Figure 5.9 An Example of Encoding Failure Can you identify the real penny? Most Americans cannot. Why? The answer is likely encoding failure. Most of us are not that interested in coins and have never bothered to encode the exact features of a penny into long-term memory, so we have difficulty in choosing the real penny. This may be referred to as forgetting, but it is more appropriately called encoding failure. You can’t really forget something that you did not put into long-term memory. The first penny (a) is the real penny.
(From Nickerson & Adams, 1979.)