What states that scores on IQ tests have steadily risen since 1920?

a. Heritability

b. Stereotype vulnerability

c. Flynn effect

d. Environmental theory

The correct answer is letter C. The Flynn Effect states that scores on IQ tests have steadily risen since 1920. This long-sustained increase in intelligence scores are observed in many different countries where standardized tests are given to people. When changes in the tests occur, sample groups are tested before it is done on a wide scale.