3. How does memory work?
In its simplest form, memory refers to the continued process of information retention over time. It is an integral part of human cognition, since it allows individuals to recall and draw upon past events to frame their understanding of and behavior within the present. Memory also gives individuals a framework through which to make sense of the present and future. As such, memory plays a crucial role in teaching and learning, as mentioned earlier in these notes.
This section covers the underlying processes that characterize or define memory, as well as how these processes may be improved or optimized.
Note:
To provide you with a practical understanding of the concepts covered, there are interactive video exercises on memory within this section. You are encouraged to take part in these exercises and apply the concepts you come across to better facilitate your understanding.
3.1 Encoding, storage, and retrieval
There are three main processes that characterize how memory works. These processes are encoding, storage, and retrieval (or recall), and they are each discussed in detail below.
3.1.1 Encoding
Encoding refers to the process through which information is learned. That is, how information is taken in, understood, and altered to better support storage (which you will look at in Section 3.1.2). Information is usually encoded through one (or more) of four methods:
- Visual encoding (how something looks);
- Acoustic encoding (how something sounds);
- Semantic encoding (what something means); and
- Tactile encoding (how something feels).
While information typically enters the memory system through one of these modes, the form in which this information is stored may differ from its original, encoded form (Brown, Roediger, & McDaniel, 2014).
3.1.2 Storage
Storage refers to how, where, how much, and how long encoded information is retained within the memory system. The modal model of memory (storage) highlights the existence of two types of memory: short-term and long-term memory. Encoded information is first stored in short-term memory and then, if need be, is stored in long-term memory (Roediger & McDermott, 1995).
Atkinson and Shiffrin argue that information that is encoded acoustically is primarily stored in short-term memory (STM), and it is only kept there through constant repetition (rehearsal). Time and inattention may cause information stored in STM to be forgotten. This is because short-term memory only lasts between 15 and 30 seconds. Additionally, STM only stores between five and nine items of information, with seven items being the average number. In this context, the term “items” refers to any piece of information. Long-term memory, however, has immense storage capacity, and information stored within LTM can be stored there indefinitely. Information that is encoded semantically is primarily stored in LTM; however, LTM also stores visually- and acoustically-encoded information. Once information is stored within LTM or STM, individuals need to recall or retrieve it to make use of said information (Roediger & McDermott, 1995). It is this retrieval process that often determines how well students perform on assignments designed to test recall.
Figure 2: The differences between STM and LTM. (Adapted from: Roediger & McDermott, 1995)
3.1.3 Retrieval
As indicated above, retrieval is the process through which individuals access stored information. Due to their differences, information stored in STM and LTM are retrieved differently. While STM is retrieved in the order in which it is stored (for example, a sequential list of numbers), LTM is retrieved through association (for example, remembering where you parked your car by returning to the entrance through which you accessed a shopping mall) (Roediger & McDermott, 1995).