During the last session it was suggested we talk about (human) development in terms of the contributions that come from genetics (nature) and from the environment (nurture). I added the term human in this statement, as I don't recall that the topic was limited only to people as first suggested.
My first reaction was that this was less a philosophical topic and more one for psychology or some other field. Behavior, learning, language, etc. fall into the field of psychology, which gladly accepts it. Here is a link that lays out the nature vs nurture argument in psychologically clear terms, and identifies the key players in their origin and development. John Locke's use of the term tabula rasa in 1690 to describe human mental development at birth as a "blank slate" upon which our environment (through learning) will provide the information to write upon it really set the argument rolling for this dichotomy of ideas.
Genetically, the viable product of an egg and a sperm will be an offspring that is related to the parents constrained only by the DNA/RNA/enzyme and protein manufacturing capabilities of the resultant cells. When I taught Intro. to Biology we dedicated a week to the basics of genetics, including genes and how they determine growth and development of an organism. We did a fruit fly experiment where we crossed red and green eyed flies, who also had a gene for either smooth or crinkly wings. We then counted how many flies had the various characters and determined dominant and recessive traits. Studies of the presence or absence of features like this make a strong case for a fundamental genetic basis to physical characteristics, which I think we can all agree upon.
Looking for references that shed some additional light on this phenomenon, I ran across this Ted Talks Blog where the relationship between our neural network and its reaction to our environment is explored. The author says that our genome reacts to the environment we put ourselves in, acknowledging the interaction between environment and our DNA, and suggests that the right sorts of stimuli we may encounter might enhance our cognitive abilities. Our brains are continually making new neurons, he says, and our environment can influence how they grow and develop. Hanging out with smart people will make you smarter? Makes sense to me.
So rather than a dichotomy of influencers, nature and nurture both play a role in human development (of course), and this is an on-going and dynamic process we can influence as individuals.
Here are a couple of things you might want to look up before our next meeting.
1. Studies of the separation of twin babies separated at birth, who subsequently grow up in very different environments. What case studies can you find? How does the influence of genetics (nature) play out in the individuals? Can we draw conclusions about the influence of the environments (nurture) on their ultimate development?
2. There was a time when this was a very hot topic. People in he past have been obsessed with the idea that language was learned by babies because of their environment, but if this stimulus could be taken away, the infant would innately use what was called a natural or Adamic language. Accounts of this being tried find their was into the literature: babies may have been actually used in these experiments where all language was withheld from them just to see how they would develop. Here is a link to the Wiki summary of 4 such studies.