Results From Comprehensive Study of Religion Globally; Religious Observance Tied to Education and In
According to a study on religion by the Pew Research Center, religious observance is higher in the developing world, in nations with low levels of education and high levels of income inequality and poverty such as those in Sub-Saharan Africa, Latin America, the Middle East and India. Religious adherence is dropping quickly in Europe, Japan, Australia, and North America, although less swiftly in the United States. Overall however, because populations are growing much faster in the developing world, the global population is becoming more religious.
The study also noted that younger people tend to be less religious than older individuals, a pattern that has also been found in recent studies of America's religious observance.
There has been quite a bit of social science research on these trends in recent years attempting to clarify why religious feelings are tied to age, income, and education and Pew outlines some of the theories.
From the Pew Study: Social scientists have proposed various explanations for age gaps in religious commitment around the world. One common explanation is that new generations become less religious in tandem with economic development – as collective worries about day-to-day survival become less pervasive and tragic events become less frequent. According to this line of thinking, each generation in a steadily developing society would be less religious than the last, which would explain why young adults are less religious than their elders at any given time.
Rising education levels are often closely tied to economic development. Some theorists suggest education could reduce religious identity and practice, although empirical findings about the relationship between education and religion are complex. In societies where access to education is spreading and the average number of years of schooling is rising, younger generations tend to receive more education than their parents and grandparents did. Directly or indirectly, this increase in education could be part of why younger adults are less religious.
This is a very complex area of study and the Pew research won't be the last word on the trends they have documented.