It should be noted that performance on standardized IQ tests may be affected by an
individual’s motivation. For instance, some experimental studies have found that offering
incentives such as cash or candy is associated with an increase in test scores, particularly among
those with low IQ scores (Almlund et al. 2011). High test anxiety may also lead to poor
performance on the IQ test. In addition, various IQ tests require factual knowledge from formal
schooling; thus, low SES groups with less education are less likely to perform well on
standardized IQ tests (Almlund et al. 2011).