In this study, we contrasted socioemotional selectivity theory (SST; Carstensen, 2006) with dynamic integration theory (DIT; Labouvie-Vief, 2003) using trajectories of quantitative and qualitative social support in later life. SST is a lifespan theory of motivational development (Carstensen, Isaacowitz, & Charles, 1999). There is a normative decline in social support networks in later life. In other words, individuals who perceive the limitation on time left for their future are likely to decrease the quantitative social support and compensate for this decrease by improving qualitative social support with emotionally meaningful social partners. The theory also postulates that age is the primary proxy for perceived limitation of individuals' lives (Carstensen, Fung, & Charles, 2003). Further, self-reported health and functional status are factors that affect older adults' perception of limitation of time left in their lives (Carstensen, 2006). In contrast, DIT is a neo-Piagetian theory that emphasizes the presence of individual differences in quantitative and qualitative social support in later life depending on individuals' levels of cognitive resources that are associated with educational levels (Labouvie-Vief & Diehl, 2000). Despite these different arguments on the trajectories of quantitative and qualitative social support in later life, SST and DIT have not been tested within a same study. The current study examined the trajectories of frequency of social contact (quantitative social support) and reliance on family members and close friends (qualitative social support) in later life. Participants were drawn from the Normative Aging Study (NAS; N = 1,067, M[subscript age] = 60.83, SD = 8.08) who completed social support surveys three times from 1985 to 1991. Using unconditional and unconditional analyses (Raudenbush & Bryk, 1986), growth models of frequency of social contact with and reliance on family members and close friends were tested. Within subject analyses found that the trajectory of frequency of social contact was a U-shaped curve with the age of 54 years at a peak, while the trajectory of reliance on family and friends were stable and linear. Random effects of age for the intercept and slope were significant in both models of frequency of contact and reliance on family and friends, although the random effect for the latter were small in both models. Between subjects analyses were conducted to examine whether cognitive resources, marital status, health status, and functional status predicted variance in the intercept and slope of both types of support. As SST hypothesized, having better self-reported physical health predicted higher levels of frequency of contact over age. Being married was associated with higher quantity of social support. However, contrary to our hypothesis based on SST, having poorer functional status predicted more frequent social contact over age. The random effect of intercept was still significant after controlling for these psychosocial predictors. The evidence to test the DIT hypotheses was examined in the model of the qualitative social support. Having memory problems predicted decreasing reliance on social partners. However, marital status and education did not significantly predict change in qualitative social relationships. Contrary to the hypothesis based on SST that posited poor self-reported health was associated with higher qualitative social support, it was better self-reported health that predicted higher qualitative social support. The random effects for the intercept and slope were still significant after controlling for these psychosocial factors. Taken together, the findings of the current study suggest that SST and DIT can be used as theoretical frameworks that are complementary rather than contradictory in their predictions of socioemotional development in later life. SST is useful to illustrate the overall trajectory of quantitative social support in a normative development in late life. DIT's stance better explains the individual differences in qualitative social support in non-normative contexts. The findings also suggest that having memory problems and poor self-reported health as non-normative developmental outcomes may be risk factors of older adults' ability to seek for social support. / Graduation date: 2012