With implicit memory, people have the ability to utilize past experiences to perform a current task despite not being consciously aware of these experiences. The process of priming has been used to prove that implicit memory exists.
Illusion-of-truth is another strange phenomenon associated with implicit memory. This basically involves an individual placing greater faith in a statement they have heard often over one they have not. Essentially, if 50 people say something it must be true which may explain how wild rumors get circulated and seen as truth. Procedural memory is part of implicit memory and enables us to perform everyday activities effortlessly. Implicit memory occurs through a mental process that is completely different to that used during explicit memory.
The illusion-of-truth effect that is part of implicit memory was tested during an experiment in 1977 with 60 different statements read out every 14 days. Those involved in the experiment were asked to rate each one according to how believable they thought the statement was.
Several of these statements were read out more often than others, some of which were true, others false.
After the experiment was completed, it was shown that the subjects believed the statements they heard most often over all others regardless of whether or not they were true. In fact, some test subjects actually rated statements they heard often as true despite being told earlier in the experiment that they were false.
Procedural memory is also part of implicit memory and is responsible for enabling us to perform activities such as riding a bike without having to think too deeply about it. It appears that procedural memory is completely different to declarative memory (explicit memory).
An experiment which involved a group of amnesiac patients and another group of healthier people asked both groups to solve a puzzle which required great mental dexterity. Both groups were asked to attempt the puzzle on numerous occasions. Despite having poor short-term memory, the amnesiac patients produced an improvement in performance in line with the other group.
Numerous other experiments show a vast difference between explicit and implicit memory. The Depth of Processing effect was studied by a pair of scholars called Dallas and Jacoby in 1981. Their experiment began by giving test subjects a list of words.
The subjects were asked to perform different tasks with each set of words. One task involved simply counting letters, another entailed answering questions about the definition of words. This was followed by a test which was designed to see if they remembered seeing the word when they were studying the list.
Explicit memory is aided by deeper concentration which means the words that required greater study (finding the definition) were remembered reasonably clearly. The subjects were finally asked to watch words flashing on a screen where they were invited to identify them. It transpired that the effect of this implicit memory test was almost the same as the test which asked subjects to remember words they studied conscientiously. This proved that the effect of priming was the same meaning that while explicit memory is completely reliant on depth of processing, implicit memory is not.