Science Forums 2

[CraigD]

Originally Posted by Moontanman

I thought all that subliminal stuff was proved to be hokum decades ago?

That it, IMHO, a more accurate summary than the common belief that it powerful and commonplace (though, in the US, illegal!), but somewhat short of fully accurate. While some claims have been clearly shown to he hokum, some instances of subliminal perception have been compellingly shown to be real.

At first glance, it’s difficult to reconcile Hassin et al’s results with body of subliminal perception experiment results and the general scientific consensus that images shown too briefly to be perceived don’t have a significant effect on measurable behavior, in particular a large, non-blind 1958 experiment involving all of the viewers of a 30 minute Canadian TV show (see the 4/22/1977 Straight Dope letter “Does subliminal advertising work”). However, there’s somewhat compelling experimental evidence that while subliminal information can’t provoke behavior (eg: cause a person to buy popcorn) it can influence a “forced choice” (ie: a multiple choice question), and very strong evidence that some unconscious part of the psyche does perceive visual information displayed for durations as short as in experiments such as Hassin et al’s (.016 sec, or about 60/sec, a good choice, as most electronic displays such as TVs can present an image no more briefly). A well-known experiment demonstrating this was done in 1972 by R. S. Corteen and B. Wood in which people were administered a mild but painful electric shock at the same instant as a nonsense 3-letter word was subliminally displayed, then measured to show an increase in Galvanic skin response when the same 3 letter word, but not another, was displayed subliminally in the absence of the shock (unfortunately, I can find no online reference to this experiment, only references in papers such as this rather good undergraduate psych student paper, which unfortunately has a broken link to apparently the Corteen and Wood paper which even archive.org can’t mend).

The abstract and full html or PDF document of Hassin, Ferguson, Shidlovski, and Gross’s paper can be read at Subliminal exposure to national flags affects political thought and behavior ? PNAS. Although some supporting appendixes are available at Supporting Information ? PNAS The experiments’ raw data are not available, only some imprecisely described ANOVA results. Without these data, I’m not comfortable having an opinion of the paper, other than that I regret the failure to publish these data.

The state of the art of psychology (as I don’t think it’s currently a true science) is such that it’s necessary, I think, to treat papers like Hassin et al’s with more than the usual skepticism. It’s also wise, I think, to note that despite Hebrew University being a first-rate university, some of its faculty of have a history of fringe science publications, including the claims to have discovered coded messages in the Hebrew language book of Genesis of Rips, Witztum and Rosenberg popularized by Michael Drosnin’s “The Bible Code”, a claim that has been convincingly discredited by many reviewers.