glossolalia

There is evidence that while speaking in tongues people experience a sharp decrease in frontal lobe function, the area of the brain that enables reason and self-control. There is also increased activity in the parietal region of the brain, which takes sensory information and tries to create a sense of self relating to the world. Psychiatrist Andrew Newberg, Director of the Center for Spirituality and the Mind at the University of Pennsylvania, studied five African-American Pentecostal women who frequently speak in tongues. As a control activity, Newberg had the women sing gospel tunes while moving their arms and swaying.*

Newberg gave the Pentecostals an intravenous injection of a radioactive tracer that allowed him to measure blood flow and "see" which brain areas were most active during the behaviors. Newberg and his associates published their findings in the November 2006 issue of Psychiatry Research: Neuroimaging. During glossolalia, the part of the brain than normally makes a person feel in control was essentially shut down. The findings make sense, says Newberg, because speaking in tongues involves giving up control and feeling a "very intense experience of how the self relates to [a] god."*

Newberg noted that the glossolalia responses were the opposite of those of people in a meditative state. When people meditate their frontal lobe activity increases, while their parietal activity decreases. In meditation, one loses the sense of self while controlling one's focus and concentration.

The Pentecostal movement seems to have originated in the 19th century,* although the Biblical basis for the practice is traced to the Acts of the Apostles. The practice of Pentecostals differs, however, from what is described in Acts. Pentecostals utter gibberish and claim that they are speaking in a language understood by some god but not by other Pentecostals, but in Acts we are told that those present not only spoke "with other tongues" but "every man heard them speak in his own language."

And when the day of Pentecost was fully come, they were all with one accord in one place. And suddenly there came a sound from heaven as of a rushing mighty wind, and it filled all the house where they were sitting.  And there appeared unto them cloven tongues like as of fire, and it sat upon each of them.  And they were all filled with the Holy Ghost, and began to speak with other tongues, as the Spirit gave them utterance.  And there were dwelling at Jerusalem Jews, devout men, out of every nation under heaven.  Now when this was noised abroad, the multitude came together, and were confounded, because that every man heard them speak in his own language.  And they were all amazed and marveled, saying one to another, Behold, are not all these which speak Galileans?  And how hear we every man in our own tongue, wherein we were born?  Parthians, and Medes, and Elamites, and the dwellers in Mesopotamia, and in Judaea, and Cappadocia, in Pontus, and Asia,  Phrygia, and Pamphylia, in Egypt, and in the parts of Libya about Cyrene, and strangers of Rome, Jews and proselytes,  Cretes and Arabians, we do hear them speak in our tongues the wonderful works of [some] god. [Acts II; 1-11]

This story is supposed to support the notion that such an event really did occur and it was prophesied by Joel that this kind of thing would happen in the last days. There is nothing in Joel, however, that prophesied that, when the last days didn't come as predicted, plan B would be to wait 1900 years and have a revival and claim that when you speak gibberish it is a sign that some god loves you.