Did Ya Know Friday - The Singapore Theory
Also known as Paranormal Stimuli and Theory of Familiarization, this practice is not widely used as you can not always be accurate. Basically, the theory is based on familiarization. If you investigate a house or location, you can try playing music or movies from a certain era in order to coerce a spirit to show itself. As sometimes you can't be certain of the "ghost" haunting the location being from a certain era, it's a hard theory to experiment with.