*Based on Cognitive load theory (Sweller, van Merriënboer, & Paas, 2019). 

Sensory memory automatically gathers information from our senses – encoding it into a format the brain can interpret. Most of this information is ignored (e.g. unless we’re eating, we don’t pay much attention to the taste in our mouths). Encoding involves establishing temporary or short-term connections between new information and our prior knowledge networks (e.g. long-term memory). “Perceiving is remembering as much as sensing, and working memory is attention focused on an internal representation” (Fuster, 2009). Attention (what we focus on) is critical. If we don’t pay attention to something, it does not get encoded. It doesn’t enter our memory system in a manner that we can consciously use the information. “The encoding of information into working memory is the result of interactions among selective attention processes and perceptual object representations that trigger related LTM object representations” (Eriksson et al., 2015).

The information that our attention falls on enters into short-term memory (STM) and is interpreted by our existing knowledge retrieved from long-term memory (LTM). This temporary connecting of information occurs in our working memory (WM) which is a part of STM and allows us to use or manipulate the information. “Information maintenance is considered to be the result of an interaction between basic building blocks of working memory, notably a selective attention process that operates on perceptual information and related long-term memory (LTM) representations” (Eriksson et al., 2015).

The information that is in our WM is what we are consciously aware of. However, WM is limited in capacity (i.e. studies have suggested between 4 to 9 slots) – so most of the information enters working memory temporarily and then leaves without being consolidated (e.g. stored) into LTM. Information that is used more (repeated) or has a high emotional value is prioritized for storage. In WM, our brain automatically retrieves our prior knowledge so that we can make these connections and try to make sense of the new information. This also means that anything new we learn, connects to something that is already there. “Storage of information is storage of relationships between objects or events” (Kukushkin & Carew, 2017).

To maintain the temporary connections in working memory (STM), we have to rehearse (i.e. use or manipulate) the information which keeps it active. The more the information is used, the more likely it is to be prioritized for storage in LTM.

To consolidate or store the information in long-term memory, the temporary connections need to be made more permanent. Hippocampal replay plays an important role. “Patterns of neuronal activity present during learning in the hippocampus are replayed during sleep.” (Breton & Robertson, 2013). Replay can also occur during periods of wakeful rest. We don’t have to sleep but we need to give our brains a break – an opportunity to repeat and consolidate information from recent experiences.

To be retrievable in the future, information held in WM has to be consolidated into LTM. LTM consists of connected networks or schema which we activate when we recall or retrieve information. Cues associated with the stored LTM are used to determine when to retrieve the stored information. Once a memory is retrieved, it becomes active and will be reconsolidated or updated as it is stored once again. Reconsolidation reveals that long-term memories are not permanent but rather they are changed whenever they are activated. Most of the information that enters our memory system is lost. In other words, it does not remain in our memory system in a manner in which we can consciously retrieve it – at least not for an extended period of time.

References

Information Processing and Storage

• Sweller, J., van Merriënboer, J. J., & Paas, F. (2019). Cognitive architecture and instructional design: 20 years later. Educational Psychology Review, 1-32.
• Breton, J., & Robertson, E. M. (2013). Memory Processing: The critical role of neuronal replay during sleep. Current Biology, 23(18), R836-R838.
• Eriksson, J., Vogel, E. K., Lansner, A., Bergström, F., & Nyberg, L. (2015). Neurocognitive architecture of working memory. Neuron, 88(1), 33-46.
• Kukushkin, N. V., & Carew, T. J. (2017). Memory Takes Time. Neuron, 95(2), 259-279.
• Squire, L. R., Genzel, L., Wixted, J. T., & Morris, R. G. (2015). Memory consolidation. Cold Spring Harbor perspectives in biology, 7(8), a021766.
• D’esposito, M., & Postle, B. R. (2015). The cognitive neuroscience of working memory. Annual review of psychology, 66.
• Cowan, N. (2008). What are the differences between long-term, short-term, and working memory?. Progress in brain research, 169, 323-338.