[Brookhaven]

The researchers believe the findings help explain why religion is such a durable feature of human society.

This exposes the fact that the underlying assumption of the study is that there is no life after death. So, they are trying to determine why people believe in something that is not true.

This excludes the option that the reason people believe in life after death, because it is true, and that the people that believe in an after life are the rational ones, while the atheists are the irrational people who are denying the evidence.

[circlecity]

"This exposes the fact that the underlying assumption of the study is that there is no life after death. So, they are trying to determine why people believe in something that is not true."

Absolutely right - you hit the nail on the head. The clear assumption here is that religion is purely a psychological phenomenon with no basis in reality.