Has there been any serious research on subliminal messaging? I certainly don't question the existence of subliminal perception which has been demonstrated many times in priming studies like those of Daniel Schacter and many others, nor do I reject the notion of the cognitive unconscious introduced by Kihlstrom (I definitely have my doubts on the psychodynamic unconscious however).

My question is about certain big claims like those of Bryan Wilson Key on subliminal messages with sexual content and consumer behaviour, those about subliminal self-help tapes or those even more suspicious that are about subliminal messages detering shoplifters to steal. Other than null results or junk science I haven't seen any convincing study supporting these claims.

On the other hand, studies by Vockey and Read (1985) challenged the effect of subliminal messages in songs and a meta-analysis carried out by Charles Trappey (1996) showed a negligible effect on consumer behavior. Also, what I get from most psychology textbooks is that the general consensus is that subliminal messaging has a poor and temporary effect (Schacter, Gilbert and Wegner, 2009).

Of course, one has to consider if subliminal perception is qualitatively and quantitatively different depending on the modality of the stimuli but then again I am unconvinced of a considerable effect of subliminal messaging on behaviour.

Any thoughts on that?



References

Schacter, D. L., Gilbert, D. T. &amp; Wegner, D. M. (2009). Psychology. New York, NY: Worth Publishers

Trappey, C. (1996). A meta-analysis of consumer choice and subliminal advertising, Psychology &amp; Marketing, 13(5): pp. 517—530DOI: 10.1002/(SICI)1520-6793(199608)13:5&lt;517::AID-MAR5>3.0.CO;2-CPDF Available FREE from National Chiao Tung University

Vokey, J. R. &amp; Read, J. D. (1985). Subliminal messages: Between the devil and the media, American Psychologist, 40(11): pp. 1231—1239PMID: 4083611 DOI: 10.1037/0003-066X.40.11.1231
First we need to define what "subliminal messaging" means. I take it you mean to send a subliminal command and make someone obey that command.
Based on that definition, here's some of what I find from googling:


  Effectiveness
  The effectiveness in subliminal messaging has been demonstrated to prime individual responses and stimulate mild emotional activity.[3][4] Applications, however, often base themselves on the persuasiveness of the message. Importantly, research on action priming has shown that subliminal stimuli can trigger only those actions that one plans to perform anyway: an action can be triggered subliminally only if the person already has the specific intention to perform this specific action.[5] The following sections have more information on specific studies in which the effectiveness of subliminal stimuli are investigated.[6][7]
  http://en.wikipedia.org/wiki/Subliminal_stimuli


An article with several links to research on the topic:


  In 1979 that nearly 50 department stores in the U.S. and Canada had been using subliminal messages over their music systems which had resulted in a significant reduction in both customer based shoplifting and employee theft.
  One East Coast chain amounted savings of 600,000 over a nine-month period.
  Another story in the Wall Street Journal in 1980 stated that subliminal messaging a New Orleans supermarket resulted in an all time low within 6 months of use - from 50,000 per six month period to a figure of 13,000! Furthermore cashier shortages dropped from 125 per week to below 10 per week.
  http://www.realsubliminal.com/subliminal-messages-scientific-research


Subliminal advertising:


  University College London researchers have found the first physiological evidence that invisible subliminal images do attract the brain's attention on a subconscious level. The wider implication for the study, published in Current Biology, is that techniques such as subliminal advertising, now banned in the UK but still legal in the USA, certainly do leave their mark on the brain. 
  http://www.sciencedaily.com/releases/2007/03/070308121938.htm


More information on subliminal and supraliminal messages and the differences:


  Generally, there are three types of subliminal messages:
  1. Subvisual messages – visual cues that are flashed so quickly (generally a few milliseconds) that people don’t perceive them.
  2. Subaudible messages – low volume audio cues that are inserted into a louder audio source, such as music.
  3. Backmasking – an audio message that is recorded backwards, with the intention of playing it forward to disguise the reversed message.
  Does that mean subliminal messages don’t work? A few decades ago, researchers would have agreed that subliminal messages were BS. They found little, if any, support that they were effective (Vokey &amp; Read, 1985).
  In recent decades, however, things have been changing. Emerging research has shown that subliminal messages can influence our thoughts and behavior (see Kunst-Wilson &amp; Zajonc, 1980 for one of the first notable studies).
  For instance, new research has shown that subliminal messages in advertising can, in fact, influence our purchasing behavior. For example, participants in one study were significantly more likely to choose a Lipton Ice drink when they were subliminally primed with “Lipton Ice” (Karremans, Stroebe, &amp; Claus, 2006). Pretty cool.
  http://www.nickkolenda.com/subliminal-messages/


..And lots more articles, if you were to ask a more specific question.