There are two opportunities for perceived information to be forgotten prior to reaching long-term memory. In both instances, it appears that the decision is based, in large part, on whether memory considers the information important.
If a sensory perception is reinforced by paying attention as well as corresponding perceptions from other senses, or multiple perceptions of the same thing, then sensory memory is less likely to discard the information. If something is simultaneously perceived through sight, sound, smell, and tactile senses, and the learner pays attention to those stimuli that information is likely to be passed on to short-term memory.
If short-term memory believes the information is important or will be recalled in the future, it will encode the information and send it on to long-term memory. Short-term memory will believe it to be important if we are attentive to the information, think about the information, or relate it to other information in long-term memory.
So new knowledge will find its way into our long-term memory if stimulus is adequate, we pay attention to it, and we have related retrievable prior knowledge in long-term memory. Willingham summarizes the process with the following two statements.
- “Memory is the residue of thought.” (Daniel T. Willingham).
- “All new learning requires a foundation of prior knowledge.” (Daniel T. Willingham).