[6][7] The theory was again challenged, this time a paper by Keppel and Underwood who attributed the findings to proactive interference.
Within the short-term memory system, evidence favours an interference theory of forgetting, based on various researchers' manipulation of the amount of time between a participant's retention and recall stages finding little to no effect on how many items they are able to remember.
[1] No evidence for temporal decay in verbal short-term memory has been found in recent studies of serial recall tasks.
These inconsistencies may be found due to the difficulty with conducting experiments that focus solely on the passage of time as a cause of decay, ruling out alternative explanations.
[1] However, a close look at the literature regarding decay theory will reveal inconsistencies across several studies and researchers, making it difficult to pinpoint precisely which indeed plays the larger role within the various systems of memory.
Current studies have always been limited in their abilities to establish decay due to confounding evidence such as attention effects or the operation of interference.
Jonides et al. (2008) found neural evidence for decay in tests demonstrating a general decline in activation in posterior regions over a delay period.
[20] Though this decline was not found to be strongly related to performance, this evidence is a starting point in making these connections between decay and neural imaging.
A model proposed to support decay with neurological evidence places importance on the firing patterns of neurons over time.
[20] The neuronal firing patterns that make up the target representation fall out of synchrony over time unless they are reset.
This proposed model needs to be tested further to gain support, and bring firm neurological evidence to the decay theory.