The message that comes out of these studies tends to be that these subliminal prompts have all sorts of interesting effects, and are probably rather more important than what the test subject says they believe.
Question is, though, are these laboratory studies at all relevant to real life?
Christianity offers an interesting case study. For most Christians, there's a regular, weekly surge in the amount of religious priming they're exposed - every Sunday, at church.
So it's interesting to take a look at Christian behaviour in the real world. There's been a couple of interesting studies recently, both of them (strangely enough) out of the Negotiations, Organizations, and Markets Unit at the Harvard Business School.
First off, Ben Edelman has analysed subscriptions to porn websites. You might've heard this one earlier in the year - it was widely talked about. Among other interesting nuggets, states with a lot of people who take a conservative Christian line actually had more porn subscribers!
But when you look at church attendance, and control for a host of other factors, the differences fade. Regions with lots of regular churchgoers had no more porn subscribers than those with few churchgoers.
But there was an interesting rhythm to porn subscribing in the regions with lots of churchgoers. It went down on Sundays, and up on the other days of the week. According to Edelman:
... a 1 percent increase in the proportion of people who report regularly attending religious services is associated with a 0.10 percent reduction in the proportion of purchases that occur on Sunday. This analysis suggests that, on the whole, those who attend religious services shift their consumption of adult entertainment to other days of the week, despite on average consuming the same amount of adult entertainment as others.
The second was a rather clever study by Deepak Malhotra - (Working Paper, available here). He collaborated with a US firm that runs online charity auctions. As the auction closes, the participants get an automated email encouraging them to up their bids.
What Malhotra wanted to know was whether changing the text of that email could change how much people bid. So he changed the text of the email to include a line that appealed to the bidders sense of charity:
“We hope you will continue to support this charity by keeping the bidding alive. Every extra dollar you bid in the auction helps us accomplish our very important mission.”
And here's what happened (see figure). On weekdays, religious people and non-religious people both bid the same. But on Sundays, non-religious people bid less, but religious people bid much more.
This is a fascinating result. For a start, the non-religious people seem to have been adversely affected by the religious prime (remember, this was in the USA, where a lot of non-religious people go to church or are otherwise affected by religious primes on a Sunday).
And when you remove the prime, both religious and non-religious people are equally charitable. Which is exactly what the laboratory studies conclude.
Edelman, B. (2009). Markets: Red Light States: Who Buys Online Adult Entertainment? Journal of Economic Perspectives, 23 (1), 209-220 DOI: 10.1257/jep.23.1.209
This work by Tom Rees is licensed under a Creative Commons Attribution-Share Alike 2.0 UK: England & Wales License.