As modern nuclear families focused their time, affection,and resources on the couple and their minor children,
they diminished investments in extended family relationships, which resulted in less child care and reproductive labor assistance from extended kin than had been characteristic of more traditional societies.
Despite popular beliefs about the prevalence of three-generation rural or frontier families,multigenerational families are actually more common in contemporary American society than they were in nineteenth and early twentieth century America (Coontz 1992, Haravan 1978). One of the driving demographic forces behind this shift is the fact that, like most
advanced industrialized countries, the United States has witnessed a substantial increase in life expectancy. In 1900, for example, the life expectancy of Americans was 47 years, whereas by 2004 it was 77.9 years (U.S. Census Bur.
2007). Such demographic changes have potentially profound effects on intergenerational relationships. In particular, they have dramatically increased the possibilities for cosurvivorship and the supply of kin available for intergenerational ties. In 2000, most 40-year-olds and 25% of 50-year-olds had both parents still living, and 44% of 60-year-olds had at least one
parent still living (Settersten 2007). Today, most people will spend the vast majority of their relationship with their parents as adults, creating longer shared lives and the potential for sustained intergenerational relations (Bengtson 2001).