Is there such a thing as a probability amplifier?

Fashion, or rather 'memes' spring to mind in the light of your question Askyourmind. The probability of say a 'Mexican wave' in stadiums throughout the world is now greatly increased, simply because the fad caught on following the Mexico Olympic Games. This seemingly spontaneous generation of the wave must have its origins in the minds of a few who perhaps noticed an accidental event at some place earlier which has now become a mind spark for generating all future and more probable waves worldwide. It seems to me many things from the wearing of similar clothes to belonging to a particular religion may become more probable due to patterns of human behaviour, the idea has only to catch on, and maybe the idea can be from design, nature, or even nurture, and can start from a single individual thought.