Principal factors that social scientist believe to be influencing personality and behavior are: A. heredity, birth order, parents, and the cultural environment
Heredity would determine hormonal level that can influence personality behavior (for example, higher testosterone individuals tend to be more aggressive). Birth order would influence them by determining social status that the person has in society.
Parents would influence personality and behavior through the knowledge and principles that they teach to the children and cultural environment would affect them by regulating the standard behaviors that considered to be 'normal' in that society.