of the self-concept is derived from memberships in social groups and categories; this is demonstrated by group processes and how inter-group relationships impact significantly on individuals' self perception and behaviors. The groups people belong to therefore provide members with the definition of who they are and how they should behave within their social sphere. Categorizing males and females into social roles creates a problem for some individuals who feel they have to be at one end of a linear spectrum and must identify themselves as man or woman, rather than being allowed to choose a section in between. Globally, communities interpret biological differences between men and women to create a set of social expectations that define the behaviors that are "appropriate" for men and women and determine their different access to rights, resources, power in society and health behaviors. Although the specific nature and degree of these differences vary from one society to the next, they still tend to typically favor men, creating an imbalance in power and gender inequalities within most societies. Many cultures have different systems of norms and beliefs based on gender, but there is no universal standard to a masculine or feminine role across all cultures. Social roles of men and women in relation to each other is based on the cultural norms of that society, which lead to the creation of gender systems. The gender system is the basis of social patterns in many societies, which include the separation of sexes, and the primacy of masculine norms. Philosopher Michel Foucault said that as sexual subjects, humans are the object of power, which is not an institution or structure, rather it is a signifier or name attributed to "complex strategical situation". Because of this, "power" is what determines individual attributes, behaviors, etc. and people are a part of an ontologically and epistemologically constructed set of names and labels. For example, being female characterizes one as a woman, and being a woman signifies one as weak, emotional, and irrational, and incapable of actions attributed to a "man". Butler said that gender and sex are more like verbs than nouns. She reasoned that her actions are limited because she is female. "I am not permitted to construct my gender and sex willy-nilly," she said. "[This] is so because gender is politically and therefore socially controlled. Rather than 'woman' being something one is, it is something one does." More