Inside our brains

Zuschauer im Kino
As if nothing had happened: subliminal advertising in films is meant to work without us even noticing it – in theory. In practice it is a different story. (Image: iStock/Geber86)

Is it true that flashing messages onto the screen for just a few milliseconds can influence us while watching a film?  The economist Prof. Dr. Andreas Fürst decided to use brain scans to find out if it really is the case.

by Ralf Grötker

In 1957, the American market researcher James Vicary invited journalists to a press conference during which he screened a brief film about fish. Writing was flashed repeatedly onto the screen for a split second, invisible to the audience. The messages only became clear when they were projected in a darker colour, appearing like a watermark over the film.

The film about fish was a demonstration of the effectiveness of subliminal advertising. The message was: ‘Drink Coca-Cola!’ As standard film projectors were not capable of projecting images for any shorter than one twenty-fourth of a second, which is still in the range of conscious perception, Vicary had to use a special projector for his showing. He had exposed viewers at a cinema to subliminal messages like this before holding the press conference. Vicary reported to the press that over the course of the six-week long experiment, more than 45,000 viewers had been exposed without their knowledge to the commands ‘eat popcorn!’ and ‘drink Coca-Cola!’ Vicary proudly presented his results to his guests: sales of Coca-Cola at the cinema rose by 18.1 percent and popcorn by no less than 57.5 percent.

„Until now, consumers have been an unknown quantity, a closed box when researching the effectiveness of advertising. We didn’t know what they were really thinking. The new procedure now allows us to open this closed box.“

This was exciting news for the advertising industry. The general public, however, was horrified. The author Aldous Huxley believed it was tantamount to the horror scenarios from his novel ‘Brave New World’ becoming reality: helplessly exposed to the manipulations of the advertising industry, people were losing control of their minds. Legal consequences were not long in coming. A number of states, including Germany, made the use of subliminal advertising a crime.

Repeats of the experiment were unable to verify the claimed effects. Vicary himself admitted in an interview published in 1962 that the cinema experiment was simply a concocted PR gimmick which he hoped would generate more work for his advertising agency ‘Subliminal Productions’. In spite of Vicary retracting his initial claims and in spite of the lack of evidence, the myth of manipulative subliminal cuts flashing on screen for a matter of milliseconds persists in popular culture.

Only now, more than sixty years after Vicary’s sensational claims, do we have the technology needed to check whether and how subliminal advertising really does work, using brain scans. Prof. Dr. Andreas Fürst, Chair of Marketing at FAU, and his team carried out an experiment in a bid to discover the truth. Fürst connected 46 participants to an fMRI scanner. fMRI can be used to measure in which areas of the brain blood is supplied with oxygen at any given time. This, according to a popular scientific hypothesis, can indicate whether an individual is currently angry, thoughtful or planning a conscious action.


Subliminal advertising does not only (allegedly) whet our appetite, but also our imagination. In an episode of the US television series Columbo from 1973, the murderer uses subliminal advertising in order to kill his victim surreptitiously. During a showing of a film, motivational researcher Dr. Bart Kepple first makes his victim Victor Norris thirsty, then flashes up advertisements for drinks for milliseconds at a time. Norris leaves the cinema to get a drink, and Dr. Kepple seizes the opportunity to strike.

‘Until now, consumers have been an unknown quantity, a closed box when researching the effectiveness of advertising. We didn’t know what they were really thinking. The new procedure now allows us to open this closed box,’ says Fürst. The 46 volunteers were shown a brief film showing a sequence of letters and other characters whilst undergoing a brain scan. For the purposes of the experiment, they were told that the film was a concentration task. The volunteers were asked to press buttons whenever they saw a sequence of characters they had been asked to look out for. Hidden in the brief film were subliminal cuts lasting 0.023 seconds advertising brands of chocolate bars. Images of two different brands and test images in which only the colours and shapes of the brand logos were shown were flashed on screen whilst the volunteers, who were split into two groups, were watching the film. As well as the subliminal images, volunteers were also shown images which could be consciously perceived for control purposes.

Andreas Fürst explains: ‘With the experiment, we hoped to discover whether the brain processes subliminal stimuli at all, and if so, if it processes them differently to stimuli which can be consciously perceived. We also tested whether neuronal processing of subliminal stimuli is influenced in any way if a person is consciously exposed to the same stimulus beforehand.’

What happens in the brain?

It is not surprising that Fürst was excited to see what the results of the experiment would be. In spite of the failed attempts to reproduce Vicary’s findings in the 1950’s, so far no-one has really been in a position to judge to what extent subliminal advertising may actually have an effect. Later scientific research was unable to come to any conclusive results. Some studies proved that subliminal advertising was capable of creating new needs. Other studies proved the opposite. Some studies proved that people could be encouraged to buy specific brands as a result. Other studies rejected this claim. In addition, Andreas Fürst explains that studies conducted to date have had intrinsic difficulties at the methodological level. ‘Whenever you hold an interview aimed at finding out whether advertising has an effect, the problem is that simply asking problems raises awareness among the interviewees of the issue. This can in extreme cases lead to a self-fulfilling prophecy.’ Would it not be possible to assess the effects by monitoring shopping behaviour directly? ‘Yes, but that would be extremely difficult to organise and would really only be feasible directly after the film is shown, as is the case of an advertisement shown at cinemas.’

Subliminal messages have been used again and again in spite of being banned. A long list of incidences can be found in the Wikipedia entry ‘Instances of subliminal messages.’ One example: During the 2000 U.S. presidential campaign, a television ad was shown berating the Democrats as ‘Bureaucrats’. A hidden subliminal message lasting milliseconds and showing the word ‘rats’ was flashed on screen Does something like this have an effect? After Fürst’s complex experiment, the results are clear. Not in the slightest! ‘When sequences were flashed on screen so briefly that our volunteers were not able to perceive them consciously, virtually no activity was monitored in the brain.’

It would appear as if the brain scan experiment is the final nail in the coffin for the idea of effective subliminal advertising. The unabridged results are to be published soon in a scientific journal. Maybe this will lead to an end of the myth set into circulation by Vicary?

About the author

Ralf Grötker is a member of the journalism agency Schnittstelle and writes as a scientific author on topics from social research, economics and philosophy.

FAU research magazine friedrich

Cover FAU-Forschungsmagazin friedrich Nr. 119This article first appeared in our research magazine friedrich. You can order the print issue (only available in German) free of charge at

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