Florida Learning Disabilities Research Center


Behavioral genetics inforgraphic
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More Than Just Achievement

April 27, 2016

For those parents who are gearing up to get young ones into elementary schools, many questions may be running through their minds. What schools are closest to their neighborhoods? Are they good schools? What are the best schools in the county? Answering whether or not a school is “good” or the “best” can be a pretty difficult endeavor, so many may choose to take a straightforward answer even if it may not be an accurate one. In Florida, school grades are that straightforward answer.

Although letter grades (“A”, “B”, etc.) are easy to remember, they don’t quite mean that the “A” schools are the best, and the “F” schools are the worst. These grades are determined by student performance on state tests and student academic gains throughout the school year. These scores and gains do not just represent something about the students, but rather they represent something about the intersection between students’ abilities, the teachers, the curriculum, and other aspects of the school environment. The question now becomes: is there something different between school’s who receive higher school grades versus lower school grades that changes how students’ genes and environments influence their abilities? Research scientists can answer this question by analyzing behavioral genetic models.
Although the name sounds daunting, behavioral genetics is really just the science that teases apart the “nature”, or genetics, and “nurture”, or environment, in human behavior. These models are interesting because they often need a certain type of participant: twins! Scientists compare identical and fraternal twins to better understand the influence of genes, shared environments—like the home or schools twins share, and non-shared environments—like twins placed in different classrooms or having different friends. So, identical twins appearing more similar than fraternal twins would suggest that there are genetic factors influencing the given outcome. If fraternal twins and identical twins are more similar, this suggests that there are shared environmental influences or something in the environment making the twins appear more similar. Finally, if identical twins differ on a given outcome, this suggests that there are non-shared environmental factors at play.

Besides individual genetic and environmental influences on behavior, recent behavioral genetic research has found that different environments may interact with a person’s genetics, also called a gene-by-environment interaction. For student achievement, this suggests two things: first, genetic factors tend to explain more of the differences we see between students in academic achievement when they are in enriched environments, such as schools that provide high quality, research-supported instruction. Second, environmental factors, like a student’s school or neighborhood, tend to explain more achievement differences when environments are poorer and less stable. The recent study by Haughbrook, Hart, Schatschneider, & Taylor (2016) used a twin study to investigate the role of school quality, measured by school grade, on early literacy skills. They expected their results to mirror the previous assumptions: that genetic influences on early literacy skills would increase as the school quality increased, while decreases in school quality would be associated with increased environmental influences on early literacy skills.

Using reading data available from 1,313 twin pairs in kindergarten through third grade from the Florida Twin Project on Reading, Haughbrook et al. (2016) analyzed five reading measures testing different early literacy skills. The twins’ schools were split up into two groups: “A” schools and “non-A” schools (i.e., all schools with a “B”, “C”, “D” or “F” grade).

Results showed that among all the schools, there were significant genetic and environmental influences on each of the five early literacy skill measures. Interestingly, there were differences in the contributions of genetic and environmental factors on early literacy skills between “A” schools and “non-A” schools, but only for pre-reading skills, such as knowing letter-names.

These findings supported the researchers’ hypotheses, indicating that there are more genetic factors influencing pre-reading skills in schools assigned the grade of “A” than for schools with lower grades. Perhaps the “A” schools provide a more consistent environmental element so that natural genetic abilities can flourish. On the other hand, shared and non-shared environments are more influential for pre-reading skills in schools not graded as “A”. This can mean that for schools with lower grades, things like lesson plans and proper implementation of these lesson plans matter more for developing proficient pre-reading skills, which are important for future reading achievement.

Interestingly, schools with better grades are often in neighborhoods with less diversity on both racial and economic fronts and are more likely to be located in wealthier communities. They also receive more government funding as a reward for their good grades as opposed to those schools with lower grades. Financial incentives allow schools to keep better teachers and purchase more educational resources for their students. On the contrary, low-performing schools do not get these financial rewards, are more likely to be in poorer communities, and tend to have a lot more diversity in the socio-economic and racial status of their neighborhoods. This work shows us that it would potentially be more beneficial for lower performing schools to get more resources, as aspects related to the instructional environment seem to be more important for these students.  More financial resources could allow these non-A schools to invest in their school instruction and create a more stable school environment in order to help their students.
The evidence from Haughbrook et al. (2016) is telling more than just the story of school quality; it’s suggesting a greater need for change in the use of school grade. This indicator of school quality may be more useful instead as a tool for improving educational environments in lower performing schools, rather than punishing them. If the school quality in lower-performing schools is improved, their learning environments may likely turn more stable. Then, maybe parents won’t have to worry as much about whether the school they are sending their children to is “good” or the “best”; schools can instead focus on improving their student’s natural abilities.

Full citation: Haughbrook, R., Hart, S. A., Schatschneider, C., Taylor, J. (in press). Genetic and Environmental Influences on Early Literacy Skills Across School Grade Contexts. Developmental Science.