Subliminal


 * Definition**

The etymology of the word “subliminal” is deceptively simple. A rudimentary knowledge of Latin roots will immediately identify the root “limin” meaning “threshold.” The prefix “sub” we know to mean “under” or “just under” and the suffix “al” means “of” or “pertaining to”. Combining these we get the straightforward definition, “of or pertaining to that which is just under the threshold.” The Oxford English Dictionary’s online database traces the term's evolution from its emergence in an early nineteenth century psychology textbook to its more familiar use in the context of subliminal messages, particularly those used in advertising (2010). What remains constant through the evolution of the term is the idea of the subliminal as a stimulus that acts upon a person’s physical senses but does so below the level of perception.

This entry will focus on subliminal messages in advertising for two reasons. First, and most importantly, the overwhelming majority of discourse among communication scholars and professionals centers on subliminal advertising and the attendant public controversy. Second, focusing on subliminal advertising will elide the discussion of the subliminal which is native to the psy disciplines; a discussion which certainly informs the communicative concept of the subliminal but carries a separate history and set of discourses.


 * Subliminal Advertising**

Vance Packard is often credited with bringing subliminal advertising to the forefront of public awareness with the 1957 publication of his book Hidden Persuaders which is often mistaken for being about subliminal advertising. In reality, Packard’s book reports on the advertising practice of using depth interviews of consumer groups to more effectively appeal to people’s desires via advertising. Packard never mentions the term “subliminal” although he briefly references the 1957 experiment by marketing professional James Vicary (Nelson, 2008; pp. 113-115). In his now infamous study Vicary infamous study if the root for much of the negative public opinion which still surrounds claims to have increased moviegoers consumption of Coke and popcorn by flashing the words “Buy Coca Cola” and “Eat Popcorn” on the screen during the movie Picnic for less than a millisecond (Perloff, 2008, p. 395). Serious critiques of the feasibility of subliminal advertising appeared in professional literature almost instantly (Bertrand, 1958, p. 149-150). Nevertheless, belief in the use and effectiveness of subliminal advertising persist among the United States public (Rogers & Smith, 1993). Surveys reveal that the public is still substantially aware of subliminal advertising: 74.3 percent (Rogers & Smith, 1993), 76 percent (Synodinos, 1988), and 81.3 percent (Zanot, Pincus, & Lamp, 1983) of respondents reported to have heard of subliminal advertising and of those who have heard of it, 61.5 percent (Rogers & Smith, 1993), 77 percent (Synodinos, 1988), and 81 percent (Zanot et al., 1983) believe that advertisers actually use such techniques.

The persistence of the belief in subliminal advertising, and its sinister nature, likely has several causes which those who study within the tradition of Communication and particularly those disciplines that deal with advertising and persuasion would do well to examine. First, there is confusion over what a subliminal stimulus is. That is, most people who understand the idea of a subliminal stimulus and how it can be used in advertising do not grasp the notion of how a stimulus is made subliminal. That is, how a stimulus can be present, but not perceivable. There are four main categories of subliminal stimuli:
 * 1) //Subthreshold stimuli:// stimuli presented at energy levels which are too low to be perceivable. An example might be words in seeming radio static that are at too low an energy level to be heard above the static.
 * 2) //Masked stimuli:// visual stimuli that have been obscured in some way.
 * 3) //Unattended stimuli// occurs when two stimuli are presented at the same time with one being intended to take attention away from the other (an example might be two messages, one presented to each ear, with one message being noticeably louder with the intention of the louder message to distract the person from perceiving the quieter message).
 * 4) //Figurally transformed stimuli:// stimuli that have been physically altered in someway so that they are unrecognizable even when attention is directed to them.

In the psychological definition of the subliminal only the first two methods would be called subliminal because they alone are stimuli presented below the threshold of consciousness. Here, the threshold refers to the point at which stimuli evoke a sensation in a respondent (Vargas, 2008). However, in the communicative application of the subliminal to advertising all four definitions are acceptable and studied (Pratkanis&Greenwald, 1988; pp. 340-341).

Second, there is confusion over the difference between subliminal perception and subliminal persuasion. Numerous experiments, especially within the psy disciplines, have proved beyond the shadow of a doubt that people are capable of picking up information without being aware of doing so (Pratkins & Greenwald, 1998; Krishnan & Trappey, 1999; are both excellent reviews of the research in this area). However, the controversy around subliminal advertising, since the time of Vicary’s study (and arguably because of the nature of Vicary’s supposed findings and subsequent proclamations) is that subliminal messages, once perceived, persuade people to alter their behavior without conscious thought and deprive the individual of choice.


 * Empirical Support for Subliminal Advertising**

Numerous studies have been done to test for a correlation between subliminal perception and subliminal persuasion. Perhaps the most famous of these studies is that of Del Hawkins who, in 1970, published the results of a study on subliminal perception in which he claimed that subliminal perception increased a basic drive (in Hawkin’s case the drive was thirst) and, to the extent that the arousal of a drive can result in action, that subliminal stimuli should be expected to produce results (p. 325). This study was cited for over a decade by multiple researchers as evidence that subliminal perception could lead to subliminal persuasion. However, almost twenty years later, Hawkins & Beatty attempted to replicate the experiment with little success, casting doubt on the original findings and, in the process, the efficacy of subliminal advertising (1989, p. 7-8). Research simply does not support the idea that subliminal advertising has the ability to significantly alter a consumer’s decision of whether or not to purchase a product (Trappey, 1996, p. 528).


 * Criticisms of Subliminal Advertising**

One of the earliest criticisms leveled at the idea of subliminal advertising was that the business of perception is so nuanced and individuated that creating a stimulus to appeal to a mass audience on a conscious level is difficult enough while the idea of creating a compelling stimulus that persuades people without their knowledge or consent is almost ludicrous (Bertrand, 1958, p. 149-150). The other enduring criticism of the concept of subliminal advertising is based on the original concept of a subliminal stimulus as any stimulus which acts on the senses below the range of conscious perception. Perloff states it succinctly, “People have different thresholds for conscious awareness of stimuli” (2008, p. 401). The likelihood that a supposed subliminal stimulus in an advertisement, broadcast to a large audience, would not be consciously perceivable for a few members of that audience is unlikely.

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Minor revisions by Sann Ryu (July 2015).


 * References**

Beatty, S., & Hawkins, D. (1989). Subliminal stimulation: Some new data and interpretation. //Journal of Advertising, 18//(3), 4-8.

Bertrand, K. (1958). The ghost of subliminal advertising. //The Journal of Marketing, 23//(2), 146-150.

Hawkins, D. (1970). The effects of subliminal advertising on drive level and brand preference. //Journal of Marketing Research, 7//(3), 322-326.

Krishnan, H.S., & Trappey, C. (1999). Nonconscious memory processes in marketing: A historical perspective and future directions. //Psychology and Marketing, 16//(6), 451-457.

Nelson, M. (2008). The hidden persuaders then and now. //Journal of Advertising, 37//(1), 113-126.

Subliminal. (2010). In //Oxford English Dictionary online//. Retrieved from http://dictionary.oed.com.proxy2.library.uiuc.edu/cgi/entry/50240799?single=1&query_type=word&queryword=subliminal&first=1&max_to_show=10

Perloff, R. M. (2008). //The Dynamics of Persuasion: Communication and attitudes in the 21st centu//ry. New York: Lawrence Erlbaum Associates.

Pratkanis, A. R., & Greenwald, A. H. (1988). Recent perspectives on unconscious processing: Still no marketing applications. //Psychology and Marketing, 5//(4), 337-353.

Rogers, M., & Smith, K. H. (1993). Public perceptions of subliminal advertising: Why practitioners shouldn’t ignore this issue. //Journal of Advertising Research, 33//(2), 10-18.

Synodinos, N. E. (1988). Review and appraisal of subliminal perception within the context of signal detection theory. //Psychology & Marketing //, //5 //(4), 317-336.

Trappey, C. (1996). A meta—analysis of consumer choice and subliminal advertising. //Psychology and Marketing, 13//(5), 517-530.

Vargas, P. T. (2008). Implicit consumer cognition. In F. Kardes, C. Haugdtvedt, & P. Herr (Eds.), //Handbook of consumer psychology.// New York: Lawrence Erlbaum Associates.

Zanot, E. J., Pincus, J. D., & Lamp, E. J. (1983). Public perceptions of subliminal advertising. //Journal of Advertising //, //12 //(1), 39-45.