The Intelligence Paradox: Why the Intelligent Choice Isn't Always the Smart One - Satoshi Kanazawa 2012
Intelligence and Criminality
Why Intelligent People Drink and Smoke More
Criminologists have long known that criminals on average have lower intelligence than the general population.17 Juvenile delinquents are less intelligent than nondelinquents,18 and a significant difference in IQ between delinquents and nondelinquents appears as early as ages 8 and 9.19 Chronic offenders are less intelligent than one-time offenders,20 and serious offenders are less intelligent than less serious offenders.21 The negative association between general intelligence and criminality is not an artifact of a selection bias, whereby less intelligent criminals are more likely to be caught than more intelligent criminals who get away, because the association exists even in self-report studies that do not rely on official police statistics.22 (Yes, people often do reveal in interviews and surveys that they have committed crimes that they are not charged with, even those that the police don't know about.)
Why is this? Why do criminals have lower intelligence than the general population? And why do more chronic and serious criminals have lower intelligence than their less chronic and serious counterparts?
From the perspective of the Intelligence Paradox, there are two important points to note. First, much of what we now call interpersonal crime today, such as murder, assault, robbery, and theft, were probably routine means of competition among men for resources and mates. This is how men likely competed for resources and mating opportunities for much of human evolutionary history. We may infer this from the fact that behaviors that would be classified as criminal if engaged in by humans are common among other species,23 including other primates such as chimpanzees,24 bonobos,25 and capuchin monkeys.26
Second, the institutions and technologies that control, detect, and punish criminal behavior in society today—the police, the courts, the prisons, CCTV cameras, DNA fingerprinting—are all evolutionarily novel. There was very little formal third-party enforcement of norms in the ancestral environment, only second-party enforcement (retaliation by victims and their kin and allies) or informal third-party enforcement (ostracism). (One need only recall van Beest and Williams's findings in their Cyberball experiment, discussed in Chapter 2, to realize how powerful a punishment ostracism must have been in the ancestral environment.)
It therefore makes sense from the perspective of the Intelligence Paradox that men with low general intelligence may be more likely to resort to evolutionarily familiar means of competition for resources (theft rather than full-time employment) and mating opportunities (rape rather than computer dating), because they are less likely to recognize and comprehend the more evolutionarily novel means (as well as often lacking access to them). It also makes sense that such men do not fully comprehend the consequences of criminal behavior imposed by evolutionarily novel technologies and institutions of law enforcement.
Why Do Less Intelligent People Commit Some Crimes but Not Others?
But if less intelligent individuals are more likely to commit crimes, why are they less likely to use illegal drugs? The consumption of psychoactive drugs, such as marijuana, cocaine, and heroin, is illegal in both the UK and the US; in other words, it is a crime to use such substances. So why aren't less intelligent individuals more likely to commit the crime of drug use?
This is the proverbial case of “the exception which proves the rule.” As I mention above, less intelligent individuals are more likely to engage in crime, not because it is criminal per se, but because most of it is evolutionarily familiar. Less intelligent individuals are less likely to engage in behavior that is evolutionarily novel, whether it is defined by the civilized society as criminal or not.
This is why less intelligent individuals are less likely to consume evolutionarily novel substances of psychoactive drugs, even though it is criminal. Less intelligent individuals are probably less likely to engage in other evolutionarily novel forms of criminal behavior, such as check forgery, insider trading, and embezzlement, even apart from the fact that more intelligent individuals are probably more likely to have the opportunity to commit such crimes. (That is true for insider trading and embezzlement, but probably not check forgery.)
Less intelligent individuals are simultaneously less likely to consume the legal substance of alcohol and the illegal substances of marijuana, cocaine, and heroin. At the same time, they are more likely to commit the crimes of murder, rape, and theft but not the crime of drug consumption. These two observations suggest that what matters is not legality or criminality per se but evolutionary novelty. Less intelligent individuals are more likely to commit crimes, but only when they are evolutionarily familiar.
• • •
Unlike the implications of the Intelligence Paradox discussed in Chapters 5 through 10, the empirical support for the implication of the Intelligence Paradox with regard to alcohol, tobacco, and illegal drugs is somewhat equivocal. Both NCDS and Add Health data provide strong empirical support for the Intelligence Paradox with regard to alcohol consumption. Both in the UK and in the US, more intelligent children grow up to consume more alcohol than less intelligent children. In addition, more intelligent American children grow up to binge drink and get drunk more frequently in their early adulthood.
The empirical support is split when it comes to tobacco consumption. More intelligent children grow up to consume less tobacco in adulthood in the UK, while the opposite is the case in the US. Only the Add Health data provide support for the prediction of the Intelligence Paradox with regard to tobacco consumption. Finally, NCDS data provide strong empirical support for the implication of the Intelligence Paradox with regard to illegal drugs while Add Health data don’t. More research is necessary to figure out what is behind the divergent results for tobacco and illegal drugs in the UK and in the US.
1. Dudley (2000)
2. Vallee (1998)
3. Vallee (1998, p. 81)
4. Dudley (2000, p. 9)
5. Dudley (2000)
6. Dudley (2000, p. 9)
7. Goodspeed (1954)
8. Wilbert (1991)
9. Goodman (1993); Smith (1999)
10. Smith (1999, p. 377)
11. Brownstein (1993)
12. Smith (1999, pp. 381—382)
13. Smith (1999)
14. Smith (1999)
15. Holmstedt and Fredga (1981)
16. Johnson et al. (2009); Batty et al. (2007); Batty, Deary and Macintyre (2007)
17. Herrnstein and Murray (1994); Hirschi and Hindelang (1977); Wilson and Herrnstein (1985)
18. Wolfgang, Figlio and Sellin (1972); Yeudall, Fromm-Auch and Davies (1982)
19. Gibson and West (1970)
20. Wolfgang et al. (1972); Moffitt (1990)
21. Lynam, Moffitt and Stouthamer-Loeber (1993); Moffitt et al. (1981)
22. Moffitt and Silva (1988)
23. Ellis (1998)
24. de Waal (1998)
25. de Waal (1992)
26. de Waal, Luttrel and Canfield (1993)