I find support for pure altruism because individuals who received additional Social Security benefits passed on 15.4 percent to children via inter vivos transfers without receiving any additional care in return

Intergenerational Altruism and Retirement Transfers: Evidence from the Social Security Notch. Anita Mukherjee. J. Human Resources August 6, 2020 0419-10140R3. http://jhr.uwpress.org/content/early/2020/08/11/jhr.58.1.0419-10140R3.abstract

Abstract: I contribute new evidence on altruistic preferences in intergenerational transfers using variation in Social Security benefits induced by an inflation-indexing mistake. The instrument is most relevant for those with low education, so I focus on this group. I find support for pure altruism because individuals who received additional Social Security benefits passed on 15.4 percent to children via inter vivos transfers without receiving any additional care in return. On the contrary, children reduce caregiving monotonically with increases in parental Social Security benefits. Adult female children appear to be the most affected as they both receive monetary transfers and reduce caregiving.