Intelligence, IQ, and Crime

1. Intelligence, IQ, and Crime History of mental testing and IQ The relationship between IQ and Crime Issues of Spuriousness Direct, or Indirect Effect Criticisms of the Bell Curve

2. Alfred Binet French scientist who began in the field of “craniometry” Began to doubt the validity of this method Around 1900, he started “psychological” testing (commissioned by government) Devised several “mental tasks” (counting coins, spatial reasoning)

3. Binet’s Admonishments 1.Scores are a practical device They do not buttress any theory of “intelligence” 2.Scores are a “rough empirical guide” for identifying retarded children They should not be used to rank normal children 3.Children identified as retarded should be helped Low scores should not mark children as “innately incapable”

4. The Creation of “IQ” Binet: eventually assigned an “mental age” to each task (normal child x years of age should complete) Subtract the physical age from the mental age to see how big the gap was (identify those in need) Later, others argued that the mental age should be divided by the physical age “Intelligence Quotient” was born

5. The American “bastardization” Binet’s methods adopted by scientists in U.S. They managed to break all of the “rules” H.H. Goddard coined the term “moron,” set at a mental age of 12 for an adult avid in the eugenics movement Lewis Terman Created the “Stanford-Binet” IQ exam Goal = “rational society” where people could be assigned jobs based on intelligence

6. IQ tests today No longer “mental age/physical age” All correlate with the Stanford Binet or other early versions Calibrated to produce a mean of 100 The “Flynn effect” Still multiple tasks covering different cognitive areas

8. IQ and Crime Early positivists (Goddard…) found large differences between criminals and non-criminals As testing improved, this difference shrunk Sutherland (1940s): it will disappear Currently: 8-10 point gap Why this difference???

9. Possible Spuriousness Race, Class, SES, Culture? Controlling for these effects, the relationship remains Detection Hypothesis? Detected vs. Undetected offenders = no difference Impulsivity? Ruled out through statistical control

10. If relationship is non-spurious The “Direct Effect Model” (The Bell Curve) Low IQ Crime Indirect Effects Low IQ school trouble Delinquency labeling process Interactive: Low IQ is proxy for neuropsychological damage (N.P. damage x Parenting) Delinquency

11. Criticisms of the Bell Curve Only 3 variables in model (not enough control) Could control for school performance, other factors IQ explains only 3% of the variation in crime The correlation is about .-06 Is this important enough to justify their policy implication?? Ranked with other “predictors,” IQ is near the bottom of the list