Brain & Nervous System Health Center

Subliminal Threats Get Through to Brain

Brain Detects and Responds to Threatening Subliminal Messages

From the WebMD Archives

May 17, 2005 -- Threatening messages may come through loud and clear in the brain, even if you aren't aware of it.

A new study shows that the brain registers and responds to threatening subliminal messages just as strongly as it responds to consciously read words and messages.

Researchers say the findings indicate that the emotional meaning and impact of words can be processed subliminally. They show that this processing happens in the same region of the brain that is involved in the conscious evaluation of emotional words.

The results appear in the May 24 issue of Proceedings of the National Academy of Sciences.

Brain Gets Messages You May Miss

In the study, researchers compared how the brains of three people responded to a presentation of a series of subliminal and consciously read words. Each of the participants had epilepsy and had electrodes placed on their brain as part of a presurgical evaluation.

The participants watched a series of words flash by on a computer screen. Some of the words flashed by too quickly to be detected and the others remained on the screen long enough to be read.

Half of the words were threatening in nature, such as "danger" and "kill," and the other half were neutral in terms of emotional impact, such as "cousin" and "see."

While the participants watched the computer screen, researchers recorded electrical activity in the part of the brain known as the amygdala that responds to threatening stimuli.

The results showed that when the subliminal, threatening words were presented, the brain reacted and produced more of an electrical response than the detected, neutral words.

However, they say that the consciously read threatening words were processed more quickly and produced a stronger and more sustained effect than the subliminal ones.

Researchers say the findings add to previous evidence that extended stages of word processing occur in the brain even in the absence of consciousness.

The research meshes with previous studies in normal subjects, which demonstrate that faces, sounds, and even abstract stimuli -- such as threatening words -- can activate the brain regions that respond to threats, the researchers write.

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SOURCE: Naccache, L. Proceedings of the National Academy of Sciences, May 24, 2005; vol 102: pp 7713-7717.
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