This is a very difficult question to answer. This age old question is the cause of much debate among physiologists and philosophers. However, the scientific research suggests it is not nature or nurture, rather a continuum between nature and nurture.
Nature is the genes we are born with and is unchangeable. You can change your jeans but not your genes. Nature impacts an individual's physical characteristics such as hair, eye, and skin color. This is a very clear example of nature.
Unfortunatly, behavior, temperament, IQ, and personality are not so straight forward. So is it nature or nurture? Probably, a little of both. A study conducted in 2010 found that genotype influenced the degree to which an individual was impacted by environmental factors. This study suggests that it is the interplay between genetics and environment that are important to examine.
Many theories of development examine the impact nurture has on development. In Bandora's famous Bobo doll experiment, he found children exposed to violence later acted more aggressively. Bandora explained this through his theory of modeling.
Bronfenbrenner's Ecological Theory accounts for all levels of environmental (nature) impact. According to the theory there are five levels of influence that impact development.
The individual is at the center followed by:
1. Microsystem- an individuals immediate environment (family, classroom, work, peers, religion, neighborhood, ect.)
2. Mesosystem- the interaction between two microsystems, such as the connection between religion and family.
3. Exosystem- environments that an individual is not directly involved with, but impact the individual (economic system, religious system, education system, ect.)
4. Macrosystem- cultural context (cultural values, expectations, values, and beliefs)
5. Chronosystem- passing of time
Bronfenbrenner said, "Development, it turns out, occurs through this process of progressively more complex exchange between a child and somebody else—especially somebody who's crazy about that child."