Atheists are smarter than Calvinists in Dutch Study. But, the Calvinists are quicker at identifying small shapes than the Atheists.
Despite the abundance of evidence that human perception is penetrated by beliefs and expectations, scientific research so far has entirely neglected the possible impact of religious background on attention. Here we show that Dutch Calvinists and atheists, brought up in the same country and culture and controlled for race, intelligence, sex, and age, differ with respect to the way they attend to and process the global and local features of complex visual stimuli: Calvinists attend less to global aspects of perceived events, which fits with the idea that people's attentional processing style reflects possible biases rewarded by their religious belief system.
Otherwise, I think this study is kinda funny... Both "ha ha" funny and "strange" funny. Don't you think?
You can see the original study here.
Lorenza S. Colzato, Wery P. M. van den Wildenberg, Bernhard Hommel (2008). Losing the Big Picture: How Religion May Control Visual Attention PLoS ONE, 3 (11) DOI: 10.1371/journal.pone.0003679
3 points will pretty much never constitute a difference in any IQ scale, unless maybe the sample size is in the tens of thousands!
The fourth sentence in the Discussion:
As our groups were matched for sex, IQ, age, educational style and socio-economic situation we can rule out an account of our results in these terms.
The main conclusion I draw from the paper is that the Netherlands is awash with college-age atheist women. Now if you'll excuse me while I contact my travel agent...
I think the IQ is swamping other factors.
The US army studied how people reacted to targets and concluded that higher IQs translated to slower reaction times. Evidently being smart speeds thinking but slows doing.
Intensive training that programmed in automatic reactions was able to counter this deficit. This has changed how soldiers are trained.