VI. Criticism of the IQ -> Crime Relationship
Although much of the research shows that there is a modest to strong relationship between intelligence and anti – social behavior, some researchers dispute the validity of this relationship. Critics argue that the empirical association between intelligence and criminal behavior may be accounted for by other factors. They highlight three general criticisms: (1) that differences in police detection ultimately account for the IQ -> crime relationship; (2) that an individual’s race and/or class may account for the relationship; and (3) that the relationship is in the opposite direction, namely, that it is antisocial behavior that leads to lower intelligence. We now examine each of these arguments in greater detail.
First, the differential detection hypothesis states, in essence, that criminals with lower intelligence are more likely to be detected by the police for their unlawful actions compared with criminals with higher intelligence. In other words, individuals with higher intelligence may be committing crimes at the same rate as individuals with lower intelligence, but only the less intelligent ones are getting caught by the police. For that reason, it is argued that studies that show a relationship between intelligence and criminal behavior are invalid because the more intelligent criminals are able to avoid being detected by the police.
Research does not support this criticism. Several studies have compared mean IQ scores of delinquents detected by the police and delinquents not detected by the police, primarily through the use of self-reported questionnaires (e.g., Ellis & Walsh, 2003). These studies have found no significant differences in IQ levels between individuals caught by the police and those not captured by the police. In all the studies, delinquents, arrested or not, scored significantly lower on intelligence compared with non – delinquents. Overall, converging evidence rejects the differential detection hypothesis.
The second counterhypothesis against the intelligence -> crime relationship stems from a traditional sociological perspective. Sociologists are not usually concerned with explaining individual differences in behavior, because they believe that people who are exposed to the same environment will respond in a similar way. Thus, it is not surprising that many sociologists discount the relationship between intelligence and criminal behavior in favor of a race and/or class hypothesis. Most sociologists view IQ test scores as a proxy for race and class and not a true measure of intelligence. Higher scores on intelligence tests, they argue, reflect how well an individual has assimilated and internalized white, middle-class values instead of a valid assessment of intellectual ability.
To assess the validity of this argument, researchers include measures of race, class, and intelligence in their analyses to determine whether intelligence remains related to crime after controlling for these other factors. These studies have shown that the relationship between intelligence and crime remains even after the influence of race and class has been accounted for (Ellis & Walsh, 2003). Moreover, in every assessment of intelligence, African Americans score lower than whites or Asians. Across thousands of studies, the IQ for African Americans averages 85, whereas whites average 102 and Asians average 105. No study that has examined racial differences in IQ has been able to account for these differences.
The third argument that questions the relationship between intelligence and criminal behavior focuses on the chronological order of these two factors. Whereas the relationship between intelligence and crime assumes that individuals with lower intelligence are more likely to engage in criminal activity, critics argue that this relationship may in fact be temporally reversed. Instead of intelligence influencing criminal behavior, they maintain, it may be that criminal behavior affects an individual’s level of intelligence. There are two main hypotheses related to this perspective. The first is called the temporal order hypothesis: Some scholars hypothesize that a delinquent lifestyle can result in lower intellectual functioning. For example, an individual can suffer from head injuries as a result of physical violence, or he or she can experience the erosion of cognitive abilities through prolonged substance abuse. In essence, it is the individual’s criminal lifestyle that is to blame for his or her limited intellectual abilities, not the other way around.
The problem with this argument, however, is that ample evidence has shown that intelligence is established well before the onset of serious delinquency. In any case, a suitable way for researchers to examine this argument is by sampling younger children in an attempt to decrease the possibility that they have already experienced the negative consequences of drug abuse and violence. These studies, along with those that demonstrate that intelligence is established early in life, cast suspicion on the delinquent lifestyle interpretation of the intelligence -> crime relationship.
The second argument stemming from the temporal order hypothesis states that delinquents are simply not motivated to do well on intelligence tests; specifically, anti – social adolescents may lack motivation for or interest in completing an intelligence test. Therefore, although it appears that criminals are scoring lower on intelligence tests, the lower scores are in fact the result of their lack of motivation to complete the test instead of a true reflection of their intellectual abilities. To address this issue, researchers have used a variety of methods to control for levels of motivation. Indeed, when controlling for these motivational issues, the relationship between intelligence and crime remains.