After the game, all players were asked if they had donated money to a religious organisation in the previous year. The team found that those who had donated – about 15 per cent of participants – exacted the most severe punishments, but only after they had been shown the subliminal religious cues.
Really 100%? And what happened before showing the cue words? And, is this correlation with donating or to religion? I'd like to see a lot more information on this.
And the conclusion:
McKay pointed out that being religious can be costly in various ways: donating money, suffering painful rites and avoiding pleasures, for example. So the team wondered how religion survived, despite these apparent costs.
"The answer may be that these sacrifices enable the group to secure more cooperation. The punishing may be unpleasant but it's in the service of the greater good for that particular group or religion, enabling them to thrive and spread the word," he said.
Building stronger groups does seem a possible explanation. Spreading the word doesn't. What is the evidence that early religions were seeking to spread the word?