What phenomenon explains the increase in IQ scores observed across generations?

The phenomenon that accounts for the increase in IQ scores across generations is known as the Flynn Effect. This effect, named after the researcher James R. Flynn, refers to the observed rise in average IQ scores over time, particularly noticeable in the 20th century. Researchers have noted that this increase tends to occur across different countries and demographics, suggesting that various environmental factors play a significant role.

Several explanations have been proposed for the Flynn Effect, including improved nutrition, better access to education, more stimulating environments, and advancements in technology, all contributing to enhanced cognitive abilities. The phenomenon emphasizes that intelligence is not solely a fixed trait but can be influenced by societal changes.

Other options are related to different concepts. The Hawthorne Effect pertains to performance changes when individuals are aware they are being observed, while the Pygmalion Effect refers to the phenomenon where higher expectations lead to improved performance. The Bandwagon Effect involves adopting beliefs or behaviors because they are popular. Understanding these distinctions helps clarify why the Flynn Effect specifically addresses generational changes in IQ scores.