Answer:
The Flynn effect
Step-by-step explanation:
The Flynn effect is an effect that has been observed and it refers to the rise over time in standardized intelligence test scores.
In other words, this effect refers to the tendency of IQ scores to change over time, by increasing in the general population in an steady rate when taking IQ tests.
In this example, a team of researchers has been tracking performance on intelligence tests over the last 70 years, and they have found that their sample has been subject to the Flynn effect, indicating that intelligence test performance has been improving.