Evolution by natural selection is the unifying principle of biology. However, it is widely misunderstood.  Over 30 years of research have shown that, even after instruction, high school students and undergraduates struggle to understand it as do many of their teachers.
Learning about evolution is difficult because natural selection is counterintuitive. It conflicts with our intuitions that traits develop to serve purposes (e.g. the giraffes evolved long necks to reach the leaves at the top of trees); that events and phenomena happen by design (e.g. the giraffes wanted to evolve long necks); or that species do not change.
These intuitions develop naturally with minimal input.
They are part of our common-sense understanding of
the world. While they are helpful in many regards, they
also make it difficult to learn about evolution. 
Given that these intuitions develop in early childhood,
children may actually be more receptive to instruction
than adolescents and adults. However, beliefs about
young children's limited cognitive abilities mean that
evolution is usually not taught until children are between
12- and 17-years-old -long after common sense intuitions
have developed and cemented themselves. 
This is why we are developing and testing materials (e.g. picture storybooks) that provide children as young as 5-years of age with a unified causal story about evolution by natural selection that includes the concepts of variation, differential survival, reproduction and inheritance. Some of our materials have already been shown to be very effective with large learning gains persisting for at least three months. 
Click here to learn more about our research. 
Click here to learn more about our teaching materials.