According to a study published in the Journal of Human Resources in 2017, firstborn children may have better thinking skills than their siblings because they receive more mental stimulation during their early stages of development.⁠ ⁠ Researchers from the University of Edinburgh, the Analysis Group, and the University of Sydney found that children who were born first typically scored higher on IQ tests than their younger siblings.⁠ For the study, researchers used data from the U.S. Children of the National Longitudinal Survey of Youth on nearly 5,000 children who were monitored from pre-birth to age 14. Every two years, the children in the longitudinal survey were assessed on a slew of categories, including reading, vocabulary assessment, and matching letters.⁠ ⁠ _____⁠ ⁠ The research found that firstborn children typically perform better than their siblings as early as age 1, which could be due to how parents treat subsequent children. According to the study, parents were less likely ...