Final answer:
The correlation between IQ and job performance is more complex than simply IQ's effect on job knowledge; it encompasses a range of cognitive skills, emotional and social intelligence, as well as being affected by socioeconomic factors, educational opportunities, and historical biases in testing.
Step-by-step explanation:
The statement that IQ is correlated with job performance primarily because of its effect on job knowledge is often debated. While it is true that IQ can be a predictor of job performance and job knowledge, it is important to consider that numerous other factors contribute to an individual's job performance. The complexity lies in the fact that while IQ tests measure a range of cognitive abilities, they do not capture all the components of intelligence that are relevant in a workplace setting, such as emotional intelligence, creativity, practical skills, and social understanding.
Moreover, the relationship between IQ and job performance can be influenced by socioeconomic factors, access to education, and institutional biases. IQ tests have historically been criticized for cultural bias, testing knowledge specific to certain cultures or economic backgrounds rather than an innate cognitive ability. Also, the role of environmental factors and stress, as indicated by research on the impact of poverty on brain development and function, suggests that many complex components influence an individual's intelligence level and, consequently, their job performance.
Therefore, to simply attribute job performance to IQ and job knowledge would be to overlook the wide array of skills required for various jobs, the importance of which was highlighted by sociologists Davis and Moore, and the vast array of additional factors, both innate and environmental, that shape an individual's capability to perform in a work setting. This explains why the use of IQ tests in job selection, such as cutoff scores, is often a topic of debate regarding their fairness and validity.