Well it seems that research is being done in fact and it seems to be pointing to the fact that subliminal persuasion does work...

Laboratory Manual from the Department of Psychology, Cornell University

quote:
In short, research on subliminal advertising suggests that subliminally presented stimuli have little or no influence on our thoughts, attitudes, preferences, or behavior. Or do they? Cognitive and social psychologists are now learning that stimuli presented subliminally can not only be perceived, but can have a considerable influence over a variety of cognitive processes (possibly even behavior). This research stands in stark contrast to the failings of subliminal advertising, and in this module we will investigate the replicability, generalizability, and validity of some of these new findings,

This study is restricted to the visual system

quote:
I should note at the outset that we will be restricting our discussion of subliminal presentations to those that are presented exclusively to the visual system. There is some evidence of subliminal perception in the auditory and tactile systems, but a discussion of these effects is beyond the scope of this module. Furthermore, we will restrict our attention to methods that have been found to reliably (but not without controversy) produce subliminal effects. Thus, audio self-help tapes with subliminal suggestions to "lose weight" or "be happy" are not considered, nor are "backmasked" messages instructing one to "smoke marijuana". Research has reliably shown that these methods produce no effects other than those expected by the listeners (Greenwald, Spangenberg, Pratkanis, & Eskenazi, 1991; Pratkanis, 1992).

Check it out for yourself http://www.csic.cornell.edu/201/subliminal

KWLee
For your consideration...

quote:
A common belief regarding consciousness is that conscious perception enables one to use the perceived information to act on the world and to produce effects on the world (cf. Searle, 1992). In contrast, unconsciously perceived information leads to more automatic reactions that cannot be controlled by the perceiver. This distinction between the active and passive consequences of perception has been captured in a number of experiments demonstrating that consciously perceived stimuli allow subjects to follow instructions, whereas unconsciously perceived stimuli lead to much more automatic reactions (e.g., Debner & Jacoby, 1994; Merikle & Joordens, 1997; Merikle, Joordens, & Stolz, 1995).

For more information see this link http://watarts.uwaterloo.ca/%7Epmerikle/papers/uncons-percept-full.html

Alex