The link between students who are interested in science and knowledge depends on the overall wealth of the country the teen calls home, according to a recent study.

New research suggests that individual science achievement may be influenced as much by broad national-level resources as it is by personal interest and motivation. Investigators wanted to understand the factors that lead to achievement in scientific disciplines, seeking to examine the joint impact of two factors -- academic interest and socioeconomic status -- that are often looked at independent of each other.

"Our results suggest that children with high levels of interest in science are able to turn their scientific interest into actual science knowledge to a greater extent when raised in more fortunate socioeconomic circumstances," Elliot Tucker-Drob, lead researcher of the study, said in a statement. "The take home message of this research is that the joint effect of socioeconomic resources and academic interest is more than the sum of its parts."

For the study, Tucker-Drob and colleagues examined data taken from the Programme for International Assessment (PISA), an ongoing international data collection project run by the Organization for Economic Cooperation and Development (OECD). For PISA, a new international sample of 15-year-olds is assessed every three years on reading, mathematics, and science skills.

Looking at the data collected in 2006, the researchers found that resources mattered, at all levels, for predicting science achievement.

Students' science interest was more strongly linked to actual science achievement when they came from home and school environments that were rich in resources. But this was also true when they came from countries that were economically more prosperous (with higher gross domestic product).

The researchers found that science interest and science knowledge were not related at all for students from poor countries.

"In the context of poor family, school, and national socioeconomic conditions, student interest in science is unrelated to science achievement," said Tucker-Drob. "This indicates that there may be a tremendous amount of untapped talent in the population, which is particularly concerning given national emphases on increasing the number of students of science and technology."

Researchers said the results highlight the considerable variation in psychological effects that can be seen across different populations.

"[T]he current results add to the growing body of evidence indicating that substantial heterogeneity in psychological effect sizes is not simply a logical possibility but in many cases an empirical reality," the researchers conclude.