I want to tell you about one of the first studies to show their relative roles of nature and nurture in how quickly or slowly children’s reading skills improve over time (http://psycnet.apa.org/journals/dev/49/10/1971). Dr. Sara Hart (http://www.psy.fsu.edu/faculty/hart.dp.html) and colleagues from The Ohio State University they tested the environments and reading abilities of children to discover the differences in children’s reading abilities. 371 twin pairs of fraternal and identical twins from ages 6 to 12 were put into groups and tested every year for six years. Each child was given a 90-minute battery of reading-based measures including word and letter identification, the ability to sound out words and the speed at which children could name a series of letters.
The researchers compared how twins scored on the tests and then used a statistical analysis to determine how much growth in their performance could be explained by genetics and how much by environmental factors.They used a technique “phenotypic and genetically sensitive latent growth modeling” to pull apart the influences of nature and nurture on kids’ reading levels”. Essentially what this means is that the inclusion of fraternal and identical twins allows for them to discover how much was due to genetics and how much was due to environmental reasons for a child’s reading development. If identical twins read identically while fraternal read differently than the difference would be genetics as opposed to environment.
The results found that when children start out reading, both genetics and environment play a role in reading skills. For example in their tests word and letter identification, genetics explained about one-third, while for vocabulary and sound awareness, it was 50/50 for genetics and environment. However, the author commented that, “ the genetic influences related to how quickly or slowly a student grows in their reading skill are not the same as the genetic influences on their skill at the first assessment. In other words, some new genetic component related to growth is coming online after that first assessment wave, and it is influencing development.” This means that some another genetic reason for reading development activates at a later point in at child’s educational years, in particular around kindergarten age.
Afterwards, however when “environmental factors increase mean reading performance across all children”. For reading skills that are taught, such as words and letters, the environment is almost completely responsible for growth.In addition, the awareness of sounds in reading, 80 percent of growth was explained by the environment.The authors of the study commented that it is indeed quite critical in the early years to choose a school that will serve your child’s reading development well. The moral, i suppose, is to choose a school and to choose it very wisely!