Each of these fundamental forces interact to shape human development. Within biological, psychological, and sociocultural forces, there are normative forces categorized by age, normative forces categorized by history, and non-normative forces. The normative forces of age and history in each domain are experienced by almost everyone at a similar point in life, as well as across generations. Non-normative forces in each domain are experienced by very few people. Biological force is the first of the four forces. This force represents the genetic and health-related factors that affect development. Puberty is an example of age-related normative forces, the 1918 influenza pandemic is an example of historically classified forces, and certain illnesses are an example of non-normative forces. Second, psychological strength which represents the perceptual, cognitive, emotional and personality factors that affect development. Language acquisition is an example of normative age classification. Technological culture during the 1970s or today among millennials is an example of normative forces spanning history. The example of non-normative forces is psychological disorders. We then move on to sociocultural forces which represent the societal, cultural, ethical/racial, and interpersonal factors that affect development. Going to kindergarten is an example of age-related normative forces. Forces linked to normative history provide the example of the Internet generation and SMS. A working woman who has children in her late 40s is an example of non-normative forces. The last of the four forces is that of the life cycle which represents the effects of certain events on people. They affect people differently depending on who experiences the event and when exactly the event occurs.