11 and age 65, but this correlation diminishes after age 75 due to age-related cognitive decline.
  • Flynn Effect:
  • From 1972 onwards, there has been a significant increase in average IQ scores in the U.S., with an estimated 3-point increase per decade.
  • This phenomenon suggests that as people are increasingly exposed to cognitive tasks and test-taking environments, their performance on IQ tests improves.

Question 8

What IQ Measures

Answer 8

• Present Functioning: IQ is a measure of an individual’s current intellectual functioning at the time of the test.
  
  • Changes Over Time: IQ can change due to traumatic brain injury, cognitive decline, or aging.
  • Contextual Consideration: IQ scores can provide a general understanding of someone’s cognitive abilities but must be interpreted carefully alongside other factors such as emotional, environmental, or motivational influences.

Question 9

Additional Considerations for Diagnoses

Answer 9

• While IQ tests are helpful in measuring general cognitive functioning, they should not be the sole measure for diagnosis or predictions about future outcomes.
  
  • Other methods such as personality measures and interviews should be used alongside IQ testing for a more comprehensive assessment of an individual’s abilities.

Question 10

Clinical Usage for IQ Tests

Answer 10

1. Estimation of General Intelligence:
   
   • Patient Referral for Therapy Suitability: IQ tests help assess if a patient is cognitively capable of benefiting from therapy, particularly in cases where therapy involves cognitive tasks and understanding.
   • Legal Requirement to Define Learning Disabilities: IQ tests are often required by legal frameworks to determine the presence of learning disabilities, as these scores help in defining eligibility for special education services or accommodations.
   • Effects of Head Trauma: IQ testing can help measure cognitive decline or deficits following a head injury or trauma, offering insights into the extent of impairment and recovery potential.
     2. Prediction of Academic Success:
   • Parents and School Selection: Parents often use IQ test results to guide decisions about which school may be best suited for their child’s educational needs.
   • Benefit from Tuition: IQ tests can provide information on whether a child would benefit from additional support, like private tutoring or specialized instruction.
   • Group Performance Comparison: IQ scores are used to assess whether a child is performing well in comparison to peers or expected standards for their specific group (age or educational level).
     3. Appraisal of Style:
   • Mistake Patterns: IQ tests help to evaluate the kinds of mistakes individuals make, which can provide deeper insights into cognitive processes and problem-solving approaches.
   • Being ‘Wrong’ in the Right Way: The appraisal also considers whether mistakes are systematic or if individuals demonstrate the ability to learn from errors.
   • Aptitude Testing for Jobs: IQ tests are often used in employment settings to assess an individual’s aptitude for specific types of jobs, helping to predict job performance and suitability for roles requiring certain cognitive abilities.