The results of a number of experiments have suggested that a "group" consciousness might exist. The Global Consciousness Project was established to test this hypothesis. The idea was to set up Random Event Generators (REGs) all over the world and have them run continuously, and compare their output at moments of global events with the greatest emotional impact. After an analysis of four years worth of data, a pattern in the REG readings emerged: when people reacted with great emotional intensity to a major event, the REG machines seemed to react as well. The degree of order in the REG machines output matched the emotional intensity of the events: the greater the emotional intensity, the greater the order. This effect was found most pronounced during the attacks of September 11 2001. Interestingly, the machines output became increasingly ordered a few hours before the first tower was hit. Researchers have suggested that 6 billion minds experienced a mass premonition.
Author Lynne McTaggart In The Intention Experiment discusses The Global Consciousness Project and REG activity before and during the attacks of 9/11 here:
The paper CORRELATIONS OF CONTINUOUS RANDOM DATA WITH MAJOR WORLD EVENTS , published in 2002 in the journal Foundations of Physics Letters, which focuses on the 9/11 attacks is found here:
In principle a REG can be anything that generates random events. RNGs (Random Number Generators) are considered as type of REG. Typically a sequence of tones or "white noise" is the event of an REG. The REG is calibrated and guaranteed to produce a "random" output. The REG does not sense events, but rather is placed in populated areas, and is effected by the thoughts people give off. Robert Jahn found people could influence the computer bits on PCs by their thoughts; it's basically the same thing. Hi emotional levels decrease the randomness, or increase the order, of the REG output. Of course the measurement is all done electronically.