(RxWiki News) Genetics may not be the only factors that influence intelligence. Some environmental factors like reading may be able to boost general intelligence as well, new research suggests.
In a recent study, researchers felt reading might improve knowledge and general intelligence. To eliminate genetic influences, the researchers compared reading skills and intelligence scores in identical twins.
The study found that the twin with stronger early reading skills had higher intelligence scores later.
"Encourage early reading skills by reading to your child regularly."
The study was conducted by Stuart J. Ritchie, PhD, from the Department of Psychology at the University of Edinburgh in the UK, and colleagues.
The researchers tested their theory that the twin with higher reading skills at an earlier age would have higher intelligence scores later.
Studying identical twins who were raised in the same household gave the researchers the chance to study children with the same genes who were exposed to similar environmental factors at home. In that way, differences in reading skills might be due to an environmental factor, such as a twin’s teacher or another person who encouraged reading.
The study included 1,890 identical twins who were part of the "Twins Early Development Study." Reading ability and intelligence were measured at ages 7, 9, 10, 12 and 16.
Intelligence testing measured verbal and nonverbal intelligence. Early intelligence testing was done by phone, using a booklet mailed to the participants. Older twins in the study took their tests online.
The researchers found the numerical difference in reading scores between the pairs of twins. They did the same for the intelligence scores.
The research team looked to see whether the differences in the twins’ reading scores corresponded to differences in their intelligence scores. They found that higher reading ability at some early ages correlated with higher intelligence scores at later testing dates.
The strongest correlation was between the difference in reading ability at age 12 and the difference in IQ at age 16. The next strongest association was between stronger reading ability at age 10 and a greater intelligence difference at age 12.
Twins with higher reading skills at age 7 were found to have higher intelligence scores than their twins at age 9.
The results also showed that, compared to their identical twins, the twins with better early reading skills had better reading scores at later ages.
The authors noted that their study did not measure whether reading skills developed before age 7 would affect later intelligence. They also reported that environmental factors other than reading that were not measured in their study may have contributed to higher intelligence scores.
The findings suggested that improving reading skills in children might improve later thinking ability, the authors noted.
“If, as our results imply, reading causally influences intelligence, the implications for educators are clear," Dr. Ritchie said in a press release. "Children who don’t receive enough assistance in learning to read may also be missing out on the important, intelligence-boosting properties of literacy."
The study was published online July 24 in Child Development.
The research was funded by the UK Medical Research Council and the US National Institutes of Health.