According to the research of carstensen, what is "the most reliable finding in social gerontology"?

Answer: Older people tend to reduce their social contacts.

Explanation: Gerontologists are social scientists responsible for studying the aged and the aging process. Laura Carstensen, a psychologgy professor at Standford University, studied the emotional experience and cognitive processing of people from early adulthood to advanced elderly years. According to Carstensen research, older people tend to reduce their social contacts.