Are generational or cohort-level changes strong?

Here is the view of Kali H. Trzesniewski and M. Brent Donnellan, in their piece “Rethinking “Generation Me”: A Study of Cohort Effects from 1976-2006”:

Social commentators have argued that changes over the last decades have coalesced to create a relatively unique generation of young people. However, using large samples of U.S. high-school seniors from 1976 to 2006 (Total N = 477,380), we found little evidence of meaningful change in egotism, self-enhancement, individualism, self-esteem, locus of control, hopelessness, happiness, life satisfaction, loneliness, antisocial behavior, time spent working or watching television, political activity, the importance of religion, and the importance of social status over the last 30 years. Today’s youth are less fearful of social problems than previous generations and they are also more cynical and less trusting. In addition, today’s youth have higher educational expectations than previous generations. However, an inspection of effect sizes provided little evidence for strong or widespread cohort-linked changes.

The pointer is from @hardsci.  As he (Sanjay) notes on Twitter: “Researchers these days just don’t make cohort arguments like they used to”  And here are some related results on narcissism.