The Salem hypothesis has at least a couple of different forms. Its original proposer, Bruce Salem, describes it:
My position is not that most creationists are engineers or even that engineering predisposes one to Creationism. In fact, most engineers are not Creationists and more well-educated people are less predisposed to Creationism, the points the statistics in the study bear out. My position was that of those Creationists who presented themselves with professional credentials, or with training that they wished to represent as giving them competence to be critics of Evolution while offering Creationism as the alternative, a significant number turned out to be engineers.
It's been around for well over 20 years now, and is fairly well known. As I mentioned above, it's been expanded beyond the basic idea that Salem came up with; there is a "hard" or "strong" version, which to my mind is less defensible. From RationalWiki
An education in the Engineering disciplines forms a predisposition to Creation/ID viewpoints.
In looking at this topic, I came across an interesting paper, "Engineers of Jihad" [PDF]
, and will quote the abstract (paragraph breaks added):
We find that graduates from subjects such as science, engineering, and medicine are strongly overrepresented among Islamist movements in the Muslim world, though not among the extremist Islamic groups which have emerged in Western countries more recently.
We also find that engineers alone are strongly over-represented among graduates in violent groups in both realms. This is all the more puzzling for engineers are virtually absent from left-wing violent extremists and only present rather than over-represented among right-wing extremists. We consider four hypotheses that could explain this pattern.
Is the engineers’ prominence among violent Islamists an accident of history amplified through network links, or do their technical skills make them attractive recruits? Do engineers have a ‘mindset’ that makes them a particularly good match for Islamism, or is their vigorous radicalization explained by the social conditions they endured in Islamic countries?
We argue that the interaction between the last two causes is the most plausible explanation of our findings, casting a new light on the sources of Islamic extremism and grounding macro theories of radicalization in a micro-level perspective.
The paper uses some data from a 1984 survey which appears to show a tendency among engineers to hold right wing political beliefs. A table from the paper:
I've only glanced through the paper, and I'm not sure how relevant it is to a discussion of the Salem hypothesis, but thought it interesting enough to merit mention here.
Do you think the Salem hypothesis has any validity? What may be behind the observed phenomenon that resulted in Bruce Salem proposing the hypothesis?