Original sentence: It is thought that memory degrades over time, some researchers state that the rate at which eyewitness memory declines is swift, and the drop-off is sharp, in contrast to the more common view that memory degrades slowly and consistently as time passes
Edited sentence: It is common knowledge that memory degrades over time, but researchers have discovered that the rate at which eyewitness memory declines is swift, and the drop-off is sharp, in contrast to the more common view that memory degrades slowly and consistently as time passes