 Lack of attention to limitations inherent in studying humans. Human behavior is a fraught area of study. On one hand it is seductive because there is a deep interest in trying to understand why we behave as we do. One the other hand, if researchers are trying to understand social behavior in general, there is little to recommend human beings as experimental subjects. First, it is unethical to perform the necessary controlled experiments on humans. Furthermore, such experiments are impractical because we live too long for researchers to conveniently follow the development and evolutionary consequences of particular behavioral traits and tendencies. In addition, a common evolutionary investigative technique is to compare traits among closely related species. However as Sterelny and Griffiths (1999) point out, human beings are evolutionary orphans. Even though there are several species of non-human primates that are extensively studied, they are simply not as numerous, nor do they form as closely a related group of species with humans, as can be found in, for example, groups of social ant or bee species. Finally, human behavior is complicated by intentionality, language and culture, which make comparisons between human and non-human animals challenging. For example, refer back Martin's (2003) critique of evolutionary explanations of rape. The notion of consent means something very different in a human as opposed to an animal context. As a result of limitations inherent to studying the evolution of human behavior, it is more challenging to draw conclusions about human behavior than about the behavior of many other groups of animals, and conclusions about human beings might need to be more tentative than conclusions about other organisms.