James March

Decay is the earliest proposed form of how information leaves sensory memory. Decay is when the information in sensory memory fades away. Interference is the more modern explanation for how information leaves sensory memory. In interference, the information is erased by new incoming information in sensory memory. In the beginning of short term memory research, decay was assumed to be the reason for forgetting. It made sense because if information did not fade away then all the information we took in would be blurred by one another. However, with Sperling's research, the idea of interferencewas recognized as being a more possible cause for forgetting. Decay Theory is similar to Interference Theory in the way that old memories are lost over time. Memories are lost in Decay Theory by the passing of time. In Interference Theory, memories are lost due to newly acquired memories. Decay and Interference Theory differ in that Interference Theory has a second stimulus that impedes the retrieval of the first stimulus. Decay Theory is caused by time itself. Decay Theory is a passive method of forgetting as no interference is produced. Interference Theory is an active process because the act of learning new information directly impedes the recollection of previously stored information.