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Researchers have suggested that IQ differences in identical twins can be as large as those between completely unrelated people. According to the study reported by Science Alert, this may indicate that cognitive abilities are less determined by genetics and more influenced by learning.
Separation between twins is relatively rare, with only nine large-scale studies conducted on this phenomenon so far.
Previous research showed that twins raised apart shared many traits, including intelligence, which suggested that IQ is largely determined by nature rather than nurture.
However, Jared Horvat and developmental researcher Kathy Fabricant reanalyzed these studies, this time including a factor previously overlooked: education.
When the researchers divided 87 twin pairs into groups based on similar or different educational levels, they found IQ differences across the spectrum. The gaps in IQ increased in line with differences in schooling, enough to go beyond the variations caused by individual teachers or peer groups.
For twins raised separately and attending different schools, IQ scores were comparable to those of strangers, with a difference of about 15 points.
It is worth noting that the study was limited by a small sample size, as it included only 10 pairs of twins whose school experiences met the criteria.
