The interesting part of this study looks into shell thickness. The bold snails always had thicker shells than the shy snails. The thick-shelled snails, can be more behavior this way because of the extra protection their shells offer them. Meanwhile, the thin-shelled snails have to be more cautious of predators, and other dangerous situations, because they are less protected.
This is where genetics plays a huge role. The thickness of a snail’s shell is an observable characteristic, a phenotype, which means it has corresponding genes that code for it. These snails inherited their shell thickness genes from their parents, which produced the phenotype of either thick or thin shells. The most amazing part of this is that these genes affected the snails personalities and level of cautiousness.
I find this to be extremely interesting because this gives insight into the age old question of nature versus nurture. This is a debate of whether genes or environment make a person who they are, and it has been debated for hundreds of years. This experiment definitely does not end the debate, but it shows a great case for the nature side. These snails were all taken from the same pond, and were fed the same diet, which according to the nurture theory would make them all equal, but this clearly was not the case. The genes these snails had for shell thickness affected their personalities, showing genetics goes deeper than just physical traits.
For more information on the genetics of introverts and extroverts click here.