Subliminal stimuli
Subliminal stimuli (; literally "below threshold"), contrary to supraliminal stimuli or "above threshold", are any sensory stimuli below an individual's threshold for conscious perception. A recent review of functional magnetic resonance imaging (fMRI) studies shows that subliminal stimuli activate specific regions of the brain despite participants being unaware. Visual stimuli may be quickly flashed before an individual can process them, or flashed and then masked, thereby interrupting the processing. Audio stimuli may be played below audible volumes or masked by other stimuli.
Effectiveness
Applications of subliminal stimuli 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 the receiver of the message plans to perform anyway: an action can be triggered subliminally only if the person already has the specific intention to perform this specific action.
The following sections have more information on specific studies which investigate the effectiveness of subliminal stimuli.
