24 A Teacher's Guide to Testing Students Potential

Briefing Document: Intelligence Testing – Brains and Bias

Source: Excerpts from "24_Testing_brains.pdf" - Dr. Sudheendra S. G. Research on Behavioural Genetics Episode 24 Brains and Bias

Date: October 26, 2023

I. Introduction: The Complexity of Measuring Intelligence

The provided text, an excerpt from Dr. Sudheendra S. G.'s research on behavioural genetics, delves into the history, methodologies, and controversies surrounding human intelligence testing. It highlights the inherent human drive to "measur[e], ranking, and comparing each other's intelligence," while simultaneously acknowledging the historical inaccuracies and ongoing limitations of such endeavors. The core message is that while we strive to measure intelligence, "most of what we've learned is simply what we don't know."

II. Current Understanding of Intelligence and Common Assessment Tools

A. Multifaceted Nature of Intelligence: Modern understanding posits that intelligence is a complex interplay of various factors. "Today, we think of intelligence as determined by a series of factors related to genetics, environment, education, perhaps even randomness itself, some aspects of which may correlate with belonging to a particular social group, and others not." A critical caveat is that the precise mechanisms and extents of these factors remain largely unknown.

B. Impact of External Factors: The text raises crucial questions about how "personal history and conditions like poverty, access to education, stress, even nutrition affect someone's scores on cognitive tests." These conditions can significantly influence individual and group performance on potentially biased intelligence tests.

C. Widely Used Intelligence Tests: The most prevalent intelligence tests today are the Wechsler Adult Intelligence Scale (WAIS) and the Wechsler Intelligence Scale for Children (WISC). These tests, first published in 1955, consist of "fifteen different sub-tests that assess things like vocabulary, similarities between objects and concepts, and patterns in letters and numbers."

D. Types of Cognitive Tests: Cognitive tests typically fall into two categories:

• Achievement Tests: Reflect what a person has already learned (e.g., a math final exam).
• Aptitude Tests: Predict an individual's ability to learn something new (e.g., WAIS and WISC).

III. Standards for a "Good" Intelligence Test

For a test to be widely accepted and considered effective, it must meet three critical criteria:

A. Standardization:

• Ensures comparability of scores.
• Requires administering the test to a "representative sample group" to establish a "standard by which to compare future test-takers."
• Assumes a "bell-curve" or "normal pattern" distribution of scores, with most falling in the mid-range.
• Effective Use Cases: Intelligence tests are most effective at the "extremes" of the bell curve. They can help identify "a gifted student" or assist clinicians in determining if someone "might have a disability or be facing some specific barrier," such as in cases of traumatic brain injury or stroke to diagnose specific language or processing issues.
• Limitations: These tests are not designed to answer broader questions like "Will Jesse get into Harvard?" or "Are women smarter than men?"

B. Reliability:

• Refers to the test's ability to "yield dependably consistent results."
• Determined by having individuals take the same test (or a similar version) multiple times; if scores "correlate," the test is considered reliable.

C. Validity:

• Measures "the extent to which a test measures or predicts what it's supposed to."
• Predictive/Criterion Validity: Scores accurately predict future outcomes (e.g., WAIS scores predicting college grades).
• Construct Validity: Scores correlate strongly with results from other similar cognitive tests (e.g., WAIS correlating with Stanford-Binet scores).

IV. The Nature vs. Nurture Debate: Genetics and Environment

The text emphasizes that both genetics and environment significantly influence intelligence. "If the history of intelligence testing has taught us anything, it's that assuming everyone is smart in the same way and for the same reason can lead to disastrously bad conclusions."

A. Evidence for Genetic Influence:

• Twin Studies:Identical twins raised together show the "highest rate of similarity in intelligence scores."
• Fraternal twins (half genes) are "much less similar," even when raised together.
• Neuroimaging shows "structurally similar" brain regions and activity in identical twins.
• "Identical twins raised apart from each other show higher intelligence correlation than fraternal twins raised together."
• Intriguingly, intelligence correlations in identical twins "increase over time," from childhood through adulthood.
• Adoption Studies:Adopted children's mental similarities to their adoptive families "get smaller over time until there's virtually no correlation by adulthood."
• Conversely, they become "more similar in terms of mental aptitude to their biological parents over time, even if they never met."
• Conclusion on Genetics: "In other words: genes appear to matter. You could take a hundred kids and raise them in the exact same way, and as adults, they'd still have different aptitudes."

B. Evidence for Environmental Influence:

• "Life experiences and environment also matter."
• J. McVicker Hunt's Iranian Orphanage Study (1970s):A "sad example" of severe deprivation, where infants received "minimal care" and no "cause and effect between their behaviors and the responses of their caregivers."
• Resulted in children being "passive, vacant lumps" with no communication skills, demonstrating how "deprivation was essentially trumping any inborn intelligence."
• Intervention: Hunt's program trained caregivers to interact, talk, and teach infants, leading to "tremendous" results as "the kids started to learn really quickly, and basically just came alive."
• Conclusion on Environment: Hunt's research showed "how malleable early childhood intelligence can be, especially in disadvantaged and stressful conditions."

C. Interaction: It is clear that "environment and heredity interact to affect intelligence."

V. Testing Bias and Stereotype Threat

A. Testing Bias:

• A major controversy arises when tests "inadvertently measures differences caused by cultural experiences or social factors instead of what we might call 'innate intelligence.'"
• Historical Example: Immigrants to the US were deemed "feeble minded" for failing questions like "Who was the first American president?"
• Modern Concerns: Bias focuses on differences within the same culture, where questions might involve "urban, upper-class concepts like taking taxis and drinking tea out of china cups or the rules of tennis," disadvantaging individuals from different backgrounds (e.g., "a poor, rural kid").
• Administrator Bias: The person administering the test can affect outcomes. "Women tend to do better with a fellow female administrator, and African Americans often score higher if their test is given by an African American instructor."

B. Stereotype Threat:

• "The risk of bias may even fall to the test-takers' own expectations."
• Defined as "self-fulfilling concern that you might mess up and inadvertently fulfill some negative stereotype."
• Example: Studies show that telling equally capable men and women that "women usually score lower than men" on a math test "negatively affect[s] the women's performance."
• First described by social psychologists Claude Steele and Joshua Aronson, it has been "demonstrated frequently across a whole host of interesting studies."

VI. Conclusion: Beyond the Score

The text concludes by emphasizing the limitations of intelligence testing and the broader complexity of human potential: "An important thing to remember next time you ace or bomb a test is that you are far more complicated and nuanced than any test score. Don't let a number puff you up or drag you down, and don't let it define you. We all have room for self-improvement. We are all full of infinite surprising potential."

The document summarizes the key takeaways: the current use of WAIS and WISC, the importance of standardization, reliability, and validity, and how genetics, environment, testing bias, and stereotype threat all impact IQ test performance.