Who do I Look like More, Mom or Dad? An Exploratory Survey about Primary Students' Ideas about Heredity

Unlike in other countries, heredity and genetics appear first in Spanish science standards in secondary levels. However, some researchers have suggested the need of progressively introducing some basic genetic ideas already from primary education levels. In this context of no formal instruction in early stages, the objectives of our work were to characterize the incipient heredity model of primary school pupils and to evaluate its progression, to identify the most appropriate time to introduce these ideas. We designed a 12-item questionnaire referred to two constructs: (1) the difference between biologically inherited and environmental acquired traits and (2) the mechanism of inheritance. 535 primary school pupils (6-12 years; grades 1-6) took part in the study. In addition, 1-2 pupils per class were interviewed, totalling 30 interviewees. The results showed that pupils clearly identified physical resemblance as inheritable but had more difficulties in assessing physiological traits. Most pupils (84%) correctly identified that accidentally acquired traits were not transmitted to the descendance. However, only 32,2% of them use terms related to inheritance (77,1% of them in G4 - G6). Regarding the mechanism of inheritance, the idea that siblings express traits of both parents becomes more prevalent from grade 3, even suggesting the appearance of new traits or the mixture of previous ones. Older pupils accepted that a trait could skip a generation, although most of them were unable to explain the mechanism, that involves the idea of dominance/ recessiveness. These results allow identifying key leverage points for constructing the inheritance model at Primary levels.