Before presentation of these pictures, participants in group A were made to watch a subliminal stimulus
of positive emotion (a smiling face) for 16ms, while participants in group B watched a subliminal stimulus
of neutral emotion (a calm face) for 16ms (cf.
One study that has repeatedly been cited in the literature showed that a simple subliminal stimulus
could be associated with arousal of a basic drive such as thirst or hunger.
Prior to the action of a subliminal stimulus
, an extrasensory apprehension of its significance serves to orient the mind toward the development of the meaning to come.
A second physiological theory states that the charge of a subliminal stimulus
does not cross the synapse between neurons, but does cause a chemical change allowing the next stimulus to cross the synapse.
For example, a person exposed to an aggressive subliminal stimulus
was more apt to be either more withdrawn or more querulous when placed in a later contentious situation, as compared to someone subliminally exposed to neutral messages.